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Hikerjim
Tinkerer
Username: Hikerjim
Post Number: 1
Registered: 09-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 12, 2010 - 03:42 pm: | 
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Ouch! I dropped my new Canon 18-135 lens and scratched the glass. Can that be repaired/glass replaced? Does it affect image? So far I see no image spots on photos. |
Glenn
Tinkerer
Username: Glenn
Post Number: 851
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 12, 2010 - 05:54 pm: |
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If the lens is new your local Canon repair centre will be able to replace the scratched element - at a price! It is rare that the odd surface scratch or two will produce visible degradation of the image, and if anything is ever visible it will more than likely be seen as flare on images taken directly into the light/sun. Take a few photographs under lighting conditions that are expected to produce flare or reduced contrast and see what happens, if all looks well forget the damage and just use the lens.
If you do get the lens repaired make sure that you fit it with a decent filter, they can stop this type of surface damage in most cases. I have only come across one dropped lens that suffered a damaged front element when fitted with a filter, and that fell 200ft onto a WWII runway from the open doorway of a helicopter during a photo shoot! You might also consider insurance, my policy has always covered incidents like this |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 181
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 14, 2010 - 01:45 pm: |
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1. Modern lenses are (disclaimer: not always, but zooms very often) designed so, that the only big lens is the front one. It's also most often the aspherical one if any is. This is to save weight, as well as cost - optical glass costs per ounce. Thus a front lens element is usually about 50-80% of lens price to replace.
2. Even noticeable scratch on front lens element isn't going to show up on film as a spot or any identifiable form. It can, however, scatter light. To repair a scratch that IS causing light scatter use black marker pen - just paint over the scratch. THIS IS SERIOUS ADVICE. You can't make this part of glass refract light right anymore, so you simply stop it from transmitting any light. You lose this way a tiny fraction of light, but save your photo from flare.
Simple, clean scratches rarely lead to light scattering, but if this is a chip, or a crack, it might.
3. I do NOT second the opinion on putting an uv filter on. A stiff lens shade does a much better job.
Marek |
Glenn
Tinkerer
Username: Glenn
Post Number: 852
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2010 - 02:50 am: |
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Of course a lens hood will offer a very good measure of protection, but the effectiveness of those fitted to large aperture 20mm - 24mm wide angles is somewhat questionable - this being based on 40 years experience as a professional photographer.
If one cared to look at insurance claim statistics, it will be seen that the majority of claims for damaged lenses are when the lens was being taken out of a bag/pocket etc and fitted to a camera body. In many instances such as this the hood is not even fitted yet.
We each have our favourite method off protecting the front element from dings etc - usually based on experience gained in the field and any protection is better than none at all! |
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