View Full Version here: : Canon and lens not focusing to points
PeterEde
15-12-2014, 10:29 PM
I've a problem. It never used to do it but last night I mounted my 60D with 100mm Macro and tried to focus. All I got was ellipses. I could not get it to sharp focus. No filters, tried various stops.
I tried my 100-400 and the same issue. It never did it before.
Thoughts?
skysurfer
16-12-2014, 05:10 AM
Was the AF on ?
And were you taking the stars ? In that case the AF will not work as it is too dark. Current generation of cameras cannot autofocus in the dark, so switch off the AF and focus manually using the optical viewfiinder.
PeterEde
16-12-2014, 08:32 AM
AF was off. I was manual focusing using live view. I've used it before. I've taken widefield before without this problem.
I'll put a lens on my 40D tonight and see how that goes
Marios
16-12-2014, 11:08 AM
Be sure to turn off Image stabilizer as this can also work against you..
PeterEde
16-12-2014, 11:13 AM
No IS on the 100mm not sure if it was on or not on the 100-400.
I just don't get why this issue has arisen. I've used it before for WF without issue
raymo
16-12-2014, 01:00 PM
The chances of both lenses getting the same problem at the same time are vanishingly small, and connection camera/ lens problems wouldn't cause
ellipses, so very high likelihood the problem is in the camera. You can eliminate the lenses easily by seeing if the camera will focus when the body is
held up to a scope focuser, and the focuser adjusted. Easier still if you have a T-ring to attach the camera to the scope properly. I just had an
improbable thought: the diopter adjuster on the viewfinder hasn't got accidently moved a long way from it's normal setting by any chance. If you have
some astigmatism, this could cause ellipses.
raymo
PeterEde
16-12-2014, 02:02 PM
the camera focuses fine using the telescope via a T adapter.
Maybe I need to clean the lens interface
raymo
16-12-2014, 02:42 PM
Definitely worth a try.
raymo
REVEREND
17-12-2014, 10:04 PM
I had a similar problem . I gave the lens and camera contacts a clean with isopropyl and it solved the problem
Cheers Reverend.
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