Sigma Bigma Problem. Any Suggestions?

Mike Werner

Hi
I've got a Simga Bigma 50-500 on a Nikon D3 (and 700). Since this trip, I've been seeing a big ring in the middle, a bit like super vignettes, covering 3/4 of the photo. The slower the speed, the lower the ISO, the bigger the rings. When it's a sunny, clear day, shooting at high speeds, there is little or no ring, but at lower speeds, the ring is very pronounced.

My take is that the lens is dead. Any ideas????

No filters are used, and the ring becomes visible when running Nikon Capture NX2 Auto-levels.

Please tell me the lens is fine...

ziggy53

My guess is that the original is a bit underexposed and also low contrast. I suspect that when you processed the image you probably added considerable contrast.

Do you have any image samples without processing?

Mike Werner

ziggy53 wrote: »

My guess is that the original is a bit underexposed and also low contrast. I suspect that when you processed the image you probably added considerable contrast.

Do you have any image samples without processing?

No, the only post processing I did was auto-level. It was misty, hence the underexposed and contrast, but even in the raw you see the ring.

ziggy53

Test the lens in another body, just to rule out a camera settings issue.

Also, take the lens off the camera and shine a small, single LED flashlight through the lens to see if there is internal fogging.

pathfinder

That would be my guess, Ziggy.

Was this lens exposed to a very high humidity for some time recently?

Moving Pictures

I had my Sigma rebuilt, and it cost very little to have the whole thing cleaned, lubed, and whatever. I suspect your lens needs the same treatment.

pathfinder

That is good to hear.

I had my Tamron 200-500 ( EOS format ) lock up in some strange electrical way, and cease operating, but it was also repaired by Tamron service and continues to work great.

I am happy to hear good things about Sigma repair as well.

Mike Werner

ziggy53 wrote: »

Test the lens in another body, just to rule out a camera settings issue.

Also, take the lens off the camera and shine a small, single LED flashlight through the lens to see if there is internal fogging.

Yeah, you're right, it looks foggy.

Pathfinder: Yes, you are right, I was in heavy fog for 3 days, waiting outside for clearings.

I used it on a D3 and D700, so I know it's not the body.

Looks like I'll need to ship it to Sigma. Problem is I'm on assignment for a magazine at this moment and the weather has just cleared.... guess I'll have to do with a 300mm. (or head quickly into a ton to find a 2x converter).

Thanks for your help

pathfinder

If you can keep it in a warm, dry spot, you might get lucky and have it improve some, but if it really has condensation on the inner elements, I think when the moisture evaporates, you may still have some stuff left on the optical surfaces of the lens elements.

I had a pair of binoculars that got condensation on the inside elements and looking through them kind of looked like your picture.

I love shooting in fog too. Like snow it really dresses up a landscape, but it can make havoc on un-sealed lenses, which I believe the Bigma is.

Mike Werner

Thanks, I'll try to keep it warm for a few days, but have already sent an email to Sigma.

Art Scott

It might help also to put it in a bag with a few silica desiccant packs to help pull the moisture out ...
I have never had anything like this happen to any of my lenses including my BIGMA... WOW...

pathfinder

Good suggestion, Art.