Dirty Lenses - Does it matter?

freeranger

freeranger

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I was watching a school photographer a couple of weeks ago, snapping pics of the kids with his canon dslr and an L series lens.

Then I looked at the front glass on the lens :eek:

It was filthy!Huge fingerprint smudges and plenty of grime. I even wondered whether he'd been smearing vaseline on the lens for special effect.

The pics arrived this week - they were amazing. Great saturation, sharp, amazing bokeh!

So...am I being overly cautious in worrying about my lenses? How do you treat your glass?
 
I'm certainly not overly fastidious about keeping my lenses clean. If I put a fingerprint on the lens, I do clean it off, though.
 
I think a lot more lenses have been ruined by overjealous cleaning than images by fingerprints. Like the previous comment, I still clean mine w/ successive applications of Acetone (2 times) on a Q-tip followed by a solution of 1/2 Gal. distilled water/ one drop of liquid dishwashing soap (2 times) on a Q-tip AFTER cleaning them w/ a rubber lens blower when I find a fingerprint, etc. I always use a hood too. I use one end of the Q-tip w/ the Acetone or water, then dry w/ the other end.
 
IMHO cleaning can do more harm than dust and fingerprints.

Dust can be easily blown-off and fingerprints cleaned with lens cleaning solution (isopropyl alcohol, or vodka for FSU lenses :D ) and microfiber cloth.

I try not to clean lenses unless absolutely necessary.
 
Yes, it matters. That's why I prevent any soiling by using permanently-placed UV filters, as well as prevent fogging by taking them out for a spin at least once a month. I cringe at the thought of having to clean them, but I cringe even more at the veiling flare caused by oil/dust/crud/fog on/in it.
 
Dust and dirt won't affect anything. The first thing they taught us in photojournalism class was to throw out our lens caps because we might miss a shot fiddling with them. (Does not apply to rangefinders!!!)
Fingerprints, on the other hand, can cause big time flaring. Clean them off with a bit of breath and a soft cloth.
 
photogdave said:
Fingerprints, on the other hand, can cause big time flaring. Clean them off with a bit of breath and a soft cloth.
Click to expand...

It could be a myth but I've read somewhere that breath is not suited for lens cleaning because the enzymes in your spit can have an effect on the coating.
 
Jamie123 said:
It could be a myth but I've read somewhere that breath is not suited for lens cleaning because the enzymes in your spit can have an effect on the coating.
Click to expand...

Never heard that, but I used to read that the oils and acids in fingerprints could etch the coatings of the lenses.

I too try to keep them clean, first by UV filters, then if not, by cleaning them if I spot anything that needs cleaning.
 
photogdave said:
The first thing they taught us in photojournalism class was to throw out our lens caps because we might miss a shot fiddling with them. (Does not apply to rangefinders!!!)
Click to expand...
Does not apply to rangefinders because... with a rangefinder you don't realize the lenscap is on and so still take the shot anyway, thus not actually missing it?
 
I also keep a filter on all my lenses...mainly for protection against banging it but also to keep dust and fingerprints off the front element.
I was shooting the kid's High School Band when I noticed how filty the lens was, mostly dust...When I viewed the shots later I was surprised how sharp the pictures were even with the dirty filter...made me rethink just how clean do you need it to be.
 
lament said:
Does not apply to rangefinders because... with a rangefinder you don't realize the lenscap is on and so still take the shot anyway, thus not actually missing it?
Click to expand...
No, because if you leave the lens cap off you risk burning a hole in the shutter.
 
I'm in the "a filter is easier to clean and cheaper to replace than the front element of a lens" camp - especially older soft-coated ones!
 
Jamie123 said:
It could be a myth but I've read somewhere that breath is not suited for lens cleaning because the enzymes in your spit can have an effect on the coating.
Click to expand...
Oh brother. . . not only is it a myth, but this spit-enzyme-harming-lens-coating myth does not even apply. Amylase, which digests starch, is the only enzyme of note in human saliva. There are other salivary enzymes, but the whole issue is moot because to clean a lens, you are supossed to breath moist air on it, not spit all over it. Moisture in the warm, moist air from the lungs condenses on the lens surface in nice teeny-tiny droplets, which you then wipe off with some form of micro-cloth. No saliva should hit the glass. Voila.

cheers,

David
 
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Some brands of q-tips (cotton buds) can be kind of scratchy. Wadded up lens paper or a microfiber cloth might be kinder to the lens coatings.
 
Damn straight, it matters- in some conditions, at least. Look at the flare around the lamp above the shed:

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That's a combination of lint specks (from my pocket) and very fine mist on the front element of an otherwise perfectly clean, freshly sanitised 50mm Summilux.
 

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Internal dust is a good bargaining point when buying lenses; I have a couple of dusty lenses that print sharp as I like at A3 (ish) size, got them a LOT cheaper than pristine examples too :)
 
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