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by Robert on Wed Apr 26, 2017 2:30 pm
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This has probably been discussed before, but a quick search yielded nothing. How do you compensate for diffraction when a shot calls for using f16 or f22, or higher? The vast majority of times I shoot at no higher than f11, but recently wanted to get a sun star effect over trillium fields and used f22 for that. Of course the f22 shots are not as sharp as f16 or f11, but yielded the best sun star effect.
I shoot with a D610 FX body.

I use LR 5.8 and have tried increasing the "detail" setting to about 50 in the sharpening process and that seems to help.

Appreciate any thoughts and suggestions.
Thanks
 

by DavidSutton on Wed Apr 26, 2017 4:33 pm
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Depending on the sensor and the output, a deconvolution sharpener should get you reasonable results at f22. For large prints I found Topaz Detail works well, but there are plenty of others. At f16 it works brilliantly and at f32 the results were still mush.
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by Mike in O on Wed Apr 26, 2017 4:56 pm
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A number of converters including DXO have algorithms for minimizing the effects of diffraction.
 

by signgrap on Wed Apr 26, 2017 6:13 pm
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Capture One Pro 10 has very good diffraction compensation that is designed for each lens. I see a noticeable improvement in image sharpness when it is clicked on.
Dick Ludwig
 

by Robert on Wed Apr 26, 2017 6:15 pm
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DavidSutton wrote:Depending on the sensor and the output, a deconvolution sharpener should get you reasonable results at f22. For large prints I found Topaz Detail works well, but there are plenty of others. At f16 it works brilliantly and at f32 the results were still mush.
David
Thanks David. I have read where LR detail tool in sharpening becomes a deconvolution sharpener when turned up, which is what I tried. But I'm not sure if that's the case or if it's a good enough tool for it. I am also wondering about Affinity Photo, since I may wind up buying that for some of it's other useful tools that LR 5.8 lacks.
 

by E.J. Peiker on Thu Apr 27, 2017 7:58 am
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As stated, one needs a deconvolution sharpener.  No Adobe product currently has this.  The basic principle is that if you know the focal length and you know the aperture, you can predict how much the light will bend due to diffraction when passing through the aperture blade and a computer algorithm can then compensate for this.  As an example if you photograph a single point of light that would normally take up just one pixel with no diffraction, but you shoot it at f/22 it could spill into all of the adjacent pixels for a total of 9 pixels including the one pixel that should have the light.  A deconvolution sharpener can remove that from the 8 surrounding pixels.  Good deconvolution sharpeners like the one built into Capture One Pro 10.3 can effectively extend you aperture range before diffraction can be seen by about 2 stops.
 

by Robert on Thu Apr 27, 2017 11:23 am
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Thanks for all the info, it's an area I haven't had to deal with before. I forgot that I had the Google Nik collection. I don't see documentation that it's Raw Presharpener Pro 3 uses a deconvolution sharpening, but I did try it and it does seem to do a better job with less noise than the LR sharpening tools. But I suspect a good deconvolution sharpening tool would do even better.

After further tests with Nik Presharpener Pro 3 vs LR, I've concluded that LR actually does a better job if I do some Noise Reduction after applying more detail in the sharpening tool. But again, this will probably pale in comparison to a good deconvolution sharpener.

Affinity Photo doesn't seem to have a deconvolution sharpener either. I wonder if there are "affordable" plugins for deconvolution sharpening, any suggestions?
Thanks again.
 

by E.J. Peiker on Thu Apr 27, 2017 4:51 pm
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Nik does not do a deconvolution sharpening.  To do it properly, it needs to be done prior to demosaicing (Raw processing).  I am currently only aware of this option in Capture One Pro.

Deconvolution sharpening is very different from capture sharpening.  Capture sharpening is a more traditional contrast based sharpening designed to undo the softening effect of a sensor anti-aliasing filter.
 

by Kim on Thu Apr 27, 2017 5:39 pm
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Why not try Focus Magic Software. It does have deconvolution sharpening.

http://www.focusmagic.com/

It is available as a plug in for Photoshop.
 

by E.J. Peiker on Thu Apr 27, 2017 7:12 pm
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Kim wrote:Why not try Focus Magic Software. It does have deconvolution sharpening.

http://www.focusmagic.com/

It is available as a plug in for Photoshop.
Cool, just read their site - still would prefer to do it before RAW conversion which this doesn't do but it looks like a good option.
 

by signgrap on Thu Apr 27, 2017 7:29 pm
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E.J. is there a problem leaving the diffraction box checked in C1 Pro 10 when the f stop is wider and diffraction isn't occurring? In other words can you leave the diffraction box checked all the time?










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by E.J. Peiker on Thu Apr 27, 2017 11:13 pm
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signgrap wrote:E.J. is there a problem leaving the diffraction box checked in C1 Pro 10 when the f stop is wider and diffraction isn't occurring? In other words can you leave the diffraction box checked all the time?
No, not really other than it does take extra processing time which is wasted time when it isn't needed.
 

by DavidSutton on Sat Apr 29, 2017 4:01 pm
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Hello Robert.
I'm getting forgetful in my old age. The product I used was Topaz InFocus and the results are on my blog at:
http://davidsutton.co.nz/2013/03/16/how ... -part-two/
David
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by Robert on Wed May 03, 2017 12:55 pm
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Ok, I just wanted to get back to this with a report on my attempts to use both deconvolution softwares mentioned, Focus Magic and Topaz InFocus. I downloaded trial versions of both. I was hoping for a "wow" experience at their magical abilities, but was underwhelmed.

First, you have to convert to a tiff file to use FocusMagic and Topaz InFocus, whereas LR does the editing on the raw file. All other file factors were kept the same, eg 16 bit, ProPhotoRGB color space. My conclusion is that LR did the best job of mitigating diffraction on the same images out of the choices of LR, FocusMagic and Topaz InFocus. I suspect this is due to the fact that LR is working on a raw file which has much more capacity of editing than does a tiff file. Not even a fair fight IMO, raw file editing vs tiff file editing. Also, there is some mention online of the LR "detail" slider using a mixture of deconvolution sharpener software when it is increased. This may or may not be true, I don't really know for a fact.

Briefly again, my editing steps in LR to compensate for the diffraction at f22 was to use a usual amount of sharpening except for the "detail" setting which I bumped up to around 50, then I would apply LR's noise reduction to taste - all while viewing at 100%.

Still, this has been an informative experience and I certainly learned more about compensating for diffraction in images, which is what makes this forum so good a resource for us all.
 

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