Diagonal Streaks In Sky on Select Shots (NOT Posterization)

Started 9 months ago | Discussions thread
MikeInOr
MikeInOr Senior Member • Posts: 1,421
Re: Diagonal Streaks In Sky on Select Shots (NOT Posterization)

Platographer wrote:

MikeInOr wrote:

I had a hard time seeing the effect you are talking about in the long exposure shot but it is more noticeable in the second shot you posted. It kind of looks like a very faded jet contrail in the picture.

If it were me I would take some identical(ish) sky shots with the Tamron and another lens then compare the two. If they both have the faint diagonal light stripe then I would suspect the camera. If only the Tamron does this then I would expect the lens. Maybe the lens has an internal reflection that is causing this light streak?

None of the similar photos taken with my Sony 16-35mm GM had this problem. But not all of the photos taken with the Tamron had this problem either. What issue with the lens or camera could cause this? Would internal reflections really create these lines? It's not just the one line--there are several around it. Some are dark and others are light, as if someone brushed straight diagonal lines in the sky and changed the exposure on them.

From your description it sounds pretty definite that it is a characteristic of the Tamron 28-200mm lens. If your 4x more expensive 16-35mm lens is not adding the same artifacts in a near identical situation in my book I would say it is safe to say that the camera is not at fault and the lens is at fault.

To me there seems to be two possibilities: 1) All Tamron 28-200mm lenses have this weakness. 2) Only your Tamron 28-200mm lens has this weakness. I do not see how you can narrow down which of these two cases it is without another sample of a Tamron 28=200mm lens.

My next step would be to experiment with many different photos using the Tamron 28-200mm with a lot of sky in them and the sun at different orientations to the lens and see at which angles this artifact occurs. As mentioned above I would also experiment with the lens hood mounted on the lens and not mounted on the lens and see if it changes the results. Once you have an understanding of the conditions under which the artifact appears you can classify it as a serious weakness or a rare weakness you can live with. At this point I would contact Tamron with example photos showing the artifact and similar example photos with other lenses without the artifact and see what their response is (If you are not under a return window time crunch).

Is the lens new and can it be returned? If so do you want to get a replacement Tamron 28-200mm and see if a different lens is any better? If not is the use case in which these artifacts occur frequent enough that the lens is no longer of value to you?

Please let us know what you figure out if you decide to experiment to find the conditions in which the artifact occurs? Also please let us know which route you decide to go with this lens?

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