12-05-2011, 03:31 PM
http://blogs.zeiss.com/photo/en/wp-conte...stagon.pdf
Some info included about problems with digital sensors.
Some info included about problems with digital sensors.
New Zeiss paper about their wide angle designs
|
12-05-2011, 03:31 PM
http://blogs.zeiss.com/photo/en/wp-conte...stagon.pdf
Some info included about problems with digital sensors.
12-06-2011, 10:37 AM
Nice article, thanks for sharing... I would like to use this as an opportunity to be informed about a specific issue... Does somebody have any idea about the relation of these statements in the article and the Nex-7 corner smearing / color shift issue? Should one be very picky when it comes to use an UWA on Nex-7? It stuck in my mind after checking the link in [url="http://forum.photozone.de/index.php?/topic/1462-sony-nex-7-non-dedicated-wide-angles/"]this post[/url]...
Serkan
12-06-2011, 11:31 AM
[quote name='PuxaVida' timestamp='1323167835' post='13474']
Nice article, thanks for sharing... I would like to use this as an opportunity to be informed about a specific issue... Does somebody have any idea about the relation of these statements in the article and the Nex-7 corner smearing / color shift issue? Should one be very picky when it comes to use an UWA on Nex-7? It stuck in my mind after checking the link in [url="http://forum.photozone.de/index.php?/topic/1462-sony-nex-7-non-dedicated-wide-angles/"]this post[/url]... Serkan [/quote] Yes, one should be <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. There are really two issies here, one being the AA-filter, and the other being the relative photosite (or sensel) well depth. With larger incident angles the sensels at the edge of a sensor will more and more lie in the shadow of its own little well edges, and this effect is stronger the smaller a sensel is. This may also cause colour shifts, as the sensel edge may well refract light itself - after all it is made of crystalline glass (silicon <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />). From tests I have seen with e.g. the Heliar 12 F/5.6, it is clear that the NEX-7 suffers more from this than, e.g. the Nex-5n. And we all know that there are problems with this regarding, e.g., the Leica M9. The smaller the sensels, and the larger the sensor, the stronger this effect will be. 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 ....
12-06-2011, 01:08 PM
Seems to me that main issues with at least M-lenses sharpness lies in AA-filter+IR filter thickness.
Both Ricoh M module & Leica do not have AA-filter & at least Leica cameras struggle to have IR filter with minimal thickness possible. It is possible, that even for mirrorless cameras this extra glass could be at least partially compensated in lens design. Read this info by lens designer of Coastal Optics 60mm f/4 UV-VIS-IR APO Macro: http://diglloyd.com/articles/CoastalOpti...notes.html Quote:The second issue relates to aberration correction. Any time you place a plane-parallel piece of glass in the path of a converging light beam you introduce aberrations. Virtually all digital cameras have a cover glass of some sort. Even if you remove the filter pack there is still a thin coverslip that protects the actual pixel structures. The vast majority of digital cameras also include a filter in addition to this coverslip. In order to achieve the best possible performance in a lens to be used with digital cameras it is therefore necessary to include the effects of all this glass near the image plane, and to counteract it by proper design of the lens.
12-07-2011, 02:09 PM
[quote name='wim' timestamp='1323171091' post='13478']
.... This may also cause colour shifts, as the sensel edge may well refract light itself - after all it is made of crystalline glass (silicon <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />). [/quote] Thanks Wim... It sounded more or less ok concerning the influence of the pixel size, but this explains the "how" part...<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' /> |
Users browsing this thread: |
1 Guest(s) |