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View Full Version : How does this happen?

jmh
Oct-09-2005, 12:46 PM
I set my Canon 20D on a tripod and took a few pictures of the moon on a crystal clear night. They all had this effect to some degree. What is happening? Is it related to camera movement as the mirror moves or is it a lens effect? The image looks perfect through the viewfinder and I used the timer to trigger each shot. I'm confused...

http://jmh.smugmug.com/photos/39304986-M.jpg


http://jmh.smugmug.com/photos/39304987-M.jpg
John Mueller
Oct-09-2005, 05:58 PM
Ill take a guess.
Do you have filters on your lenses?
Looks like a reflection.
Welcome to the forum.
David_S85
Oct-09-2005, 06:06 PM
Filters or... lens flare. Did you shoot wide open?
Nikolai
Oct-09-2005, 06:21 PM
Not as prominent as yours, but still had it (was easy to remove in PS, hence I didn't care much about it).
http://nik.smugmug.com/photos/39227247-L.jpg
Funny, didn't have it on a full moon shots, with the virtually identical conditions.
Most likely the UV filter... (Mental note to self: remove when shooting at night).

What lens were you shooting with?

Thanks!
jmh
Oct-09-2005, 06:28 PM
I was using a Sigma 50-500 with a UV filter. I tried numerous f-stop / speed combinations and saw the same problem every time until I backed out to less than 200mm. Does this help narrow it down?
GREAPER
Oct-09-2005, 07:11 PM
Interesting. I have never seen this before so all I can do is guess.

I would try taking the UV filter off for these shots.

Maybe the light is reflecting off your lens, hitting the filter and bouncing back into the lens. FWIW I think you are overexposing the shots a bit too as the "refection" looks better exposed than the original.
jmh
Oct-09-2005, 07:38 PM
I think I'll try it sans filters next time. I chose to post the overexposed shots as they showed the reflection much better than the ones with proper exposure. I tried a number of speed and stop combinations to eliminate the ghost image but posted the 'worst' ones here so the effect would be easy to see. Some of the shots were fair but all had the 2nd image until I zoomed back to about 200mm. After I get a chance to try again I'll post the results on this thread. Thanks everyone who commented!!!