Canon EF-s 18-135mm IS lens with issues

[mr.mike]

Hi,
I just purchased a Canon EF-s 18-135mm IS lens with some damage to the front element. It shows a couple of light scratches and a bit of pitting. I realize the front element can be changed, but if it works as is without having to change the glass, I think I'll just leave it alone. My question is, would leaving it alone have a negative effect on the good glass elements in time? I bought this lens as a backup for my extra Canon 40d. I paid $50.00 for it, and thought I'd take a gamble. Lens arrived this afternoon, and this is what it looks like. Pits only appear on the outer portion of the outer element. Can't see any problem with photos. Wondering if there's a way to remove the pits, or maybe I should leave it as is.
Thanks,
Mike

 

[john.margetts]

First, physical damage to the front surface of the front element cannot affect the other glass surfaces in the lens. The only damage that can spread is fungus infection.
Second, light scratches and a bit of pitting will only have a very slight effect on the contrast of the image produced - too small for a human eye to see in most cases. If you are shooting towards a bright light, you might get a bit of flare.

 

[mr.mike]

Thank you very much for your response. I'll post results as soon as I'm able.
Mike

 

[mr.mike]

First, physical damage to the front surface of the front element cannot affect the other glass surfaces in the lens. The only damage that can spread is fungus infection.
Second, light scratches and a bit of pitting will only have a very slight effect on the contrast of the image produced - too small for a human eye to see in most cases. If you are shooting towards a bright light, you might get a bit of flare.

Hi,
Just received the lens and added a photo. Please let me know what you think. I took a couple of pix, and can't see any sign of an issue. Looking forward to hearing from you. The pitting only appears on the outside of the front element. Inside is clean.
Mike

 

[john.margetts]

Shouldn't cause any problems. If you do get flare from the damage, you can go over the pits with a black Sharpie and the flare will go away.

 

[mr.mike]

Shouldn't cause any problems. If you do get flare from the damage, you can go over the pits with a black Sharpie and the flare will go away.

Thank you for your quick response. The seller mentioned scratches and I can't seem to find any. So far I don't see any flaring, but I'll have to try the bright light test. I'll let you know how I make out.

Thanks again,
Mike

 

[TCampbell]

Shouldn't cause any problems. If you do get flare from the damage, you can go over the pits with a black Sharpie and the flare will go away.

Thank you for your quick response. The seller mentioned scratches and I can't seem to find any. So far I don't see any flaring, but I'll have to try the bright light test. I'll let you know how I make out.

Thanks again,
Mike

To catch flaring, point the camera "near" (but not "at") a bright light source (don't use the sun... use a street light or any reasonably bright BUT SAFE light source that wont physically blind YOU or risk damage to the sensor) -- so that the bright light is at the very edge of the frame (or possibly even just barely out of the frame) and then deliberately over-expose the image by several stops (that way if the flare was present, but not bright enough to notice, your deliberate over-exposure will make them more evident). This should allow you to determine to what extent you are getting any issue from these scratches.

My guess is that it may not cause flaring but could cause a slight loss in contrast... but that's just a guess and I really don't want take a claw hammer to front of a lens to test that theory.

 

[mr.mike]

Still playing around with this lens, but as of now, I can't seem to find any serious issues. I can't see any scratches on this lens, just a few small pit marks. I'll give your suggestion a try and let you know how it goes.
Thank you Tim