topic Re: EOS 5D mkII with 24-105mm L f4 AF problems in EOS DSLR & Mirrorless Cameras

EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Sun, 02 Mar 2014 11:40:02 GMT

My last two jobs using the EOS 5D mkII with 24-105mm L f4 have lost about 50% of the images through poor focus.

I use the centre focus point, one shot, with the expanded 'invisible' AF points disabled. Focus beep enabled & focus search after focus failure disabled. Firmware is updated to 2.1.2 & all electrical connections have been cleaned.

I set up a high-contrast & low contrast subject as a control test. The EOS 5D mkII with 24-105mm find the focus on the high-contrast subject but not on the low contrast subject. If I put the lens on an EOS 5D or EOS 400D it finds the focus on the low-contrast subject. If I put a 50mm f1.8 or 20-35mm zoom on the EOS 5D mkII it finds the focus on the low-contrast subject.

Is there an issue with the EOS 5D mkII with 24-105mm combination using the phase AF? I toggled the IS which makes no difference.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Wed, 26 Feb 2014 20:35:57 GMT

"Is there an issue with the EOS 5D mkII with 24-105mm combination using the phase AF?"

I have use that combo a extensively over the last several years (1000's pf photos) and never seen any problems.

Other than cleaning the contacts on the camera or possibly the sensor and area, I don't know why it would not focus properly.

Maybe a C&C by Canon is in order?

Re: EOS 5D mkII with 24-105mm L f4 AF problems

amfoto1 — Wed, 26 Feb 2014 21:50:05 GMT

Hi,

I assume you have used the combination of lens and camera without any problem prior to these last couple jobs where you had trouble. If so, have you changed anything? If so, that might be the cause.

If not, since the lens seems to work fine on other cameras, and the 5DII works fine with other lenses, it's pretty baffling.

I would have suggested things you wrote that you have already done: firmware update, cleaning the lens to camera contacts (and checking that the corresponding spring-loaded pins in the front of the camera are not sticking), and using the center AF point only.

If you haven't already done so, I'd also do a "reboot" of the camera, just to be certain there are no bad instructions "stuck" in the camera's memory.

In order to reboot the 5DII, first you need a jeweler's cross point screwdriver to get at the little time/date memory battery that's on the lefthand side of the camera (right below the various input/output sockets). Use the screwdriver to remove the single screw that keeps the small battery drawer in the camera. Turn the camera off. Remove both batteries. Switch the camera on and press the shutter release button once. It won't fire, of course, but this will drain any remaining power in the circuitry and should force the camera to reboot. Switch camera back off and reinstall the batteries. Then turn the camera back on check the date/time. If it needs to be reset, you got a proper reboot. If not, try again. If it still doesn't reboot, try leaving the batteries out overnight.

There are no guarantees... In fact I suspect it's rather unlikely to help with a focus issue. But it's free and easy to try, and sometimes it helps with various issues.

Enabling the "assist points" or not shouldn't matter at all. Those only work in AI Servo mode. You wrote that you are using One Shot mode and those additional points will not function.

Turning IS on or off also shouldn't matter. Some people swear IS makes lenses focus more slowly. I think it actually helps with accuracy and focus speed.

One thing though... Are your test shots and the problem shots on the job done on a tripod? If so, the 24-105 is one of the lenses where IS needs to be turned off if the camera is solidly mounted on a tripod. If there is no movement, the IS can go into sort of a feedback loop that causes movement. The overall blur this causes can look like missed focus.

I have never heard of a specific problem with the 5DII and 24-105 combo.

Hope this helps! Keep us posted.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Wed, 26 Feb 2014 22:10:23 GMT

Thanks for the feedback...

Will try a reboot as this is the only suggestion I haven't already tried (did a function reset). Tests were handheld (as were the last 2 jobs which suffered from image losses).

I mentioned the assist point as I did try all the AF focus modes to see if it resolved the issue.

I am a bit baffled too ...as there seems no logic to the test results!

One point that seems unlikely but worth a mention. I recently used a Yongnuo ST-E2 flash controller with AF Assist. It stopped working second time I used it & is currently in China being repaired. Is it possible that a 3rd party accessory could corrupt the Canon AF in the way I am experiencing? I will report on the hard reset.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Fri, 28 Feb 2014 14:16:04 GMT

Over the years I have heard of every conceivable calamity possible blamed on 3rd party off-brand accessories. Now whether true or coincidence remains elusive. So the answer is, yes. But not proven.

As always it is best to use Canon equipment with Canon equipment.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Fri, 28 Feb 2014 14:33:10 GMT

I have discussed it with Canon UK & Fixation repairs.

The only advice I could get was tinkering with the sharpness in the various custom functions. Not ideal. Needless to say, they both recommended a full body service.

It looks like this is what I will do...

Re: EOS 5D mkII with 24-105mm L f4 AF problems

cale_kat — Sat, 01 Mar 2014 18:27:28 GMT

@ebiggs1. I notice that you use Lightroom with your Canon. So an Adobe product is OK but not a Yongnuo product? I'm trying to follow your logic in this example which involves AF electronics.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Sat, 01 Mar 2014 18:54:08 GMT

I not sure I follow the Lightroom connection.

When shooting I use no tethered software, only what is in-camera. I mentioned the Yongnuo as I was using its AF Assist when it 'died' on the camera. It has just returned from China where they have reinstated its ability to fire a speedlight but not to control the light output.

I am resigned to a full camera service.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

cale_kat — Sat, 01 Mar 2014 18:46:56 GMT

@20pictures, Your mention of using the focus assist made me wonder if this problem (difficulty locking on in low contrast scenarios) didn't exist before you used the auto focus accessory.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Sat, 01 Mar 2014 18:51:05 GMT

Yes, it did. The AF Assist was an attempt at a work-around which is why I did not include it in the Control Tests I performed.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Sat, 01 Mar 2014 19:31:37 GMT

"@ebiggs1. I notice that you use Lightroom with your Canon. So an Adobe product is OK but not a Yongnuo product? I'm trying to follow your logic in this example which involves AF electronics."

Sorry, but you really lost me with that statement!

"I'm trying to follow your logic ..."

Lightroom in no way interacts with the camera. It can not accurately be described as a camera accessory! It does not send electronic signals to the circuitry in the camera. Now whether a 3rd party flash is at fault, is not known. I don't use them nor do I recommend anyone else use them. But if it is your cup of tea, more power to ya.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

cale_kat — Sat, 01 Mar 2014 22:00:00 GMT

If the problem is a software issue, which is what would be suggested for a focus accessory causing selective (it only troubles the OP in low contrast scenarios) auto focus trouble, then it's a corruption or virus issue. I think it's just as likely you could bring that on through memory card use. At some stage you're inserting a compact flash card into a card reader and tether with a computer. Reuse of that card carries the same risk, possibly much higher, of creating corrupt files or bringing a computer virus into the camera.

I only remarked on the Lightroom because it's in your signature and it is so popular with photographers.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Sat, 01 Mar 2014 22:58:42 GMT

You may have a point about the memory card but it isn't possible for the camera to get a virus. Unless you consider some firmware swapping Trojan. It just doesn't have the necessary resources to process a virus. Plus there are so many different internal workings of DSLR's it isn't practicable.

At the very least, I have never heard of a camera being infected with a virus but ..........................

Re: EOS 5D mkII with 24-105mm L f4 AF problems

cale_kat — Sat, 01 Mar 2014 23:41:02 GMT

At the very least, I have never heard of a camera being infected with a virus but ..........................

I haven't either. I'm speculating, of course, about the cause of any auto focus malfunction. But I'm struck by the high and low contrast test and the differences in test results.

I believe the 5D Mark II has two systems (contrast and phase detection) but only one is available when using the optical viewfinder. I'm not technically knowledgable about the system, so you'll undoubtedly have to correct me, but it seems that the low contrast subject matter does not register on the auto focus sensor with sufficient strength to allow the camera to resolve the focus point.

The OP also had success focusing on the low contrast subject with different lenses. One lens, a 50mm f1.8, is considerably faster than the 24-105 f4. The other lens was posted with a typo, I believe. The results of this comparison suggests that the lens is to blame. However, when transferred to a different body, the lens works properly. The 5D, however, does not have live view but has a very similar auto focus system. That points to a communications (software) problem between the mk ii body and lens. The 400D test, which also accepted the 24-105 lens without problem, has a different auto focus system. It would be difficult to make a judgement based on this last test.

I have gotten just as far as speculation will take me. I am guessing that the lens is confused by the instructions it has received from the body but have no idea how to resolve this problem.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Sun, 02 Mar 2014 11:40:52 GMT

Thanks for taking the time to discuss this issue. It's a shame I have not been able to correct the fault.

With regards to my tests the lenses used were:

CANON EF 50mm f1.8 II
CANON EF 50mm f1.2L US
CANON EF 20-35mm f3.5-4.5 (discontinued)
CANON EF 24-105mm f4L IS USM

There was a typo...!

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Sun, 02 Mar 2014 14:46:27 GMT

I am going to fall back to my original suggestion.

"Maybe a C&C by Canon is in order?"

Send it to Canon for a "clean & check".

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Tue, 11 Mar 2014 16:03:19 GMT

OK ...I've sent the lens & the body to Canon to fix the focussing issue.

They contacted me today to say that the lens is giving an Error 01 & that the power diaphragm needs replacing. I'm at a bit of a loss. The fault is a focus issue & I never have any error messages in all the years I have used this lens/body combination. They had stripped & cleaned the lens but I am wondering if they damaged it during the service.

Any comments?

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Tue, 11 Mar 2014 16:07:54 GMT

"... I am wondering if they damaged it during the service."

In a word, No.

Re: EOS 5D mkII with 24-105mm L f4 AF problems

20pictures — Tue, 11 Mar 2014 16:25:15 GMT

I am curious to know why their service software would show an error that doesn't show on-camera? I assume the error would display on the preview screen but (as said) I have never seen one.

They have yet to test the AF...

Re: EOS 5D mkII with 24-105mm L f4 AF problems

ebiggs1 — Tue, 11 Mar 2014 16:37:09 GMT

They have far more intense diagnostics than your camera does.