I have a Canon G2 digital that has started putting a spot on its pictures. When I look at the lens, I don’t see any foreign substance on the lens. However, I’ve noticed that when I wipe it with an alcohol dampened lens cloth, I can see a spot on the surface of the lens, but only while the lens is still wet with the alcohol. As soon as the alcohol evaporates, the lens surface looks normal and clean.
Have I damaged the coating on the lens, or is this just a contamination that isn’t soluble in alcohol?
If the coating is damaged, is it repairable?
If it’s a strange subtance, is there a better solvent than alcohol?
Unless you can see an actual smudge on the lens, I think it’s much more likely that your problem is that you have some crud on the actual sensor of the camera (or possibly on the interior of the lens).
Is the spot more noticeable in bright light photos where the camera is stopped down to the smallest f-stop? (That’s symptomatic of dust on a sensor.)
No cite, but a spot on the front surface of the lens would be unlikely to cause a visible spot on the photo. It’s so close that it would be way out of focus. A dirty lens would cause an overall “fuzzyness” or loss of contrast.
Is the spot always in the same place on the photo? Does the spot have any color to it? Is the edge of the spot sharp or blurred? Can you post a sample anywhere we it might be viewed?
My advice is never to use anything but lens cleaning solution and lens tissue. Available from any camera shop. Normally, lens tissue alone is sufficient.
In your case, hard to say what the spot is, but probably worth having lens checked out by a shop. Hopefully the alcohol did not ruin the coating. Also wonder if it might be a defect on the CCD chip?
Is the spot sharp or diffuse? Crud on a lens will normally just give an overall degradation of the image because, as has been stated, it will be so far from the point of focus. Where it is visible as a spot it would be large and very diffuse. It would also change size as you zoom. Crud on the sensor will likely be more hard-edged.
Here’s a picture. The spot appears at about the same area that I see the wierdness on the less when it’s wet. The spot changes density and its edge “fuzziness” changes with different focal lengths (using autofocus). It’s worse when focused at infinity. I guess I should try switching to manual focus and see how that affects it.
Yeah, that’s looks a lot like a sensor or internal dust problem. You can try shaking the camera and see if the location of the dot changes. But if this diagnosis is correct, it’s not good news. You have to disassemble the camera to fix it which is often tricky due to the use of fragile ribbon cables in the construction of the camera.
If you can find a service location near you, it looks like CCD cleaning goes for about $50. Otherwise, if you’ve been thinking of upgrading to a different camera, this would be a good time to do it.
On digital SLRs, where the sensor is exposed whenever you change lenses, it’s easy to clean the sensor (but still risky as sensors are fragile little things!) but on a pocket camera, it’s really out of the realm of sensible ideas to try it yourself unless you’re either desparate or better than the Average Joe at disassembling and successfully re-assembling tiny complicated things.
It’ll be a learning experience anyway! You might learn to clean cameras, or you might learn to never try it again!
Many years ago, about 45 years in fact, I learned to not clean the front surface in an SLR with dry lens tissue. Cost about $35 to get a new mirror installed. That was a lot of money to a 16 year old back then.
