Quote:
Originally Posted by Garyh
Hi Leon,
I do things similar to you in most of this, but I can never get it to focus spot on with any of my lenses. with a crescent moon or more there is no probs but just on a star or even venus its always out. Maybe the 5d does a better job of it or that my camera has been modded but I always have to tweak the lense closer to the infinity mark after using autofocus on a star..
Go-figure..?
cheers
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I think it is due to a fact that focus circuit is not using the main sensor.. and if mirror is slightly out, you have a problem.
In old film days, I had to re-adjust my Practica mirror position, to achieve good focusing (I have build a special microscope for this purpose, to be able to monitor the image in the focal plane (where film was supposed to be) and the image on the screen. After mirror position adjustment, I applied the shelack solution to fix the mirror lower position (I did not have the access to locktight or anything similar then, and super glue I considered dangerous to internals of the camera because of evaporations).