cpclee Posted October 22, 2017 Author Share #21  Posted October 22, 2017 Advertisement (gone after registration) These were not the right targets and were not setup completely properly, but fwiw.  Top Left Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/?do=findComment&comment=3379890'>More sharing options...
Advertisement Posted October 22, 2017 Posted October 22, 2017 Hi cpclee, Take a look here 75 Summicron AA corner degradation. I'm sure you'll find what you were looking for!
cpclee Posted October 22, 2017 Author Share #22  Posted October 22, 2017 Lower Left Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/?do=findComment&comment=3379891'>More sharing options...
cpclee Posted October 22, 2017 Author Share #23  Posted October 22, 2017 Top Right Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/?do=findComment&comment=3379892'>More sharing options...
cpclee Posted October 22, 2017 Author Share #24  Posted October 22, 2017 Lower Right.  To me they are all quite equally at f2.8.  Bear in mind that at 2.8 and being just about 2m away from the wall, the DoF was very thin.  My focus was on the center of the frame, so all four corners were slightly off the plane of perfect focus.  But the fall off is to my eye quite uniform in all four corners, especially given the wall itself might be slightly off from being perfectly perpendicular to the sensor plane. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/?do=findComment&comment=3379895'>More sharing options...
mdemeyer Posted October 22, 2017 Share #25  Posted October 22, 2017 Glad it was of help. I’ve followed Jim for years and he’s a really competent technical guy as well as a very interesting photographer.  Relax and enjoy the lens! Good shooting Link to post Share on other sites More sharing options...
wlaidlaw Posted October 22, 2017 Share #26  Posted October 22, 2017 I used similar charts to confirm my suspicion that the 120 film carrier was not sitting square in the back of my Mamiya 645J. It was tilted on the diagonal, so two diagonal corners were in focus and the other two had back focus on one and front focus on the other. Mamiya happily replaced it with another one, which was at least equally bad. That made me suspect that either the injection mould was sloppily made or it had worn badly. The 220 film carrier was fine and I used that, until they stopped making 220 film, at which point I sold the camera.  Wilson Link to post Share on other sites More sharing options...
hoppyman Posted October 22, 2017 Share #27 Â Posted October 22, 2017 Advertisement (gone after registration) I suggest that sending the lens to Wetzlar is the best way to get an authoritative report to determine if it is working to specification . Widest aperture at close distance is of course most demanding and the corner performance can never match the centre. However you are concerned with differences in different corners I think? .Their test and calibration facilities are the benchmark (literally) with the most elaborate and precise equipment and regime. Should it prove to need work then of course you may get a quotation from them. If it is in specification then you can consider everything else in your image chain, whether camera, adapters, methods etc etc. the testing should define for you what is normal or not under the conditions that you explain too. Test shooting of course may be different to just taking advantage of DoF control for three dimensional subjects as with portraiture for example Link to post Share on other sites More sharing options...
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