No circular aperture on the 200mm APO G telephoto

G

Guest

I am thinking about trying to find an affordable used Minolta APO G 200mm telephoto lens. It is, according to any website and magazine, the best 200mm that is out there, with an incredible performance wide open. This sounds good, and even the size and build quality is cool.

However, the lens does not have circular aperture. I own the old Minolta 100mm 2.0 with circular aperture and love the bokeh it produces. Question is, why didn’t Minolta ever make a circular aperture on that still going strong lens? Last few year, even a lot of their cheap lenses take advantage of the circular aperture. Some lenses did not change in lens design, only cosmetically and… circular aperture… Why did the 200mm G never follow this trend? What will defocused reflections look like from wide open to 4.0 on the 200mm G? Is not having a circular aperture on this lens really a pity or not?
 
H

honenshonin

I'm guessing that if it's truly wide open, the aperture will be circular anyway, as this seems to be true of lenses in general (at least this is the case with my Sigma 28-70 f2.8). It's that space between wide open and about f4 that you really notice the difference, since your aperture loses circularity as you stop down, but your foreground/background is still fuzzy enough that you get little 7-sided "blobs" where there are points of light. These look a lot nicer when they're round.

I have no experience with the 200mm lens you speak of, but even the lenses designated as "circular aperture" lenses, you will find, quickly lose circularity as you stop down. Even at f4 (when using my 50mm f1.4) I can see corners starting to form on by background "blobs"--I was shooting a picture of a flower, and there was a glint of light off the chrome of a car in the background. My recommendation is to go to the camera shop, put the lens on your camera, and take a look around. Try to focus on something near you from an angle at which there are glints of light in the background (reflections of a glass counter?). Shift through several f-stops using the DOF preview button and see what you get.

I'm envious of you--I've eyeballed that lens myself.
 
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