Canon 90D with Sigma 70-200 overexposes all pictures taken through the viewfinder (live view ok!)

[philippelang]

Hi,

I'm the happy owner of a Canon 90D. I have just bought a Sigma 70-200 lense, and I noticed that all pictures taken through the viewfinder are overexposed, no matter what I do. If I want to have a picture that is close to reality, I have to compensate the exposition with -2/-3. Tha't's a lot, not just "fine-tuning". With the other lenses, I never had this problem: Sigma 18-35mm f1.8, Canon 50mm f1.8...

Is that Sigma firmware problem? 90D firmware problem?

[jrhoffman75]

[cn4873]

Thanks! I'm pretty sure I'm up to date on my firmware but I will check when I get Home. I know I need to do a lot more work before giving up on the camera but I see some of the photos people are posting from this camera and it makes me wonder if I might have received a dud. I'll admit I'm rusty with the whole photography thing. It's been a long time since the 70's and 80's but My life is in electronics so the change from film was not an issue. I purchased the Rebel T7 last year and learned a lot very fast I've taken some amazing shots of BIF. So I thought it was time to step up and hand down my T7 to my daughter. But the 90D has got me frustrated. I also have problems with focus. And yes I've done my homework and continue to research I'm just waiting on some targets. I'll check all my lenses and test different conditions.

Thanks Again

Rich

[ebiggs1]

Here is what you do and it sounds like this is a very good idea since you may be a bit rusty.

First reset the 90D. Menus, tools, clear all setting and clear all custom settings, too. Now set the 90D to P mode, Set ISO to 200, do not use auto ISO for this test. Set  WB to daylight. Use One shot not Ai-servo and center focus point. Dismount the lens and remount the lens. Set to AF. Now, nice day, go outside and shoot random shots of various subjects. Some close, some far and make sure some have vertical lines like trees or fences or buildings, etc.

If it works, it works. There is nothing wrong with camera or lens. If you still have issues one or the other, or both, is faulty. The lens may need the FW update or the 90D may need attention.

[cn4873]

I'll give it a shot. Like I said I don’t mind putting the work in. I'm falling in love with photography all over again.

Thanks

Rich

[ebiggs1]

"If it works, it works."

This may be good or bad depending on how you look at it.    Good that there isn't anything wrong if it works but bad because it is how you are using the gear!

[philippelang]

Hi John, yes, I saw this firmware update (which I have) and the description, but either it "optimizes" a situation which is even worse or - more likely - it doesn't work for me. I still have an exposure problem through the viewfinder.

[Camilo06]

I had a 24-70L and i didn’t have this problem, is happening only with sigma lenses

[Waddizzle]

That might be true. But it is strange that my Canon rebel T7 takes flawless pictures with it.


Why is that strange? I don’t think the 90D existed when the lens was released.

[cn4873]

I'm sorry! I'm not sure I understand your question? All of my lenses came out before the D90. In my experience cameras are backward compatible with lenses in the same classification. And every report I've read states that the Sigma gets high marks when paired with the D90 and that was one reason for me choosing it. I had a limited budget and wanted to keep my lenses.

Thanks

Rich

[jrhoffman75]

I think we're in speculation regime until the firmware version is checked. 

I find it info that the firmware update applies to both the 90D and the 1D X Mark III. Both are recent Canon cameras. There may have been changes in the camera communication system in those bodies. Since Canon knows their bodies and lenses they can handle things in the body firmware.

Third party suppliers need to reverse engineer; thus the Sigma firmware update.

if the lens firmware is up to date then the camera should be sent to Canon for a check.