Autofocus deterioration

FidelCastrovich · Oct 22, 2009

Does anyone know if there is such a phenomenon?
Does the autofocus mechanism's performance deteriorate with time?

Is there any regular maintenance that can be done? Like cleaning the focusing screen professionally?

I feel like all the cameras i've used lately had a major or at least noticeable deterioration in autofocus capabilities over time.

Derrel · Oct 22, 2009

Yes, there is a routine cleaning thing you need to do,and that is to clean the AF sensor area, located down on the botom of the mirror box area, located a few mm in front of the sensor. Set the camera to BULB exposure mode, turn the camera off, remove the lens, turn the camera back on, make sure it's still set to BULB, and press the shutter release to swing the mirror UP. Look down into the mirror box, and there is a small, perhaps 2.5 x 3.5 millimeter depression or area where the autofocus sensors are located.

If any hair, fiber, sand, or debris gets onto the AF sensor area, it can affect the AF performance. You need to blow that depression out with a clean bulb blower using just air. Not canned air, but just air from a bulb blower. I know you live in a dusty part of the world,so I suppose it's possible that very fine,airborne particulate matter might have found its way down into that area. Even a sweater fiber or two can mess up the AF system.

musicaleCA · Oct 22, 2009

*ahem* Bulb mode should NOT be used to keep the shutter open for cleaning. Doing so means that the sensor is active, and thus will attract more dust. Use the camera's cleaning mode as described in the manual instead.

In this case, you shouldn't even need the shutter to be open. It would be prudent to simply use mirror lock-up instead to get the mirror out of the way so that you can access the AF sensor. When you're done, just put a lens or body cap back on, and then release the shutter (or turn off the camera, or switch mirror lock-up off, whatever).

Garbz · Oct 22, 2009

MusicaleCA is right, except not all cameras have a Mirror Lockup, whereas all cameras have some kind of a cleaning mode.

You can take it also to be done professionally. For about $90 from a local authorised repair dude he'll remove the AF sensor and clean it properly. Some designs like many of the Nikon designs will have tiny holes in the bottom of the camera for the position of the individual AF sensors. This means that any air you manage to some how blow into the tiny hole may not create enough turbulence to get the dust out. I guess this is very camera specific though. I definitely don't like my chances of cleaning the D200 AF for instance.

FidelCastrovich · Oct 22, 2009

I knew i wasn't seing things! It made sense to me, but photogs that i asked here didn't know what i was talking about.

Thanks alot, i think i'll take it to a shop then, Mack will(should) cover it.

iolair · Oct 22, 2009

I've been reading in reviews on amazon of the Canon 50mm 1.4 that a fair few have the autofocus deteriorate and die over time (if they do it, it sounds like they wait until JUST AFTER the warranty period expires!). People were mentioning similar repair cost to that mentioned above.

Mackcam · Oct 28, 2009

FidelCastrovich said:
I knew i wasn't seing things! It made sense to me, but photogs that i asked here didn't know what i was talking about.

Thanks alot, i think i'll take it to a shop then, Mack will(should) cover it.

My name is Desiree and I am the Customer Relations Supervisor for Mack Camera. Please let me know if I can be of assistance with the repair of your unit. I can be reached via email at [email protected].