Quote:
Originally Posted by AlexN
What is the shape of the internal iris stopped down to f/3.5 Bojan?
My tokina 300/2.8 gives fairly bloated stars at f/2.8, but tiny pinpoint stars at f/4. The only problem at f/4 due to the rough shaped internal iris I get slightly odd star shapes with some weird aberrations. I'm testing some home made aperture masks to see where best performance lies then I will get something 3D printed.
Unfortunately my lens goes directly from f/2.8 to f/4 with the internal iris. I suspect f/3.5 will give me the performance I'm after.
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Hi Alex,
The shape of internal iris at f/3.5 is not so good.. f/4 is OK.
External aperture behaves much better, as far as diffraction is concerned.
I will do comparison between internal and external and post the results as soon as possible.