03-02-2014 04:24 PM
03-02-2014 10:06 PM - edited 03-02-2014 10:24 PM
03-03-2014 03:01 AM
03-03-2014 09:31 AM
Are you talking about a add-on lens that you attach to the 58mm front filter threads of your 18-55?
I can't think of any reason that would have any real effect on AF operation. Maybe it was just the low battery causing problems?
03-03-2014 11:38 AM
If you are still on the original T1i battery, it is almost a sure bet it is the problem. Buy a new Canon battery. Fully charge it and you should be all set.
The Bower lens has nothing to do with this and is just a coincidence.
03-04-2014 12:45 AM - edited 03-04-2014 12:47 AM
I don't shoot video with my DSLRs, so this is just a guess...
You mention you were shooting video... Can the T1i even auto focus during video? I thought it was manual focus only, in video mode.
When you put the fisheye lens on, that has such deep depth of field that everything near to far is in focus anyway, I suspect. When you switch back to the 18-55mm, at some settings depth of field is fairly shallow, so anything out of focus is more obvious than with the fisheye.