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03-20-2016, 11:00 AM   #1
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K-1 and diffraction

I understand that a full frame sensor will result in less DoF than I'm used to with my various APS-C bodies. So, I imagine for landscapes I might have to shoot at f/11 rather than f/8. In some cases, I might even need to go to f/16. So, does the full frame sensor change anything when it comes to lens diffraction? Usually, in most cases I would not use f/16 for fear of diffraction making the photo less sharp, so this is a little bit of a concern. Thanks for any input!

03-20-2016, 11:05 AM - 2 Likes   #2
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@ 36mp if you print at anything less than 16"x24" you will never see diffraction @ f/16 or even f/22. If you plan on printing bigger than that then "maybe" you will see it -- or maybe not. It would depend on the subject matter in my experience. Or put another way: don't worry too much about that dreaded diffraction -- this is a discussion that keeps the pixel peepers up all day and all night forever obsessing about it. Yawn.

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03-20-2016, 11:05 AM - 1 Like   #3
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You will have roughly the same diffraction as you did with the K-5 but with many more pixels and each pixel being a smaller part of the overall image you should not notice it as much at the same size printout. Translation - you can probably get away with more than you could even though at the pixel level you would see some blurring. If you have the K-3 now then you will see a direct improvement in diffraction performance on top of the increase in pixels. All of this assumes you have the right lens to frame this similarly to what you are used to getting.
03-20-2016, 11:07 AM - 1 Like   #4
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Diffraction is only visible, when the effect is larger than the sensor pixels. The pixels of the 36 MP sensor are larger as the pixels of the K-3, so diffraction is a smaller problem, you can use a smaller aperture.

03-20-2016, 11:22 AM - 1 Like   #5
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QuoteOriginally posted by Austro-Diesel Quote
Diffraction is only visible, when the effect is larger than the sensor pixels. The pixels of the 36 MP sensor are larger as the pixels of the K-3, so diffraction is a smaller problem, you can use a smaller aperture.
QuoteOriginally posted by UncleVanya Quote
You will have roughly the same diffraction as you did with the K-5
Good answers already. Bottom line is f8 should be perfect, but f14 should still be acceptable. If you are shooting web size photos or making small prints, you can go to f16, and just add some more digital sharpening. Though, I generally avoid going above f11 on 16MP APSC (with no AA). It comes down to a compromise and your personal needs
03-20-2016, 11:35 AM   #6
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The output size is the other limiting factor whether the diffraction is visible or not. My statement is a good rule for pixel peepers in 1:1 view.

The smaller you print the picture the more you can use smaller apertures without harm.
03-20-2016, 11:41 AM - 1 Like   #7
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QuoteOriginally posted by loco Quote
I understand that a full frame sensor will result in less DoF than I'm used to with my various APS-C bodies. So, I imagine for landscapes I might have to shoot at f/11 rather than f/8. In some cases, I might even need to go to f/16. So, does the full frame sensor change anything when it comes to lens diffraction?
Diffraction in equivalent aperture / DoF settings is simply the same*.

*=assumed: same viewing distance.If you want to "make use of additional megapixelcounts", meaning you watch images from more closely or print them larger - which is the same - then this additional enlargement also makes any unsharpness from diffraction more visible.
03-20-2016, 12:23 PM   #8
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Thanks very much for the replies and good information! It sounds like there should be a small improvement, but larger printing will still reveal a bit of blurring at apertures of f/16 and smaller. I don't often print large myself, but I do occasionally sell prints at larger sizes, so this is very helpful.

03-20-2016, 04:00 PM   #9
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It might just be me but I find it very hard to see a diffraction problem even at f/16 or f/22. The only times I've really seen bad diffraction issues is when using f/16 on a 5:1 macro shoot, so the effective aperture is actually f/96. Then it's easily visible. YMMV
03-20-2016, 04:20 PM   #10
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Don't forget that the K-1 and K-3II both have diffraction correction settings, just like they have marginal luminance compensation.
03-20-2016, 06:21 PM - 1 Like   #11
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QuoteOriginally posted by Austro-Diesel Quote
Diffraction is only visible, when the effect is larger than the sensor pixels. The pixels of the 36 MP sensor are larger as the pixels of the K-3, so diffraction is a smaller problem, you can use a smaller aperture.
The the full frame lenses should have a larger physical aperture than APS-C DA lenses, so you should see diffraction later at a higher f-stop. Compound that with larger pixels and you should be able to go higher.

People knock dxomark, but I like using their tool to see the sharpness at different apertures. You can typically see when diffraction affects the lens/sensor combo.
03-20-2016, 10:16 PM   #12
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QuoteOriginally posted by ppppsssstttt Quote
The the full frame lenses should have a larger physical aperture than APS-C DA lenses, so you should see diffraction later at a higher f-stop. Compound that with larger pixels and you should be able to go higher.
Since the f stop is a ratio of focal length and doesn't include image circle I assume you are comparing the equivalent field of view which will use a longer focal length lens for the same basic shot from the same location. Even so it was my understanding that f stop impact on diffraction only cared about the pixel size and f ratio, not the absolute aperture measurement.
03-21-2016, 01:40 AM   #13
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QuoteOriginally posted by UncleVanya Quote
diffraction only cared about the pixel size
Pixel size for "usual" approaches is completely irrelevant, unless your approach is to look at the pixel level (which is completely valid, but a very different one).
If that is the case though, you'd need to only consider this with regards to diffraction, but with regards to all effects.
For a starter for dummies you'd also have to only look at the "screen" tab on DxOmark for any results for example.
Which then will quickly lead you to understand that you gain absolutely nothing from a FF sensor.
03-21-2016, 10:16 AM - 6 Likes   #14
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I frequently shoot at diffraction-limited apertures in order to get the depth of field I desire in landscape compositions - f/22 on the 645Z, f/16 on fullframe, f/11 on APS-C. I also print big, 40" x 30" being my standard size and a recent print order was 54", so I need to combat diffraction. The solution for me is to use a deconvolution sharpening algorithm in the capture sharpening stage when I'm developing the raw file.

Irident Raw Developer has that function, and perhaps there are other raw converters that do too now. The most popular software that has this capability is Lightroom, but you must activate it: in the sharpening panel within the Develop module, sliding Detail all the way to the right turns the algorithm into essentially 100% deconvolution, according to Jeff Schewe who helped create LR's sharpening section. I typically start with Amount 45, Radius between 0.8 and 1.0 (a higher radius for softer images), Detail at 100 as noted, and vary the Mask per image to avoid too much noise in blue skies and other areas of smooth tone.

Deconvolution works wonders for me in capture sharpening - it brings much of the detail back that was dulled from diffraction, and it gives a natural look to the file similar to looking at drum scans from my 4x5 film. It's much better to my eye than traditional unsharp masking at this stage of processing.

Cheers,
Ross
03-21-2016, 10:27 AM   #15
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QuoteOriginally posted by SeattleDucks Quote
I frequently shoot at diffraction-limited apertures in order to get the depth of field I desire in landscape compositions - f/22 on the 645Z, f/16 on fullframe, f/11 on APS-C. I also print big, 40" x 30" being my standard size and a recent print order was 54", so I need to combat diffraction. The solution for me is to use a deconvolution sharpening algorithm in the capture sharpening stage when I'm developing the raw file.

Irident Raw Developer has that function, and perhaps there are other raw converters that do too now. The most popular software that has this capability is Lightroom, but you must activate it: in the sharpening panel within the Develop module, sliding Detail all the way to the right turns the algorithm into essentially 100% deconvolution, according to Jeff Schewe who helped create LR's sharpening section. I typically start with Amount 45, Radius between 0.8 and 1.0 (a higher radius for softer images), Detail at 100 as noted, and vary the Mask per image to avoid too much noise in blue skies and other areas of smooth tone.

Deconvolution works wonders for me in capture sharpening - it brings much of the detail back that was dulled from diffraction, and it gives a natural look to the file similar to looking at drum scans from my 4x5 film. It's much better to my eye than traditional unsharp masking at this stage of processing.

Cheers,
Ross
Thank you very much for this. I had not heard of deconvolution and will have to experiment with this approach in Lightroom. I really appreciate you sharing this!
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