A little help needed (Page 5): Because the OP also said: "2nd set of pictures taken without polorizer. Still slight vignetting at 20mm." I was responding to this message. I looked up...

CatMarley Loc: North Carolina

Zone-System-Grandpa wrote:

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CatMarley, I will not argue the point with you that the lens may cause vignetting, but we must remember that the OP had told us that he had a circular polarizer screwed onto the front element of the lens. Being this is the case, how can you not also say that the circular polarizer, which even extends out further, is not also responsible for causing the vignetting effect which the OP's photo has shown us ?

Because the OP also said: "2nd set of pictures taken without polorizer. Still slight vignetting at 20mm." I was responding to this message. I looked up the reviews on the Sigma 18 - 300 and found the lab tests that showed a 2 stop fall off at 18 and a 1 1/2 stop fall off at 300. This lens vignettes to as much as two stops NORMALLY, so a thick filter will only cause a more extreme problem! Even so, if another lens of the same make and model does NOT show the same extreme and asymmetrical fall off, then HIS lens may have a manufacturing defect as well.

CatMarley Loc: North Carolina

Zone-System-Grandpa wrote:

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CatMarley, I will not argue the point with you that the lens may cause vignetting, but we must remember that the OP had told us that he had a circular polarizer screwed onto the front element of the lens. Being this is the case, how can you not also say that the circular polarizer, which even extends out further, is not also responsible for causing the vignetting effect which the OP's photo has shown us ?

Another point of reference. On my film cameras I used a 20mm lens with a polarizer and never had any extreme vignetting such as presented by the OP. So the lens is responsible in part at least. What is more suggestive of a lens problem is the ASYMMETRIC darkening with the top corners fading to BLACK while the bottom corners are just a normal soft vignette. A shadow from the filter frame should cause a SYMMETRIC darkening of the edges of the frame. The asymmetry suggests something is cockeyed in that lens.

cjc2 Loc: Hellertown PA

CatMarley wrote:

Another point of reference. On my film cameras I ... (show quote)

I agree that something might be wrong with the lens as well. I also point out that this is just one consideration when using a zoom of that range. Something must give, or the lens would be huge and very expensive. While these lenses have a place, a couple, with less range, will most likely produce better results than an all-in-one zoom.

CatMarley Loc: North Carolina

cjc2 wrote:

I agree that something might be wrong with the lens as well. I also point out that this is just one consideration when using a zoom of that range. Something must give, or the lens would be huge and very expensive. While these lenses have a place, a couple, with less range, will most likely produce better results than an all-in-one zoom.

Agreed. To put such an enormous focal length range into a fairly compact and light weight package involves serious compromises. and luminance falloff at the edges is one of the least objectionable. But the user has a right to expect that this aberration at least will be symmetric.

dbeals Loc: Washington State

My next step is to try a different lens on my camera to determine if it's a lens issue or camera. I called B & H where I bought lens and filter 3 months ago and it is not covered under their warranty. I was referred to Nikon and Sigma regarding issues I face

CatMarley Loc: North Carolina

dbeals wrote:

My next step is to try a different lens on my camera to determine if it's a lens issue or camera. I called B & H where I bought lens and filter 3 months ago and it is not covered under their warranty. I was referred to Nikon and Sigma regarding issues I face

Good plan. If you can document a difference between your lens and another identical one - (take lots of photos with both) - then Sigma should be willing to repair or replace.

marty wild Loc: England

looks like you are at max with you lens distance back the shot off a little increase iso to around 300 to 450 you don't say what f stop you are on?

dbeals wrote:

I'm just getting getting familiar with my new but refurbished D7100 and can't figure out why on the top corners it has dark rings on the edge. I'm shooting with circular polarized filter only no lens hood. This is the first time out with camera.

cjc2 Loc: Hellertown PA

CatMarley wrote:

Good plan. If you can document a difference between your lens and another identical one - (take lots of photos with both) - then Sigma should be willing to repair or replace.

If the lens was purchased new it is well within its warranty period. I would call Sigma tech support for assistance. It is likely they will want to see your photos, so have them at the ready. Also, be ready to give the specifics about how you took the shot. I can't imagine they won't assist you and do whatever is needed to fix any possible issue with your lens. Good luck and please let us know how helpful Sigma was.

romanticf16 Loc: Commerce Twp, MI

Rongnongno wrote:

Ok the filter guys...

If there is a problem with the filter it would be IN THE FOUR CORNERS!!!!

Only if he was holding the camera parallel to the subject with no lens tilt. It is also possible that the misalignment is in the lens barrel?

dbeals Loc: Washington State

I took the D7100 and Sigma lens out with another member of the photo club I joined. He experienced the same problem with the lens and I had no problem with his lens on my camera. Therefore, it is the Sigma 18-300 mm lens that I've had for 3 months. It will be sent back for repair.

dbeals Loc: Washington State

cjc2 wrote:

If the lens was purchased new it is well within its warranty period. I would call Sigma tech support for assistance. It is likely they will want to see your photos, so have them at the ready. Also, be ready to give the specifics about how you took the shot. I can't imagine they won't assist you and do whatever is needed to fix any possible issue with your lens. Good luck and please let us know how helpful Sigma was.

Called Sigma and they did not want to see pictures just mail the lens to one of their repair sites. It will be on its way soon.

cjc2 Loc: Hellertown PA

dbeals wrote:

Called Sigma and they did not want to see pictures just mail the lens to one of their repair sites. It will be on its way soon.

Sounds like a great start. Let us know how you make out so we can advise others who may ask. Thanks for this info. Best of luck.

dbeals Loc: Washington State

cjc2 wrote:

Sounds like a great start. Let us know how you make out so we can advise others who may ask. Thanks for this info. Best of luck.

Thank you for your reply. They told me 4-6 week waiting time once sent in.

Photocraig

Dngallagher wrote:

A polarizer may not be needed on every shot, so it should not be left on the lens at all times, only when needed based on the conditions and needs.

If it is indeed the polarizer filter ring being too thick, you will either need to replace it with a thinner model or shoot at 20-28mm or higher, or crop out the vignette in post.

OR, perhaps you're stacking the Polarizer on top of a UV or Skylight filter. Another source of vignetting is an incorrectly positioned/fastened lens hood. For an 18mm wide end, surely you have a tulip shaped hood. be sure the short leaf is horizontal when it is attached.

You don't have to re-create the scene to test your lens. Just shoot the open sky at different focal lengths, eg. 18, 20, 24 etc. Then you will see the vignetting with the filter in place. Remember, don't stack filters and be sure the hood is on right.