6D with a Tamron 28-300mm Di PZD Lens.

[AHC6D]

I have had terrific experience with this combo until recently. On a trip to Scotland the camera would not respond to the shutter being tripped. The lens would not auto focus when shutter button was pushed. After several tries the 6D would fire, but not always. I have cleaned and dried the contacts between the lens and body which did not seem to have any impact. When it fires all is fine - lens focusses and image is captured. This anomaly has continued on a periodic, but not predictable pattern. Looking for thoughts on the underlying issue. Thanks,

[Waddizzle]

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@AHC6D wrote:
I have had terrific experience with this combo until recently. On a trip to Scotland the camera would not respond to the shutter being tripped. The lens would not auto focus when shutter button was pushed. After several tries the 6D would fire, but not always. I have cleaned and dried the contacts between the lens and body which did not seem to have any impact. When it fires all is fine - lens focusses and image is captured. This anomaly has continued on a periodic, but not predictable pattern. Looking for thoughts on the underlying issue. Thanks,

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I would try resetting the camera in "P" mode, but only as a resort.

You could have a poor connection between the camera and lens, but I doubt it.  Bad mechanical connections problems do tend to be intermittent, but they also get progressively worse over time.  But first, I would check the usual suspects.

Make sure the subjects have sufficient light.  Double check that you are in One Shot mode, or AI Servo mode.  Double check that you do not have accidentally BBF enabled.  Make sure that you have sufficient light, and are observing the Minimum Focusing Distance.  There is also a setting in the camera that causes it to stop trying to hunt for focus, when and if it gets lost trying to acquire focus. 

If you are experiencing problems focusing when you switch from short focal lengths to pretty long focal lengths, then this may be normal behavior.  Many wide range telephotos have trouble refocusing from the short to the long end, or vice versa.  The same could be said about switching focus between very close objects, to fairly distant objects.

As a last resort, try resetting the camera.  It must be done in two places.  The second is clearing custom functions, and even then not all functions and custom settings are cleared. 

[RobertTheFat]

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@AHC6D wrote:
I have had terrific experience with this combo until recently. On a trip to Scotland the camera would not respond to the shutter being tripped. The lens would not auto focus when shutter button was pushed. After several tries the 6D would fire, but not always. I have cleaned and dried the contacts between the lens and body which did not seem to have any impact. When it fires all is fine - lens focusses and image is captured. This anomaly has continued on a periodic, but not predictable pattern. Looking for thoughts on the underlying issue. Thanks,

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The usual explanation for that symptom is that there isn't enough light for the lens to focus correctly. Try setting the lens to manual focus and see if the problem goes away.

Assuming that is the problem, and you don't want to focus manually, one solution is to use an external speedlite. Many Canon speedlites provide an infra-red "assist beam" that can help the camera focus. If you set it up correctly, you can use it even in venues where flash isn't allowed. Where flash is allowed, the speedlite can use visible light for the assist beam. On some cameras with built-in flash (I forget whether the 6D is one), the built-in flash can be programmed to provide an assist beam (using visible light).

[AHC6D]

Thanks for the prompt suggestions to fix my issue.  

In order of your thoughts:

1. I agree, not time to reset via "P" mode.

2. Have cleaned contacts just to be sure.

3. Shooting in plenty of light.  Mostly daylight.  In One Shot mode.  Not sure what "BBF enabled" means.

4. Issue happens with long focusing distance and short.  Not consistent.

5. The camera does not stop hunting for focus, it never stops.  Almost like the body and the lens are not communicating consistently.

6. When autofocus is functioning, it works fine at all lengths even when shooting video and changing length during exposure.

7. No custom settings loaded.  But, cleared them anyhow.

Any other thoughts?

Thanks much.

[AHC6D]

thanks Bob.

6D does not have built in flash.  But this issue was not related to available light as it occured during strong daylight with well lit subjects.  Again, it was not consistent and no clear pattern of when it would happen.

Question:  Could a high humidity environment cause a problem with the connectors between the body and the lens?

Thanks, Alan

[Waddizzle]

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@AHC6D wrote:

thanks Bob.

6D does not have built in flash.  But this issue was not related to available light as it occured during strong daylight with well lit subjects.  Again, it was not consistent and no clear pattern of when it would happen.

Question:  Could a high humidity environment cause a problem with the connectors between the body and the lens?

Thanks, Alan

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A high humidity environment is not good for most consumer electronics.  I store cameras and lenses in plastic bags.  I use dessicants for long term storage.  My 20, 30, 40 year old gear is still in pristine condition.

The winning for strategy trouble shooting problems is to logically eliminate possibilities, not speculate on possible causes, and then testing to confirm or deny that hypothesis. 

[AHC6D]

I agree with your strategy point. Just wondering about things to test for.

[Waddizzle]

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@AHC6D wrote:
I agree with your strategy point. Just wondering about things to test for.

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Troubleshooting electronic circuits involves the low level tracing of the signal paths from start to finish.  Eventually, you will find a point where the signals break down, and this is where the fault lies.

A similar approach can be used to perform high level troubleshooting.  The first question to resolve is whether or not the problem lies with the camera body, or the lens.  Try the lens on a different camera body, to see if the problem "moves" with the lens.  Try a different lens on the camera body, to see if the problem "persists' with the camera body.

[kvbarkley]

It also helps to really know the system - this works for cars, too. Someone said that Feynman could "Fix radios by thinking!", which is the idea here.

You get to know the system really well, so that you can piece together all the symptoms and pinpoint the problem. Recently we were having trouble with a computer that would crash. Sometimes the hard disk would freeze, sometimes the internet would freeze and sometimes the graphics would be screwey. We had just replaced the graphics card, but I got to thinking what could be common to all those systems...the power supply! I replaced that and so far things seem to be working.

[ebiggs1]

" I have cleaned and dried the contacts between the lens and body which did not seem to have any impact."

This rarely to never works.  It is usually a waste of time.  The act of mounting and removing the lens tends to 'clean' the contacts.  People that put the lens on and never remove it can benefit from cleaning.

All camera/lens combos have their limits.  You probably exceeded yours.

 The way to tell is to clear all settings.  Set the 6D to 'P' mode.  The lens to AF.  ISO around 200 to 400.  Go outside on a nice sunny day and try it.  Shoot a subject 25 to 30 feet away and see if it works.

If it does there isn't anything wrong with the gear.  If it doesn't or in still internment, call Canon Service as you will need it.