I recently came across a great deal on a Zeiss 100mm zf.1 makro-planar locally. I checked the lens out today and it looks great with one exception - the aperture blades were uneven. The unevenness was more apparent at smaller apertures, and as the lens opened up became less of an issue. It seemed one of the blades sometimes didn't sit flush with the rest of the group, which I felt was probably causing the non-symmetrical look. The unevenness was not consistent. Sometimes the shape of the blades was completely symmetrical, sometimes it was a bit distorted and uneven.
Is this a real problem? Will it be a liability issue down the road with the lens? Is this a reason not to buy the lens?
The link below has a picture example of what I'm talking about. The Zeiss I saw was probably a little worse than this.
When will this issue manifest itself in use of the lens? I'm guessing the bokeh will just look a little funny? Wide open the blades are a nice perfect circle, but by around f/5.6 the unevenness becomes apparent. I guess in real world use this is not something that will affect the actual utility of the lens but the OCD in me says to pay a few hundred more and get a "flawless" copy.
Not a very experienced photographer so I don't really have any experience with this. Please advise!!
I have several Nikkors like that and they have been fine for years. Perhaps there is more of an effect of asymmetrical aperture blades at f/16 or smaller, but diffraction cuts IQ there anyway. Obviously if it is a new lens you should be able to return it and find a better one.
