It has been a hot summer here in Montana with 3 fires on the Rez so far this year (1 human caused, 1 lightening and 1 from an electric fence - supposedly an electrocuted snake ignited the fire!!). it has been difficult not to just wish it away with thoughts on the cooler, more colorful autumn.
Here is an image from "home" taken in mid-October a couple of years ago with the 50 Apo-L. There was a slight breeze on the water and I had forgot to bring any filters. So, I stopped down to f16 for a 1.3 sec exposure (Sony A7RIII, ISO 100). I recently re-worked this photo and notice a definite softness to it in the detail that I am guessing is due to diffraction. I don't think you will see it on this compressed, reduced image, but it is there. Dynamite sharpness at f5.6 and f8, not so much at f16.
graytrekker wrote:
It has been a hot summer here in Montana with 3 fires on the Rez so far this year (1 human caused, 1 lightening and 1 from an electric fence - supposedly an electrocuted snake ignited the fire!!). it has been difficult not to just wish it away with thoughts on the cooler, more colorful autumn.
Here is an image from "home" taken in mid-October a couple of years ago with the 50 Apo-L. There was a slight breeze on the water and I had forgot to bring any filters. So, I stopped down to f16 for a 1.3 sec exposure (Sony A7RIII, ISO 100). I recently re-worked this photo and notice a definite softness to it in the detail that I am guessing is due to diffraction. I don't think you will see it on this compressed, reduced image, but it is there. Dynamite sharpness at f5.6 and f8, not so much at f16.
Regarding diffraction at f/16, this is of course expected. If you use Lightroom, on the Detail Panel, bring the 'detail' slider all the way to 100. This will greatly mitigate the diffraction effect you see.
Fred Miranda wrote:
Hi Doug,
Beautiful lighting and composition.
Regarding diffraction at f/16, this is of course expected. If you use Lightroom, on the Detail Panel, bring the 'detail' slider all the way to 100. This will greatly mitigate the diffraction effect you see.
Thanks for the compliment and suggestion, Fred.
Is this what they call "Capture Sharpening"? After listening to Mark Metternich and others, I am a little reluctant to do that. What about the export sharpening? Looking to learn more about that stuff.
Of course the real solution is to avoid f16 - right?
graytrekker wrote:
Thanks for the compliment and suggestion, Fred.
Is this what they call "Capture Sharpening"? After listening to Mark Metternich and others, I am a little reluctant to do that. What about the export sharpening? Looking to learn more about that stuff.
Of course the real solution is to avoid f16 - right?
Cheers
Doug
I don't think the name is that important. Some call it deconvolution sharpening.
The trick for diffracted images is to move the LR's "Detail" slider to "100". Then lower the "Radius" below "1.0". I use from 0.6 to 0.8.
After that just play with the "Amount" slider until you start seeing all the fine detail back to your image. Basically you would be increasing the apparent detail. Try it on the image you posted and see what it does to it.
Yes, I would avoid f/16 or smaller apertures if possible. For this image, I would think that f/4 would give it the best results.
I'm on my third copy of this lens now — having sold my previous two. Hopefully this time I've learned my lesson and will keep it for the long haul. Such a great lens.
It also just got a lovely review from Alyn Wallace
graytrekker wrote:
As I mentioned, I did not have my filters so I stopped down to lengthen the exposure.
Normally, I rarely go above f8 if I can help it.
Would DXO DeepPrime work on these types of diffraction issues?
Yes, it's definitely a workaround when not carrying ND filters.
There is another one: You can take multiple exposures (like 32 or 64 images depending on the scene) and average them in Photoshop using a "Mean" stack. This will mimic the effect of NDs but also provides the advantage of much lower noise. Like that you can shoot at optimal apertures as well.
I have never tried DeepPrime on diffracted raws. It's a worth a try but the strength of this app is noise reduction.
I often shoot in the f/11-f/16 range. While DxO PureRAW has sharpening that might take into account f stop, I turn sharpening off in PureRAW and do some basic sharpening (slider to 30) in LR. From Lightroom, I take my shots into Photoshop and sharpen in Topaz Sharpen AI. You could try that if Fred's suggestion doesn't get it to where you want it to be.
There is a difference between the 'traditional' sharpening, i.e. unsharp mask, and the more advanced, modern, deconvolution sharpening that's now available. That said, deconvolution sharpening has been around for many decades in the astronomy field, where it was called 'Lucy-Richards Adaptive Restoration', after its creators; it was an early form of iterative software interpolation, used to sharpen those fuzzy images of distant stars and galaxies.
Unsharp mask still works fine on images that aren't diffraction limited, but diffracted ones have lost the higher frequency information, which makes it difficult for unsharp mask to do a good job, so best stick to the deconvolution ones, rather than just cranking up the unsharp mask slider on those f11 or f16 images.
graytrekker wrote:
Thanks for the compliment and suggestion, Fred.
Is this what they call "Capture Sharpening"? After listening to Mark Metternich and others, I am a little reluctant to do that. What about the export sharpening? Looking to learn more about that stuff.
Of course the real solution is to avoid f16 - right?
Cheers
Doug
If conditions don't allow a focus stack, then you may need to use f16 for very deep depth-of-field scenes.
The best way to think about it, Doug, is that when you stop down beyond about f8, although diffraction becomes an issue, the net sharpness of your foreground and background may increase - due to increased depth-of-field overriding the diffraction losses, and if that's more important to your overall composition than some loss of sharpness at/or near the focal plane, then it can be a good move. Of course you do reach a point where it becomes a net loss everywhere - and that will depend on your cameras pixel pitch and/or how big you intend to print/display etc
Agree with Petegh here. If avoiding f/16 doesn't give you the depth of field required for the vision you're trying to share, then it's worse than shooting at f/16 and dealing with diffraction. No one is going to look at your photos and say "I wonder if he stopped down and there's diffraction", but they will notice a blurry bright red leaf on a rock in the foreground in a beautiful autumn waterfall shot. (Well okay...maybe they won't...but I think there is a bigger chance they will.)
You can shoot at f/16 and still have "sharp" images.
itai195 wrote:
I'm on my third copy of this lens now — having sold my previous two. Hopefully this time I've learned my lesson and will keep it for the long haul. Such a great lens.
It also just got a lovely review from Alyn Wallace
Yes - nice review - thanks. I love this lens, too, although I have not used it for night photography (yet). I also love its twin - the 35 Apo.
Petegh wrote:
If conditions don't allow a focus stack, then you may need to use f16 for very deep depth-of-field scenes.
The best way to think about it, Doug, is that when you stop down beyond about f8, although diffraction becomes an issue, the net sharpness of your foreground and background may increase - due to increased depth-of-field overriding the diffraction losses, and if that's more important to your overall composition than some loss of sharpness at/or near the focal plane, then it can be a good move. Of course you do reach a point where it becomes a net loss everywhere - and that will depend on your cameras pixel pitch and/or how big you intend to print/display etc...Show more →
Usually when I need a lot of DOF, I capture two images: One at the lens optimum aperture (Usually f/5.6 or f/8) and another at f/16, f/18 or f/22 depending on how close foreground elements are. Then I blend them in post getting the best of the two.
Usually, I use the smaller aperture capture for the foreground elements, sky and water and the rest of the image remains at the sweet aperture spot. I find this technique faster than focus stacking while providing more natural results.
I call it aperture stack and it is just an alternative to using focus stack. It's fast and easy in the field too! Just focus on your primary subject at the optimal aperture and then just change the aperture (not focus) to a small opening like f/18 for example. In post, combine them using Zerene or Photoshop.
Petegh wrote:
There is a difference between the 'traditional' sharpening, i.e. unsharp mask, and the more advanced, modern, deconvolution sharpening that's now available. That said, deconvolution sharpening has been around for many decades in the astronomy field, where it was called 'Lucy-Richards Adaptive Restoration', after its creators; it was an early form of iterative software interpolation, used to sharpen those fuzzy images of distant stars and galaxies.
Unsharp mask still works fine on images that aren't diffraction limited, but diffracted ones have lost the higher frequency information, which makes it difficult for unsharp mask to do a good job, so best stick to the deconvolution ones, rather than just cranking up the unsharp mask slider on those f11 or f16 images....Show more →
The error in the image caused by diffraction is well understood mathematically. So a deconvolution to mathematically reverse the error makes sense. One of the issues is the image taken will have photon shot noise present that can cause artifacts with the deconvolution. If a good lens starts to get a reduction in sharpness around f/5.6 on a a7Riv that means diffraction is also present at wider aperture, just not the limiting factor in sharpness. Overall to me it seems like more good than harm. I typically run deconvolution for all images f/4 or higher.
