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Replies: 18 / Views: 4,908 |
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Pillar of the Community
 United States
4038 Posts |
You can't actually correct diffraction, it is a limitation of physics. But diffraction affects the image differently from other unsharpening mechanisms, and I suppose they have figured out an algorithm that improves the sharpness of an image that is primarily affected by diffraction vs other mechanisms. There won't be more information in the image but perhaps it will look better/sharper.
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Pillar of the Community
 2087 Posts |
Quote: I wonder how much better the resolution is with this software? As most of you know: Phase one is a medium format Camera company and the Capture software is their flag ship raw editing program. They are the people who produce the 100mp back IQ-1. The capture application is described as intuitive, but I haven't found it so. Despite that, with my basic experience, I love the results it produces in the 9 version. However I have nothing to compare to ( I haven't used LR). As for how sharp it is in the new version I also would love to know. Quote: You can't actually correct diffraction, it is a limitation of physics. May be its a matter of semantics, perhaps compensation might be a better word. As a limitation of physics I would have thought its effect on images would be predictable, and with the correct algorithms the effects of diffraction could be "reversed" ( note the inverted commas). I know that since 2014, possibly earlier, some brands of Micro four thirds cameras have built in diffraction compensation software. With the pixel packing on those small MFT sensors, diffraction is an issue in normal photography ( let alone macro) All I would like to know is how well it works.... which is just repeating the question how sharp can it make the pictures? Edit: I should note for anyone unfamiliar with this phase one software it works best on a 64 bit system( I don't think it works on 32 bit OS )
Edited by austrokiwi 12/14/2016 3:41 pm
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Pillar of the Community
 United States
4038 Posts |
Quote: May be its a matter of semantics, perhaps compensation might be a better word. As a limitation of physics I would have thought its effect on images would be predictable, and with the correct algorithms the effects of diffraction could be "reversed" ( note the inverted commas). No, can't be reversed. Diffraction causes permanent loss of information by spreading data from one pixel around to the adjacent pixels. Some compensation can be performed to improve the appearance of a diffraction-softened image using sharpening algorithms, but the data loss is permanent.
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Pillar of the Community
 2087 Posts |
Quote: No, can't be reversed. rmpsrmps you are absolutely exacerbating READ what I wrote... What in the world do you think the inverted commas are for?... I even pointed out I used inverted commas: it was not a quote but rather an indication of a very loosely used word... Stop being so pedantic and read the meaning AND STOP looking for fault. Even if my punctuation was unusual( for you) the very context of what I wrote makes it clear I was being loose with the term...IT looks like you just want to pick another fight, particularly so, as your past behavior was the reason I made sure I used the inverted comas on this occasion. You are truely an "expert" It was a huge mistake asking this question here! It won't be made again. Edit: Just to make it clear I was using the inverted commas as scare quote marks. Meaning I was using them to distance myself from an inaccurately used word. Formal definition: Quote: noun plural noun: scare quotes; plural noun: scarequotes
quotation marks placed round a word or phrase to draw attention to an unusual or arguably inaccurate use.
Edited by austrokiwi 12/15/2016 12:51 am
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Pillar of the Community
 United States
4038 Posts |
Sheesh, it always ends up being a personal battle with you. Why can't you just stick with the facts? I don't want to pick fights at all AK, just want to stick with the facts.
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Pillar of the Community
Canada
2784 Posts |
diffraction is that caused by the lens or is that a result of the sensor. possibly is this a combination of both. this is new to me. but I would like to understand it.
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Pillar of the Community
Canada
2784 Posts |
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Pillar of the Community
Canada
2784 Posts |
here is a statement by Cambridge . Diffraction-Limited Imaging
If an image is made through a small aperture, there is a point at which the resolution of the image is limited by the aperture diffraction. As a matter of general practice in photographic optics, the use of a smaller aperture (larger f-number) will give greater depth of field and a generally sharper image. But if the aperture is made too small, the effects of the diffraction will be large enough to begin to reduce that sharpness, and you have reached the point of diffraction-limited imaging.
If you are imaging two points of light, then the smallest separation at which you could discern that there are two could reasonably be used as the limit of resolution of the imaging process. Presuming that diffraction is the determining factor, then the generally accepted criterion for the minimum resolvable detail is the Rayleigh criterion.
This shows the intensity curves for the radial distribution of the diffracted light for different separations. Your eye sees the characteristic bullseye distribution of light as illustrated below.
While perfect imaging of the source would be smaller perfect circles of light, this shows the smearing of the light by diffraction into the bullseye patterns.
For modern digital photography where the images are projected onto a CCD, the information is collected on pixels of the digital detector. At left is an attempt to show the effect of diffraction on such imaging in cases where the diffraction is the phenomenon that limits the resolution. If the image is in focus and free of visible affects of lens aberrations, then it may be that it will fit on one pixel. But if the aperture is small enough, then diffraction can spread the image onto neighboring pixels and constitute the limit on the resolution of the image.
References:
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Pillar of the Community
Canada
2784 Posts |
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Valued Member
United States
441 Posts |
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Pillar of the Community
Canada
2784 Posts |
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New Member
United States
43 Posts |
I know that this is an old thread, but one other thing to consider when dealing with diffraction limitation would be the anti-aliasing filter used in almost all digital cameras. Since the effect of diffraction is a slight spreading of the light, then compounding it with an anti-aliasing filter would seem to intensify and effectively increase the diffraction limitation of the aperture. So say a lens and camera body who's aperture setting at which the diffraction limitation is approximately f16, could it be closer to f22 if the anti-aliasing filter is removed? I know the effect of the anti-aliasing filter is minimal and is designed to help prevent moire in very high detail subjects as well as prevent stair stepping when a straight edge is at an angle. But the effects of diffraction are fairly small as well.
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Pillar of the Community
 United States
4038 Posts |
The AA filter has the effect of about a stop of diffraction, but the effect goes opposite or your conjecture. If the non-AA DLA is f11, then the effective DLA with AA would be f16.
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New Member
United States
43 Posts |
Hmmm.. Thanks for the info Ray, it sure seems counterintuitive. Is it because the AA filter masks the effects of the DLA?
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Pillar of the Community
 United States
4038 Posts |
The AA filter spreads information across multiple pixels, so that it takes more diffraction from the system before it becomes diffraction limited.
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