OK, so here's a weird one...

Several months back, I bought myself a Lens Flipper. It seems to be a really useful thing to have! More recently, I bought a couple of Sigma lenses. Last night, I discovered something baffling: Even though both the Sigma lenses fit perfectly on my Nikon camera body, neither of them will mount properly on the Nikon-fit lens flipper. One lens will mount on one end of the flipper but not the other, the second lens point-blank won't mount onto either end [at least, not without applying far more force than you should apply to a delicate piece of precision engineering!]

I don't understand how this is physically possible. The mount on the lens flipper and the camera are identical. All my Nikon lenses mount effortlessly on both. The Sigma lenses mount perfectly on the camera body... but somehow not on the lens flipper. What's going on??

  • 1
    \$\begingroup\$ Contact the manufacturer to see if they have solution. \$\endgroup\$ Commented Nov 28, 2016 at 23:30

1 Answer 1


Different lenses protrude into the body cavity more or less, so even though the mounting ring is identical you may find that the sigma lenses have a different shape inside this ring.

I have several pentax and sigma lenses with a pentax fit, and I find that not all dust caps work on all lenses - looking closely its down to the shape of the lens inside the mounting ring.

  • \$\begingroup\$ Huh, interesting... I never thought that would be a thing. \$\endgroup\$ Commented Nov 29, 2016 at 19:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.