Anyone repaired their own lens?

[EOM]

I bought a lens off of ebay last year; a Sigma 20-40mmD f/2.8 EX. I can apparently only use it at f/2.8. Anything else the camera meters it as if it's at the smaller aperture and my pictures are over exposed by several stops. I've tried the f6 option and turning the aperture dial manually but no dice.

It appears that the spring that (at least on ALL of my other lenses) snaps the aperture down in the absence of pressure doesn't have enough pressure... or there's too much friction due to dirt? I took the first three layers of "stuff" off to look in there and located the spring. Also the zoom ring is a bit stiff(dirt?).

Just apply some oil?

 

[jtvang125]

It's possible that it could be dirt or sand that's causing the problem but I think more likely it's oil that got onto the aperture blades. From what I read the oil comes from the lubricant breaking down with age or high temps (hot car, direct sunlight for too long).

I had two old MF lens that had oily blades. They'll stay wide open but when you try to stop down using the aperture ring, you can see the blades either staying wide open or slowly closing down but never completely. On the blades themselves you can see that they appear wet. That's the oil. I tried opening them and cleaning with rubbing alcohol and they'll get snappy for a few days but go bad again. Just tossed them as they were only a few bucks each.

 

[Paladin3]

I'd hit up youtube and watch some repair videos of lenses with the same problems. I couldn't find a repair video of that exact lens, but lots on similar lenses with the same issues.

 

[Brian Stirling]

I was at Yellowstone and lugging 2 cameras, a tripod with leveling base and ballhead, and about 7 lenses and when I picked up one of my cameras sitting on a bench by the lens the camera strap got caught on the bench and the zoom barrel on the lens unsnapped and exposed the inner workings of the lens. I fumbled with it a minute of two and put it away in may bag to look at later in the hotel.

So, I get back to the hotel and pull the camera out and take a closer look. I noted the groves and notches on the zoom barrel and matched them up with the components on the lens, set the zoom the wide I think, and was able to snap the barrel back into place and all works well. Camera was a Nikon D800E and the lens was the newer Nikon 24-120 Zoom lens I've had for a few years that replaced the first version 24-120.

I had the shutter die on my older Canon 1DsMII lens and had to send it back for replacement. I also dropped my Canon 1DMII camera a year or two earlier and it introduced a focus issue where the focus would change from right to left so I guess the mount must have been tweaked from the fall. That one cost me about $300 if I remember correctly.

So, some things you can do yourself and others ... not so much.

I had to do manual sensor cleaning pretty often with the Canon's but in the 4 years I've had the D800E's I've never had to do a manual cleaning of the sensor. The built in sensor cleaning function appears to do a pretty good job and maybe the chamber design is better, whatever the reason I'm happy not to be cleaning the sensor every other month.


Brian