topic Re: Canon Lens 75-300mm AutoFocus Issues in EF & RF Lenses

Canon Lens 75-300mm AutoFocus Issues

mdbailey07 — Sat, 05 Sep 2015 20:42:44 GMT

Hello Guys. I'm hoping somone can give me some insight on the current issue I am having. 🙂 I recently purchased a Canon Rebel T5 EOS 1200D that came with 2 lenses. I am having issues with my 75-300mm lens. It sometimes tells me that there is a faulty connection between the camera and lens and to clean the contacts. I have done that numerous times. Now I have a new problem. This lens will not work in Auto Focus. When i try to take a picture in autofocus, it says the camera is busy in the lower left size of the screen and the auto focus just spins and it will never take a picture. Im new to this camera so I was wondering if it was a setting that needed to be changed or what may be the issue. I've tried every option on the camera, and it still won't work. I have no problem with the EFS 18-55mm lens taking pictures in autofocus, or with connection. I have done troubleshooting online and came to a dead end. Thank you in advance for any advice. 🙂

Re: Canon Lens 75-300mm AutoFocus Issues

ScottyP — Sat, 05 Sep 2015 21:02:49 GMT

Hi,

if if you go outside in really bright sunlight does the problem go away?

Failure to autofocus can be several things, including:

1.) light is too dim for the camera's (not the lens's ) autofocus sensor, or

2.) you are too close to the subject for the lens's minimum focus distance (59.1 inches for that lens!), or

3.) you are trying to focus on somethingfeatureless like a solid color wall, that lacks contrasting patterns or edges for the camera to grab onto.

Re: Canon Lens 75-300mm AutoFocus Issues

mdbailey07 — Sat, 05 Sep 2015 21:15:58 GMT

Hi. Scott. I have tried taking photos outside in really bright light and it still doesnt work. This issue started about 2 months ago and I have tried all sorts of things to try to get it to take a picture and have been unsuccessful. Thank you for the great advice. I'll keep the autofocusing tips in mind while I try to figure this out. 🙂

Re: Canon Lens 75-300mm AutoFocus Issues

ScottyP — Sat, 05 Sep 2015 23:53:09 GMT

Hmmmm.

Assuming your other lens works fine, then, I am kind of thinking that might be a bad lens. Normally with a new user you first suspect it is something the user is doing, but with all the connection error messages, plus your answers above, I really can't think what you could be doing wrong; it seems you are doing things right.

Does Bob or Tim or Biggs or anyone here think otherwise?

Re: Canon Lens 75-300mm AutoFocus Issues

RobertTheFat — Sun, 06 Sep 2015 04:17:31 GMT

@ScottyP wrote:
Hmmmm.

Assuming your other lens works fine, then, I am kind of thinking that might be a bad lens. Normally with a new user you first suspect it is something the user is doing, but with all the connection error messages, plus your answers above, I really can't think what you could be doing wrong; it seems you are doing things right.

Does Bob or Tim or Biggs or anyone here think otherwise?

I don't. I've had autofocus fail for all three of the reasons on your earlier list, and once because I stupidly went into a photo shoot with autofocus turned off. But the OP's experience doesn't appear to match any of those situations. So no, I don't have a better idea.

Re: Canon Lens 75-300mm AutoFocus Issues

ebiggs1 — Sun, 06 Sep 2015 20:20:22 GMT

Yup, that is about it.

One word, stop cleaning the contacts! It is very rarely dirty contacts that stop communicating with the camera.

And, did you do something to the lens/camera? Like drop it? Get it wet? Even a little wet?

Re: Canon Lens 75-300mm AutoFocus Issues

mdbailey07 — Sun, 27 Sep 2015 20:09:02 GMT

Thank you guys for all of your input. It is currently with geek squad.... for 19 days to be exact! They have finally determined that the lens is faulty and are sending me a new one as well as a new camera. Thank goodness we got the replacement plan. 🙂 Thanks again for your tips and advice.

Re: Canon Lens 75-300mm AutoFocus Issues

ebiggs1 — Tue, 11 Apr 2017 20:39:00 GMT

Two words of caution;

That lens is a fairly fragile one. Don't treat it roughly or get it wet at all. Not even splashed on. Don't move the focus ring when it is auto focusing. Not even accidentally.

Cleaning the contacts almost never to never works. You may do it for piece of mind but don't be discouraged when it doesn't help. The only time I ever remember seeing it work was a person that never changed his lens. Changing the lens, as you do with two lenses, tends to clean the contacts.

Re: Canon Lens 75-300mm AutoFocus Issues

yaroslav_stetsy — Tue, 10 Sep 2019 13:32:57 GMT

I heva exactly the same issue and what I found out - it's diaphragm that stuck in about f/11 position and doesn't move any way. Before taking picture it should be open (f/4.0 for this particular lens) to allow maximum light to go to the AF mechanism. When it's stuck in closed position my (and I believe your) camera can autofocus only on very bright objects.

Re: Canon Lens 75-300mm AutoFocus Issues

Peterman6 — Tue, 01 Oct 2019 06:51:47 GMT

Yep thats what I was guessing it was. I think I might just leave it as it is, I'm just an amateur when it comes to photography so I don't want to be spending too much money upsers, I'll probably just stick to using the manual focus, I've gotten used to it at this stage.

Re: Canon Lens 75-300mm AutoFocus Issues

yaroslav_stetsy — Mon, 30 Sep 2019 13:40:15 GMT

Yesterday I started fixing my lens and when I took everything apart I found that flex cable that goes to diaphragm is damaded. I ordered new cable for just $6 and will try to fix my lens. Problem looks like in holder of this flex cable and at some condition cable starts touching lens's body and when you zoom in/out it wears away. Please see attached picture.