90d: Photos over exposed (double iso) when shooting in non live view mode

[vizualequalizer]

I have a Canon eos 90d and the photos are over exposed when shooting in non live view mode (when switching back-and-forth between live view and viewfinder modes; the ISO doubles), or another words looking through the viewfinder, the ISO will double. There's no exposure addition or subtraction on exposure stops. I am confused please help!

[kvbarkley]

Could this also be a sticking aperture on the Sigma lens?

[Waddizzle]

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@kvbarkley wrote:

Could this also be a sticking aperture on the Sigma lens?

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Anything is possible.  Except for the that John's test shot results had a wide variation in exposure, while mine did not. 

???

[vizualequalizer]

Hey guys, I really appreciate all the feedback and help. 

I did do outdoor testing and the same issue. I should have thought of this earlier, but I tested it with my Rebel 1Ti and have the same issue although it is much less exagerated, only about 1/3 - 2/3 stop difference. 

I will post my findings and conclusion in new post more approriately named something like OVF over exposure vs LV. ISO double is incorrect title for this issue, I belieive. I will post the link to that new thread in here via edit.

I will say that most of us are experienced photographers and that this over exposure issue is simple. The eos 90d does it in every setting that I continue to explore.

That being said, it's not like the eos 90d is some super complicated mystery. I haven't found any elusive or secret settings that could be the perpetraitor. I just find it very odd that the OVF adds almost a full 2 stops of exposure versus LV mode.

I'll post new link here to new post aptly named with some outdoor shots and shots with the Rebel T1i and details.

Thanks to all for collaboration and constructive criticism and help. Post will be later today at the earliest.

Thanks.

[Waddizzle]

Make the mirror box is dust free with a rocket blower.  I do not think 1/3 of a stop is major, but 2 stops is bad.

[vizualequalizer]

I'm not sure I understand your last post @waddizzle. Are you saying make sure the mirror box is dust free, and use a rocket blower?

[Waddizzle]

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@vizualequalizer wrote:

I'm not sure I understand your last post @waddizzle. Are you saying make sure the mirror box is dust free, and use a rocket blower?

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Yes, I am.  Make sure the image sensor is clean for Live View metering.  The OVF metering sensor is probably inaccessible because it is located at the top of the mirror box [viewfinder].

Make sure your locked AF point is the same for both modes.  Using a tripod works best.

[vizualequalizer]

Okay. I don't have a rocket blower or the like. Regarding your AF points being the same, I was just about to upload pics for this thread, when in fact, the focus points are different, which I'm pretty sure like you are saying influences the meter!

As soon as I can I will reshoot and nail down the constants and post the results.

Thank you kindly for your time and attention, viz

[Waddizzle]

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@vizualequalizer wrote:

Okay. I don't have a rocket blower or the like. Regarding your AF points being the same, I was just about to upload pics for this thread, when in fact, the focus points are different, which I'm pretty sure like you are saying influences the meter!

As soon as I can I will reshoot and nail down the constants and post the results.

Thank you kindly for your time and attention, viz

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Use "1-pt AF" point selection for both OVF and LV modes.  LV does not default to 1-pt AF.  Also, use One Shot AF mode, so that the metering locks when focus locks.

According to my light meter, all of my Canon bodies overexpose about almost 1/3 of stop in the OVF.  I have never tried the same tests with the LV mode.  I think this is done to capture more details in shadows.

[jrhoffman75]

I guess it would depend on a definition of error if you believe your stand alone meter is correct.

"According to my light meter, all of my Canon bodies overexpose about almost 1/3 of stop in the OVF".

Unlike the other metering modes, Evaluative Metering has no set pattern. It is an intelligent mode that prioritizes its evaluation based on where the focus point is, since it assumes that is the location of interest.

The greater the number of metering zones the more precisely the camera can determine the conditions surrounding the focus point. I believe that can contribute to a different exposure reading between OVF and Live View, particulary for complex lighting situations like the original images that were posted. Throw in Auto AF point selection and the potential for differences grows more. Add in the fact that both methods use different sensors for measuring exposure. I would be more surprised if they gave the same result, just like two cameras side by side could give different readings. 

One could call it an error if a particular mode is deemed correct and the other mode is producing a different result.

[Waddizzle]

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@jrhoffman75 wrote:

I guess it would depend on a definition of error if you believe your stand alone meter is correct.

"According to my light meter, all of my Canon bodies overexpose about almost 1/3 of stop in the OVF".

Unlike the other metering modes, Evaluative Metering has no set pattern. It is an intelligent mode that prioritizes its evaluation based on where the focus point is, since it assumes that is the location of interest.

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I am using a Sekonic L-858D.  I measure both reflected light and incident light.  I use 1 pt AF using the center AF point.  I use Partial Metering and Evaluative Metering, and I get identical exposure settings in the cameras..

Histograms in the cameras confirm the slight overexposure, as do both LR and DPP.  It is a pretty consistent result across six different DSLR models, and my M3.  All of the histograms "expose to the right", so to speak.

I never said it as an error.  It just seems to be how Canon "bakes" their images.