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Bad lens?

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#1 pcardinal42

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Posted 15 March 2019 - 07:55 PM

How do you tell if you have a bad lens? I have a Sony A7 II and am using a 50mm 1.8. I was just trying to take a shot of Orion, all manual settings and I tried multiple f stops from 1.8 - 3.5, ISO from 400 - 1600, exposure times no greater than 10" - 2", and using live view to focus on a bright star and get it as sharp as possible. All the stars in the picture look like they have wings. I am shooting from a tripod and it was a little windy last night so maybe that is what it is. I'm trying to get some pics uploaded but having trouble. Any tips or suggestions are helpful.



#2 kyle528

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Posted 15 March 2019 - 08:51 PM

When you say your stars have "wings", is this effect the same across the entire star, or more pronounced on one side of each star? Is this only happening on the edges of your image or in the center as well? How are you releasing your shutter? With my limited AP experience only a few things come to my mind which could be trailing, (but 2 seconds at 50mm shouldn't give that much trailing), bumping the camera by releasing the shutter (use a remote shutter or self timer if you aren't already), or coma, which generally results in clean stars in the center of the image, progressively getting worse toward the edges of the image. If you can get a photo to upload, I'm sure someone will tell you exactly what is going on. Sometimes I have trouble with images nearing the 500kb limit, it thinks they are bigger than they are, usually my images uploaded directly to the forum need to be under 350kb. 



#3 Ian Robinson

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Posted 15 March 2019 - 10:24 PM

Show us a typical image so we can see.


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