topic Re: Exposure issues with 5D MK IV and Tamron 150-600 in EOS DSLR & Mirrorless Cameras

Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sat, 10 Jun 2017 02:17:43 GMT

I seem to be experiencing e posture issues with my 5D MK IV when using my Tamron 150-600. I did send the Tamron for the latest firmware update. I took the camera and lens on a trip and was shooting with auto ISO and shutter priority. All of a sudden, the exposures were dark. I switched to my Canon 24-105, and then everything was dark. Called Canon and they had me reset the camera settings. Appears to have corrected the 24-105 issues. For the most part, the 150-600 is working, but at the 150 range appears to randomly underexposed. I looked and the auto ISO is being set to a very low ISO. I was using evaluative metering.

called Canon and they basically told me I was using an inferior lens and that was the problem. This has been working fine until now. Not sure whether to send the camera to Canon, he lens to Tamron. I used partial spot metering and the exposures seemed better.

Re: Exposure issues with 5D MK IV and Tamron 150-600

Waddizzle — Sat, 10 Jun 2017 03:48:42 GMT

When you're shooting with shutter priority and ISO Auto, then you're letting the camera set two legs of the exposure triangle, something which I personally try to avoid because I get the occasional outlier exposure.

You can configure the camera to automatically control any one, any two, or all three legs of the exposure triangle. I typically shoot in manual with Auto ISO under widely changing light conditions. You can set an ISO upper limit in the menus. I rarely use anything but the default setting of Evaluative Metering when shooting handheld.

I have also questioned whether or not the WB setting can impact the exposure metering. Even though I shoot RAW, I have switched to shooting with a specific setting, instead of letting WB drift wherever it wants to go. Again, the occasional bad exposure has become even more rare with this change.

Re: Exposure issues with 5D MK IV and Tamron 150-600

TTMartin — Sat, 10 Jun 2017 14:15:54 GMT

@SSipple wrote:
I seem to be experiencing e posture issues with my 5D MK IV when using my Tamron 150-600. I did send the Tamron for the latest firmware update. I took the camera and lens on a trip and was shooting with auto ISO and shutter priority. All of a sudden, the exposures were dark. I switched to my Canon 24-105, and then everything was dark. Called Canon and they had me reset the camera settings. Appears to have corrected the 24-105 issues. For the most part, the 150-600 is working, but at the 150 range appears to randomly underexposed. I looked and the auto ISO is being set to a very low ISO. I was using evaluative metering.

called Canon and they basically told me I was using an inferior lens and that was the problem. This has been working fine until now. Not sure whether to send the camera to Canon, he lens to Tamron. I used partial spot metering and the exposures seemed better.

What was the maximum ISO you had set for 'Auto ISO'? You may have 'a very low ISO' set as the maximum.

Also, make sure you don't have any exposure compensation dialed in.

Accidentally setting exposure compensation is one of the leading causes of 'exposure problems'.

Re: Exposure issues with 5D MK IV and Tamron 150-600

ebiggs1 — Sat, 10 Jun 2017 14:28:42 GMT

"I seem to be experiencing e posture issues with my 5D MK IV when using my Tamron 150-600."

I admit I have not used the big Tammy on a Mk IV but I have used it on six or seven other cameras. Even a couple that don't have Canon printed on them! It has always worked well. Of course this doesn't mean it will work on a Mk IV after all it is not a Canon product but it does say something.

The only time I use auto ISO is on a G1x point and shoot. Set you ISO to a specific spot. Don't let the camera decide for you.

I always use raw anymore. There just isn't any good reason not to.

Whether or not auto WB affects exposure, it can't be very much. Not enough to make a big or even a noticeable difference to raw. I leave it set to auto WB. Why? Because WB has no effect on raw. It makes no difference where it is set.

Most settings have no effect of a raw file. However auto ISO does. That is why you need to pick what you want.

Do the basic test on a bight day. Pick a subject. Use normal settings and try the combo. Perhaps, f8, SS 1/1000, ISO 400.

If it works as it should, it is OK and good to go.

I'll bet it is.

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sat, 10 Jun 2017 14:30:00 GMT

Max ISO was set at 25600. There was no exposure comp dialed in.

Re: Exposure issues with 5D MK IV and Tamron 150-600

Waddizzle — Sat, 10 Jun 2017 14:30:18 GMT

Tom's post reminds of another suspected issue that I had with the occasional over/under exposure. I suspect that my thumb may have been hitting the exposure lock button, which would lock the automatically adjusted exposure settings.

This becomes an issue when you point the camera in a different direction, such as recomposing. Make sure your thumb is not acccidentally hitting AE lock. I began paying attention to this possibiity, and the mystery over/under exposures have all but vanished. I made few changes in how I did things all at the same time, so I cannot be certain which change may have cured the bad exposure problem.

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sat, 10 Jun 2017 14:32:09 GMT

Thanks, good thought, but I know that wasn't the issue.

Re: Exposure issues with 5D MK IV and Tamron 150-600

TTMartin — Sat, 10 Jun 2017 14:37:10 GMT

@SSipple wrote:
Max ISO was set at 25600. There was no exposure comp dialed in.

Could you post an example of the under exposure with the full EXIF data intact.

Re: Exposure issues with 5D MK IV and Tamron 150-600

ebiggs1 — Sat, 10 Jun 2017 21:33:59 GMT

"... but I know that wasn't the issue."

It would not be if you reset the camera like the Canon rep said. That is the first thing to do when something isn't as it was.

Re: Exposure issues with 5D MK IV and Tamron 150-600

TTMartin — Sat, 10 Jun 2017 21:45:41 GMT

@SSipple wrote:
Max ISO was set at 25600. There was no exposure comp dialed in.

Also just to be clear, Max Auto ISO is set to 25600? Not just Max ISO was set at 25600, those are two different settings.

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sat, 10 Jun 2017 22:42:14 GMT

Yes, I am well versed with auto ISO. Both are set at 25600

Re: Exposure issues with 5D MK IV and Tamron 150-600

Waddizzle — Sun, 11 Jun 2017 00:05:51 GMT

@ebiggs1 wrote:
"... but I know that wasn't the issue."

It would not be if you reset the camera like the Canon rep said. That is the first thing to do when something isn't as it was.

Really? If you reset the camera to factory defaults, doesn't the AE button lock exposure settings?

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sun, 11 Jun 2017 03:04:06 GMT

I did reset it and in mist circumstances it is working. Prior to the reset, everything was being underexposed

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sun, 11 Jun 2017 03:09:29 GMT

Not sure of your question here. I was not using AE lock. Some of the photos are fine, others are not

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sun, 11 Jun 2017 03:40:44 GMT

Here are 2 images shot seconds apart using auto ISO. As you can see, one was shot at iso 20000 and the other at 8000. Both were shot at 1/400 sec and f5.6

Re: Exposure issues with 5D MK IV and Tamron 150-600

TTMartin — Sun, 11 Jun 2017 13:16:14 GMT

@SSipple wrote:
Here are 2 images shot seconds apart using auto ISO. As you can see, one was shot at iso 20000 and the other at 8000. Both were shot at 1/400 sec and f5.6

My guess is that Canon is correct it has to do with the lens's programing. Tamron reverse engineers how the EOS lenses are supposed to operate. They also have the lens 'lie' to the camera about its aperture so that an f/6.3 lens like the 150-600 can work with a camera that can only auto focus with a lens with a maximum aperture of f/5.6. Looks like somewhere there is a flaw in the Tamron's programming.

FWIW, the Canon EF 100-400 L IS II is a superb lens. Even with a 1.4X TC III it is still sharper than the Tamron.

Re: Exposure issues with 5D MK IV and Tamron 150-600

ebiggs1 — Sun, 11 Jun 2017 14:49:50 GMT

"Here are 2 images shot seconds apart using auto ISO."

The obvious is to turn off auto ISO and try it. I bet it works without the exposure issues you are experiencing. Neither of the two Tamron 150-600mm's I have do that. As a matter of fact none of the Tamron lenses I have do that either. But I don't use, I don't even like, auto ISO. And, like I said I have not tried it on a 5D Mk IV.

What do you have to lose? Just give it a try. BTW, are you perhaps using spot metering?

Re: Exposure issues with 5D MK IV and Tamron 150-600

SSipple — Sun, 11 Jun 2017 15:09:25 GMT

Thing is, I have been using it since February and have not experienced this issue until the camera went out of whack and started underexposing everything. I used auto ISO because I usually shoot concerts where the lighting changes will and you don't have time to be adjusting. Sure, I can get around it, but shouldn't have to. I like to shoot manual and auto ISO

Re: Exposure issues with 5D MK IV and Tamron 150-600

ebiggs1 — Sun, 11 Jun 2017 15:28:25 GMT

"...until the camera went out of whack and started underexposing everything."

Whoa! I missed this. Are you saying it happens with more than just the big Tammy on your Mk IV? Perhaps auto ISO is not working as it should. Do try a few shots of known good conditions with out auto ISO turn on. Fix it to a middle of the road 400 or so. If it works, it works, and something else is a foot. Also try your other lenses?

One thing about Canon support is, you get what you get. I mean all techs are not created equal. I have received great support, up and beyond with some, even most of them. But, there is always a 'but' isn't there? But once in a while you get a dud. In that case call back and you will likely get a different tech.

Re: Exposure issues with 5D MK IV and Tamron 150-600

TTMartin — Sun, 11 Jun 2017 17:05:54 GMT

@SSipple wrote:
Thing is, I have been using it since February and have not experienced this issue until the camera went out of whack and started underexposing everything. I used auto ISO because I usually shoot concerts where the lighting changes will and you don't have time to be adjusting. Sure, I can get around it, but shouldn't have to. I like to shoot manual and auto ISO

Since a simple camera reset fixed the underexposure on everything, but, the Tamron lens, all things point to the Tamron lens as the issue.

If you are having issues with the Tamron lens you should be contacting TAMRON not Canon.