[jsherman999]

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Was taking some shots yesterday with the 50-135, and started noticing
FF... Uh-oh.

Cropped - should be much sharper than this:



Later, looking at the downloaded shots, it was actually both FF and BF,
consistently, with pretty much every shot, so I knew it wasn't user error on
a few.




Took off the lens, and lo and behold, a fine layer of an oily/sooty substance was
on both the body contacts and the lens contacts. ????

Turns out and older lens I had on the camera earlier in the day was the culprit -
it left the residue on the body.

After a polishing with a cotton cloth, the lens is back to tack-sharpness, same
level as before:

1)

2)

3)

4)

5)

6)

7)

8)

9)

10)

11)

12)


focus was on the flower, bee flew in
13)

14)



Lesson learned - clean all your lens contacts (& body contacts) often!


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