Bryan Peterson vs. Diffraction
rehess
Loc: South Bend, Indiana, USA
burkphoto wrote:
My old 1960s to 1980s Nikkors are not nearly as sharp on my camera as my native Lumix lenses... But they do have those markings.
I'm using film-era lenses on a film camera, I believe digital users over-rank 'sharpness'.
rehess wrote:
I'm using film-era lenses on a film camera, I believe digital users over-rank 'sharpness'.
I vastly prefer sharp images to the work I shot with my Nikons in the '70s. I recently revisited thousands of old slides and negatives and digitized them. Even with software enhancement, they are not as sharp as digital files. They're sharper than the prints I made 50 years ago with an EL-Nikkor enlarger lens, but not up to modern standards.
TriX
Loc: Raleigh, NC
flyboy61 wrote:
GOOD info! He has made that assertion in at least two of his books, and nobody yet has had the "facts" to gainsay his (documented) statements. But still, the everlasting wisdom of "common knowledge" keeps the discussion going on...and on...
Seems to me people should enjoy this magical pastime or career, and not get too worked up about the trivia!
img src="https://static.uglyhedgehog.com/images/s... (
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You’ll find the actual “facts” on page 1. Now whether you choose to accept them or act on them is up to you.
burkphoto wrote:
It depends on the context... my favorite answer for all of photography and life.
The smaller the sensor, the worse the diffraction at wider apertures.
If you are looking for it and comparing images of the same subject taken at the same time at different apertures:
Based on 20 to 25 MP sensors, diffraction annoyance starts:
> Around f/8 on Micro 4/3.
> Around f/11 on APS-C.
> Around f/16 on full frame.
> Around f/22 on medium format digital.
Higher megapixel count sensors may show diffraction at wider apertures.
Degree of enlargement matters.
Whether you're a pixel peeper, or not, matters.
Lens cleanliness matters.
Lens coatings matter.
Subject contrast and brilliance matter.
Lens corrections and sharpness matter.
Your experience may vary from mine, so it is recommended that each of us make our own tests to determine a "diffraction limiting aperture." I avoid using smaller apertures than those listed above, when I can.
I'll add that MEASURABLE diffraction occurs at wider apertures than those I listed, as evidenced by Tri-X' graphs, below. That's one reason I say, make your own tests to determine what you'll accept in your circumstances. I came up with my "rule of thumb" answer by doing that over the years.
It depends on the context... my favorite answer fo... (
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We've discussed this before.
Some of those older photogs used bigger fil. 4x5, 8x10 INCH.
An f22 could be 1/4" inch. Diffraction occurs at the edges, but it's too small here.
Get out that micro 4/3 puppy, and f22 isn't much more than a pin prick. diffraction is all.
Look at lens design. Some are kinda pointy at the edges. Old RU lenses had a "sweet" spot.
The better ones were blunted and the edges coated black. Nothing but sweet spot.
Like this guy said, there's more than one issue here.
MY "fix" for me is by using my better FX lenses on my Nikon DXs.
The diffraction area is cropped off by the sensor- just the sweet spot is used.
.
And yes my old 70-210 pumper from the 1990s was a fabulous lens. In the 1990s.
Tried it recently against the "kit" 50-200- yucko? My 400 film sorta disguised the funky IQ.
It's actually pretty good in the middle of the range. Distorts at the ends.
The 55-200 is a lil goody. MAYbe a litttle weird at 200, but still good 'til 190.
TriX
Loc: Raleigh, NC
Harry02 wrote:
We've discussed this before.
Some of those older photogs used bigger fil. 4x5, 8x10 INCH.
An f22 could be 1/4" inch. Diffraction occurs at the edges, but it's too small here.
Get out that micro 4/3 puppy, and f22 isn't much more than a pin prick. diffraction is all.
Look at lens design. Some are kinda pointy at the edges. Old RU lenses had a "sweet" spot.
The better ones were blunted and the edges coated black. Nothing but sweet spot.
Like this guy said, there's more than one issue here.
MY "fix" for me is by using my better FX lenses on my Nikon DXs.
The diffraction area is cropped off by the sensor- just the sweet spot is used.
.
And yes my old 70-210 pumper from the 1990s was a fabulous lens. In the 1990s.
Tried it recently against the "kit" 50-200- yucko? My 400 film sorta disguised the funky IQ.
It's actually pretty good in the middle of the range. Distorts at the ends.
The 55-200 is a lil goody. MAYbe a litttle weird at 200, but still good 'til 190.
We've discussed this before. br Some of those olde... (
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You’re possibly confusing diffraction with vignetting or other forms of softness at the edges - diffraction affects the entire image, not just the corners or edges
TriX wrote:
You’re possibly confusing diffraction with vignetting or other forms of softness at the edges - diffraction affects the entire image, not just the corners or edges
Indeed but diffraction is dependant on the actual physic size of the opening rather than the f-stop.
Larger format cameras have longer focal lengths for a given Field of View, so have larger physical openings for the same f-stop.
Assuming a normal lens is used on each format:
f/22 on 5x4 would have a 6.8mm (150/22) opening
f/22 on FF would be a 2.27mm (50/22) opening
f/22 on MFT would be a 1.14mm (25/22) opening
f/22 on the Pentax Q (5.64x crop) works out at ~0.4mm
Diffraction gets progressively more significant on each of these. Even at f/1.4 the Q sees more diffraction than the large format camera at f/22. A shame as the Q is much easier to carry around :)
Gee, you are qualified to be a University President!
rehess
Loc: South Bend, Indiana, USA
burkphoto wrote:
I vastly prefer sharp images to the work I shot with my Nikons in the '70s. I recently revisited thousands of old slides and negatives and digitized them. Even with software enhancement, they are not as sharp as digital files. They're sharper than the prints I made 50 years ago with an EL-Nikkor enlarger lens, but not up to modern standards.
In the Age of Film, standards were different. Now we’ve become used to the “clean-ness” digital delivers; I’m just not certain it is a real improvement.
TriX
Loc: Raleigh, NC
petrochemist wrote:
Indeed but diffraction is dependant on the actual physic size of the opening rather than the f-stop.
Larger format cameras have longer focal lengths for a given Field of View, so have larger physical openings for the same f-stop.
Assuming a normal lens is used on each format:
f/22 on 5x4 would have a 6.8mm (150/22) opening
f/22 on FF would be a 2.27mm (50/22) opening
f/22 on MFT would be a 1.14mm (25/22) opening
f/22 on the Pentax Q (5.64x crop) works out at ~0.4mm
Diffraction gets progressively more significant on each of these. Even at f/1.4 the Q sees more diffraction than the large format camera at f/22. A shame as the Q is much easier to carry around :)
Indeed but diffraction is dependant on the actual ... (
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Exactly correct which is why diffraction becomes more important as you decrease format size. My point was that using a FF lens on an APS-C body may help with corner/edge softness, but the diffraction affects the entire image.
rehess wrote:
In the Age of Film, standards were different. Now we’ve become used to the “clean-ness” digital delivers; I’m just not certain it is a real improvement.
I believe in approximating reality as best I can. I can always degrade it in post processing if needed...
TriX wrote:
Exactly correct which is why diffraction becomes more important as you decrease format size. My point was that using a FF lens on an APS-C body may help with corner/edge softness, but the diffraction affects the entire image.
Yep. Cutting the center out of the projected image cone makes a more consistently less sharp image, edge to edge. You miss the aberrations in the corners, but magnify all other flaws by the crop factor. Depending on cropping and degree of print enlargement, this may or may not be a problem.
Full frame film lenses on Micro 4/3 were a problem for me. They were soft.
Photographer 1 - I buy the best lenses and never use a filter because I can't tolerate a possible 0.3% impact on the sharpness of my images.
Photographer 2 - Do you purposefully shoot at small apertures?
P1 - Yes, of course, I want the sharpest results from my premium equipment.
P2 - Do you know anything about diffraction?
P1 - Bryan Peterson says it's not important.
P2 - So, you lower your expectations to match your results.
P1 - That's right.
P2 - That's right ....
TriX wrote:
You’re possibly confusing diffraction with vignetting or other forms of softness at the edges - diffraction affects the entire image, not just the corners or edges
Nope.
For some lenses and shots, the vignetting was a plus. focusing the focus to the center.
I used to shoot some old Russian stuff- and the softness at the edges were they're own vietting.
What I'm thinking the diffraction was the fringing, purple on one side and green on the other.
At certain sun angles, and at small apertures.
Are the fringing and diffraction different?
I've been calling them the same (cause and effect ) for over a half century!
Harry02 wrote:
Nope.
For some lenses and shots, the vignetting was a plus. focusing the focus to the center.
I used to shoot some old Russian stuff- and the softness at the edges were they're own vietting.
What I'm thinking the diffraction was the fringing, purple on one side and green on the other.
At certain sun angles, and at small apertures.
Are the fringing and diffraction different?
I've been calling them the same (cause and effect ) for over a half century!
I call 'up' as 'down'. And 'left' as 'right'. Alas, most no one accepts my statements as valid nor useful, now after 57-years ... My best is when I talk about how many gallons it takes to walk from the street to get a meter of milk.
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