Dust inside the canon ef 24 85mm lens

check for dust inside lens area: find the pins where they connect to the frame of camera clean the contacts with a pencil eraser you may want to check the battery see if has enough power to run zoom lens. check the settings on the camera, if none of these issue than take to a camera shop.

Canon's error 99 is a catch all for several things the short answer is an electronic connection. Something isn't making contact and the first place to go is to the "gold" contacts between the lens and the camera body. Make sure the camera is off and remove the lens, place the camera lens side down on a clean dust/lint free surface or put a body cap on. Take the lens and holding as vertical as possible with the gold contact points down use a soft rubber red pencil eraser to lightly clean the contacts. You can remove any rubber dust and partials with a lens cleaning cloth NOT TISSUE. Make sure the area is clean of lint and dust, place the rear lens cap on or stand the lens up on a clean dust and lint free surface. the camera is a bit more tricky as you need to clean the contacts inside the mirror box. Hold the camera as best you can face down and again use the pencil eraser to lightly clean the contacts. Holding the camera as mus as possible lens side down. This will minimize any dust, dirt or lint getting into the camera body and eventually ending up on the sensor. Remove any rubber dust with a lens cloth not tissue and don't use any liquid, don't use a puffer either all that will do is drive dust partials into the camera. Once that's done install the lens, next remove the battery and do the same cleaning trick with the battery contacts, if you have a battery grip do the same thing. Okay now check out the camera if everything is go and works then you are good to go. If not then I would suggest doing a camera firmware update, all updates can be found on the Canon web site they are free and will correct any issues your camera has with the internal programming which may also be the cause of your error 99.

Possible power problem make sure the camera has sufficient battery power and is functioning as it should (less the lens) if this is okay then the problem is between the lens and body gold contacts. It's a quick and easy repair you can do yourself. Shut the camera off remove the lens and put the body cap on the camera if you don't have a body cap place the camera on a clean lint free surface like a glass table or counter top. Use a new clean red pencil eraser to gently rub the gold contacts on the lens. Hold the lens as vertical as possible when you are doing this to minimize the rubber dust getting into the rear lens element. Clean the area of rubber dust with a puffer blower or lens cloth not a tissue. Set the lens down on the clean lint free surface and gently clean the gold contacts in the camera body keeping the camera lens mount down to minimize any rubber dust from getting into the sensor area. Clean the contacts with a lens cloth only do not use a blower/puffer, re-install the lens and it should come on. When installing the lens make sure it makes a solid click and locks securely in place.

First question: where is the dust?
If the dust ist outside the cam: no problem. Try a soft brush and remove bigger particles, then take a thin microfibre cloth and clean the dust film on the lens. Be careful - every sand particle scratches the coating, so use the brush!
If the dust is internal it's more complicated.
May be the dust is on the focussing screen. If you dismout the lens, there is a litte lock on the top inside the cam. Do not open without having special tool. Each fingerprint on this little plastic plane is not removable. It's an extreme sensitive fresnell lens.
Don't try to clean that with cloth or brush. Only airflow is allowed.
If this dosn't help - use the Canon service or replace the focussing screen with a new one (as Example Canon EF-D).

'Error 99' indicates some problem with the AF contacts. This is a common error in Canon lenses. It could indicate a very simple problem like dirty contacts or a much serious one like the breakage of USM cable.
As a first step, you can try cleaning the lens and body contacts (the metal contacts between the lens and body) using a pencil eraser. Be careful to hold the body facing down so that no dust falls inside. After cleaning both the lens and the body contacts, re-attach the lens and try shooting. If the AF does not work still, you need to take the lens to an authorized service center.

Most likely it is dirt/dust on inside the lens. If it is in the bottom of the picture, the dirt will be on the top edge of the lens. If it is inside the lens, you will probably not be able to clean it your selves.

If the dust is inside the lens, then you are unlucky. Canon lenses (except for a select number of the L series lenses) are not dust or weather sealed. So each time you work the zoom mechanism on a inexpensive EF 75-300mm f/4-5.6 III lens, the mechanism is working like a giant billows allowing air (and dust and moisture) to flow through the lens and camera body. Sometimes large dust particles can accumulate on the different lens elements, but it does not have any impact on the quality of the photo

If the dust is creating problem fro your picture get it fixed from service center i will suggest you should not try to open it

Regards

I had this problem too, then my camera started getting Error 99 (there is some problem) and not working.
If you look at this website and follow the steps under Update 2
http://www.richardsnotes.org/archives/2005/04/29/50mm-lens-contact-points/
I think you will fix your problem. The connections between lens and camera probably have a little dust in them, use a soft rubber eraser to clean them. Make sure no dust or pieces fall into the camera or lens when cleaning!

Hi,

you can have a look here:
http://www.ejarm.com/photo/ef5018iidis/
and here:
http://nis-lab.is.s.u-tokyo.ac.jp/~ybando/rgb_filter/disassembly.pdf

HTH,

Jean-Marie.

Not by a user This seems to be a faulty item so Canon Customer support should be advised.