enter image description here

Can anyone point me to what might be at the root of this diagonal line appearing on each photo. It does not appear to be a crack, but am curious to see if any of you had come across a similar issue before.


  • 13
    \$\begingroup\$ looks like a hair on your sensor \$\endgroup\$
    – dav1dsm1th
    Aug 12, 2015 at 9:40
  • \$\begingroup\$ is it on every image with with every lens used? if so, does it also show up if you take a shot without a lens? Have you tried a air duster to blow out any stray fibres, hairs or dust lately? \$\endgroup\$ Aug 12, 2015 at 9:41
  • \$\begingroup\$ This link may be helpful -photo.stackexchange.com/questions/12/… \$\endgroup\$ Aug 12, 2015 at 9:50

1 Answer 1


That appearance is very typical for a hair sitting on the sensor. Fortunately they are also very easy to get rid of. Either go to a camera store or do it yourself.

Detach the lens in a dry and particle free (as particle free as possible) and lock the mirror up while opening up the shutter. This can often be done easily in a sensor cleaning mode from the camera menu. Otherwise just use a very long exposure time and take a shot. Note that when the sensor is active and gathering light it's charged and may attract even more dust.

Use an air blower to very carefully remove the hair. A filtered air blower is preferred since using an unfiltered blower directly onto the sensor can introduce more dust. Make sure to nut touch the sensor since it can easily be damaged.

When you're done point the camera to the sky and take a picture at a high F-number to make sure the dust is gone.

When using the equipment you'll eventually get a hair or alike on the sensor. It's very hard to avoid, but you can minimize the risk by only changing lenses in safe environments and preferably covering the camera's opening to not let dust in.

  • 1
    \$\begingroup\$ Whether or not it works, I've read that others take care to always change lenses with the camera facing down for this very reason. As long as your lens has no fluff on the rear element or otherwise trapped inside, this seems like it would work. \$\endgroup\$ Aug 12, 2015 at 16:27
  • \$\begingroup\$ And absolutely use an air blower. Don't use your mouth because that will trade the line for dots of spittle. \$\endgroup\$ Aug 12, 2015 at 18:10
  • \$\begingroup\$ Also, only do the cleaning in the camera's manual cleaning mode. Do not just take the lens off and take a long-exposure photograph, since the charge on the active sensor will attract even more dirt (and, if a timed exposure rather than bulb mode, you risk the mirror coming back down while you're cleaning). \$\endgroup\$ Aug 12, 2015 at 18:13
  • \$\begingroup\$ @DavidRicherby Not all cameras have a cleaning mode, but if they do use it as i wrote in my answer. The electically charged surface of the sensor isn't going to attract more dust than the existing hair contributes with so it's better than not removing it at all. Also using bulb mode will require one more hand so unless you've got an assistant a timed long exposure is an alternative. \$\endgroup\$
    – Hugo
    Aug 12, 2015 at 18:33

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