Luminous Landscape Forum
Equipment & Techniques => Mirrorless Cameras => Topic started by: FrankG on February 18, 2016, 06:53:55 pm
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Is it possible that at f16 (or even f11) diffraction could cause softening focus of the image with panasonic 20mm and 42.5mm and GX7 body ?
The body has some IS and the 42.5 has it's own.
I was hand holding at around 1/100 and need the dof for landscape.
It could be me being unsteady, but was wondering with the lenses stopped down, if diffraction could be the culprit?
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Hi,
This images should give you some idea, check left column:
http://echophoto.dnsalias.net/ekr/index.php/photoarticles/49-dof-in-digital-pictures?start=1
16 MP APS-C camera used.
Best regards
Erik
Is it possible that at f16 (or even f11) diffraction could cause softening focus of the image with panasonic 20mm and 42.5mm and GX7 body ?
The body has some IS and the 42.5 has it's own.
I was hand holding at around 1/100 and need the dof for landscape.
It could be me being unsteady, but was wondering with the lenses stopped down, if diffraction could be the culprit?
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Thanks for that. It demonstrates the effect which is real, but as per the remarks it's an overestimated issue.
So maybe it's a bit of diffraction and a bit of the hand holding (=unsteadyness @ too slow shutter speed), & also a not very effective IS system.
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in general, the equivalent depth of field ( and diffraction) for APSC is one stop larger than FF and for 43 2 stops. so f16 for micro 43 is roughly equivalent to f32 FF and diffraction becomes pretty serious. f11 is my limit for 43 and should provide enough depth of field for just about anything except macro. good 43 lenses are sharpest at f4 (f8 FF) usually without noticeable softening at f5.6.
for landscapes it's just about always important to manage the depth of field, and getting familiar with dof tables/calculator is a good idea. rule of thumb is to focus 1/3 of the way in to the scene to maximize dof
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Yes, I went overboard with the aperture (I didn't think about the FF equivalence), wanting near to far in focus (focused about 1/3 way). I should've used a tripod for sure.
Paid the price!
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Hi Frank,
Years ago in FF days I did a lot of shooting at f16 focusing 1/3 of the way, as suggested above. However, I often did not find that approach satisfying because the foreground was not really sharp, meaning that we expect things close to us to be in sharper focus than distant objects. Nowadays, I always try to make the foreground sharp, relying on the depth of field to give a "natural" blurring in the distance. If everything needs to be sharp everywhere I do focus stacking. On m43 I have found that f4.5 gives pleanty of DOF for most purposes.
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I get around this in landscapes by doing a few exposures. I can shoot at F/8 and do two different focus points and blend them in. Or if I find myself out doors without my filters and I need to push a long exposure for water to be "dreamy" (for example) I take two shots still. One shot at F/16 or 22, or whatever I need. Then I take a shot at F/8 for anything not moving. I paint in the dream flowy parts of the scene. This really only works with a tripod though. I find F/8 to be about as far as I go on M43. F/11 I will do, if I feel I need it. After that it is noticeable softening due to diffraction.
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Thanks.
I found out the hard way (I cant get back to redo those shots) just how very soft stopped down images are with m43.
I'm not going past f8 any more (unless on a tripod and experimenting with multiple exposures)
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Its not just m43. I do the same thing with full frame DSLRs. Instead of F8, on those I can go to F/11. F/16 is really pushing it on subjects with detail. On Medium format I can get to F/16. In reality though, that is giving me roughly the same level of DOF across all those platforms. I just had to stop down less on the M43 to get there. Some times that is a huge benefit! Sometimes its a huge drawback. Same with any system really. More often than not, in the way I use M43, i love getting extra DOF with a faster shutter speed.
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Interesting. Back in the day, 8x10 shooters would go to f64, 4x5 often at f45 or f32, medium format commonly at f22 and so on.
But I guess, as you said earlier, that is probably not far off M43 at f8
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One anomaly to this... the Fuji X100. I have always loved the idea of a fixed lens camera whose lens was optimized for the sensor and the sensor optimized for the lens. I can do F/11 just fine in the original X100. Also, on the S and T versions, they have apparently added a form of compensation for diffraction so F/16 is usable as well with no noticeable degradation in quality. Surprisingly...it's not that bad. For an APS-C sensor with usable F/16 with a built in 3-stop ND filter...the X100 is quite the sleeper landscape camera. I always have one as a backup with me.
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One anomaly to this... the Fuji X100. I have always loved the idea of a fixed lens camera whose lens was optimized for the sensor and the sensor optimized for the lens. I can do F/11 just fine in the original X100. Also, on the S and T versions, they have apparently added a form of compensation for diffraction so F/16 is usable as well with no noticeable degradation in quality. Surprisingly...it's not that bad. For an APS-C sensor with usable F/16 with a built in 3-stop ND filter...the X100 is quite the sleeper landscape camera. I always have one as a backup with me.
To overcome diffraction you would have to overcome the laws of physics. How did they manage that?
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Software magic it seems!
http://www.fujifilm.com/products/digital_cameras/x/fujifilm_x100s/features/page_02.html
And from one of their press releases:
"The camera uses Lens Modulation Optimizer to reduce optical effects such as lens diffraction, which occurs when light passes through a lens. Even when stopped down to F16, the X100S retains sharpness and texture in the smallest details, demonstrating the extent of the sensor and lens combination's capabilities, perfectly."
Nifty trick...no ridiculous artifacts either.
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I wonder if it's the same with the 35mm fixed lens FF Sony RX1R (I think that's the name of the model)
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Not sure about the sony. That would be great...but wow is it pricey. I have contemplated getting the X100T. The wifi and updated features are nice. I just don't get along well with the X-trans. At all other apertures but 11 and 16...the original is virtually indistinguishable quality wise. 4mp is not a big deal. I have many large (48" - 150" ) prints from the X100. Properly upresed with AS Blow Up, the detail the sensor and lens combination gets at F/11 is very surprising. It is also a leaf shutter. That may help too.
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Its not just m43. I do the same thing with full frame DSLRs. Instead of F8, on those I can go to F/11. F/16 is really pushing it on subjects with detail. On Medium format I can get to F/16. In reality though, that is giving me roughly the same level of DOF across all those platforms.
Yes, the DOF vs diffraction trade-offs are independent of format; you just get a given combination of OOF blurring and diffraction blurring (when viewing at the same size etc.) with a different aperture ratio: from f/64 in 10"x8" to f/32 on 5"x4" to f/8 in 35mm to f/4 in 4/3" to about f/1.2 on a phone. (And so the shutter speed goes up and/or the ISO speed goes down as the format gets smaller.) I have not pushed beyond f/11 in 4/3" format, just as I did not go beyond f/22 with 35mm film cameras, but some macros might benefit from f/16 plus suitable sharpening.
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As others I settled on f8 for my M4T Olympus EM5 sweeping landscape pictures with focusing in slightly less than a 1/3 into the picture. Tested on tripod throughout the aperture range and various focus ranges. I have the Olympus 12-50mm F3.5-6.3 (kit lens) and the Olympus 9-18mm f/4.0-5.6. Both lens produce disappointedly unsharp pictures throughout the frame. I am thinking about renting a prime lens to see if it the poor sharpness is just the M4T sensor or the cheaper lens.
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"Olympus 9-18mm f/4.0-5.6"
I have this lens and haven't noticed horrendous widespread unsharpness. When I get the chance I can post some crops.
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"The camera uses Lens Modulation Optimizer to reduce optical effects such as lens diffraction, which occurs when light passes through a lens. Even when stopped down to F16, the X100S retains sharpness and texture in the smallest details, demonstrating the extent of the sensor and lens combination's capabilities, perfectly."
Nifty trick...no ridiculous artifacts either.
A number of other Fujifilm cameras—including the X-E2, the X-T1 and the new X-Pro2—offer this "LMO" feature, but it only works (1) with Fuji lenses and (2) when you're shooting JPEGs. I haven't found a technical explanation of how it works (it's proprietary Fuji technology), but apparently it's another lens correction that is applied by the in-camera JPEG rendering firmware which Fuji claims only affects fine detail that may be diffraction-limited when you stop down; i.e., supposedly it doesn't modify any of the other parts of the image that are not affected by diffraction. I'm not aware of any Fuji documentation that explains whether the correction parameters are stored in the body firmware of interchangeable-lens cameras or the lens firmware—presumably the data must be customized for each lens—but this is clearly proprietary stuff. To make the technology available to external post-processing software, Fuji would need to emit the lens corrections as raw file metadata and reveal how to apply them, which would require sharing the algorithm used to tweak the diffraction-limited fine detail without clobbering anything else.
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As others I settled on f8 for my M4T Olympus EM5 sweeping landscape pictures with focusing in slightly less than a 1/3 into the picture. Tested on tripod throughout the aperture range and various focus ranges. I have the Olympus 12-50mm F3.5-6.3 (kit lens) and the Olympus 9-18mm f/4.0-5.6. Both lens produce disappointedly unsharp pictures throughout the frame. I am thinking about renting a prime lens to see if it the poor sharpness is just the M4T sensor or the cheaper lens.
My copy of the 12-50mm is very disappointing as you get to longer focal lengths. Honestly, I pretty much detest that lens. I usually run the Oly 25mm f1.8 and it is basically as sharp as anything else in the system, which means to say pretty good. I am very happy with it's results.
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Yes, the DOF vs diffraction trade-offs are independent of format; you just get a given combination of OOF blurring and diffraction blurring (when viewing at the same size etc.) with a different aperture ratio: from f/64 in 10"x8" to f/32 on 5"x4" to f/8 in 35mm to f/4 in 4/3" to about f/1.2 on a phone. (And so the shutter speed goes up and/or the ISO speed goes down as the format gets smaller.) I have not pushed beyond f/11 in 4/3" format, just as I did not go beyond f/22 with 35mm film cameras, but some macros might benefit from f/16 plus suitable sharpening.
Interesting, as Ming Thein has it that diffraction turns (primarily, at least) on pixel pitch (and what is THAT for film?!) --to wit : "diffraction limits vary with pixel pitch, not sensor size". So, 16mpx APS-C ~= 36mpx 135, 16mpx m4/3 worse. (Though I recall Ming's asserting that HE could detect diffraction in m4/3 16mpx at f/5.6, I see also him saying that at this same aperture the diffraction "starts to kick in" for the smaller yet higher-resolution 1" sensor'd RX100 --when I'd think one should expect then f/4.) (My eyes resolve more of these arguments than my brain.)
-d.
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Interesting, as Ming Thein has it that diffraction turns (primarily, at least) on pixel pitch (and what is THAT for film?!) --to wit : "diffraction limits vary with pixel pitch, not sensor size". So, 16mpx APS-C ~= 36mpx 135, 16mpx m4/3 worse. (Though I recall Ming's asserting that HE could detect diffraction in m4/3 16mpx at f/5.6, I see also him saying that at this same aperture the diffraction "starts to kick in" for the smaller yet higher-resolution 1" sensor'd RX100 --when I'd think one should expect then f/4.) (My eyes resolve more of these arguments than my brain.)
I would say that sensor size and pixel pitch both must be considered. A perfect lens will render a point of light (such as a star) as an Airy disc, whose diameter in microns is approximately equal to the reciprocal of the f/number. A binary star or other closely spaced points of light will be projected on the sensor or film as an Airy disc whose diameter is approximately equal to the reciprocal of the f/number. When the discs overlap to a significant degree (defined as the Rayeigh limit (https://en.wikipedia.org/wiki/Angular_resolution)) the stars can no longer be resolved. When the Airy disc exceeds about 1.4 to 2 times the pixel pitch, the sensor is diffraction limited. However, its resolution will be no worse than that of a less dense sensor. If you increase the size of the sensor or film, more non-overlapping Airy discs can be accommodated and lead to higher resolution in terms of line pairs per picture height.
Bill
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I was reading the book Understanding Exposure recently and the author Bryan Peterson uses f/22 on his 35mm camera all the time. His photos look very sharp and he seems to have sold many. Is this just an acceptable amount or would he compensate somehow with better lenses or bodies?
I have seen it (I think) at f/22 on APS-C but haven't really noticed on MF and I don't have anything 35mm besides film now.
Based on this it seems the problem could be overblown for many situations.
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Hi,
Diffraction is essentially a function of aperture. Pixel pitch has no effect on diffraction at all. Clearly, diffraction will be more noticable with a high resolving sensor than with a low resolving sensor. It will also be more noticeable with a good less than with a less good lens. That is because the more you have the more you loose.
If you have the same lens and shoot say f/11 instead of f/5.6 that may be the optimum aperture on a camera having say 16 or 36 MP the 36 MP camera will always held some advantage over the 16 MP camera.
The easiest way to see this is that each component of the lens/sensor system has an MTF and the MTF of the system is the product of the MTF of it's components.
A high resolution sensor has a higher MTF than a lower resolution sensor. So the system MTF will be higher with the higher resolution sensor. This holds valid until MTF of one component is zero.
Now, if you look at a picture on the screen at actual pixels, the picture from the sensor having smaller pixels will be more magnified than the image from the sensor with the larger pixels.
Now, if we assume a larger sensor and make say an A2-size print than we need less magnification than would be make the same size print from a smaller sensor. A2 is around 16"x23".
- 37x49 would need 11x
- 24x26mm would need 17x magnification
- 4/3 would need 34x magnification
So the diffraction circle would be magnified 11x on the MFD, 17x on the 24x36 mm and 34x on APS-C.
That means that you could shoot f/11 on MFD, f/8 on 24x36 and f/4 on 4/3 For the same diffraction effect in print. On the other hand, those apertures would also give the same depth of field.
I have both MFD and 24-36 mm, my best MFD lenses reach optimum performance at f/5.6 and loose some sharpness stopped down to f/8, but that is more measurable than visible. The best 24x36mm lens I have reaches optimum at f/4.
An important parameter in imaging is sharpening. Digital imaging should always include some sharpening and better sharpening is possible with more pixels. Sensors with less noise also allow more sharpening.
All things equal and ignoring depth of field a larger sensor will always deliver better image quality than a smaller sensor.
But smaller sensors need less stopping down for a given DoF and a lens designed for a smaller sensor can often have better resolution and MTF than a lens designed for a larger sensor.
Best regards
Erik
Interesting, as Ming Thein has it that diffraction turns (primarily, at least) on pixel pitch (and what is THAT for film?!) --to wit : "diffraction limits vary with pixel pitch, not sensor size". So, 16mpx APS-C ~= 36mpx 135, 16mpx m4/3 worse. (Though I recall Ming's asserting that HE could detect diffraction in m4/3 16mpx at f/5.6, I see also him saying that at this same aperture the diffraction "starts to kick in" for the smaller yet higher-resolution 1" sensor'd RX100 --when I'd think one should expect then f/4.) (My eyes resolve more of these arguments than my brain.)
-d.
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- 37x49 would need 11x
- 24x26mm would need 17x magnification
- 4/3 would need 34x magnification
So the diffraction circle would be magnified 11x on the MFD, 17x on the 24x36 mm and 24x on APS-C.
That means that you could shoot f/11 on MFD, f/8 on 24x36 and f/4 on APS-C. For the same diffraction effect in print. On the other hand, those apertures would also give the same depth of field.
In my digesting this, I think you slipped from 4/3 to APS-C (and '34' to '24'--though that might be nearly right for APS-C!--, but then f/5.6 re DoF)?
Thanks,
-d.
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Thanks!
Mistakes when typing, thanks for pointing out the errors.
Best regards
Erik
In my digesting this, I think you slipped from 4/3 to APS-C (and '34' to '24'--though that might be nearly right for APS-C!--, but then f/5.6 re DoF)?
Thanks,
-d.