It's said that a lens is designed best at specific focus distance, is that true? Then will a normal lens suffer from image quality decrease when focusing at very near distance? Or a micro lens perform worse at infinite focus distance?
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I think it could be the case for older or cheaper lenses, but isn't so much a problem for more modern lenses. They can move element groups independently in a complex manner to help correct for focus with distance more so than older/simpler designs which extend a large section for example.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
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[quote name='mousefire' timestamp='1321338467' post='12932']
It's said that a lens is designed best at specific focus distance, is that true? Then will a normal lens suffer from image quality decrease when focusing at very near distance? Or a micro lens perform worse at infinite focus distance?
[/quote]
Not an issue to worry about at all. With OLD lenses you may see a real impact though. My Nikkor 55mm f3.5 Micro, the first version, is said to be (one of) the sharpest Nikon SLR lens(es). But only when used as close up lens. For photography at infinity, it is not so sharp anymore at all. The 2nd version of this lens already has a different focus group that makes it better usable for "infinity" focus.
Most lenses even perform well when used outside their designed envelope (non macro/close up lenses used with extension tubes for instance). Obviously there are some exceptions... for instance my Tokina 12-24mm f4 is not a stellar performer with a 12mm extension tube attached.
As already mentioned the modern macro lenses offers incredible optical perfronace at closeup and infinity. Just look at PZ test results – all macro lenses scores better than the rest.
Howevers there are still some caveats.
1. AF performance of some macro is worse at infinity. Good example is my Tokina 100 macro. Optically It is sharp at it get straight from 2,8, but the hit ration at infitity shoots is pretty low. It start to frontfocus randomly for distances higer than 5m. The answer lays in Focus scale – from MFD to 3m the focus ring rotates 320 degree and from 7m to infinity is only few degree – lets say 2..4degree. This combined with conventional dc- AF motor makes the picture complete. Manual focus is joy to handle for macro distances bit when it come for long distances it is useless. Just for indication – the hyperfocal distance is about 200meteres and you have few degree between 3 and 200mters. That thinks goes worse when we go to 7-Infinity range
2. A lot of zoom suffers of significant IQ decrease at MFD. Sigma 50-150/2,8 is a good example. One of my favourite lens Tamron 17-50 have such problem too – not so big, but still distinguishable compared to incredible performance at longer distances. I have heard that canon 70-200/4.0 IS is worse at MFD than the old 70-200/4.0 non IS.
At the end of the days who cares. With my little experience I can say that all modern lenses are sharp, most of them are flare resistant and randers the image good. I’m outdoor photopgrapher – landcapes, macro and wildlife.
The most technical problem that I have are caused by
1. camera shake
2. incorrect DOF
3. incorrect AF
4. wrongly included reflection – forgotten to put the Polarizer.
The optical flaws has newer been an serious issue.
All of above mentioned problems ware gone since I move to tripod shoots few years ago.
Not sure if that could be the case with some lenses, but at least with my lenses I don't see the problem.
My AF-S 85/3.5 and AF-S 40/2.8 are both macro lenses and are both sharp even wide open at long distances. In fact the 40 seems extremely sharp for landscape shots.
On the other hand, my AF-S 16-85 does not suffer from using it at the closest possible focus distance. And even my AF-S 55-300 is usable as a kind of close-up lens when shot at 300mm and minimum focus distance. No worries.
[quote name='mousefire' timestamp='1321338467' post='12932']
It's said that a lens is designed best at specific focus distance, is that true? Then will a normal lens suffer from image quality decrease when focusing at very near distance? Or a micro lens perform worse at infinite focus distance?
[/quote]
A very informative document shared by Klaus some time ago:
[url="http://blogs.zeiss.com/photo/en/wp-content/uploads/2011/07/en_CLB_40_Nasse_Lens_Names_Planar.pdf"]http://blogs.zeiss.com/photo/en/wp-content/uploads/2011/07/en_CLB_40_Nasse_Lens_Names_Planar.pdf[/url]
I hope you can find what you look for (beginning from page 8 and onwards)...
Serkan
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Hi miro,
[quote name='miro' timestamp='1321349055' post='12942']
As already mentioned the modern macro lenses offers incredible optical perfronace at closeup and infinity. Just look at PZ test results – all macro lenses scores better than the rest.
Howevers there are still some caveats.
1. AF performance of some macro is worse at infinity. Good example is my Tokina 100 macro. Optically It is sharp at it get straight from 2,8, but the hit ration at infitity shoots is pretty low. It start to frontfocus randomly for distances higer than 5m. The answer lays in Focus scale – from MFD to 3m the focus ring rotates 320 degree and from 7m to infinity is only few degree – lets say 2..4degree. This combined with conventional dc- AF motor makes the picture complete. Manual focus is joy to handle for macro distances bit when it come for long distances it is useless. Just for indication – the hyperfocal distance is about 200meteres and you have few degree between 3 and 200mters. That thinks goes worse when we go to 7-Infinity range
2. A lot of zoom suffers of significant IQ decrease at MFD. Sigma 50-150/2,8 is a good example. One of my favourite lens Tamron 17-50 have such problem too – not so big, but still distinguishable compared to incredible performance at longer distances. I have heard that canon 70-200/4.0 IS is worse at MFD than the old 70-200/4.0 non IS.[/quote]
I can confirm this; this certainly is my experience. When used with extension tubes I found the 79-200 F/4 IS showed smearing in details, where the non-IS version did ok. It is one of the reasons why I sold my 70-200 F/4 IS after acquiring a 135L. The latter does very well in (semi-)macro mode.
Generally speaking, tele-zooms do better at macro then do standard and (U)WA zooms, mainly because of the rather large relative increase in incident and refraction angles caused by the larger AoV and closeness of subject with (U)WA lenses, and accompanying increase in optical aberrations. This apart from any issues involving extension tubes causing the WD to become negative, IOW, to fall within the lens rather than outside of it <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='  ' />.
Quote:At the end of the days who cares. With my little experience I can say that all modern lenses are sharp, most of them are flare resistant and randers the image good. I’m outdoor photopgrapher – landcapes, macro and wildlife.
The most technical problem that I have are caused by
1. camera shake
2. incorrect DOF
3. incorrect AF
4. wrongly included reflection – forgotten to put the Polarizer.
The optical flaws has newer been an serious issue.
All of above mentioned problems ware gone since I move to tripod shoots few years ago.
You could also use flash <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='  ' />.
I tend to use a flash, or even two or three, and the camera mounted on a large flash bracket with large handgrip. This allows me to hold the camera as a camera in an underwater housing, and that allows for a lot more stability, while being able to move quite freely, either using the focusing screen to determine focus, or even LiveView (although I prefer th efocusing screen, using an -s type precision matte).
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
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[quote name='deroppi' timestamp='1321349065' post='12943']
Not sure if that could be the case with some lenses, but at least with my lenses I don't see the problem.
My AF-S 85/3.5 and AF-S 40/2.8 are both macro lenses and are both sharp even wide open at long distances. In fact the 40 seems extremely sharp for landscape shots.
On the other hand, my AF-S 16-85 does not suffer from using it at the closest possible focus distance. And even my AF-S 55-300 is usable as a kind of close-up lens when shot at 300mm and minimum focus distance. No worries.
[/quote]
Minimum focus distance normally isn't a problem. Extension tubes my cause a problem, although less so with tele-zooms than with shorter zooms.
However, using telezooms for macro generally benefit from the use of a good quality close-up lens (multi-coated doublet/achromat) of approximately the same FL or longer of the longest FL of the zoom. This will give one a WD of approximately the same distance as the FL of the close-up lens, and an extra magnification of longest zoom FL divided by close-up lens FL.
The FL of a close-up lens is equal to 1000 mm/diopter number of the close-up lens, so in the case of the 70-300, a ~300 mm or approximately 3 diopter achromatic multi-coated close-up lens would be a great, simple, effective, and fairly cheap addition to do real macro shots with that particular lens, allowing for a WD that no macrolens can provide at those magnifications <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=' ' />.
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
[quote name='PuxaVida' timestamp='1321363408' post='12948']
A very informative document shared by Klaus some time ago:
[url="http://blogs.zeiss.com/photo/en/wp-content/uploads/2011/07/en_CLB_40_Nasse_Lens_Names_Planar.pdf"]http://blogs.zeiss.com/photo/en/wp-content/uploads/2011/07/en_CLB_40_Nasse_Lens_Names_Planar.pdf[/url]
I hope you can find what you look for (beginning from page 8 and onwards)...
Serkan
[/quote]
Thanks, it's very helpful. I see it's a challenge to optimize a lens for both close and distance subjects. However the modern design of Zeiss Lenses has solved the problem. I guess other manufacturers have also made progress in this area.
[quote name='mousefire' timestamp='1321426550' post='12978']
Thanks, it's very helpful. I see it's a challenge to optimize a lens for both close and distance subjects. However the modern design of Zeiss Lenses has solved the problem. I guess other manufacturers have also made progress in this area.
[/quote]
Well, I wouldn't say biased, but it's an article from Zeiss site <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='  ' />... OTOH, I'll give Zeiss that, 100mm f/2 is said to be a remarkable lens. I don't have experiences with it, but owners tell that it does a great job both in close up and infinity.
Serkan
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