Floyd Loc: Misplaced Texan in Florence, Alabama

Has your 6 year warranty from Tamron expired? If you are the original owner and the warranty hasn't expired, all it will cost you to have the lens cleaned and brought up to factory standards is $6 to cover the cost of a "Signature Required" on delivery. Just got mine back and am within less than 2 months of 6 year expiration.

tcosmic

I have same lens and same issue. I read that some have a bad seal. It only shows when shooting things like air shows with bright sky. Talked to Tamron a month ago and they said to send it to them. How ever Tamron is not accepting repairs now do to Covid-19.

jerryc41 Loc: Catskill Mts of NY

It really doesn't matter.

https://photographylife.com/what-to-do-with-dust-inside-lens
http://kurtmunger.com/dirty_lens_articleid35.html
http://www.lensrentals.com/blog/2008/10/front-element-scratches

revhen Loc: By the beautiful Hudson

My understanding is that any dust on a lens element would be so out of focus (the light rays passing around it would compensate for the dust spot) that it would not appear in the photo. I had a recurring spot and -- yep -- it was a spot on the sensor. Sent it out to Canon -- not cheap! -- and had it cleaned. I'd rather spend the money than destroy my camera!

davesit Loc: Media, PA

The problem on this lens is that all the dust, sand and other detritus (not just tiny dust particles) collect on the back surface of the second element because of a terrible seal of the first lens element group. My lens literally looked like it has a sandbox inside after using it to shoot high school baseball for a couple of years. It is a known problem of the lens, especially if you use it in a dusty environment.

Architect1776 Loc: In my mind

kymarto Loc: Portland OR and Milan Italy

Dust within the lens absolutely should not show up on a photo, with the rare exception of dust on the rear element or front element of an ultra wide lens stopped down.

My guess is that it is a sensor issue. Sometimes you get a sticky particle that resists easy removal. In rare cases you can get a small nick on the glass filter in front of the sensor. The former case can be resolved with wet cleaning; the latter means the glass must be replaced. It probably shows up with the long lens because of the small maximum aperture.

One way to quickly check is to hit the lens release button and twist the lens while looking through the camera. If, as the lens is being rotated, the spot moves, it is something with the lens. If the spot remains in the same place it is something with the sensor.

davesit Loc: Media, PA

Check out this thread:

https://www.dpreview.com/forums/thread/3865939

amfoto1 Loc: San Jose, Calif. USA

It is very rare for dust in a lens to show up in photos. If there's a lot, it may cause flare and reduce resolution... but it won't show up very clearly.

It's very likely you are seeing something on your sensor, not anything in your lens. You can test this with other lenses and checking if the specks are in the same place. Just stop the lens down to f/16, point it toward something bright and plain (a light colored wall or clear blue sky), de-focus it and take a shot.

Four things that pretty much all need to be in play for dust inside a lens to show up in images....

1. There has to be a lot of dust... but to appear in images the specks need to be very large... more like "hunks" (I've seen lenses with internal light baffle flocking flaking off that would qualify).

2. Wide angle lens are more likely to show internal dust near the front element, telephoto lenses more likely to show near the rear element.

3. It's more apparent when the lens is focused close, near its minimum focus distance.

4. It's more apparent when a very small lens aperture is being used.

See the following article from someone who handles, tests, cleans and repairs hundreds of lenses:

https://www.lensrentals.com/blog/2011/08/the-apocalypse-of-lens-dust/

Roger shows sample images where there are fairly large pieces of Post-It note stuck onto 24mm and 85mm lenses.

Notice how those pieces of paper (much, much bigger than any speck of dust) on the front element of the 85mmt are apparent at f/16 aperture, less apparent at f/6.3 and how they virtually disappear at f/2. It's then repeated with the pieces of paper on the lens' rear element, where it's a bit more obvious at all apertures.

Next he repeats the test comparing how they appear on the front element of 24mm lens versus 85mm lens (more apparent on 24mm).... then on the rear element of the same two lenses (more apparent on the 85mm).

But, again reference the image showing how large those pieces of paper have to be to cause them to show up in images.

Here's another article where the shows a couple lenses with a lot of dust inside, which he's not bothering to have cleaned because both lenses work fine and it has no noticeable effect on images:

https://photographylife.com/what-to-do-with-dust-inside-lens

Finally.... Disassembling lenses is not a good idea. You risk ending up with it entirely out of calibration, far worse than what dust might cause. If you still feel the cleaning is necessary (i.e., a sensor cleaning doesn't solve the problem), have the lens professionally cleaned.

I know you said the sensor has been cleaned, but it's rare for dust in a lens to show up in images. I'd look into the sensor as the much more likely cause of spots in your images.

If you do your own sensor cleanings, have you done a "wet cleaning"? If not, it's even more likely that it's a dirty sensor you're seeing. More info about cleaning sensors can be found here:

http://www.cleaningdigitalcameras.com/

Fredlog Loc: Emmett ,Idaho

Depending on where one lives, dust is a very common problem. I live in the country where there's lots of dust!! I use a Cannon EOS to photograph cowboys, scenery, and super fast action shots. I bought complete cleaning equipment from Amazon for ~$100. In addition Amazon has "how to" instructional videos from beginners to advanced. Another option is to have your camera cleaned professionally which is costly.

davesit Loc: Media, PA

I think most people don't realize how bad the dust (and sand and other particles) problem is. See attached photo. What you are seeing is all the detritus collecting on the back surface of the second element, which is back of the first lens elements assembly.

Attached file:
(Download)