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

philippelang
Contributor

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?

44 REPLIES 44

kvbarkley
VIP

Since Sigma has to reverse engineer the lens mount to get it to work, it must be a Sigma issue.

 

Is the aperture wide open when measuring the exposure? Try the depth of field preview button to see if the viewfinder lightens and darkens.

Yes, I've been taking test pictures at aperture wide open: f2.8.

 

And apprently the depth of field preview button works just fine: when I press on it the viewfinder darkens when I increase the aperture f-number. And depth of field increases in the same time.

 

Someone mentioned having the same problem years ago with another Sigma lense, and that it was solved with a Canon 90D firmware update.. Could that be a body firmware has to be updated in order to offer support for lenses that appeared after the firmware release?


@philippelang wrote:

Yes, I've been taking test pictures at aperture wide open: f2.8.

 

And apprently the depth of field preview button works just fine: when I press on it the viewfinder darkens when I increase the aperture f-number. And depth of field increases in the same time.

 

Someone mentioned having the same problem years ago with another Sigma lense, and that it was solved with a Canon 90D firmware update.. Could that be a body firmware has to be updated in order to offer support for lenses that appeared after the firmware release?


Go to the Sigma support site.

 

Screenshot 2021-01-14 184636.jpg

 

 

John Hoffman
Conway, NH

1D X Mark III, Many lenses, Pixma PRO-100, MX472, LR Classic

Bravo John!

 

@phillipeliang, you'll need a Sigma USB dock.  Great investment if you own one or more of Sigma's Global vision lenses.

 

 

 

 

~Rick
Bay Area - CA
~6D2(v1.1.1) ~Many Lenses ~DxO PhotoLab Elite ~Windows10 Pro ~EVGA RTX 3080Ti FTW3 Ultra ~ImageClass MF644Cdw ~Pixel6 ~R5C On Order

I love this USB dock, and I have used it a lot for the past weeks, for calibrating my Sigma lenses. A great investment, yes!

I found the culprit: it's the 90D body. A test with another 90D body shows the lens works great. I guess some hardware must be faulty, because cleaning configuration and even re-flashing the same 1.1.1 firmware did not help.

 

But still, that's strange: other lenses have no problem on this 90D body, only the 70-200.

Maybe the problem is not a hardware problem on one of my 90Ds. I took the time to make tests, with two 90Ds and 3 lenses:

 

Sigma 70-200

sigma70200-resume.png

 

Canon 50

canon50-resume.png

 

Sigma 18-35

sigma1835-resume.png

 

It shows the problem is Sigma-specific, when taking pictures through the viewfinder. And apparently not all 90Ds are equal: some overexpose more than others. It really looks like a complex Sigma firmware bug.

"It really looks like a complex Sigma firmware bug."

 

I can't tell you any useful info about using the Siggy lens on a 90D since I don't own one but I can tell you the Sigma 70-200mm f2.8 zoom lens works perfectly on both my 1D Mk IV and 1DX. 

 

You might want to reset your 90D back to factory default.  You could have a setting incorrectly set and not be aware of it. Make sure you clear all "custom" settings when you do the reset.  That is probably where the error might be.

EB
EOS 1DX and 1D Mk IV and several lenses!

I did a reset, and even a firmware reinstallation. I checked all menu configurations one by one between both 90Ds, but nothing that explains this behaviour on my second 90D.

 

It's really strange... Either it's a Sigma firmware bug with 90Ds or one of my 90Ds is faulty in my humble opinion.

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