topic Canon T6i Exposure Issues in EOS DSLR & Mirrorless Cameras

Canon T6i Exposure Issues

FelipeOsti — Thu, 25 Oct 2018 20:22:22 GMT

Hello,

I made a day long exposure photo recently, and after that I got a message on my live view "Exp.SIM", it was the exposure simulator telling me that I wouldnt get the result I was viewing. After that I reseted my camera settings, hoping to get rid of that message and getting my camera set to normal.

But now Im having issues with exposure, all my pictures are being underesposed and Im having to raise iso up to 1600 or 3200 to take pictures under natural light.

I searched all over the internet, Youtube, Facebook, etc etc and couldnt even find a mention to this issue.

I would really appreciate if someone help me.

Thanks

Re: Canon T6i Exposure Issues

kvbarkley — Thu, 25 Oct 2018 21:14:19 GMT

Do you have exposure compensation on?

Is the lens Aperture stuck? You can tell be looking in the lens when the camera is off. Can you see the blades?

Re: Canon T6i Exposure Issues

FelipeOsti — Thu, 25 Oct 2018 21:43:44 GMT

Thanks for the reply.

Im using a sigma 17-50 2.8. I can adjust apperture normaly and see the blades moving.

I think its something related to the sensor, because the sensibility to light seems to be low. Im having to increase ISO a lot.

For some reason Im not being able to adjust my exposure compensation manually, my camera is set to Manual Mode, but I can only adjust it in Av or Tv

Re: Canon T6i Exposure Issues

kvbarkley — Thu, 25 Oct 2018 22:10:49 GMT

It is expected that you cannot adjust exposure compensation in M mode. Exposure adjusts from some baseline and in manual mode, there is no baseline.

Go outside on a sunny day, set the ISO to 100 and see if your camera follows the sunny f/16 rule.

https://en.wikipedia.org/wiki/Sunny_16_rule

It could be that you damaged your camera with a "day long exposure".

Re: Canon T6i Exposure Issues

Waddizzle — Thu, 25 Oct 2018 23:53:34 GMT

@kvbarkley wrote:
It is expected that you cannot adjust exposure compensation in M mode. Exposure adjusts from some baseline and in manual mode, there is no baseline.

Go outside on a sunny day, set the ISO to 100 and see if your camera follows the sunny f/16 rule.
https://en.wikipedia.org/wiki/Sunny_16_rule

It could be that you damaged your camera with a "day long exposure".

I would think a “day long exposure” would possibly damage the image sensor, not the metering sensor. I do not know where the metering sensor is located in a T6i, but in most Canon DSLRs it seems to be located close to the viewfinder. This location would meant that a raised mirror would block light from reaching the metering sensor.

Re: Canon T6i Exposure Issues

FelipeOsti — Thu, 25 Oct 2018 23:55:12 GMT

It was a 4 seconds long exposure photo in a place that was not so bright, but it was still day light. If the sensor was damaged, coult it still take pictures?

Re: Canon T6i Exposure Issues

FelipeOsti — Fri, 26 Oct 2018 00:08:23 GMT

I just checked and the camera is changing the lens apperture as I change ISO speeds

Re: Canon T6i Exposure Issues

Waddizzle — Fri, 26 Oct 2018 00:09:08 GMT

@FelipeOsti wrote:
It was a 4 seconds long exposure photo in a place that was not so bright, but it was still day light. If the sensor was damaged, coult it still take pictures?

A four second exposure should not damage anything, assuming you were not photographing the Sun.

If the image sensor were damaged, then your images would come out poorly, but the metering system should still read properly. If the image sensor were damaged, then your images would look bad. If you need to crank the ISO to get a proper exposure, ignoring high ISO noise for the moment, then I would look elsewhere besides the image sensor.

When light enters the camera body from the lens, it hits a mirror in front of the main image sensor. This mirror is made so that some of the light is reflected up to the viewfinder, and some of the light is reflected down to the AF sensor.

When the light enters the viewfinder, it gets split in two directions by another specialized mirror. This time some light is reflected to the viewfinder, and some is reflected so that it continues upwards to the metering sensor.

I have been looking for an image, but cannot find one that illustrates the metering sensor. If you followed my description, then it should be apparent that the metering sensor is only exposed to light when the mirror is “at rest”, or not raised.

Because the metering sensor is blocked when the mirror is raised, this is why Live View uses a different focusing and metering system compared to using the viewfinder.

Re: Canon T6i Exposure Issues

ebiggs1 — Fri, 26 Oct 2018 14:39:56 GMT

"I would really appreciate if someone help me."

However it may have happened it sounds like something is failing or faulty. Call Canon service 1 (800) 652-2666.