# Unwanted spots and reflections with canon EF 50mm f1.8 II night shoot



## stealers (Jul 29, 2009)

Yesterday I wanted to see the performance of my newly purchased EF 50mm f1.8 II and took a few shots. I am disappointed. Mounted my 40D on a tripod with cable release and I played with different settings  in bulb mode, 1 exposure, Av mode with wide open f1.8, Tv mode, etc. Dont know why I am seeing those unwanted spots and Reflections. I marked with Red pen on the pictures. My 50mm lens has a UV filter on it. No other filters.  I cleaned up the outer surface, made sure no dust. I didnt get a chance to change lens to my 17-55mm, take same shot  that way I know does it need a sensor cleaning? Any suggestions what could have gone wrong?

Picasa Web Albums - Phani - EF 50mm night...
Thanks.


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## Overread (Jul 29, 2009)

Did you try taking the filter off? Could be that the filter is causing reflections on the glass - the lighspots certainly appear to be reflections of bright light spots in the shot so try shooting without the filter.
Modern DSLRs already have UV filters built in so the filter is mostly just a screen protector and not much else - further if it is a cheap filter and not multicoated then there is a very strong chance that it is the cause


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## Big Mike (Jul 29, 2009)

Those are most likely lens flare or reflections from within the lens.  This can happen when you have brights lights in an otherwise dark scene.  The light is reflecting off of the sensor, or part of the lens, then bouncing around in the lens.  It's not dust on the lens or on the sensor etc.

Part of the problem is probably due to your cheap lens.  I don't think they put a lot of anti-reflection coatings in the 50mm F1.8 lens.  That's why it's $80.  Also, the UV filter could be another cause of these reflections.

Another factor might be the aperture you are shooting at.  Most lenses are weakest at the extremes...their max aperutre for example.  This lens, for example, will usually give much better quality at F2.8 than it will at F1.8.  I'm not sure if that would help reduce the flare though.


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## Soocom1 (Jul 29, 2009)

If the filter is thick, or the front element is deeply recessed back from where the threads are located or where the filter sits, then as Mike said it can be a refraction of light bouncing around the inside of the lens. Look through a double pained window at night some time. Youll see multiple reflections of lights. Same consept.


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## gsgary (Jul 29, 2009)

That is specular light Specular reflection - Wikipedia, the free encyclopedia
Get rid of the filter and don't shoot so wide open stop down to about F11


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## UUilliam (Jul 29, 2009)

I use a Hoya UV vilter (£5.99)
 on my 50mm II f1.8 
Had nothing like this happen.


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