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

[SSipple]

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.

[ebiggs1]

"I had the firmware updated prior to purchasing the camera."

Not the firmware of the camera but the firmware of the lens?  DId you have it updated?  Canon will not include instructions on the Tamron lens in their firmware.  You need to have Tamrom update the lenses firmware.  You can't do it yourself.

Regaurdless of the negative posts, the Tamron will work.  You are on the right path to have Canon check out the Mk IV and have Tamron check out the lens.  If you are a review reader, seems to be the thing here, you will see the Tamron is a highly reguarded lens.  I have two of them.  One for Canon and a brand-N version.  They both work very well.

The G2 is even better!

[SSipple]

Yes, the firmware upgrade was done through Tamron.   My camera salesperson made me aware of thiis need when purchasing the camera, so I sent the lens for the update while I was waiting for my camera to arrive.

i love my Tamron lens.    As I mentioned, I had the version one of the Canon 100-400 and the Tamron was far superior.   My 100-400 sat in the bag collecting dust until I traded it when purchasing the Mark IV

[TTMartin]

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@SSipple wrote:

i love my Tamron lens.    As I mentioned, I had the version one of the Canon 100-400 and the Tamron was far superior.   My 100-400 sat in the bag collecting dust until I traded it when purchasing the Mark IV

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The EF 100-400 L IS II is a much better lens than either the EF 100-400 L IS or the Tamron 150-600. As I've said even with a 1.4X TC III it is sharper than the Tamron.

Canon 7D Mk II with EF 100-400 L IS II + 1.4X TC III - 560mm, 1/1250, f/8, ISO 500

[SSipple]

TTMartin, that is a very nice image, but it is no better than what I have shot with the Tamron 150-600.   I see absolutely no reason to purchase the Canon lens to replace what is an already excellent lens.  There is an issue with either the camera or lens that needs to be addressed and then everything will be fine.   The below image was shot while on a moving vehicle.

[TTMartin]

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@SSipple wrote:

TTMartin, that is a very nice image, but it is no better than what I have shot with the Tamron 150-600.   I see absolutely no reason to purchase the Canon lens to replace what is an already excellent lens.  There is an issue with either the camera or lens that needs to be addressed and then everything will be fine.   The below image was shot while on a moving vehicle. 

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Nice shot. That is a big if though. If the issue is with the lens are you willing to wait for Tamron to come out with a firmware fix, if they ever do.

These were also shot from a vehicle using the EF 100-400 L IS II and 1.4X TC III

edit: You can see the reflection of the vehicle in the Ostrich's eye.

[SSipple]

Update:  

I got the camera back from Canon, and low and behold.....there was a problem with the camera!   They found that the adjustment of the ae assembly was incorrect and causing unevennuess in exposure!   I guess it is a good thing that I followed my instincts and sent the camera back as well as the lens!  

[ebiggs1]

"I followed my instincts and sent the camera back as well as the lens!"

Bingo!    Good to hear. I was kinda leaning that way, too.

[ebiggs1]

"i love my Tamron lens."

I like mine too. Obviously since I bought it twice.   Just like Canon saw the need to upgrade the 100-400, Tamron saw fit to upgrade the 150-600 super zoom.  The G2 is noticeably better in both IQ and AF. The thing is, if you need and want 600mm one of these super zooms is the way to go.  Most people don't want to or don't like fiddling around with tele converters.  f-stop penalty and IQ loss.  I know I don't.  I like the native 600mm better.

Of the current crop of lenses in this range I actually prefer the Sigma 150-600mm f/5-6.3 DG OS HSM Sports Lens.  But you need to stick to your plan and have both checked out.  I am really concerned about the auto ISO.  I can see it as the culprit.

[TTMartin]

 f/stop penalty and IQ loss are nice push button catch phrases when it comes to teleconverters.

But here is the reality, the Canon EF 100-400 L IS II with a teleconverter is still sharper than the Tamron 150-600 without a teleconverter. That really says something about the superb image quality of the EF 100-400 L IS II. 

As for the f/stop penalty Tamron already has a 1/3 stop 'penalty' since it is a f/6.3 lens at the long end. So the real f/stop penalty of using a teleconverter on the Canon EF 100-400 L IS II is 2/3 of a stop (f/6.3 vs f/8).

I'm not sure how the Tamron 150-600 G2 compares to the Canon EF 100-400 L IS II, but, I do know if the original Tamron 150-600 lived up to all its hype, Tamron would not have replaced it after only 3 years with a G2.

[SSipple]

I am not quite sure what you are trying to prove here.    I shoot professionally for a local concert venue and have relied on my Tamron for years.   My shots will compare with anyone out there.     I don't think it is appropriate for you to continue to make comments to the effect that the lens is a piece of junk.    You like Canon...that is wonderful and I respect that.  It seems that you should respect that I have been very pleased with Tamron and the quality of my shots.   The shot I displayed of the elephant stands up against any shot out there.    

I came to this forum to see if by any chance anyone knew of any issues and an 'easy' fix that I was unaware of.    My camera is currently with Canon and the lens is with Tamron.     I am confident that both companies will do right by me in the end.