Dvlee

Joined on Nov 29, 2011

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Total: 212, showing: 201 – 212
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On article EXIF tracking services help find missing cameras (78 comments in total)

If they can use the EXIF DATA to track pictures taken with a stolen camera, how about a service that tracks the unauthorized use of copyrighted photographs?

Link | Posted on Jan 2, 2012 at 18:52 UTC as 12th comment
In reply to:

f_stops: Hooray Samsung -
Finally a company that understands why cell phones are replacing pocket snapshooters. Connectivity.

Not a coincidence Sammy is a major cell phone manufacturer. And hooray for a product that won't incite law suits from Apple. :)

But the kind of person this sort of 'innovation' is intended for is the person who already has a cell phone with a camera...they don't really want to carry around another device that duplicates what they can already do with their smart phone.

Since Samsung is already well entrenched in the smart phone market, they don't really need to create a new product to capture that market segment. But I could see Nikon or Canon doing this.

Eventually there will be a merging of smart phone and point and shoot technology. Samsung is well positioned to lead that segment but other phone and camera companies will have to acquire new technologies.

These hybrid point and shoots are of little use to most of us. When most of us have cell phones that can do more than these kinds of cameras could and DSLRs and ILCs that have image quality and finctions far beyond what can be crammed into a point and shoot, these kinds of cameras are redundant.

Link | Posted on Jan 2, 2012 at 18:28 UTC
In reply to:

jcmarfilph: Would have been much easier and less costly had they put in a mirror in lieu of that front LCD. =D

Spot on! One could just as easily stick a mirror on the camera side of their smart phone.

Link | Posted on Jan 2, 2012 at 17:53 UTC

The first thing I teach young enthusiasts is to know which end of the camera has the lens and which has the viewfinder and which way they should be pointed.

While there are a few artists that have made a name for themselves by doing self portraits, generally speaking, whether one is a fine artist or just a rank amateur, the best photography happens when the photographer points the lens away from themself!

Yes, I know that cameras like these are intended for teens and youngsters who are only interested in posting pictures of themselves on facebook. They can get satisfactory results with their smart phones, they don't really need a camera specially designed for the purpose.

The camera companies are trying to hang onto the point and shoot market that is losing ground to smart phones by cramming them full of gimmicky functions. As a result point and shoots have become too complicated for the market they are intended for.

Link | Posted on Jan 2, 2012 at 17:48 UTC as 26th comment
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

kolas: 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!

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.

Link | Posted on Dec 11, 2011 at 06:46 UTC
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

tbcass: 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.

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"

Link | Posted on Dec 4, 2011 at 03:25 UTC
On article Macro photography: Understanding magnification (127 comments in total)

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.

Link | Posted on Dec 4, 2011 at 03:19 UTC as 25th comment
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

EXX: 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?

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.

Link | Posted on Nov 30, 2011 at 19:21 UTC
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

EXX: 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?

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.

Link | Posted on Nov 30, 2011 at 19:05 UTC
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

EXX: 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?

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.

Link | Posted on Nov 30, 2011 at 18:35 UTC
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

EXX: 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?

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.

Link | Posted on Nov 30, 2011 at 18:13 UTC
On article Macro photography: Understanding magnification (127 comments in total)
In reply to:

SemperUbiSubUbi: 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.

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?

Link | Posted on Nov 29, 2011 at 05:16 UTC
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