Are MFD’s usually quoted by the manufacturer from the plane of the sensor? How sharp is the lens at MFD? Where can one find charts to show sharpness versus distance?
MFD's
- Thread starter chrysoberyl
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Yes, MFD is measured from the plane of the sensor. Working distance is measured from the end of the lens.
Sharpness at MFD is dependent on the lens. Some lens designs are better than others, certainly macro lenses are optimized for close sharpness. Some lenses, like the 70-300L, use a floating focus group to improve close focus image quality. There are consequences - for example, in the case of the 70-300L, the MFD is the same as the 70-200/2.8L IS II, and the max magnificaiton is also the same, even though one is at 300mm and the other at 200mm. In other words, the 70-300L has bad focus breathing, and you're getting less than 200mm equivalent focal length at the MFD (that's also true for macro lenses, for example the 100/2.8L is effectively 68mm at 1:1 mag).
I'm not aware of any testing that shows sharpness vs. focus distance. You could use FoCal to do that yourself, though...
Sharpness at MFD is dependent on the lens. Some lens designs are better than others, certainly macro lenses are optimized for close sharpness. Some lenses, like the 70-300L, use a floating focus group to improve close focus image quality. There are consequences - for example, in the case of the 70-300L, the MFD is the same as the 70-200/2.8L IS II, and the max magnificaiton is also the same, even though one is at 300mm and the other at 200mm. In other words, the 70-300L has bad focus breathing, and you're getting less than 200mm equivalent focal length at the MFD (that's also true for macro lenses, for example the 100/2.8L is effectively 68mm at 1:1 mag).
I'm not aware of any testing that shows sharpness vs. focus distance. You could use FoCal to do that yourself, though...
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Yes, the MFD is the distance between the plane of the image sensor and the object being photographed.
Usually "non-macro" lenses have their sharpness tested at medium distances. To scientifically test all lenses in your MFD, you would need to create test cards of various sizes, for ultra wide lenses, up to super telephoto.
The reviews of Chistopher Frost on youtube test the sharpness of lenses also in your MFD.
Usually "non-macro" lenses have their sharpness tested at medium distances. To scientifically test all lenses in your MFD, you would need to create test cards of various sizes, for ultra wide lenses, up to super telephoto.
The reviews of Chistopher Frost on youtube test the sharpness of lenses also in your MFD.
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neuroanatomist said:
Thank you. I wonder sometimes whether and how my photo's could be better. The technical support provided in this forum provides clarity...I really appreciate it.
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ajfotofilmagem said:
Thanks very much. I am concerned about Sigma 135 Art MFD quality. I know - using a telephoto for close-ups is probably not the wisest technique. But this lens is so sharp that I can't help but compare it to my macro lenses. Thanks again.
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D
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chrysoberyl said:
Well about 20% of my photography is done with my Canon 800mm with extension tubes to reduce the MFD and I haven't noticed any loss of quality. If you are concerned about operating your 135mm at it's MFD then just add a 12/13mm extension tube and you won't be operating at MFD! Though you will loose infinity focus. The third party extension tubes are as cheap as chips - just make certain you get the AF capable ones and don't spend more than £15/$19 as there is no point!
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johnf3f said:
Thanks! I have four ET's and my concern was IQ when using a 20mm with the 135. I was shooting a wildflower in rain and biting insects, and with limited time. In retrospect, I probably was closer than MFD.
What were you shooting with your 800 and extension tubes?
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SecureGSM said:
Interesting. Is this typically true of tele's? I'll keep this in mind as I run my Sigma 135 vs. Milvus 100 tests. Thanks.
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I've been enjoying shooting my Sigma 135 at MFD, but I do find that sometimes a I stray into the <MFD territory, and the resulting blur is my own doing. I have the same issue with the 100-400 II. It does such a good job of getting a semi-macro shot, that I'll often test its MFD, and when that happens some breaths have it in focus, and some breaths heave it just below the MFD. It's hard to judge that level of sharpness on the back screen. I often find it useful to give myself an extra inch and then I find in post that almost everything is spot on.
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Hi tiggy.
Thank goodness, I thought I was half mad using my 100-400II on my 7DII for as you say semi macro shots! I was not quite at mfd, I already learned to take a step back, what I did find was that after a fairly brisk walk my breathing was making One Shot AF useless, (One Shot for static subjects, AiServo for moving subjects!) such a shallow DoF, so I switched to AiServo and was stunned to see the image sharp as I swayed back and forth, I know the Servo is good at tracking things, but following my sway as I breathed, I never imagined it would be that good! I am blessed to have this tech helping me turn crap composition out of focus shots in to crap composition in focus shots! ;D
Cheers, Graham.
Thank goodness, I thought I was half mad using my 100-400II on my 7DII for as you say semi macro shots! I was not quite at mfd, I already learned to take a step back, what I did find was that after a fairly brisk walk my breathing was making One Shot AF useless, (One Shot for static subjects, AiServo for moving subjects!) such a shallow DoF, so I switched to AiServo and was stunned to see the image sharp as I swayed back and forth, I know the Servo is good at tracking things, but following my sway as I breathed, I never imagined it would be that good! I am blessed to have this tech helping me turn crap composition out of focus shots in to crap composition in focus shots! ;D
Cheers, Graham.
tiggy@mac.com said:
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I've had some lenses besides macro's do well at or near MFD. The 100-400L, the 17-55mm EF-s. Some like the 135mmL seffer at MFD.
If you asre looking for a lens that does well at MFD, I'd read reviews, many of them comment on performance at MFD even though they do not publish numbers.
One lens that is supposed to do well at close distances, the Canon 24-70mm f/4L has reviewers saying IQ is reduced at close distances.
I expect the new TS lenses that are rumored for announcement later this month, will be very good at MFD whem used without tilt Tilt always seems to reduce IQ somewhat.
If you asre looking for a lens that does well at MFD, I'd read reviews, many of them comment on performance at MFD even though they do not publish numbers.
One lens that is supposed to do well at close distances, the Canon 24-70mm f/4L has reviewers saying IQ is reduced at close distances.
I expect the new TS lenses that are rumored for announcement later this month, will be very good at MFD whem used without tilt Tilt always seems to reduce IQ somewhat.
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