Could holding my camera lenses backwards ("free-lensing") for macro photography cause damage?

Question

Recently, I have been experimenting with some macro photography by flipping my camera lenses backwards and then taking pictures ("free-lensing, not using a reversing adapter").

Since this is a non-conventional technique, I'm concerned. Could this damage my lenses? Is there anything else I should know before continuing this experiment?

Here are some of my shots: (since the focus on the lense doesn't work when it isn't attached to the body, some of these are pretty bad)

Here is a picture that I took with the lense on forward after taking some backwards pictures:

Answer 1

Whenever you're freelensing (holding the lens against the camera, rather than securing mounting it), you do run the danger of getting stuff inside the camera body (including stray light), but as long as you watched out to make sure nothing comes in contact with the lens elements, you probably aren't damaging your lens. The main "issues" (or features, depending on your POV) with freelensing are the fact that you can introduce light leaks and that you can inadvertently shift or tilt the lens [see the Wikipedia view camera article section on movements]. Most folks, in fact, use freelensing because of these two things.

If you want to avoid them, however, I'd recommend looking into get a reverse mount ring (which has the bayonet mount on one side, and filter rings on the other) or a rig of some kind, which eliminates the gap between the body and the lens, and if it offers electronic communication may allow you control over the lens aperture and/or autofocus. Focusing is still primarily going to be done by adjusting camera distance from the subject, as with any of the so-called "poor man's macro" methods.

You can also reverse mount a lens onto the face of a mounted lens, using a simple male-to-male filter "coupling ring" (probably the cheapest method gear-wise).

The other methods include macro-converters (aka close-up filters) and extension-tubes.

Answer 2

As far as I know, the only potential for damage is through hitting something with the exposed end of the lens, or with things ending up inside the lens. So long as you aren't shooting in wet or dusty conditions, you should be fine.

Personally, I'd suggest macro tubes for a cheap alternative. I spent something like $10 on a bare-bones metal set, and you don't have to worry as much then.

Answer 3

It isn't inherently dangerous for your lens, but some camera bodies have their lens mount sticking out a bit. If the front element of your lens is wider than the body mount, then just be careful not to scratch the lens on your camera itself.

Also, the way some lenses are designed creates an opening in the rear element when zooming or focusing. If dust or anything else gets in there while you are freelensing (or just changing lenses for that matter), you'll probably never get it out and you'll have dust inside the lens.

Answer 4

I free lens quite regularly. I also have extension tubes that I ... free lens with as well. This photo I had extension tubes on without the end piece that I then slid an old projector lens into. Not attached at all. It was taken outside in broad daylight with lots of other plants and stuff around, I didn't remove them in post either. This is entirely out of camera:

If you're worried about your lens they sell Protectors as you can see in this question: Is there any protection ring available for reversed lenses?

Otherwise the more dangerous part is to your sensor. I don't get incredibly worried about that though. Just means I need to clean it a little more often than others might. No big deal. Beyond that there's really nothing that makes free lensing inherently more risky to your lenses than mounting them. Well, I guess if you drop it that's on you as well.