Small Apertures & Diffraction. Yeah, Whatever...

Newsflash: people like to view their prints up close. I like printing 13x19 or sometimes larger because not only can you see the print fairly well across a room, but you can plant your nose 12 inches away and fine detail in the print. Like others have said: if you don't scrutinize your picture very much you don't need more than 3 or maybe 5MP.

This whole talk of MPs is depressing. I sell cameras as a part-time job and I have to try and explain to Joe Sixpack that looking for a 12MP p&s in order to view on a 1680x1050 screen is utterly useless. They get suspicious when I tell them that their new 22" monitor or 46" "full HD" TV have less than 2MP. It's getting crazy; I've had people choose a samsung p&s w/13MP (amazingly bad camera) over the rather nice 9MP Panny TZ5 just based on resolution. I regularly ask these customers how large they plan to print and it's never more than 8.5x11. I then show them an 11x14 shot of Montreal City Hall taken by an old 4MP 1D, which sometimes convinces. I think I should borrow a 12MP p&s and a Nikon D40, shoot a scene with both and print both at A3; this will be an interesting comparo and I suspect the D40 will win. Anyways, enough of an OT rant from me, it just gets under my skin sometimes

--
-Scott
http://www.flickr.com/photos/redteg94/

therickman said:

As I'm looking through my various photography magazines..

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You didn't have to go any further than that. Unless you're buying enormous magazines (that don't exist, btw), you're not seeing the photograph in a large enough print to notice the limits of diffraction.

Normal-sized magazines simply aren't large enough to reveal diffraction limiting.

As others have said, you are also probably looking at MF (or larger) sensor-captured images.

I suggest you read a little more about pixel pitch, DPI, and print sizes before you claim diffraction-limited resolution is an urban legend.

Didn't you see my above post. Not just the image I referred to, but many others in this competition and others are printed at large sizes. I certainly don't think diffraction is an urban legend and have taken lots of shots to test how it works in real photographs. I am thinking of starting a thread on this because a lot of people are missing one important point. Image detail on or near the plane of focus certainly starts to soften due to diffraction. But only a small distance away from this the detail is actually more clearly defined with a smaller aperture than a more optimum aperture. This image information can be important to the viewer in their perception of the photograph. In a lot of photographs, especially in my field of macro photography only a very small proportion of the total image actually lies on this plane of focus and most of the image information that makes up the shot is actually away from this plane of focus. So even with some diffraction softening a photograph taken at a smaller aperture well into the diffraction limited zone can actually appear sharper than a shot taken at a more optimum aperture.

therickman said:

As was stated by someone else earlier, in reality, you will never,
NEVER view the final image at the 100% level.

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Never is a long time, dude. Never also doesn't cover the hundreds of times I've looked at my photos and other people's photos at 100%.

In your world, I guess I and other people like me don't exist then, eh ?

SteB said:

... especially in my field of macro photography ...

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How myopic (pun intended) of you. What applies to the field macro photography does not apply to photography in general. Macro photography is unfortunately (painfully) limited by DOF requirements that are far more stringent (unforgiving) than most other fields of photography.

Also, just because you realize there is a balance (trade-off) between DOF and diffraction doesn't make you the Great Enlightened One generously passing on secret knowledge to all of us ignorant photographers. Chances are, most the readers of these forums are already fully aware of the trade-offs between DOF and diffraction.

Personally, I'm well aware of the relationship between aperture, DOF, and diffraction. If I choose to have a certain part of my photo in focus and as sharp as possible (while perhaps sacrificing focus in other parts of the photo), so be it, and those parts in focus should be as sharp as possible. Hence, I (and tons of other photogs) do indeed worry about the trade-offs between DOF and diffraction-limited resolution.

More photos have been, and still are softened by camera shake and atmospheric conditions than by diffraction, at least where it is obvious to the human eye, when prints are viewed at reasonable distances and not under a magnifyer.

Regards,
Peter.
--
http://fleurieubirds.freehost.net.au/GX20/index.html

http://gowerphotos.tripod.com

David C Harris said:

SteB said:

... especially in my field of macro photography ...

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How myopic (pun intended) of you. What applies to the field macro
photography does not apply to photography in general. Macro
photography is unfortunately (painfully) limited by DOF requirements
that are far more stringent (unforgiving) than most other fields of
photography.

Also, just because you realize there is a balance (trade-off)
between DOF and diffraction doesn't make you the Great Enlightened
One generously passing on secret knowledge to all of us ignorant
photographers. Chances are, most the readers of these forums are
already fully aware of the trade-offs between DOF and diffraction.

Personally, I'm well aware of the relationship between aperture, DOF,
and diffraction. If I choose to have a certain part of my photo in
focus and as sharp as possible (while perhaps sacrificing focus in
other parts of the photo), so be it, and those parts in focus should
be as sharp as possible. Hence, I (and tons of other photogs) do
indeed worry about the trade-offs between DOF and diffraction-limited
resolution.

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Firstly, I find it amusing that you imply I am pompous and egotistical whilst sanctimoniously spouting a lot of very inaccurate generalisations.

This is what you stated:

David C Harris said:

David C Harris said:

therickman wrote:
As I'm looking through my various photography magazines..

Click to expand...

Click to expand...

David C Harris said:

You didn't have to go any further than that. Unless you're buying enormous > magazines (that don't exist, btw), you're not seeing the photograph in a large > enough print to notice the limits of diffraction.

Click to expand...

David C Harris said:

Normal-sized magazines simply aren't large enough to reveal diffraction limiting.

Click to expand...

David C Harris said:

As others have said, you are also probably looking at MF (or larger) sensor-
captured images.

Click to expand...

David C Harris said:

I suggest you read a little more about pixel pitch, DPI, and print sizes before you
claim diffraction-limited resolution is an urban legend.

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It is not just macro photographs taken at smaller apertures that win competitions and get published, but landscapes and other types of photographs. You try denying this by claiming that they must be taken with with MF or larger formats. When the camera details often clearly state that they were taken with DSLRs with smaller than FF sensors.

Just take the Wildlife Photographer of the Year competition I linked to. This is widely recognised as one of the most prestigious competitions of its type and many of the top Pro Wildlife Photographers enter this competition or have built their reputations on winning it or getting awards in it. There are numerous travelling exhibitions and very large prints are used in these exhibitions. You can order prints up to 1000mm x 700mm yourself.

Okay let us forget macro as you don't seem to think it is real photography. Take a look at the overall winner. It was taken on a Canon 350D at f16. Then take a look at the overall winner of the Urban and Garden Wildlife category - it was taken with a Canon 20D and Sigma 18-200mm superzoom at f22. Both APS-C sized sensors, definitely not macro photographs and not a MF camera in sight. So anyone who sees a published photograph using a smaller diffraction limited aperture is mistaken because they were with MF cameras etc, heh?

Here are the links, I could provide lots more but I'm sure you are not really interested in facts that contradict your arrogant, but mistaken assertions. Perhaps you might like to explain how and why the very successful professional photograhers who judge this competition don't understand photography in the way a real expert such as yourself does - or otherwise they would realise that actually these were rubbish photographs because they were taken with such small apertures on APS-C sensored cameras. Didn't those judges realise you shouldn't do this because of diffraction, how ignorant of photography they must be. What are you going to do, send them back to photography school with all the incompetent picture editors that keep selecting these photographs at diffraction limited apertures to appear in their publications. Obviously none of them know anything about "pixel pitch, DPI and print sizes" - I'd contact them and offer them lessons if I were you. Self-evidently you know much better than all of them. Who is it that thinks they are "the Great Enlightened One generously passing on secret knowledge to all of us ignorant photographers"?

http://www.nhm.ac.uk/visit-us/whats-on/temporary-exhibitions/wpy/photo.do?photo=2450&category=54&group=4

http://www.nhm.ac.uk/visit-us/whats-on/temporary-exhibitions/wpy/photo.do?photo=2424&category=9&group=1

Redteg94 said:

Newsflash: people like to view their prints up close. I like printing
13x19 or sometimes larger because not only can you see the print
fairly well across a room, but you can plant your nose 12 inches away
and fine detail in the print. Like others have said: if you don't
scrutinize your picture very much you don't need more than 3 or maybe
5MP.

This whole talk of MPs is depressing. I sell cameras as a part-time
job and I have to try and explain to Joe Sixpack that looking for a
12MP p&s in order to view on a 1680x1050 screen is utterly useless.
They get suspicious when I tell them that their new 22" monitor or
46" "full HD" TV have less than 2MP. It's getting crazy; I've had
people choose a samsung p&s w/13MP (amazingly bad camera) over the
rather nice 9MP Panny TZ5 just based on resolution. I regularly ask
these customers how large they plan to print and it's never more than
8.5x11. I then show them an 11x14 shot of Montreal City Hall taken by
an old 4MP 1D, which sometimes convinces. I think I should borrow a
12MP p&s and a Nikon D40, shoot a scene with both and print both at
A3; this will be an interesting comparo and I suspect the D40 will
win. Anyways, enough of an OT rant from me, it just gets under my
skin sometimes

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But why blame 'Joe Sixpack'? After all, he is just a victim of the industry's marketing propaganda. The camera industry wants to sell new cameras. On a large scale. Every year. The way thay manage this is to innundate the uninitiated with the MP lie. It sells lots of cameras. Joe Sixpack deserves a break. It's the industry, man, the industry (ah, man, it's the industry...)

Drake

David C Harris said:

therickman said:

As was stated by someone else earlier, in reality, you will never,
NEVER view the final image at the 100% level.

Click to expand...

Never is a long time, dude. Never also doesn't cover the hundreds of
times I've looked at my photos and other people's photos at 100%.

Click to expand...

Seriously, what do you get out of looking at other people's photos at 100% pixel level? If you ever visited the Sistine Chapel and looked up at Michelangelo's beautiful work, would you bring a ladder so you could examine how sharp his lines are? Look out for paint diffraction caused by old frayed paint brushes!!

David C Harris said:

In your world, I guess I and other people like me don't exist then, eh ?

Click to expand...

Obviously, you do exist. But while you're pixel-peeping some insignificant area of the image right in front of your face at 100%, critiquing pixel pitch this and sharpness that...



...I'm standing back and enjoying the ENTIRE photo, just as the photographer intended.



--
Insert obligatory quote here...

I just want to say that I agree with a lot of the basic premise of what you state. Out of interest you might be interested to know that the 2008 Wildlife Photographer of the Year Competition was won with a shot from a 350D/Rebel XT and an aperture of f16. One of the other category winniers used f22 on a 20D. This is one of the most prestigious competitions of it's type in the world with a big travelling exhibition of larger prints. There are other examples of f16 or smaller apertures used in this years competition and previous years competitions. So I don't understand why others keep saying you must be mistaken and these shots were taken with larger format cameras.

Check out the links:

http://www.nhm.ac.uk/visit-us/whats-on/temporary-exhibitions/wpy/photo.do?photo=2450&category=54&group=4

http://www.nhm.ac.uk/visit-us/whats-on/temporary-exhibitions/wpy/photo.do?photo=2424&category=9&group=1

I don't deny the effects of diffraction and generally try to keep below f16 with a normal lens on my 40D. However it also depends on what I am trying to get and I simply use the aperture that works. Whereas with the Canon MP-E 65mm my effective aperture is often far smaller than this. I use what works, not what some theory tells me. I think the problem is the use of the word "diffraction limit" and the way in which some mistakenly think this means you shouldn't go beyond that aperture. Whereas in fact all it means is that wider than the "diffraction limit" a lens' performance is only limited by it's glass and design, whereas past the diffraction limit it is the physical properties of light passing through the small aperture that limits resolution and no amount of better lens design can improve upon this. It does not mean you should use such an aperture though.

John K said:

You'll never win an argument with a measurebater. Ever.

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Exactly, that is why I found the posting of your images in this particular discussion odd.

John K said:

John K said:

Going back to the original
parent post, I don't put a whole lot more stock in the settings used
by "professionals" than I do by the advice of folks on forums.

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I'm at a loss for words on that one. Considering all of the "I got a
bad copy of lens 'x' " posts on this forum I wouldn't put a whole lot
of stock into what I read here. There are more bad photographers than
there are bad lenses...

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Exactly again. I think you reversed my meaning. I put little stock in the advice gained on forums. I also don't think that getting an image published in a magazine (especially one that includes EXIF data) necessarily makes the photographer more knowledgeable. Even if they are, knowing what settings they used to take a brilliant photo is marginally useful at best. I'm not the same person with the same eye, the same gear, the same physical abilities, in the same location at the same time of day. What worked for them may not work at all for me. What satisfied them may not satisfy me. There are some general guidelines (e.g., the relationship between aperture and DOF, to pick one), and some specialized knowledge (like knowing which range of shutter speeds create good prop blur on shots of prop driven aircraft - even this differs by airplane), but these are not entirely trivial to generalize out of pictures in a magazine and a set of settings. That was what was behind my comment to the original parent post.

Is it worth knowing that diffraction happens? Absolutely. That way, when you aren't happy with a photograph taken at some ridiculously small aperture you can explain it and correct for it (rather than coming here to whine about how soft your new lens is). But, like I said, I would put far more stock in trying it with my own equipment and judging the results myself then I would on the relatively anonymous advice obtained online or from images in a magazine.