Is my Sigma lens dead?

October 11, 2008 6:50 AM

Is my Sigma lens dead?

Well... in short no it's not. However, whilst cleaning it today I had a look down through the glass and noticed tiny bubbles of condensation on one of the glass elements.

It's an autofocus lens for a Pentax film camera and I've never had a film through using this lens – it's been in a camera bag for a couple of years so I don't know how long the condensation has been there, it's definitely not progressed into fungus and all the mechanisms are working fine.

I'm going away to shoot some indoor live photography in tiny dirty venues and will more than likely not use it again afterwards, it's just got such a great wide angle. I can't really afford to buy another one right now, so I'd like to use it but I obviously don't want to run 20 rolls of film through the camera and they all turn out to be totally useless.

So really, I'm asking – will I notice the condensation in photographs or will it work out just fine? They're most likely going to be lo-fi black and white indoor shots with the built in flash – people doing stagedives and dancing in the crowd.

posted by stackhaus23 to media & arts (5 comments total)

It's probably usable in that scenario.

In an indoor shot, you'll probably have the aperture wide open, which tends to minimize the effect of stuff on the lens (because it gets blurred out). Crudely put, the reason you can have dust and smudges on the lens and not always or often notice them is because the aperture is large relative to them and they are not lying in the plane of focus.

You might notice increased glare, or a little haze on the final image. Nothing you can't fix in the darkroom. You would have less glare with less on-axis light or flash, but I wouldn't stress about it.

There are some things you can do. First, try a single roll of film out in a bar or similar environment. If it's bad, you haven't wasted much to get that knowledge. Second, put the lens in a sealed container with a dozen or so silica gel packets, the little "DO NOT EAT" packets that come with your sneakers and electronics. You can even by big versions of those packets. You might be able to try the condensation away.
posted by fake at 7:17 AM on October 11, 2008

The lens should be fine. The condensation will go away but you do need to let it evaporate.
You can try the silica bag trick or you can just place it in a warm dry area. I would think direct sunlight may not be ideal because the condensation might leave some spots on the elements.
posted by WickedPissah at 7:49 AM on October 11, 2008

Fake is possibly right that that the condensation is out of the plane of focus at the aperture that you want to be shooting, depending on how wide that lens will go. But you might have a problem with the autofocus and you'll want to make sure that's working correctly in a similar lighting environment.

We managed to get some water in our Canon EF 70-200 2.8L IS USM this summer. We were on a hike through the Bornean rain forest and got hit by a sudden massive downpour. Rain in the rain forest, who knew?

It ended up being an expensive lesson that our camera bag wasn't as water resistant as we thought. We did the silica gel packet trick, even brought some of those along with us just in case. While it did get the water out after about a week, it left very visible water spots. While nothing was wrong with the electronics, autofocus was no longer able to determine where to focus. We ended up sending it back to Canon for repair, which came to $180, not including the price we paid to ship it there. I'm sure we could've gotten it repaired for cheaper at some 3rd party but figured it wasn't worth the risk with that particular lens.
posted by dereisbaer at 8:02 AM on October 11, 2008

Lacking silica, you could also throw it in a bag of rice. That will have some absorbing qualities. It's worked for me for laptop spills in the past.

Don't know about water spots.
posted by asavage at 10:57 AM on October 11, 2008

I hadn't considered the autofocus issue.

Following asavage, another good improvised absorbent material is crystal cat litter -- it usually consists of silica gel crystals, bentonite clay, and in some cases, baking soda. Just be sure to use a fragrance-free variety.
posted by fake at 12:18 PM on October 11, 2008