This statement threw me. On first reading, it seems like "Why stop down an expensive lens and get the performance of a kit zoom". By F8, most lenses are quite good and give reasonable performance. I'm hard pressed to tell the difference between a $1000 50mm lens and a $100 50mm lens at F8. But I'll stop both down to F8 if I need the DOF.
semilog
curmudgeonly optimist
Of course!
In the 70s, I worked with a Physicist that specialized in X-Ray Crystallography that referred to "Conservation of Inconvenience". Seems appropriate here, DOF gain vs Diffraction Loss.
ampguy
Veteran
Hi Brian
Hi Brian
good summary. The only other real world issues I have concerned myself with relating to this is I never know what images I may eventually want ultimate resolution, and I have been in situations where I needed to use the aperture to stop down, specifically for some long exposures with water where I didn't need more DOF, and didn't have slower film/sensor or ND filters on-hand, but needed the slow shutter speed for the effect I wanted.
If you browse say the u4/3 and smaller sensor forums and galleries, you will see diffraction limited images (especially reds), no pixel peeping needed.
Hi Brian
good summary. The only other real world issues I have concerned myself with relating to this is I never know what images I may eventually want ultimate resolution, and I have been in situations where I needed to use the aperture to stop down, specifically for some long exposures with water where I didn't need more DOF, and didn't have slower film/sensor or ND filters on-hand, but needed the slow shutter speed for the effect I wanted.
If you browse say the u4/3 and smaller sensor forums and galleries, you will see diffraction limited images (especially reds), no pixel peeping needed.
semilog
curmudgeonly optimist
Once more, with spirit:
If you can see it in micro 4/3, you can see it in APS-C. As I demonstrated above, diffraction can make a 200% or even 300% difference in linear resolution in APS-C, while the difference between 4/3 (or micro 4/3) and APS-C is 17 to 20%.
semilog
curmudgeonly optimist
A major chunk of my professional work since 1998 has depended on ultra-high resolution (position detection at or below 1 nm accuracy, using light with wavelengths of 530 nm [green] to 1064 nm [IR]) and/or ultra-high sensitivity (single molecule) microscopy. Sensor efficiency and diffraction (and, less germane to the present discussion, the chemical and physical properties of fluorescent probes) are the limitations in these kinds of work. So yeah, I've spent a lot of time thinking about this stuff.
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Ok, I'm curious... Ted, how do you detect diffraction limited images? What characteristics do you look for to see the effects of diffraction? Truly, I'd like to know what to look for...
semilog
curmudgeonly optimist
Apropos of this discussion, this video (about perhaps the most beautiful experiment in physics, which concerns diffraction) is just wonderful.
http://www.youtube.com/watch?v=DfPeprQ7oGc
Yes, but...
wouldn't a closer examination of the results of the single slit be more relevant here? The amount/nature of the spreading & diffusion as the waves/particles are affected by the edges of the slit, with varying slit widths?semilog
curmudgeonly optimist
Yes, but...
The double-slit experiment is highly relevant for photography. Any analysis of an optical system using waves instead of linear ray-tracing (that is, a simplification where photons are treated as ballistic particles instead of waves) must deal with diffraction and interference. Interference explains why a diffraction-limited optical system will always draw a point source of light (a distant star, for example) not as a point, or as a gaussian, but as a point spread function with a visible Airy disk.
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ampguy
Veteran
nope
nope
4/3 diagonal is 21.6mm, Nikon/Pentax/Sony APS is 28.4mm, 35mm FF is 43.3mm.
4/3 will in theory, and in practice become diffraction limited before a larger sized sensor of the same technology and relative pixel pitch size and spacing.
nope
4/3 diagonal is 21.6mm, Nikon/Pentax/Sony APS is 28.4mm, 35mm FF is 43.3mm.
4/3 will in theory, and in practice become diffraction limited before a larger sized sensor of the same technology and relative pixel pitch size and spacing.
ampguy
Veteran
summary please?
summary please?
Would you mind giving a couple sentence summary of the youtube content?
The last 2 youtube links you posted were about the video quality of a hacked Panasonic GH1, which is interesting for video folks, but was unrelated to the thread topic.
summary please?
Would you mind giving a couple sentence summary of the youtube content?
The last 2 youtube links you posted were about the video quality of a hacked Panasonic GH1, which is interesting for video folks, but was unrelated to the thread topic.
ampguy
Veteran
Hi Doug
Hi Doug
It looks like a smearing, but also has a characteristic of reduced resolution and contrast, but different than high iso noise characteristics.
Take a look at this demo that shows diffraction limitation from f8 to f22 or so:
http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
scroll down to "what it looks like"
Hi Doug
It looks like a smearing, but also has a characteristic of reduced resolution and contrast, but different than high iso noise characteristics.
Take a look at this demo that shows diffraction limitation from f8 to f22 or so:
http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
scroll down to "what it looks like"
semilog
curmudgeonly optimist
We've now established that (1) you can do arithmetic; and (2) you get the same answers as me and everyone else who can also do arithmetic. Congratulations.
Here is the question that you are avoiding: how do you get from there to being "able to see diffraction" in micro 4/3 pictures at web resolution (I'll be generous: 800 pixels wide), without (you claim) pixel peeping?
(Sneak preview: you don't.)
Here's the problem that you face: At f/22, with a 10 mpix 4/3 sensor, the Olympus Zuiko 50 mm macro delivers a measured resolution (MTF-50) corresponding to >740 line pairs/ph along the picture's short axis (and hence 1000 lp/ph along the long axis).
That's at f/22, as far as the lens stops down.
Here are the measurements.
In other words, no, you can't see diffraction in images from a 4/3 sensor at web resoution - unless by "web resolution" you mean images larger than 1500 x 2000 pixels, and images taken at f/22 or smaller.
At a more reasonable aperture, f/8, the same lens is Nyquist-limited (right out to the corners!) for the same 3648 x 2736 sensor.
So you can "see" the diffraction limitation of images (and separate this limitation from other sources of noise and contrast degradation) taken on 4/3 cameras on web-based images, exactly how?
I'm deeply skeptical.
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semilog
curmudgeonly optimist
One last point: I encourage anyone who still thinks that there's a huge difference between the resolution of 4/3 and APS-C systems under diffraction-limited conditions to check out this comparison: a tale of two macros. Set both lenses to f/22 and see what you get.
Seriously. Check it out.
By the way, these lenses are not cherry-picked. You'll get pretty much the same result with any two similar (or even dissimilar) lenses of decent quality.
Seriously. Check it out.
By the way, these lenses are not cherry-picked. You'll get pretty much the same result with any two similar (or even dissimilar) lenses of decent quality.
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semilog
curmudgeonly optimist
It's a nicely-illustrated short lecture on the classical experiments that demonstrated the particle-wave duality for electrons (and, in similar experiments, for photons and other elementary particles), with no math.
For a longer, but still non-mathematical treatment of this and related quantum weirdness, I can't suggest Richard Feynman's brilliant, thin book QED: the strange theory of light and matter too strongly. It's really wonderful.
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Sparrow
Veteran
Yep me too, an example would be good, I set up the worst combination I have, my 12mm and my daughters GF1, the camera was on auto and while I can see there are differences between f5.6 and f22 I'm unsure what I'm actually looking at
this was the set-up
these are the too shots one wide open at f5.6 and the other at f22
[URL="http://www.flickr.com/photos/19217760@N05/4940859321/sizes/l/in/photostream/"]
[/URL]
The above image is like finding the "missing objects between these two drawings".
The focus scale on the J-8 is missing! The white lettering has disappeared when compared with the second image. The grain on the table is missing.
Was the lighting held constant?
A guy that worked in my building during the 80s won the Nobel prize for work in diffraction and X-Ray Crystallography. He recently retired.
The focus scale on the J-8 is missing! The white lettering has disappeared when compared with the second image. The grain on the table is missing.
Was the lighting held constant?
A guy that worked in my building during the 80s won the Nobel prize for work in diffraction and X-Ray Crystallography. He recently retired.
surfer dude
Well-known
Well, I can never understand the hate that non-users of 4/3 cameras have for the format. If I listened to you ampguy I'd just trash the 1000s of photos I took with my E3 and E1 because obviously they're rubbish (technically at least). And to say that you can TELL the inferiority of the format just by looking at a web post just indicates the inane sort of garbage that gets spoken.
Sparrow
Veteran
Well you know my skill with digi-cams, it was on auto it did one at f22 1/30 and 400 asa, the other f5.6 1/40 at 100 asa, for whatever reason
The lighting was the same on both
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