D60's ( APS-C )sensor is too small to stop down below f/11?

mcohran wrote:
Ah, the Franken-thread arises again.....

Or, in the words of Emerson, Lake, & Palmer....

Welcome back my friends
To the thread that never ends.
We're so glad you could attend,
come inside! come inside!

mcohran wrote:
Ah, the Franken-thread arises again.....

LOL

Still, it is good reminder that you can't simply stop down a lens to get a sharper image. Yes, DOF will increase, but with poorer resolution after a certain f-stop.

It was interesting that this thread was dug up since I just finished another article regarding 35mm format where the author recommends not stopping down past f/8 with 35mm unless you need DOF. If you are stopping down because the scene is too bright, use a good ND filter.

Yes, I agree with you Scott, but that doesn't change my argument that the number of crystals on a 35mm film neg, when taking into account the size of the neg in dimensions, means that the Airy disk problem will hit EVERY single SLR ever made That was the gist of my argument. I'm not concerned about the "data" that each pixel/crystal holds, but the amount of pixels/crystals for a given area, which is what will determine these "airy disks" according to physics.

I come from a background in hi fi - and I can most certainly tell you that human senses are incredibly adept at "interpolating" data.

Dave

Hey Tom,

Actually, the 5D is a great choice for avoiding visible diffraction when shooting with small apertures. Its pixel density is only 122 pixels/mm. Diffraction just begins to inhibit 5 lp/mm resolution in a 300 dpi print when you stop down to f/14.3.

Compare that to some of today's digicams, like the Olympus SP-500UZ, which has a ridiculous pixel density of 491, with diffraction inhibiting 5 lp/mm resolution in a 300 dpi print at all f/stops below f/3.6. Ouch!

Despite all the contention I suffered in the first few months following my original post for this thread, it's pretty common knowledge now that keeping the pixel density down (by increasing the sensor size along with the number of megapixels) is a good thing. Diffraction simply will not allow us to increase the pixel densities without shrinking the range of useful apertures.

Mike Davis

Tom W wrote:
Maybe it should be a sticky - in a secret category.
BTW, I shot the 5D at f/22 last night!

OK, I know that I'm not helping anything. But the thread isn't hurting anybody at this point.

Well, if you run the numbers the 5D doesn't have as small pixels as the D60 does. The D60 would scale up to around the 1Ds II in density, so you obviously can't use small apertures with it either. Maybe that explains all the interest in L glass - people want to shoot at larger apertures for better IQ. Anyone seen a schmoelzel shot at f/5.6 or smaller? :{)#

. . . now where did I leave that spare padlock?

The neverending thread continues. Yes, I'm working on a firmware hack to keep my 5D at f/14 or larger aperture. If I had a 20D, I'd set the limit to f/10.

I stole it and gave it to Belmondo.

It's true,. I tried to shoot my Infra Red converterted D60 at F22 the other day.. the camera almost self destructed from the forces I unleashed by attemting this insanity.. it heated up so much that all the images were pure red!!!!!!!!

It's amazing people aren't killed trying to do this every day.. there needs to be warning labels I tell you........

Beware the Airy Disk! It will swallow your soul!

I just stumbled across this thread and felt my brain expand with new knowledge. Keep it open!

Hi Tom,

Tom W wrote:
The neverending thread continues. Yes, I'm working on a firmware hack to keep my 5D at f/14 or larger aperture. If I had a 20D, I'd set the limit to f/10..

Do you always print your uncropped, 4368x2912-pixel 5D captures to a 300 dpi print size of 14.56 x 9.71 inches or larger?

Have you made the choice to limit the resolution of all your prints to a minimum of 6 lp/mm?

Does your audience always view your prints at distances no farther than 10-inches?

If the answer to any of these questions is "No," feel free to stop down below f/14.3 when using the 5D.

I suspect your answer to all these questions is "No" - which leads me to believe that one of the following must be true:

a) You were unaware that these qualifications have already been covered in this thread.

b) You actually are aware that these qualifications have been covered previously, but would like everyone who reads your comment to believe that I’ve not made any such qualifications.

c) You are aware of the qualifications and understand them perfectly, but you think the majority of readers are too simple-minded to accomplish this feat.

d) You were just trying to be funny.

To which my responses are...

a) Read the thread.

b) You're comment is divisive and misleading.

c) Other readers might actually be as intelligent as you.

d) Please add a disclaimer to your jokes to make it clear that you do not disagree with the party you are targeting.

If you disagree with the method I chose for normalizing comparisons of two digital cameras' vulnerability to diffraction, feel free to suggest an alternative approach.

No where in this thread will you find me saying that prints must always be made at a specific size, or at any specific resolution, or that they must be viewed at any minimum distance. Why do you (and others) make arguments that require this assumption?

Mike Davis

Ron,

For decades, a lot of 35mm shooters have practiced avoiding f/22 when the intent was to produce prints larger than 8x10 to survive scrutiny at distances less than 15 inches, for example. Surely they were "on to something," something significant and worth taking the time to understand.

This thread equips readers with the math required to determine precisely when diffraction will begin degrading images they capture with their digital cameras. All they need is a 4-function calculator and the interest to proceed. I'm not willing to assume they lack the intelligence or the will to learn. Are you?

References to this thread can be found on many servers. Anybody speak Hungarian?

http://forum.fotoklikk​.hu …0&postorder=des​c&start=15

It has even been included in an encyclopedic reference:

http://www.factbites.c​om/topics/Airy-disk

We can never know how many people have been introduced to the Canon Digital Photography Forum by this thread, but surely it's considerable.

Why do you want to censor it?

Mike Davis

The answer is generally "no" to all three, but not always. There is no way to answer such general questions with absolute answers.

I've read the entire thread over time (too much time), and I don't wish to read it all again. In general, it's a drastic over-analysis of the situation in which the limitations of diffraction are sometimes overstated. There is no "barrier" beyond which diffraction suddenly becomes intolerable. It is a gradual change that may or may not be noticeable as a camera is stopped down beyond the theoretical limit. Sometimes, it's noticeable, and sometimes not. In most cases, the increased depth-of-field that one seeks when stopping down is considerably more important than a modest increase in possibly visible diffraction (shooting close macro would be a good example).

I have.

Such can be said for much of this thread, including the original premise. That it still exists is rather humerous in an odd way.

Of course they are, and probably moreso. Where have I stated otherwise?

I don't see that as necessary - the intelligent readers are generally capable of recognizing humor. Besides, I might just disagree with a given party.

I'm really not concerned with your methodology - the results are, I'm sure, measureable. The problem is that there is a great deal of overanalysis for something that, except in rare circumstances, isn't of significant importance.

/me stakes a piece of history before the padlock kills us all....


what do airy disks look like anyway? anyone got a really small and dense sensor and stopped down really far?

Leo

Tom,

This explains why you find this thread "humerous".

The math I've used is as old as the hills - I haven't crafted it from thin air. The formulas have long been deployed by astronomers and serious photographers - by people who do not consider the exercise to be an "overanalysis".

It's apparent that the point at which diffraction begins to impact the resolution you desire in your digital captures is of little significance to you - but I do find it significant, as do a lot of other people.

Those who share your apathy for this topic can laugh along with you, but if you find humorous that which the rest of us find significant and useful, please, at least allow us the privilege of fueling your laughter without calling for censorship.

Mike Davis

No kidding!

I just jumped onto www.dpreview.com and searched their forum for the word diffraction. Just this morning, a poster named Bob Stothfang, contributed this article:

http://forums.dpreview​.com …rum=1021&messag​e=17757005

Quoting the poster: "be sure to scoll down to the "What It Looks Like" section with the photo of a piece of cloth. If you hover your cursor on f8 below the cloth and observe the photo then position it on each of the higher f stops you can see the degradation in the image quality. You don't need to click on the f stops, just hover your cursor over the number."

Just in case the link to the dpreview article doesn't work, here's the page Bob's article refers to:

http://www.cambridgein​colour.com …ffraction-photography.htm

Here's another example - from a page reviewing the Sony Cybershot DSC-V3:

http://www.dcresource.​com/reviews/sony/dsc_v​3-review/

Scroll down to the pair of images showing a brick clock tower. One was taken at f/4. The other was taken at f/8.

Do you find the difference to be significant?

Mike Davis

This should be very old news by now. Why don't you guys simply try this test, take a series of pictures in good light with your sharpest lens from f8 in 1/3 f stop increments all the way to f 22, of course using MLU, timer and on a tripod. Emperically decide for yourself where the added DOF balances out with loss in resolution. The larger the pixel pitch the smaller aperture you will be able to use without significantly compromising resolution. For myself, I have decided that the 1DmkII/5D limit is f/16. YMMV!
Read this
http://www.cambridgein​colour.com …ffraction-photography.htm
Go to the table "Visual Example: Aperture Vs pixel Size" and find your camera. Place the cursor over it and without clicking move over the toe f stop column. Look at the graph, which represents the circle of confusion. You can see that the D2x is the most limited dSLR due to its fine pixel pitch.
Mike K