BetterPhoto Q&A
Category: New Questions

Photography Question 
Danny Wouralis
 

Circles in Digital Pix ?


 
  Gymshow
Gymshow
© Danny Wouralis
 
 
Every time I take a digital picture at my child gym...these circles/bubbles appear in the image.

What gives?


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4/8/2003 12:23:21 PM

 
Jeff S. Kennedy   When was the last time you cleaned your lens?


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4/8/2003 10:37:57 PM

 
John A. Lind
BetterPhoto Member Since: 9/27/2001
  These "circles" are classic symptoms of "aperture flare" from the bright lights in the gymnasium . . . from the bright overhead lights shining on the surface of the lens . . . some of which may be just outside of the photograph itself but still enough in front of the camera to strike the lens objective.

With a film camera these often appear as polygons picking up the shape of the aperture diaphragm. With a digital that doesn't have an aperture diaphragm it would take on the circular shape of the lens barrel. Aperture flare is a product of both the bright lights shining on the front of the lens (the objective element) and the lens design. It is so bright compared to the rest of the image that they become prominent.

About the best you can do is use a lens hood and watch your image composition to keep bright light sources from directly illuminating the lens objective. Jeff is correct about keeping the lens clean. This may also help.

The culprit is usually the lens design: lack of proper light baffling and/or "flocking" on the inside the lens barrel to prevent/reduce internal reflections of light bouncing around inside the lens. If it's an inexepnsive lens, it may also lack anti-reflective coatings on some of its internal glass elements (these circles appear to be white which makes me suspicious of this too). The real solution is a lens with a better design that isn't prone to this.

-- John


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4/10/2003 9:13:11 PM

 
Danny Wouralis   The Lens was cleaned prior to taking picture.

Thank you John for your detailed explanation.


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4/11/2003 7:49:40 AM

 
Sven    With all respect for John's answer, I think there might be another reason, or did you notice this phenomenon only in photos that include bright overhead lights?

I can see from your photo that you were shooting with a flash. When flash bounces back off the dust in the air you get spots like that.

Regards,


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4/15/2003 4:27:02 AM

 
Ray Landolfi   When I was looking to purchase a digital camera I was warned against certain manufacturers. Some cameras incorperate the use of plastic lens (as opposed to glass). I was told the plastic ones are more prone to lens flare or glare spots.


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4/15/2003 6:28:18 AM

 
Jeff S. Kennedy   The reason I asked if your lens was clean is because flare doesn't usually show up this randomly. It looks more like you have dust or scratches on your lens.


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4/15/2003 9:06:07 AM

 
Amie Kyte   Danny,
I'm curious as to what camera you have?? I have a Canon G2 (which otherwise serves me well) and I have the same problem. I seem to lean towards the lighting as the problem. Gyms seem impossible for me to get the shot I want. I haven't tried a lense hood and wonder if that would really help. ANY MORE HELP from the pros here will be great>>


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5/30/2003 9:14:05 AM

 
Sven    I still think it is light from the flash that is reflected in the dust. Could it be that there is a lot of dust stirred up at the gym?


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5/30/2003 9:17:32 AM

 
Amie Kyte   In my case, there's not any unusual amount of dust.... I've had this problem and several different gyms, all with the same type of lighting. Dances, basketball games, programs.... all with the same effect. It's annoying but I hope to find a solution.


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5/30/2003 9:39:10 AM

 
Ray Landolfi   Have they all been with the same camera? would be my first question.
If so, have you cleaned the lens with any solution that might leave residue that might refract the light in a different manner than just the lens. Similar to the rainbow effect of oil in a puddle. Maybe fingerprints. If not the the optics of the camera might be the cause. plastic lenses are used in some brands.
I would start with making sure the lens is cleaned with a solution recomended for cameras....or bring an extra camera use both and see if it happens to that one too.


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5/30/2003 9:51:45 AM

 
Amie Kyte   My camera is a Canon G2 digital and I'm 99% sure it's not plastic. Also, the lens is clean but I only have this problem with my digital. I haven't really noticed with my Canon slr. I hope Danny (the original q&a post) and I find a cure... or I guess we'll have dotted gymnasium photos


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5/30/2003 2:19:23 PM

 
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