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Old 18-08-2023, 03:09 PM
By.Jove (Jove)
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By.Jove is offline
 
Join Date: Aug 2021
Location: Sydney
Posts: 140
Quote:
Originally Posted by AstroViking View Post
Hi all,

... all the stars came out a sort of 'V' shape, mostly seeming to point into the centre of the frame.
That is coma, and "collimating" wont fix it. Don't waste your money on this, move it on and buy a better lens.

The lack of a decent name from the film era (ie Pentax/Takumar, Nixon, Canon) should be a clear warning it's a "yum-cha" cheapie with poor performance.

Another thing to bear in mind is that the resolution of most 35mm films was around 20 microns. Lens performance (spot sizes) aimed to match that. But 30 years later in this age, the pixel spacings of modern sensors are 2-5 microns - and a lens with a 20 micron spot size will appear very soft on a modern camera.
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