08-09-2011, 08:11 AM
[quote name='karlmera' timestamp='1312875537' post='10534']
And macro lenses?
[/quote]
Well, as mentioned it all depends upon design priorities. A macro lens is certainly optimized to deliver great results at max. magnification but this doesn't mean that it's worse at infinity. If you look at the Zeiss 100/2 MTF charts you will notice that it's still better at infinity and 1:10 than at 1:2. At infinity it seems even insignificantly better than at 1:10 (40lp/mm = resolution).
I'm not a designer but basically they feed the optimization points into their optimization algorithms. So for a prime lens they define a couple of hot spots within the focus range that are supposed to be important. Infinity focus will always be in there. Macro lenses will certainly have a hot spot at max. mag whereas portrait lenses have a hot spot at -say- 3 meters. That's all simplified of course.
True macro lenses tend to have FEs (floating elements( (just like the Sigma or the Zeiss lens) which are meant to optimize the close focus performance. Technically this is the primary differentiator compared to conventional lenses.
Remember that many users own macro lenses but will rarely use them as such - after all they are compact and offer high performance and their comparatively large max. aperture makes them suitable for portrait photography as well. I also used to own a couple of macro lenses without doing actual macro work. Even macro photographers don't always shoot at 1:1 but often just at 1:5 or 1:10. That's also something that the manufacturer keep in mind when designing such lenses.
And macro lenses?
[/quote]
Well, as mentioned it all depends upon design priorities. A macro lens is certainly optimized to deliver great results at max. magnification but this doesn't mean that it's worse at infinity. If you look at the Zeiss 100/2 MTF charts you will notice that it's still better at infinity and 1:10 than at 1:2. At infinity it seems even insignificantly better than at 1:10 (40lp/mm = resolution).
I'm not a designer but basically they feed the optimization points into their optimization algorithms. So for a prime lens they define a couple of hot spots within the focus range that are supposed to be important. Infinity focus will always be in there. Macro lenses will certainly have a hot spot at max. mag whereas portrait lenses have a hot spot at -say- 3 meters. That's all simplified of course.
True macro lenses tend to have FEs (floating elements( (just like the Sigma or the Zeiss lens) which are meant to optimize the close focus performance. Technically this is the primary differentiator compared to conventional lenses.
Remember that many users own macro lenses but will rarely use them as such - after all they are compact and offer high performance and their comparatively large max. aperture makes them suitable for portrait photography as well. I also used to own a couple of macro lenses without doing actual macro work. Even macro photographers don't always shoot at 1:1 but often just at 1:5 or 1:10. That's also something that the manufacturer keep in mind when designing such lenses.