12-09-2010, 09:41 PM
Hi Lars,
[quote name='Lars' timestamp='1291887332' post='4899']
Hello,
there are now Adapters for EF-lenses available with built-in aperture:
[url="http://www.dl-kipon.com/en/articledetail.asp?id=30"]http://www.dl-kipon....etail.asp?id=30[/url]
[url="http://www.43rumors.com/new-canon-eos-to-micro-four-thirds-adapter-with-built-in-aperture-control/"]http://www.43rumors....erture-control/[/url]
So, a question for the optics-specialists:
As I assume, the position of the aperture blades in the lens ist important for the IQ.
What do you think?
Is the IQ degraded if you close this aperture within the adapter?
Thanks
Lars
[/quote]
The position of the diaphragm generally determines the amount of barrel or pincushion distortion one gets. Depending on the lens design you may start seeing this effect. Furthermore, one has to wonder about reflections of this probably quite cheap diaphragm with regard to all kinds of IQ-degrading effects. I obviously have never used any of these, and being able to stop down in some cases is better than not being able to stop down, but in such cases i would rather buy a good old manual everything lens and fit a plain adapter to it. Actually, that is exactly what I do <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.
Kind regards, Wim
[quote name='Lars' timestamp='1291887332' post='4899']
Hello,
there are now Adapters for EF-lenses available with built-in aperture:
[url="http://www.dl-kipon.com/en/articledetail.asp?id=30"]http://www.dl-kipon....etail.asp?id=30[/url]
[url="http://www.43rumors.com/new-canon-eos-to-micro-four-thirds-adapter-with-built-in-aperture-control/"]http://www.43rumors....erture-control/[/url]
So, a question for the optics-specialists:
As I assume, the position of the aperture blades in the lens ist important for the IQ.
What do you think?
Is the IQ degraded if you close this aperture within the adapter?
Thanks
Lars
[/quote]
The position of the diaphragm generally determines the amount of barrel or pincushion distortion one gets. Depending on the lens design you may start seeing this effect. Furthermore, one has to wonder about reflections of this probably quite cheap diaphragm with regard to all kinds of IQ-degrading effects. I obviously have never used any of these, and being able to stop down in some cases is better than not being able to stop down, but in such cases i would rather buy a good old manual everything lens and fit a plain adapter to it. Actually, that is exactly what I do <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 ....