Some recent discussion on Nikon v Sony lenses sent me scurrying off to the net for a quick literature search of tests and I found something interesting about myself. That there were parts of tests I cared deeply about, and parts I didn't give two hoots about. Since then, over a coffee, I've had a think about what I care about in more detail. And here's my results....
1. Resolution. Why? I can correct pretty much everything else in processing - that simple - whereas if the data didnt make it through the lens onto the sensor and out, I'm screwed. But within resolution, what matters to me:
a) center resolution wide open (wide open I expect a narrow DOF anyway so edges are irrelevant)
b) maximum achieveable resolution at any setting
c) across the frame performance in the f4-f8 range.
2. Flare. Can be fixed but very hard and seems to always crop up at the worst time.
3. Bokeh - not that interested in grading it, I find that impossible to characterize across all different scenarios, but I look for problems.
4. Anything else that's much worse than the norm and so bad I'd have to spend more time than its worth to fix it.
5. I do also look for something "special" dont know what it is, but I know when its missing. My Zeiss 50 has it, my Sigma 20 has it, my other Sigmas dont. Its feel, its weight, its smoothness, its coolness, its that special X, factor, the David Bowie bit.
As always these are whats important to me given what and how I shoot and process.
How do others assess glass? Whats important to you?