Best way to get goop off a lens

[tmfabian]

Ok...so i've spent the better half of the day trying to clean some crud off the rear element of one of my lenses. I was out shooting the other day and was swapping lenses when all of a sudden a bubble from god knows where lands smack on the rear element.

there's a second half to this question as well....if I can get it pretty darn clean and can't see anything when I look through the lens but can still see a few smudges with a pinpoint flashlight at an oblique angle...is that clean enough? (I mean I can't even see the smudge in normal light held at an angle...just a pinpoint flashlight held almost 90 degrees to it and only from certain views can I see the smudge.)

 

[nikon_sam]

Fog the glass with your breath then wipe it dry with some lens tissue...fog it again and inspect the glass for this smudge pattern you think is there...if you can see it while it's fogged it's not yet clean...
Depending on the lens...there may be smudges on it and you would never know it by the results...some lenses will render a blurry image if there's anything on it...
Just don't try so hard that you actually damage the glass...

 

[payasam]

I'd first do what Sam advises. If that doesn't work, some rolled up lens tissue damp with colourless booze like vodka.

 

[tedwin]

Lens coatings are good on modern lenses, so if its pretty new you can afford to go quite hard. I had to use cellulose thinners once on a front element after my subject miss-understood the word 'pretend' and spray painted me and my camera! Despite some nerves there where no ill effects.
Although if its an old lens I wouldn't be so confident.
Breath isn't going to offer much assistance and will require more rubbing than something like methanol. I reckon for very stubborn marks the harsh chemical will do less damage than the rubbing.

Like I said though, I reckon.

Ted.

 

[tmfabian]

Lens coatings are good on modern lenses, so if its pretty new you can afford to go quite hard. I had to use cellulose thinners once on a front element after my subject miss-understood the word 'pretend' and spray painted me and my camera! Despite some nerves there where no ill effects.
Although if its an old lens I wouldn't be so confident.
Breath isn't going to offer much assistance and will require more rubbing than something like methanol. I reckon for very stubborn marks the harsh chemical will do less damage than the rubbing.

Like I said though, I reckon.

Ted.

Ok, so I tried EVERYTHING I had in my apartment short of bleach. So I hopped down the block to the photo store and picked up some sensor swabs and used that liquid and voila....no smudges, streaks, or damage.

Thanks for the tips...usually I just huff on it and rub it down with a cloth, but that soap bubble left a nasty goo that just would not come off with anything.

 

[Bill58]

I use lab-grade Acetone, followed by distilled water on Q-tips with fine results.

 

[eli griggs]

I like Everclear liquor as a lens and general purpose camera cleaner, it's effective and non-toxic so long as you don't drink it ;-)

Cheers

 

[majid]

My preferred cleaning option for finishing is Zeiss disposable lens towelettes. If there is strong surface contamination, ROR in combination with PEC-Pads. It's important not to reuse the cloths because grit can get trapped in the weave and turn the tissue into sandpaper.

 

[Al Kaplan]

Just be careful not to flood the lens with liquid. You don't want anything to seep down around the edges of the les element where it might damage any cement gluing the elements together. Choosing a solvent can be really hit or miss depending on what kind of crud that is on the element, and usually we first see the crud long after it got there. Newer lenses have some really tough coatings so a bit of rubbing won't hurt. Lately I've been using microfiber which usually works without any liquid.

Regular lens cleaner is water based but for some types of crud you might need an alcohol based cleaner, and some things will only yield to something like lighter fluid (naptha). Don't squirt it on the lens! Dampen a cotton swab with it. After you get the gunk off the lens finish up with regular lens cleaner.

 

[FallisPhoto]

Solvents in general use for lens cleaning are:

1. distilled water -- for general dirt and crud (a little distilled white vinegar can be added for especially stubborn crud)
2. methanol, ethanol or denatured alcohol -- for tar based crud (pine pollen, tree sap, cigarette smoke residue and deteriorated light seal goop)
3. naptha -- oil based crud (especially good for fingerprints)
4. 50/50 mix of ammonia and hydrogen peroxide -- for lens fungus, mold and mildew

Short of cleaning up paint, you should never need anything more than these for cleaning your lenses, and they are usually pretty benign. Nevertheless, don't soak the lens in them -- a little goes a long way -- and keep solvents out of the electronics. Bear in mind also that these are solvents for cleaning glass. Don't use them for general cleaning. If you were to get some of that alcohol, or the ammonia mix, on an SLR's focusing screen, for instance, the focusing screen would probably turn opaque. Also, generally speaking, the only thing that should ever touch a vintage rangefinder's semitransparent mirror is a puff of air (and even that can be risky). Finally, on cameras made before about 1975, the lenses are often soft-coated. Pentax discovered, a little before then, that baking lens coatings fused them to the glass and hardened them; this is what made multicoating possible. Prior to then, some harsh chemicals, especially ammonia, could cause the coating to seperate from the glass.

If you want to avoid "cleaning marks" (abrasions to the lens surface), use cotton swabs. Twist the swab as you go, so as to lift the crud away from the lens and not rub it against the glass. You will go through a lot of swabs. Whatever solvent you are using, always finish up with distilled water. Naptha, for instance, is really good at dissolving the grease and oils in fingerprints and removing it, but it isn't going to do much about the other crud in the fingerprint (which responds better to distilled water).

 

[peterm1]

I have given up being pedantic about this issue. Far more damage is done to lenses by over enthusiastic cleaning than is ever done to images by faint marks on lenses.

It seems unlikely to me that the image will degrade by the faint smudges you describe.

But having said this I would be a tad more concerned to make sure that I clean off an unknown liquid from a lens as I have seen lens coatings damaged by stuff that has gotten onto lenses in this way.

 

[tmfabian]

I have given up being pedantic about this issue. Far more damage is done to lenses by over enthusiastic cleaning than is ever done to images by faint marks on lenses.

It seems unlikely to me that the image will degrade by the faint smudges you describe.

But having said this I would be a tad more concerned to make sure that I clean off an unknown liquid from a lens as I have seen lens coatings damaged by stuff that has gotten onto lenses in this way.

Yeah...it was caused by a bubble landing on the rear element while switching lenses...so i really wanted to get rid of all the gunk possible since I don't know the extent to which that kind of soap residue would've damaged the lens...all in all, it worked out pretty well.