Macro photography: Understanding magnification

Photography, like any other art, demands both compelling content and expert technique to create a pleasing result. In my previous article, I discussed some of the aesthetic choices involved in creating a successful macro image. Technique, however, is an absolute must; it's the artist's tool to convey his artistic vision.

Nature, landscape and wildlife are some of the most technically challenging fields of photography, and macro photography comes with its own unique set of technical considerations. In this article I'll be discussing one of the most important ones; magnification.

Photographer Allon Kira making sure his image is technically perfect.
For macro photographers this often requires a great deal of
concentration and patience, but the results are well worth it. 

Some of the greatest challenges in macro photography arise from the simple fact that we shoot from very close distances. Thus the magnification of our subject becomes of primary importance. The magnification ability of a given lens is stated in its specifications but in my experience, few photographers understand the meaning and implications of this designation.

To understand the concept of magnification, it's worth taking a very brief look at how a photographic image is created. Every point in a given scene reflects light rays. The front element of the camera lens 'captures' these rays and then focuses them onto the imaging sensor, producing a projection of the scene at the location of the sensor.

This is a simplified diagram of the photographic process. Light rays reflected from an object pass through a lens, which then produces an image projection on the camera's sensor.

Magnification - or more precisely, the magnification ratio - is simply the relationship between of the size of the (in-focus) subject's projection on the imaging sensor and the subject's size in reality. Perplexed? Here are some examples. Suppose that we're photographing a small child, 1 meter in height. Imagine that the height of the child's projection onto the sensor is 1cm. The magnification ratio is 1cm/100cm, or 1/100. Magnification is typically notated using a colon, so we write it as 1:100, and pronounce it, 'one to one hundred', meaning the child is 100 times larger in real life than its image as projected on the sensor. Similarly, if the subject is a 10cm long lizard, and its projection on the sensor is 2cm long, the magnification ratio is 2cm/10cm or 1:5. The lizard is five times larger in real life than its projection on the sensor.

When your subject(s) fills the frame with no cropping involved, it is easy to determine the magnification ratio from a captured image provided you know the size of your subject and the dimensions of your camera's sensor, which can be found in the specifications section of the user manual.

Two thistle mantis (Blepharopsis mendica) nymphs, as positioned above are roughly 150mm across. The sensor on the camera is 22mm across. The magnification ratio is approximately 22mm/150mm, or 1:6.8. This dragonfly is about 60mm in width. Again, the sensor is 22mm wide, so the magnification ratio is 22mm/60mm, approximately 1:2.7.

We've seen in the examples above that sensor size can be used to calculate magnification, but the degree of magnification itself depends on focal length and subject distance exclusively (assuming that the lens is not used with any extenders or magnifying filters). Sensor size does not alter magnification. With a fixed focal length and subject distance, an APS-C sensor, for example would just crop the frame compared to a full-frame sensor, not enlarge it. Magnification is a property of the projection, regardless of the size of sensor (or film format) you are using. With a full frame sensor you'd just make calculations using 35mm as the sensor width instead of 22mm, but the subject would then be proportionally larger, cancelling out the sensor size difference.

Sensor size does have an effect on the image's appearance though, a topic I will address in an upcoming article.

What happens if the subject is the same size in real life as its projection? If we shoot a 1cm fly and its projection on the sensor measures 1cm as well, the magnification is 1:1. The 1:1 ratio has an important meaning for macro enthusiasts. Technically speaking, macro photography means shooting at a magnification ratio of at least 1:1. Therefore, a 'true' macro lens has the ability to produce a magnification ratio of 1:1, or higher.

A small subject like this shield bug required approximately a 1:1 magnification.

At this point you may understandably ask, what's so special about a macro lens? Surely one can take any old 50mm f/1.8 lens and just move it closer to your subject until you reach 1:1 magnification. The problem, however, is that a regular lens will not be able to focus at such close distances. A more specific definition of a macro lens, then, is one whose minimal focus distance is short enough to allow photography of a focused subject in 1:1 magnification.

Let me take this opportunity to point out that many lens makers employ a very liberal use of the term, and happily write 'macro' on a variety of zoom and prime lenses that are not capable of 1:1 magnifications. This is a sales tactic, and you can easily find so-called macro lenses that can only produce 1:4 or 1:3 magnification ratios. One can, of course, produce great results with such lenses, and it is often possible to achieve higher magnifications on these lenses with the use of optional accessories. When shopping for a macro lens, however, you'll want to look carefully at the magnification specs; most 'true' macro lenses will actually have 'macro 1:1' prominently displayed on the barrel. That removes any ambiguity.

Once you have a macro lens, how do you accurately calculate its level of magnification at an arbitrary focus distance? The easiest way, by far, is to use a ruler, as shown in the examples below.

I photographed the ruler from a measured subject to sensor distance of approximately 65cm. Forty-four 1mm notches fill the entire width of the frame, thus the subject's projected size is 44mm. The width of my camera's sensor is 22mm. It follows then that for this lens, the magnification ratio achieved at this focal distance is 22mm/44mm, or 1:2.
In this image I moved the camera closer so that now thirty-three 1mm notches are visible in the frame. This 22mm/33mm relationship yields a magnification ratio of 1:1.5.
Finally, by moving the camera even closer, twenty-two 1mm notches are visible in the frame. As you'd expect, 22mm/22mm equals a 1:1 magnification ratio.

I should point out that with a regular macro lens, 1:1 magnification is achievable only at the very closest focus distance. Using a longer focus distance necessarily means the magnification will be lower. Indeed, for a fixed focal length, magnification is inversely related to subject distance. This relationship isn't linear, i.e. if I get a 1:4 magnification from a shooting distance of 40 cm, I won't necessarily get a magnification of 1:2 (twice that) from a shooting distance of 20cm. However, getting closer will always result in a larger magnification and vice versa, meaning that for our purposes we can use the terms magnification and proximity somewhat interchangeably.

Some subjects are so tiny they need extreme magnifications. This close-up
portrait of a robber fly required a whopping 4:1 magnification ratio, meaning
that the image projected on my camera's sensor was 4x larger than the fly itself.

There are cases (such as the image above) where we wish to shoot at magnifications greater than 1:1. These so-called 'extreme-macro' magnifications are possible using special lenses or other equipment, and I'll discuss how that's done in a future article.


For further reading on macro photography take a look at Erez's previous articles in this series:

What we want in a macro shot - Background
What we want in a macro shot - Detail
The what and why of wildlife macro photography
What we want in a macro shot - POV and special scenes


Erez Marom is a nature photographer based in Israel and a regular contributor to Composition magazine. You can see more of his work at www.erezmarom.com and follow him on his Facebook page and deviantArt gallery.

The views and opinions expressed in this article are those of the author and do not necessarily reflect the views and opinions held by dpreview.com or any affiliated companies.

Comments

Total comments: 113
Muhammad Farooqi
By Muhammad Farooqi (6 months ago)

thanks .. excellent informaiton...
i'm using macro filters .. availablel in market i.e 1+, 2+, 4+ 10+... what ration of magnification these things do.. and what about the reverse lense.. i've one kit lens 18-55 and a tele 55-250... can i use them as macro ?
any suggestion.. ? thank you

0 upvotes
Loperman
By Loperman (8 months ago)

Thx Erez for the lucid explanation.
I am an Iridologist, not a camera buff so always have need of good explanations like this.
Shooting the spherical surface of the human iris all day with my Canon Rebel Xti, Sigma 105mm macro 1:2.8 lens and iridology-modified w a xenon + fiber optic lighting/flash unit I still get a lot of sharp eyelashes and out of focus iris surface! I'd like better DOF so this does not happen...say, about a half inch DOF so even if an inexperienced iris photographer in our clinic shoots, we'll get every iris in crisp focus. I should mention that the f/ setting for a light blue eye and a dark brown eye have to be widely variant.
Any suggestions?

Comment edited 47 seconds after posting
0 upvotes
RKwong
By RKwong (10 months ago)

I am starting to take up macro photography and now has a DSLR Nikon DX 18-135mm camera. Can someone suggest a fairly good macro lens (not necessary Nikon) but compatible for my pursuit. Thank you.

R.Kwong

0 upvotes
nacs
By nacs (Nov 2, 2012)

Hello,
I want to take detailed pictures of 2 mm long stick.
Can you suggest me some good technique on how to do it and what camera and lens combination will be most suitable

Thanks a ton

0 upvotes
Erez Marom
By Erez Marom (Dec 7, 2012)

For extreme macro I use the Canon MP-E 65mm. As for technique, there's too much to tell, please keep reading the series and you'll get answers to your questions.

0 upvotes
randomchuck
By randomchuck (Apr 9, 2012)

Macro video of red velvet mite.
http://www.youtube.com/watch?v=Kxs8KIgPTTk

0 upvotes
firemachine69
By firemachine69 (Mar 17, 2012)

What an excellent article. I'm just catching up on these, and I've already learned so much!

1 upvote
keyfin
By keyfin (Feb 11, 2012)

nice

1 upvote
gizzywhicker
By gizzywhicker (Jan 6, 2012)

I'm a macro enthusiast. The more I can learn about the subject, the happier I'll be.

1 upvote
photoamitsharma
By photoamitsharma (Dec 22, 2011)

Merry Christmas !! Very good article,thanks
Amit
Photographer @ http://www.indianinstituteofphotography.com

1 upvote
solsang
By solsang (Dec 17, 2011)

A good macro lens is the one that allows you to shoot insects at enough distance to leave them sitting instead of becoming scared or shaded by the lens; any compact saying macro within 1cm of the lens is pretty useless for this!

Thus a macro lens ought to have the maximum magnification at a specified distance written on it, assuming you put the lens on a normal camera (mostly aps-c) so we can be able to choose from real-world usefulness.

1 upvote
sajjadkhalid
By sajjadkhalid (Dec 6, 2011)

Thank you for sharing such useful information.

1 upvote
kolas
By kolas (Dec 5, 2011)

Seems the traditional definition of macrophotography linked to 1:1 or greater lens magnification received a lot of attention in the comments. The truth is, times have changed since film days. Resolving power of today's digital sensors (especially those in compact cameras and cellphones) greatly exceeds that of any film. Therefore one can capture similar amount of detail with camera setups of various sizes.

Example: Take 12MP fullframe Canon 5D with a 100 mm "true macro" 1:1 magnification lens and a 12MP 4/3 camera with a 50 mm "fake macro" 1:2 magnification lens. The same FOV, the same perspective, very similar level of detail captured. But according to the traditional definition, only one of the photos is a true macro photograph! Does that make sense? To me not so much.

Let us redefine macrophotography!

Comment edited 1 minute after posting
0 upvotes
kolas
By kolas (Dec 5, 2011)

I would suggest to define macrophotography based on resolution: A true macro photograph is one that shows real-world details as small as 10 microns (0.01 mm) or smaller.

Unlike the traditional one, this new definition deals directly with the result - the photo - and not with the equipment used to obtain it.

You may ask how I got to the 10 microns. Well, I took the good old Canon EOS 10D with a 1:1 macro lens. Now 22.7 mm of real world are projected onto 22.7 mm of sensor covered with 3072 sensels. That gives 135 dots per mm. Taking AA filter and demosaicing into account as well as lens imperfections, the real resolution can be estimated to 75% of the theoretical maximum. That leaves us with 101 dots per mm, equal to resolution of 9.9 microns. 10 microns just look better...

2 upvotes
Weia
By Weia (Dec 5, 2011)

Thanks Kolas for this calculation. My best combination gives 428 pixels per mm, so smallest details are about 3 microns. I did not realize that the micron was so nearby.

0 upvotes
Dvlee
By Dvlee (Dec 11, 2011)

An 18 mpx APS-c sensor would capture exactly the same image magnification as a 10 mpx.

If you make an 8 x 12 of the full frame at 300ppi, both prints would yield exactly the same magification. The 10mpx will yield an 8 x 12 at 300ppi without uprezing. To make a print from the 18mpx you will have to toss some pixels away by downrezing the file size.

The 18 mpx will yield a print up to 11 x 17 without uprezing. The 10 mpx would have to be uprezed slightly so there would be some loss of details but would yield a print of exactly the same magnification.

Beyond 11 x 17, both files will need to be uprezed to maintain 300ppi, so both files would be suffering a degradation of image quality at larger sizes.

While a higher resolution sensor might capture more detail per mm, that may not translate into more details in the final output.

Resolution of detail is a seperate charactoristic than magnification.

0 upvotes
Noogy
By Noogy (Dec 4, 2011)

Ok I will pretend for a moment I understood the confusing magnification "rule" with respect to distance, sensor size, etc. Now back to simply trying to take good photos!

0 upvotes
Dvlee
By Dvlee (Dec 4, 2011)

Some may question why this information is even relevent. Well it's relevent in deciding which lens or accessories to buy to achieve the degree of magnification desired.

Once the equipment is in hand, you're not really going to think about it, your just going to use what you've got.

Of course it''s really handy to know exactly how much magnification a so called macro lens is really delivering. It might be that the so called macro lens really isn't delivering the goods. I know I've got a few of those. I never purchased them with macro in mind. If macro capability were something I was looking for in a lens then I certainly want to know exactly how much magnification the lens is really delivering before making my purchase decision.

I use a number of different close up photography tools including reversal rings, extension tubes, etc. By using the methods described in the article I can determine the exact magnification that each method is capable of delivering.

3 upvotes
tbcass
By tbcass (Dec 3, 2011)

OK here's an analysis of the article from a former physics teacher. His use of the term magnification is misleading. True magnification only happens when the image on the sensor (or film) is greater than 1:1. When printed or viewed on screen the image is magnified in relation to the size on the film or sensor but in that case all viewed or printed images are magnified for viewing. When the resulting image as viewed is larger than life then magnification results. Other factors such as pixel count, lens quality and Monitor size have to be considered because there is the issue of effective magnification where the amount of detail retained has to be taken into account. Magnification without retaining a corresponding amount of detail is useless. Sorry to be picky but I had to get that off my chest.

Comment edited 2 times, last edit 7 minutes after posting
2 upvotes
Dvlee
By Dvlee (Dec 4, 2011)

As I mentioned in an earlier reply, in macro photography perspective is very important. Just blowing up an image shot from a distance does not give the same result as actual close up photography.

And while longer focal legnth macro lenses allow a longer working distance they do not provide the same perspective as a shorter focal legnth macro used very very close.

I always make the distiction between in camera magnification and post production magnification by refering only to the former as magnification, the latter is more appropriately described as "enlargment"

Comment edited 1 minute after posting
4 upvotes
olyflyer
By olyflyer (Dec 5, 2011)

Magnification can be negative as well. 1:100 is also a magnification, just like 2:1. In the former case the magnification is 0.01 times the original size and in the later case it is two times. As a former physics teacher you should know that.

1 upvote
Weia
By Weia (Dec 2, 2011)

I do not use magnification, I only need to know how to measure the length of say an insect under certain standardized circumstances. With a Sigma 150 macro on Olympus E-3 at closest focus I have 210 pixels for a millimeter. With a 2x extender it becomes 428 pixels to a millimeter.

But now something very strange. At a holiday I did not want to carry too much so only took my 18-180. At close focus and f=180 it uses only 53 pixels to a millimeter. I bought a 5 diopter close focus lens and it became 107 pixels to a millimeter. But in the field strange things happened when focusing so I did new tests and found out I had to move backwards and to focus on infinity to have the biggest magnification! Now it is 190 pixels for a millimeter. Completely contrary to expectation, unexplicable, but very useful for identifying small insects! Of course the optical quality of the combination is not extremely good.
Just to let you know. Maybe I should buy a close focus lens for the Sigma too.

Comment edited 2 times, last edit 1 minute after posting
0 upvotes
BenFrantzDale
By BenFrantzDale (Nov 30, 2011)

You say "This relationship isn't linear, i.e. if I get a 1:4 magnification from a shooting distance of 40 cm, I won't necessarily get a magnification of 1:2 (twice that) from a shooting distance of 20cm."

That's only sort of right. You should be precise about the "shooting distance". The only sensible distance is the distance from the subject to the entrance pupil (which is almost always inside the lens). In an ideal camera in which you can change the lens power while maintaining the pinhole geometry (e.g., an adjustable-power lens at the aperture), then halving the distance from the subject to the entrance pupil will exactly double the magnification.

In reality, the details of how the lens focuses will affect things, so the distance from the projection center to the sensor may change.

PS,
The illustration at the top with the red and blue ray bundles should show an aperture. As illustrated it's beyond telecentric -- the entrance pupil is beyond infinity.

1 upvote
RickBuddy
By RickBuddy (Nov 30, 2011)

I've read similar articles before and came away understanding a portion of what was written.

This article is written so clearly and succinctly that I understand the subject a lot more clearly.

Very well conceived and written.

Thank You

4 upvotes
EXX
By EXX (Nov 30, 2011)

Second example: I take again a Sony A77 (24 megapixel APS-C) and a Konica-Minolta Dynax 7D (6 megapixel, APS-C).I put the same macro lens with magification 1:1 on both cameras and take a picture of the ruler at maximum magnification. I will end up with 2 pictures that show the same: 24 mm of the ruler. However, when I crop the A77 picture down to 6 megapixel, I suddenly have again 2 pictures with the same resolution of 6 megapixel, one showing 12 mm and the other 24 mm of the ruler.

Would it be a good idea to start using a kind of "35mm equivalent magnification factor" by involving the sensor size, just like is is done for the focal length? So a 0.5x lens would have a 0.75x "35mm equivalent" magnification on APS-C.

Comment edited 2 minutes after posting
0 upvotes
Victor Engel
By Victor Engel (Dec 1, 2011)

No, that would be a bad idea, just as using 35mm focal length equivalences is a bad idea.

0 upvotes
EXX
By EXX (Dec 1, 2011)

Why is this a bad idea (in both cases, so for the magnification and the focal lenght). It is common practice for the focal length everywhere to compare lenses on small sensor, 1", (micro) 4/3, APS-C and Fullframe cameras.

Comment edited 7 minutes after posting
0 upvotes
EXX
By EXX (Nov 30, 2011)

The whole magnification thing has become a mess. In the old days, it all just depended on the magnification factor of the lens. Now sensor size and resolution also play a role.

First example: I take a Sony A900 (24 megapixel, fullframe) and a Sony A77 (24 megapixel, APS-C). I put the same macro lens with magification 1:1 on both camera and take a picture of the ruler at maximum magnification. I will end up with 2 pictures that are both 24 megapixels, but the A900 picture shows 36 mm and the A77 picture shows 24 mm of the ruler. This should both be called 1:1 magnification?

Comment edited 1 minute after posting
1 upvote
Dvlee
By Dvlee (Nov 30, 2011)

Yes. The ruler method of determining magnification is based upon the size (width) of the imaging media. In your case the A900 full frame size is 36mm wide and the A77 APS-C size is 24mm. If yiou were shooting 4x5, then you would see 5 inches of ruler, 2 1/4 film? You'd see 2 1/4 of ruler....and so on.

In all these cases the ratio of the projected image size to the actual subject size is 1:1.

If you were to shoot a 1:1 image on 35mm film and then on 4x5, the size of the subject would be exactly the same on both films. The 4x5 would show much more space around the subject but the actual subject size would be identical.

Therefore a subject 10mm wide would be 10 mm wide on both the 35mm and 4x5 film. If both images were exposed on the same film, say tri x, and printed without changing the enlarger height, they would both yield images of the same size and same grain.

Things get a bit dicey with digital because of the variable in pixel counts.

1 upvote
Dvlee
By Dvlee (Nov 30, 2011)

Continued...Remeber that magnification ratio is a the realtionship between the actual subject size and the size of its image at the focal plane. It make no difference what kind of media or what size media it is projected upon.

However, the charactoristics of the capture media will have an effect upon the degree to which the image can be enlarged. This is true for both film and digital. It's a matter of resolution.

The advantage with film is that even at a relatively small print size like 8x10, a super fine grain film like Tech Pan would look smoother and sharper than the same image shot of tri x.

But at 300 DPI, image shot on a 10mpx sensor would yield a print of 8x12 without interpolation, wearas the image shot with an 18mpx sensor would yield a print of 11.5 x 17.25. At 8x12, the 18mpx image would actually have to be downrezed. At that size the 10MPX image would contain as much detail as the 18mpx. But at larger sizes the 18mpx would have more details.

1 upvote
Dvlee
By Dvlee (Nov 30, 2011)

Part three...if the pixel density of the full frame and APS-c frame are the same, and the full frame image was cropped to match the APS, the resulting image size would be the same.

But in your case, the pixel density of the 24mpx APS-c is greater so you would be able to get a greater degree of enlargement at 300DPI.

Remember, image magnification is the charactoristic of the lens. How big an image we can get from the captured image is the degree of enlargment, not magnification.

In a nutshell, magnification is the degree of image magnification at the focal plane and is not dependent upon the media it is projected upon. Enlargment is the degree magnification of the captured image and is dependent upon the resolution of the capture media. Makes no difference whether it's film or digital, same rules apply. The size of the media is irrelevent.

1 upvote
Dvlee
By Dvlee (Nov 30, 2011)

Last words....Using the same lens at it's closest focusing distance, the size of the subject at the focal plane would be the same on both the full frame and APS-c . If the subject fills the frame at 1:1 on the APS-c camera, the full frame will capture a wider field of view and have more space around it, but the magnification will still be the same.

Macro photography is more than just a matter of magnification, it is also a matter of perspective. Just enlarging a piece of an image that was shot from a distance will not yield the same kind of image as on that was shot close up. Likewise using a longer macro lens that allows a greater working distance from the subject will not yield exactly the same image as using a shorter lens very close to the subject. It's a matter of perspective.

1 upvote
EXX
By EXX (Dec 1, 2011)

Thank you for your clarification. BTW, I am really looking forward to the next articles about this very interesting subject.

0 upvotes
olyflyer
By olyflyer (Dec 5, 2011)

EXX, sensor size plays no role in magnification. It is about the relationship between the object and the image. That relationship is the same regardless of sensor size. If your object is 1 mm in size and the magnification is 1:1 then the recorded image is 1 mm is 1 mm on an FF sensor as well as on an APS or FourThirds. That's what 1:1 magnification is.

0 upvotes
madeinlisboa
By madeinlisboa (Nov 30, 2011)

"The problem, however, is that a regular lens will not be able to focus at such close distances". Unless you reverse them ;)

0 upvotes
Prashant Bande
By Prashant Bande (Nov 30, 2011)

Great article.....

2 upvotes
Dan Tong
By Dan Tong (Nov 30, 2011)

Excellent article as usual.

Thanks!

2 upvotes
Renard DellaFave
By Renard DellaFave (Nov 29, 2011)

All I want to know in the end is maximum pixels-per-inch (or resolvable lpi at best aperture) I can get of the subject, and at what distance that happens. I can see why magnification exists as a figure, now, though, since it's the only number that ignores the camera and just talks about the lens. Seems odd to me since it has been 15 years since I had a lens that wasn't integral to its camera.
The use of "1:1" as anything special seems kind of like it only is for te same reason the year 2000 was special.

0 upvotes
Victor Engel
By Victor Engel (Dec 1, 2011)

It's somewhat arbitrary, but it's also not arbitrary. For a simple lens, it is macro if the lens is as least as close to the subject as it is to the focal plane. For a non-macro lens, it is always closer to the focal plane than to the subject. The lens is exactly half way between the focal plane and the subject at 1:1.

Of course, the lenses we use are not simple lenses, so the actual situation varies from this by lens design.

0 upvotes
liviutza
By liviutza (Nov 29, 2011)

I understand most conventions around macro photography and do quite a lot of macros myself, but with the advent of various-sized systems, compacts and zooms macro conventions could really use a serious revamp
For example, a 1/2.5 sensor compact fits in the frame the same subject as a full-frame with 100mm macro. FoV aside, for the user and even for practical purposes the final image produced by the two ensembles is quite similar in terms of reproduced subject.
I used a number of close-ups platforms from the specialist MP-E 65 lens from Canon to compacts, and I am trying to focus on what the used system allows me to frame rather than ratio. In this respect I would rather think of "how many millimeters will my camera/lens fit in how many megapixels". Only downside of this is that on interchangeable lens cameras the body is also a factor to take into account, but i see it as more useful reference, especially for compact cameras that deliver quite stunning close-ups at their closest focus

0 upvotes
NJani
By NJani (Nov 29, 2011)

Dear Author,
Sorry to say but your article in some points is not correct. To put things into perspective let's talk about what the magnification ratio means.
The magnification ratio is not depends on sensor/film size. It depends only on how the lens magnifies the subject. The ratio stands between the subjects real size (lifesize) and between the subjects projected size what you will get on sensor/film. The magnification ratio 1:1 (AKA lifesize) means that the subject will occupy the same physical size on the sensor/film as it's on size. If the subject is 1cm x 1cm size, it will occupy on sensor/film 1cm x 1cm territory if the magnification ratio of the lens is 1:1. No matter how big is the sensor/film. If you use smaller sensors/films and will make prints with the same size (for eg. A3), of course you will get virtually bigger enlargements of the same subject but it is only because the smaller sensor/film does cropping. But the subject on all sensors/films will occupy the same size.

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

Are you serious? Have you read the article?

10 upvotes
NJani
By NJani (Nov 29, 2011)

Sorry, not all! Started to read and scrolled down the screen. Stopped at dragonfly and read the notes below it where you wrote: "sensor is 22mm wide, so the magnification ratio is 22mm/60mm, approximately 1:2.7." That was the point what I misunderstood. Now a read the article and have to say that it is absolutely correct. Sorry about my post, hope you can forgive.

0 upvotes
Michael Gunawan
By Michael Gunawan (Nov 29, 2011)

Dear NJani,
which part of the article makes you think that Erez didn't say exactly what you're stating ?

1 upvote
anthonyGR
By anthonyGR (Nov 30, 2011)

Why would he read the article before responding? this is the internet.

7 upvotes
DanCee
By DanCee (Nov 30, 2011)

typical shout first before reading...

0 upvotes
probert500
By probert500 (Dec 1, 2011)

An apology was proffered - why would this be responded to in such a rude way -oh it's the internet. Gee I'm stupid like a fox.

0 upvotes
hammerheadfistpunch
By hammerheadfistpunch (Nov 29, 2011)

one question i have with magnification and macro is its benefit for portrait work and video interview. I was going to get a 45 mm macro for video interview but is there any reason to get a 1:1 lens for that type of work when a non-marco of the same focal length will do, i have heard conflicting information. whats the benefit?

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

The only difference between a macro lens and a non-macro of the same focal length is the macro lens' ability to focus from a much shorter distance.
Many use macro lenses fro non-macro work because of their image quality, which is almost always fantastic.

1 upvote
Ashley Pomeroy
By Ashley Pomeroy (Nov 29, 2011)

Assuming you're talking about the Leica/Panasonic 45mm macro for the four-thirds system, it won't hurt, and indeed that lens would be pretty good in that role (assuming you're shooting with the camera on a support). Having said that, you won't need or use the macro range unless you're testing the subject's iris response, and in practice a zoom will probably be more useful. Nonetheless that particular lens would be a good choice - and it can't *hurt*. Sadly there's a dearth of good portrait lenses for micro four-thirds, although conversely there's a huge surplus of old 35mm 50mm f/1.8s and f/1.4s you could adapt, if you don't mind manual focus.

0 upvotes
PicOne
By PicOne (Nov 29, 2011)

Another common use for macro lenses for non-macro work is that these lenses tend to provide a flatter field of focus than non-macro lenses with less distortion, and as such are optimal for eg. artwork reproduction uses.

1 upvote
wkay
By wkay (Nov 29, 2011)

What's the point of this whole article? Seems to be some sort of vague engineering discussion. If my subject fills the frame, focuses, and gives me a pleasant compostion, what the h do I care what the magnification is? Am I supposed to be taking critical measurements off the image for scientific purposes? I'm sure there are better tools for that. And who on earth needs to Tweet or Facebook this? My life is going fast enough, I dont need to waste any more of it on frivolties that I already am. Sorry to carry on, but these DP 'tutorials' are just proving a general waste of time as they are just superficial overviews that dont provide sufficient info to really improve my skills.

1 upvote
ryansholl
By ryansholl (Nov 29, 2011)

I hate it when life is going so fast that I don't have time for articles such as this, but not quite so fast that writing a post to complain about it isn't worth my time. It's a strange conundrum, eh?

Comment edited 26 seconds after posting
19 upvotes
TomCreek
By TomCreek (Nov 29, 2011)

I've used a Canon autobellows going on 30 years now, and continue to use it with my now EOS system. I use macro lenses on it, non-macro, and even a bellows-only lens. I know the potential magnification with some of these is well beyond 1:1, but I've never bothered to look at the scale or calculate the magnification. So you can be into macro without the scientific/technical end. Oh by the way I'm an engineer, but as you say, all I care about is the composition. Be gentle though because a growing segment of the population gets off on metadata and technical details, as evidenced byt the large segment that is Tweeting and posting on FB meaningless krap.

0 upvotes
StephenSPhotog
By StephenSPhotog (Nov 29, 2011)

I'm happy to tell you that you have successfully missed the point. Congratulations!

Comment edited 32 seconds after posting
2 upvotes
sacundim
By sacundim (Nov 29, 2011)

"If my subject fills the frame, focuses, and gives me a pleasant compostion, what the h do I care what the magnification is?"

So if your subject won't fill the frame in sharp focus, how do you suggest we approach the matter?

3 upvotes
JWest
By JWest (Dec 1, 2011)

@sacundim - get a bigger subject.

0 upvotes
jcmarfilph
By jcmarfilph (Nov 29, 2011)

Oh take note that my HS10 + Raynox DCR-150 can fit in 9mm in the frame so technically magnification ratio is bigger than 1:1 of this article but when computed based on your formula it will only be *1:1.46. =D

0 upvotes
Chris Savage
By Chris Savage (Nov 29, 2011)

The sensor in your HS10 is only ~ 6mm wide so if you're 'fitting in' 9mm your magnification ratio is indeed only ~ 1:1.5

1 upvote
jcmarfilph
By jcmarfilph (Nov 29, 2011)

But in real-world, it will produce bigger magnification lthough you can crop the DSLR to match that result. I'll be doing a comparison between a DSLR with 55-250mm and my HS10 soon.

0 upvotes
Rachotilko
By Rachotilko (Nov 29, 2011)

Sorry for off-topic, but :

has anybody else found that dpreview's forum message index froze 7 hours ago ? All posts are 7 hours old or older. Or is it my brower playing some nasty game with me ?

Comment edited 3 minutes after posting
0 upvotes
MPA1
By MPA1 (Nov 29, 2011)

My biggest wonder about macro is this:

How on earth do you get something such as an insect to stay where you want it to be whilst you set up the shot?!

6 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

How am I supposed to keep you reading these articles? ;-)

2 upvotes
Daniel Lowe
By Daniel Lowe (Nov 29, 2011)

Superglue!
Works a treat (bug doesn't work afterwards)

2 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

Oy vey...

2 upvotes
Cy Cheze
By Cy Cheze (Nov 29, 2011)

A shield bug is apt to sit still or move slowly. The robber fly may have to be poisoned and stuck on a pin. Looks like this polyoptic fly has some "lens dust."

0 upvotes
TomCreek
By TomCreek (Nov 29, 2011)

Freezing insects work, as does the chemical whose name escapes my brain, used to use in biology, which kills the insect. This is well known.

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

All images in these articles were achieved WITHOUT ANIMAL ABUSE. I do *NOT* hurt, kill, maim, freeze, squash, glue, heat, refrigerate, skewer, disembowel or perform any other abuse on my subjects. I'll write about all my methods and techniques - I beg of you, please refrain from animal abuse until then.

3 upvotes
StephenSPhotog
By StephenSPhotog (Nov 29, 2011)

Freeze it. It's just a bug.

0 upvotes
MPA1
By MPA1 (Nov 29, 2011)

Even to freeze it, you have to catch it!!

Also, how about if you want to photograph it flying? You can hardly toss it in the air with a cry of "Fly my pretty! Fly!" after you have frozen the poor thing!

0 upvotes
Erland Nielsen
By Erland Nielsen (Nov 29, 2011)

If you want natural images, you don't catch the insects. It's quite simple. And if you hope to capture images showing behavior, it''s quite obvious.
Finding, approaching and photographing insects is something you learn by trial and error. It takes time, and more time.

Comment edited 17 seconds after posting
0 upvotes
Roman Korcek
By Roman Korcek (Nov 29, 2011)

@Erez Marom:
"please refrain from animal abuse until then"
And even during and after.

2 upvotes
TomCreek
By TomCreek (Nov 30, 2011)

Formaldehyde. That's the chemical we had in a small bottle with a dropper for insects in my biology days. It's also in photography chemical process and woodworking glues etc.

0 upvotes
David Pastern
By David Pastern (Dec 1, 2011)

One should NEVER freeze insects or arachnids or interfere with them in any way. Artie Morris doesn't tranquilise birds does he? Moose Peterson? John Shaw? nope. If you can't get the shot as is, then leave the insect or arachnid be. What you are suggesting is completely immoral and defeats the purpose of being a nature photographer in the first place.

re: the article - I guess from a technical point of view, it's nice, but it isn't strictly required knowledge from my experience imho. I've been shooting macro for near 10 years now, so I'm not exactly a newbie, so newbs may find this article of interest.

Dave

0 upvotes
ptodd
By ptodd (Nov 29, 2011)

I understand what magnification is; reassuring to have this knowledge consolidated.

What I don't understand is why '1:1' is so special? Using a smaller sensor, lower magnification ratios will yield essentially similar results (in terms of subject size relative to captured image, of course other variables like DOF will be different).

For example, why is it useful to the poster with an HS10 & close-up filter to directly compare the magnification ratio of their system to a user of a 35mm SLR? It seems to have little direct bearing on the subjects they will be able to capture or the images the will be able to produce. The magnification may be useful as an intermediate value for calculation, but why insist that only 1:1 is 'true macro', when for practical purposes the capacity of the system is so dependent on other factors?

I suppose the answer is that it is useful when comparing lenses of different focal length for use on the same size sensor (which in the old days was more fixed).

1 upvote
ptodd
By ptodd (Nov 29, 2011)

How long before we start having '35mm equivalent magnification ratio' like we have '35mm equivalent focal length' (rather than FOV which would actually be meaningful)... just to really arbitrarily obfuscate things for anyone learning about photography from scratch...

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

I agree completely. On top of that, I never consider magnification in the field. I only try to achieve my desired composition, and so magnification is but a byproduct.
I only explained magnification because:
a) It's good to know what people are talking about and to solve misconceptions.
b) It's highly relevant for future technical discussions.

Comment edited 15 minutes after posting
5 upvotes
ptodd
By ptodd (Nov 29, 2011)

That makes good sense, thank you for responding.

Certainly it is worthy of explanation; I can remember struggling a little with the concept at first, reading about it and understanding what was written, but refusing to take it on board because it seemed rather arbitrary... so months later, I'd see it mentioned again and think "surely there must be something more meaningful about this number that I haven't realised yet".

Perhaps the relevance of the '35mm equiv' aspect could be further emphasised to better avoid the misconception that it is meaningful to use this number as an absolute comparison between systems with different sensor sizes.

I look forward to the future discussions.

1 upvote
_sem_
By _sem_ (Nov 29, 2011)

> What I don't understand is why '1:1' is so special?
Because most (D)SLR macro lenses reach 1:1 at close focus, and because specific macro issues (thin DoF, loss of light, etc) show up to such extent that one can't just ignore them as with lower magnification close-ups. And, one needs special equipment to magnify more than 1:1.

I think an article like this is pointless without an example with compact cameras (small sensor, preferably several sizes). Which would show that frame coverage (in mm) or "equivalent" optical magnification is more useful than the "naked" one.

0 upvotes
Chris Savage
By Chris Savage (Nov 29, 2011)

"What I don't understand is why '1:1' is so special?"

To you or me it probably isn't.

Many technical fields of photography -- engineering, biology, archaeology spring to mind -- rely on being able to make direct size comparisons of subjects.

3 upvotes
Mostly Lurking
By Mostly Lurking (Nov 29, 2011)

Why 1:1 is so special is because that is the minimum magnification that can truly be called a 'macro'. Here are the definitions:
>10:10, normal photography.
10:1 to 1:1, close-up photography. (Yes, there are over-laps.)
1:1 to 1:10. macro photography.
1:>10 micro-photography.

0 upvotes
Victor Engel
By Victor Engel (Dec 1, 2011)

@Mostly Lurking, your information is incorrect and/or includes typos. In general, A:B is macro if A is greater than or equal to B. You say 1:1 to 1:10 is macro photography. That is incorrect. It would have been correct of you had said 1:1 to 10:1.

Not sure what 10:10 is supposed to be. Usually, one of the numbers is 1. It doesn't need to be, though. It's just a ratio, which can also be expressed as a number. A 1:1 macro image and a 1X macro image are the same thing. A 3:2 macro image, 1 1.5:1 macro image and a 1.5X macro image are all the same thing. The image is 1 1/2 times the size of the subject.

0 upvotes
Maxim Ge
By Maxim Ge (Nov 29, 2011)

I think that the claim "Sensor size does not alter magnification" is arguable. To be more exact magnification definition itself does not quite fit the "real world".

You define maginifcation as "simply the relationship between of the size of the (in-focus) subject's projection on the imaging sensor and the subject's size in reality". I think it has to be coupled with crop factor.

Consider an example. You have a frame 24x36 and make a photo where subject size = 18mm, projected size is 36 mm, so maginification is 2:1, that's correct, but remember - we see that 18mm subject takes the entire frame.

Now we take a tiny camera with crop = 18 and make a photo where subject size = 18mm and projected size is 2 mm. Magnification = 1:9 ? But we continue to see that 18mm subject takes the entire frame.

So 2:1 and 1:9 give same result - strange, isn't it?

I think that crop factor should be added to magnification definition, in this case both considered pictures would have same magnification.

1 upvote
Erez Marom
By Erez Marom (Nov 29, 2011)

It may seem strange, but that doesn't change the fact that magnification ratio is just a definition, and that's exactly how it's defined. This definition is required for other discussions, and believe me, nothing will ever change it... :)
Indeed, in order to fill the frame with a compact as compared to a FF camera, significantly different magnifications are required, but when you think about sensor sizes, it makes sense.

0 upvotes
Maxim Ge
By Maxim Ge (Nov 29, 2011)

Agree, but if we define magnification this way than thesis "macro photography means shooting at a magnification ratio of at least 1:1" looks a little bit strange. Compacts give significantly lesser magnification still they shoot macro ( so they have 1:1 being multiplied by crop factor).

0 upvotes
zebarnabe
By zebarnabe (Nov 29, 2011)

That kinda troubles me as well... usually one should talk about certain terms in 35mm film equivalent due to the lack of better standard. Even in modern days most people know what the size of a negative film frame is.

With that in mind a 35mm equivalent 1:1 macro shot would mean a 36x24mm rectangle filling the frame (aspect ratios aside - take the diagonal of the frame as a measure) no matter what the sensor size or lens focal length/focus distance, the given magnification definition given on the article is correct though.

"(...) 22mm/22mm equals a 1:1 magnification ratio." in 35mm terms terms it would be 1.64:1 magnification ratio. If you simply say 1:1 the details about subject size are lost.

0 upvotes
sacundim
By sacundim (Nov 29, 2011)

"I think that the claim "Sensor size does not alter magnification" is arguable. To be more exact magnification definition itself does not quite fit the 'real world'."

Indeed. I've long argued that it really makes more sense to talk about what I call the "print-to-life" ratio: the ratio of the size of the subject in the print (or computer screen) to the real-life subject. The print-to-life ratio is the product of what we may similarly call the life-to-sensor ratio (the traditional "magnification") and the print-to-sensor ratio (the traditional "englargement").

As to how to define macro photography, I think the best definition is simply photos of small subjects in the same size range as a coin.

1 upvote
Mostly Lurking
By Mostly Lurking (Nov 29, 2011)

That 'crop- factor' provides magnification is a fallacy, perpetrated by statements such as 'on an x crop factor camera, it's th same as a x mm lens.' If isn't the magnification they're talking about, it's the Field of View. The magnification is the same.

2 upvotes
kff
By kff (Nov 29, 2011)

I expect a special AF macro software of cameras (firmware ... it is posible for Pentax K-5, K-7 etc.) for several macro shots with a good bokeh of fast lens and travelling AF points from the front to the back for compound exposition with choosing a range of blur field as bonus :)

... or Do You want to buy a special and an expensive macro gear for it and spend money and time with software in the computer, today?

Comment edited 5 times, last edit 7 minutes after posting
0 upvotes
OneGuy
By OneGuy (Nov 29, 2011)

A widely available parameter on a given camera is the 'minimum focusing distance.' Knowing the sensor size, can I calculate the (optical) magnification just from this parameter? Or do I have to use a ruler at that distance to get the object size?

I checked (quickly) DPR specs on Oly PM1 and did not find the optical magnification ratio (proportion) there -- only 'Live View Magnification." Is this the same thing? If not, what would be the benefit of including the optical magnification on the DPR spec sheet?

0 upvotes
J.K.T.
By J.K.T. (Nov 29, 2011)

You'll need the ruler too. If you knew the focal length and the minimum distance, you could calculate the magnification. Unfortunately the given focal lengths are for infinity focus. The focal length at minimum focus can be (and usually is) different.

1 upvote
gillbod
By gillbod (Nov 29, 2011)

the minimum focus distance often doesn't give a good measure of magnification.

the problem is that the focal length changes during focussing. typically, focal lengths are measured at infinity. when you focus near by, the focal length is often less (sometimes much less) than the focal length at infinity. how much less depends on the design of the lens. this is the reason for the optical magnification appearing on many lens spec sheets.

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

Indeed. That's also why macro lenses usually have a magnification scale alongside the focal distance scale.

0 upvotes
Victor Engel
By Victor Engel (Dec 1, 2011)

The sensor size is irrelevant. You can approximate the magnification from the focal length and minimum focus distance, but it's very important to know what the MFD is measured from.

At 1:1 magnification, a simple lens is exactly half way between the subject and focal plane. Additionally, the distance from the lens to the focal plane is exactly twice the focal length.

This information can be used to approximate the magnification, but lens design will generally affect this. Best is to do an actual measurement if the information is not readily available.

0 upvotes
elitver
By elitver (Nov 29, 2011)

thank you, great reading

3 upvotes
Debankur Mukherjee
By Debankur Mukherjee (Nov 29, 2011)

Good Article......

2 upvotes
SemperUbiSubUbi
By SemperUbiSubUbi (Nov 29, 2011)

I should start by saying I have a very limited knowledge of optics - but the definition of magnification as size of the projection on the sensor over size of the subject seems strange to me. Surely pixel density must come into the equation? What if your sensor had a single really large pixel? If I print an image on a larger piece of paper - have I magnified it? I seems o me that what is spectacular about the picture of the bugs eye in the article is not the fact that the picture of the eye is larger than the eye of the fly - but that the detail on the picture at the size it is displayed is such that to the human eye it seems perfectly clear. It is not intuitive to me that magnification should be invariant to pixel density.

2 upvotes
Dvlee
By Dvlee (Nov 29, 2011)

This has always been a matter of some confusion, even with film.

Simply put, when we refer to the magnification factor of a lens we are describing an optical quality of the lens, not the possible magnification of the final output. The stated manification is the degree of magnification the lens produces at the focal plane, regardless of the resolving power of the sensor or film it is projected upon.

The magnification factor of the lens is not effected by the resolving power of the media it is projected upon. But the resolution of the sensor will determine how large the image will be at native resolution.

But if you were to make full frame 8x12 prints of a macro image from an APS-C 10 mpx and an APS-C 18 mpx sensor, the magnification in the print would be the same. If you were to make very large prints, the 18mpx picture would be sharper than the 10mpx, but the magnification would still be the same.

Does that make sense now?

3 upvotes
SemperUbiSubUbi
By SemperUbiSubUbi (Nov 29, 2011)

Thanks - that's helpful. Makes sense that magnification is simply a property of the lens.

0 upvotes
KaiserAng
By KaiserAng (Nov 29, 2011)

Great article, cleared up my confusion regarding magnification ratio!

1 upvote
Morderator
By Morderator (Nov 29, 2011)

nice! :)

1 upvote
Nate21
By Nate21 (Nov 29, 2011)

I love the articles i have been shooting for about 5 yrs and i learn new information with the articles posted i was wondering has/will there be an article about editing and understanding RAW formats. I personally don't shoot in RAW and i don't spend to much time in workflow either

1 upvote
Erez Marom
By Erez Marom (Nov 29, 2011)

In the articles about post processing I'll talk about RAW. Please stay tuned :)

0 upvotes
MPA1
By MPA1 (Nov 29, 2011)

If you don't shoot in RAW you are throwing away a big chunk of your sensor data every shot you take!

I never shoot anything but RAW unless the client needs the images then and there in a format that they can immediately use.

Think of it like this: all images begin as RAW. If your camera is set to RAW, it saves 100% of the raw unprocessed sensor data to your card. All the settings for white balance and so on have zero effect on that data.

If your camera is set to JPEG, the camera takes the raw data, processes it according to the settings for saturation, contrast, white balance etc and creates a JPEG file. It then simply throws away the raw data forever. You are stuck with the choices made by the image processing engine in the camera.

At least shoot both RAW and JPEG so you can create other versions of the image in Aperture, Lightroom etc later if you want to.

2 upvotes
Nate21
By Nate21 (Nov 30, 2011)

I already know of that thanks for the information if a camera has Raw capabilities shot both simultaneously RAW shooting is idea if selling Pictures somewhat the foundation of Film for overall detail and preference while JPEG attempts to correct the image.

0 upvotes
jcmarfilph
By jcmarfilph (Nov 29, 2011)

Good article . My HS10 + Raynox DCR-150 has a 1 :1.46 magnification ratio. Not bad right?

0 upvotes
Pritzl
By Pritzl (Nov 29, 2011)

I think I have the Raynox DCR-250. Great little add-on that allows me > 1:1 with my 55-250 lens.

0 upvotes
jcmarfilph
By jcmarfilph (Nov 29, 2011)

Yes DCR-250 allows the lens to get closer. Prolly you will get 1.5:1 with it.

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

Not bad at all. The main problem with those filters is that the focal distance range they give is quite limited. Otherwise they offer an excellent and affordable solution.

0 upvotes
frosti7
By frosti7 (Nov 29, 2011)

Excellent work Alon, grettings from d-spot.co.il :)

0 upvotes
Erez Marom
By Erez Marom (Nov 29, 2011)

Erez.
Allon was the model ;-)

Comment edited 2 times, last edit 2 minutes after posting
0 upvotes
mermaidkiller
By mermaidkiller (Nov 30, 2011)

Nice article !

I found out that mounting most lenses reversed on the body can make excellent macro lenses. See this link how.
http://sky.velp.info/macro.php

0 upvotes
cgarrard
By cgarrard (Nov 28, 2011)

Excellent article! Great review on this subject too.

C

2 upvotes
Total comments: 113