[Klaus]

[url="http://www.opticallimits.com/canon_eos_ff/536-zeiss85f14eosff"]http://www.opticallimits.com/canon_eos_ff/536-zeiss85f14eosff[/url]



A bit sharper than the C85L but I'd rate the Canon somewhat better from a field perspective (bokeh, higher contrast @ large apertures).

[genotypewriter]

[quote name='Klaus' date='25 July 2010 - 06:45 PM' timestamp='1280047502' post='1285']

[url="http://www.opticallimits.com/canon_eos_ff/536-zeiss85f14eosff"]http://www.opticallimits.com/canon_eos_ff/536-zeiss85f14eosff[/url]



A bit sharper than the C85L but I'd rate the Canon somewhat better from a field perspective (bokeh, higher contrast @ large apertures).

[/quote]



Thanks <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' /> Must have been very difficult to account for the field curvatures and any focus shifts while taking measurements for different parts of the frame. I imagine it must have been a nightmare.



While the MTF figures show the ZF being around 21xx in the corners at f/1.4 and the 85LII being 20xx at f/1.2, the 85LII has far less CA. In my experience, low CA increases apparent resolution by a great amount but MTF figures don't seem to capture this. What are your thoughts on that?



Thanks again for the review...



GTW

[Klaus]

Correcting lateral CAs is basically a non-issue these days. However, if you don't want to bother it'll certainly decrease the quality perception quite a bit.

[wim]

Thanks, Klaus. Interesting lens. I do think I'll stick with the 85L, however <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.



Kind regards, Wim <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />

[genotypewriter]

[quote name='Klaus' timestamp='1280049560' post='1288']

Correcting lateral CAs is basically a non-issue these days. However, if you don't want to bother it'll certainly decrease the quality perception quite a bit.

[/quote]



Thanks. I guess it depends on what people need. Personally, I prefer not to do any context sensitive digital fixing, if any fixing at all, because even the best of it can't bring back what was lost in the capture.



I think I'm with Wim on this one... but I got a chance to try out a CP.2 85 T2.1 on a 5D2... an extremely well behaved lens fully wide open. Shot a bright light in the corner of the frame and saw zero fringing... CA was very very little.

[Brightcolours]

[quote name='genotypewriter' timestamp='1280131520' post='1311']

Thanks. I guess it depends on what people need. Personally, I prefer not to do any context sensitive digital fixing, if any fixing at all, because even the best of it can't bring back what was lost in the capture.



I think I'm with Wim on this one... but I got a chance to try out a CP.2 85 T2.1 on a 5D2... an extremely well behaved lens fully wide open. Shot a bright light in the corner of the frame and saw zero fringing... CA was very very little.

[/quote]

CA can be an exception, depending on which colour(s) are the offending one, and the method of CA "correction".



I am not totally sure, but to me (having looked at samples) it seems that for instance Nikon does not correct CA in-camera (shooting JPEG) "correctly". It seems to filter out coloured edges. Again, I can be wrong in my perception.





La CA is basically one colour of light (or more) bending more (or less) through the optical system than the other colours. This means that if for instance the red colour is bending less, the projected red image is smaller on the captured image than the projected green and blue images.



Two ways to correct LaCA:

• Filtering colour edges. This indeed does not fix, nor bring back what was lost. The muddy fuzziness brought on by the CA remains.
  
  
• Shrinking or expanding the "offending" colour channel. This will bring the image of that channel in line with the rest. This will get rid of the coloured edges on contrasty areas, and it will get rid of the muddy fuzziness. This method does fix what was wrong, and you gain sharpness and contrast.
  
  
  
  
  
  

Of course, lower CA in lenses is by far preferable.

[Yakim]

[quote name='Klaus' timestamp='1280047502' post='1285']

A bit sharper than the C85L [/quote]



And a bit less sharp than the plain-jane C85. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />

[wim]

[quote name='Brightcolours' timestamp='1280147057' post='1315']

CA can be an exception, depending on which colour(s) are the offending one, and the method of CA "correction".



I am not totally sure, but to me (having looked at samples) it seems that for instance Nikon does not correct CA in-camera (shooting JPEG) "correctly". It seems to filter out coloured edges. Again, I can be wrong in my perception.





La CA is basically one colour of light (or more) bending more (or less) through the optical system than the other colours. This means that if for instance the red colour is bending less, the projected red image is smaller on the captured image than the projected green and blue images.



Two ways to correct LaCA:

• Filtering colour edges. This indeed does not fix, nor bring back what was lost. The muddy fuzziness brought on by the CA remains.
• Shrinking or expanding the "offending" colour channel. This will bring the image of that channel in line with the rest. This will get rid of the coloured edges on contrasty areas, and it will get rid of the muddy fuzziness. This method does fix what was wrong, and you gain sharpness and contrast.

Of course, lower CA in lenses is by far preferable.

[/quote]

LoCa is actually also completely correctable in PP without any loss of detail, sharpness, or colour. However, that is a rather long-winded and convoluted process, where specific colour channels or even parts thereof are treated for correction, and with lots of masking layers involved. I did read a write-up on this half a year or so ago.



If I can find that article again, I'll post the link here.



I guess that that is method #3 <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.



Kind regards, Wim

[Guest]

It is still little difficult to accept that Samyang and Zeiss have same value for money? Regarding MTF and other charts, it's pretty much dead race, and price difference is huge.

[Klaus]

The Zeiss provides focus confirmation in the viewfinder, a camera controlled aperture and it's simply a bit better.