Originally posted by Just1MoreDave If you still have these cameras, I have both a Miranda and Nikon T-4 adapter I can send you. It always seems like the interesting lenses come with non-Pentax T-4 and TX adapters.
I have tried "focus-bracketing" on my latest test. I focus as best I can, then take a series of shots after moving the focus ring back and forth in small increments. It can identify focus errors and maybe help if the lens has a curved field. Subject choice is very important too. The right subject can emphasize focus errors. I also like to have something detailed in the corners to look at.
Testing is tedious, even for simple sharpness, and it's difficult to rule out all potential errors. I think each test is useful and adds to the body of knowledge, even if it's not definitive.
Thanks, but the Miranda and Soligors are long gone. I do still have a couple of moldy Nikons, but their only use is as bookends these days.
I still don't like my results with or trust AF for critical focusing and I find I'm habitually tweaking the focus anyway. With my growing collection of A lenses I don't have a choice of course. I'm definitely finding it difficult to get what I want with the K200D. I find the viewfinder dim and the focus screen vague at best. I've got the eyepiece loupe and am waiting on a split-image screen, but expect to upgrade to a K20 soon.
I've been practicing with focus bracketing with the intent of just incorporating the method into my habits. In the film days I would bracket exposure and focus when the situation allowed, but it's only been lately that I've felt the need to be that critical again.
Agreed, subject as well as many other factors effect the importance of focus accuracy and lens characteristics. When the situation allows I too search the composition for a reference point.
I don't think any field test can really be definitive and even a lab test really only applies to that particular sample. The process though is very valuable if only to increase familiarity with ones equipment.
Okay, need to stop dreaming about my next lens now and do some work.
cheers