Policar Posted February 5, 2015 Share Posted February 5, 2015 On an Iscorama pre-36 (on APS-C) would I be better off with a 35mm f2.8 than a 35mm f1.4 stopped down to f2.8? I figure I could bring the rear anamorphic element closer to the optical center.... Assuming 28mm is a no-go. What about a 77mm threaded wide angle adapter on the Iscorama itself? Quote Link to comment Share on other sites More sharing options...
richg101 Posted February 6, 2015 Share Posted February 6, 2015 not an easy question to answer. if anything 'hard vignette' - a clear masking of the image due to the mechanical limitations of the optical path will be more obvious when closing down a faster lens since natural roll off of the taking lens will be less since its projected image circle gets wider when closed down. field of view also changes very slightly when closing the aperture down and this might contribute to a small change. 35mm on a 'isco 36 on aps-c shouldnt cause any vignette when shooting 16:9 in aps-c. The main issue with a 35mm f1.4 is that the actual front pupil will be a lot bigger than the rear of the isco. this wont cause vignette, but might limit overall transmittence. closing the f1.4 lens down to f2.8 will yield in most cases much better results than a f2.8 lens used wide open. in my experience the zeiss/contax/sl35 distoagon 35mm f2.8 is a superb taking lens on aps-c with the '36. Quote Link to comment Share on other sites More sharing options...
Policar Posted February 7, 2015 Author Share Posted February 7, 2015 Thanks... I'm using the pre-36 (wish I could find a cinegon to combine the single coating flares with the larger rear element). It's funny how a tiny "prosumer" lens from the 1960s solves the flare issues and mumps/breathing issues that high end anamorphic lenses had at that time... if anything, even this single coated lens could benefit from flaring more.My Nikon 35mm f1.4 (which is infamously garbage wide open, but in a very pretty way) seems sharp at f2, but there's a lot of flare from internal reflections... I think with a slower, more modern lens the internal reflections would be fewer and less pronounced, but I can't really justify it.I'm sure the contax looks brilliant. Beautiful glass.28mm has vignetting, but it's not as bad as I'd expected.I have half a mind to stay a 0.8X wide angle adapter on the Iscorama itself. Assuming it didn't vignette, that would get me a 28mm 1.5X lens, with a horizontal FOV similar to 18mm... aka... wide enough. Quote Link to comment Share on other sites More sharing options...
ken Posted February 7, 2015 Share Posted February 7, 2015 Imo, vigenette less:1, less diameter of the taking lens2, less deepness of the front glass on taking lens3, pancake lens Quote Link to comment Share on other sites More sharing options...
Policar Posted February 7, 2015 Author Share Posted February 7, 2015 Imo, vigenette less:1, less diameter of the taking lens2, less deepness of the front glass on taking lens3, pancake lens Make sense. You could get closer to the rear element, too. Quote Link to comment Share on other sites More sharing options...
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