jcolwell Offline Upload & Sell: On
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I think my Rok would look sharper at f/1.4 in the middle on the test chart. OTOH, it's not easy to get critical focus on a fast, short telephoto, when it's wide open. Could you describe your procedure ? Just askin'. I generally do this kind of shot (i.e. test pattern/resolution target) on a tripod, with MLU and self-timer or remote release, and using LiveView for manual focus. I take at least three images, and use the 'best' for comparison with other 'best' images. It also helps to have really good lighting, or use flash (which helps with WB).
The second set of images of the keyboard shows significant CA. It's probably 'lateral CA', or 'bokeh CA' - I forget the term (there are many, it's not a well-defined vocabulary - at least, not widely agreed)... Anyway,
This CA is most obvious in the first image at f/1.4, but is also apparent in the other two, too. The light-dark edges in the foreground have pronounced reddish (magenta) colour, and those in the back have pronounced green edges. Note that the front right (south-west) corner of the J key has little or no CA. That's on the plane of sharp focus. It extends to the left and right. The "J" on the J key is behind the plane of focus, and so it doesn't look very sharp. The "M" is softened by CA, while the N and bottom of the K are very well defined (i.e. good resolution), but the generally low contrast of the image makes them look 'not sharp' [apparent sharpness = resolution + contrast].
I can also see slight CA in the test pattern shots, but not more than could be expected.
Of course, if you want to take sharp close up photos without CA, you should use a good macro lens.
The 'slight haze' effect you describe might be the effect of an extremely shallow DOF, combined with CA, in at least some cases. Your comment that you can see haze in sebboh's "flower with honey bee" photo is interesting. IMO, the full image is sharp and clear - the bee and front row of flowers, and slender leaf plus stick debris at the bottom, all look great (i.e. plenty sharp). The rest of the image shows what "well behaved" bokeh should be. The Zeiss Planar 85/1.4 and Leica Summicron 90/2 would look a lot more 'nervous' in the background. Things aren't quite so sharp-looking in the 100% crop of "sebboh's bee", but it has sufficient detail to tell me that I could make a large print (e.g. 16 x 24) with no worries.
I suggest that you should spend more time with your Rokinon in real world situations, before deciding if you have a problem or not. If you still perceive the same problem after a few days, then maybe you could return it and try another. It's not a perfect lens (none are), but it can produce fantastic images.
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