When I'm not using the camera, or when the lenses are packed at home, should the lens switch be at AF or MF? Or does it make no difference?

And by the way, is it better to leave the lens on the camera? Or separately, each one with the respective cover on?


Indifferent. In AF it will prevent movement of the focus ring but if the ring is forced somehow, it could cause damage to the focus gears or motor (if it isn't full time MF capable). In MF, you don't have to worry about damage to the gears, but the lens itself may now loosen up and may cause added wear and tear on the lens from actuating.

Both cases are unlikely to be a problem though. Personally I leave my lenses on AF mode simply because I prefer to have them locked down when in storage (or they are full time MF and it doesn't matter either way).

  • "if focus ring is forced somehow, it could cause damage to the focus gears or motor" - any credible source to support that statement? Lens manuals that I know, don't say anything like that. When AF is selected, focus ring does not affect focus gears nor focus motor. I tested it many times on both Canon and Nikon lenses.
    – user28169
    Jun 20 '14 at 14:59
  • 3
    @MikołajBartnicki try it on a cheap lens. Good lenses have what is known as full time manual and have no direct link, but lenses without full time manual have a mechanical link between the motor and the focus element. If the motor is powered down and locked, then trying to turn the focus ring should be impossible without breaking things or at a minimum adding excess wear and tear.
    – AJ Henderson
    Jun 20 '14 at 15:04
  • @MikołajBartnicki See gdlp01.c-wss.com/gds/5/0300003405/02/ef50f18ii-im3-eng.pdf
    – Michael C
    Jun 22 '14 at 20:49
  • @MikołajBartnicki Also page 4 of the EF-S 18-55mm IS II manual: gdlp01.c-wss.com/gds/7/0300004937/01/ef-s18-55f35-56isii-en.pdf
    – Michael C
    Jun 22 '14 at 20:53

Generally speaking it doesn't matter if you leave the lens in AF or MF. AF will prevent the lens barrel from moving, however, so might be the safer choice.

You should take the lens off your camera only when absolutely necessary to avoid getting dust in the camera itself. There's no need to take the lens off the camera when not in use.

  • 1
    Many (most?) DSLR users have more lenses than cameras so always have at least one lens in storage off-camera. Jun 20 '14 at 14:48
  • What's your point? Jun 20 '14 at 15:36

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