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Occasional Contributor
Posts: 17
Registered: ‎06-09-2017

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

Yes, I am well versed with auto ISO. Both are set at 25600
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VIP
Posts: 9,236
Registered: ‎08-13-2015

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


@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?

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Occasional Contributor
Posts: 17
Registered: ‎06-09-2017

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

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

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Occasional Contributor
Posts: 17
Registered: ‎06-09-2017

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

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

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Occasional Contributor
Posts: 17
Registered: ‎06-09-2017

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

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 

 

SAS_5743.jpgSAS_5743.jpg

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Respected Contributor
Posts: 1,971
Registered: ‎02-26-2015

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


@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. 

 

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VIP
Posts: 12,272
Registered: ‎12-07-2012

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

"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?

EOS 1DX and 1D Mk IV and several lenses!
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Occasional Contributor
Posts: 17
Registered: ‎06-09-2017

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

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
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VIP
Posts: 12,272
Registered: ‎12-07-2012

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

"...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.

EOS 1DX and 1D Mk IV and several lenses!
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Respected Contributor
Posts: 1,971
Registered: ‎02-26-2015

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


@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.

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