HELP! 1DIII is underexposing ( Due to odd focus screen )

Hey everyone;

I just got my 1DIII back from Canon and now it is underexposing more then I can set on the dial, so more than 3 stops.

It didnt underexpose before I sent it in to them.

They cleaned the sensor and replaced the mirror box.

They also updated the firmware but it was already updated to the latest release.

I reset all the camera and CF settings and no go. I tried all metering modes and no go, I tried all camera modes like TV and AV and M and no go.

I tried different lenses and different lighting and no go. In bright light it gets a really bad hot spot that is way blown.


I dont know what to do about it. I told Canon that I needed it for the weekend and they 2 day shipped it back to me (Got it today) and I think in doing so they forgot to calibrate the camera after replacing the mirror box.

Does anyone have any idea's or clues on how I can fix this?

If I send it back to Canon there is no way I am going to get it back in time for the 3rd and 4th.

Thanks everyone.

-Eric-

post some samples? especially of the hot spot?

That is strange.

Can a custom focusing screen cause underexposure?

The camera has an odd focusing screen that is a dotted box around the outside of the frame that has green and red and black speckles making up the lines.

I cant find this screen for sale anywhere and the little tab says " CIA "

NeoTokyo wrote in post #8204655
I cant find this screen for sale anywhere and the little tab says " CIA "

If it looks like the picture below it's Focusing Screen Ec-H


In the custom functions menu, CF IV-11 sets the proper focusing screen, certainly worth a try. I would think that this setting would have more to do with proper focusing than exposure but it doesn't hurt to set it correctly and see if that helps.

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Nope, thats not it, its kinda close though. No crosshair or bullseye and the dotted sides need to be longer.

NeoTokyo wrote in post #8204623
Can a custom focusing screen cause underexposure?

The camera has an odd focusing screen that is a dotted box around the outside of the frame that has green and red and black speckles making up the lines.

YES! A custom screen will definitely alter your metering. You need to set it to the appropriate one in you CFn.

Here is a picture of it, I used my sidekick's junky cam but it got the job done.

What focus screen is this? 1D Mark III -Pic inside-

Hey everyone;

I am trying to figure out what focus screen I have. I am having bad exposure problems with my 1D Mark III after it came back from Canon having the mirror box replaced.

They also cleaned the sensor, reset the settings and updated the firmware (Even though it was already current.)

I didnt have exposure problems before and was wondering if the screen might have something to do with it.

I need the Camera this weekend and I will have to try my best by overexposing by 3 stops.

Everything acts like it should and meters in the center.

Thanks everyone.

-Eric-

-Sorry for the bad pic, it was taken through the VF with my sidekicks cell-camera.-

Just put in a "real" focusing screen, made by Canon for that camera, then set the C.Fn appropriately to tell the camera which it is, and give it a try.

HOLY CRAP!

Through Live View it exposes correctly but when I go back through the VF then it under exposes!

Does that mean for sure that it is the focus screen?

And it is roughly 3 stops when looking at the pics side by side

The metering when using the camera normally is behind the focusing screen.
When metering in live view, the focusing screen is not involved.

Follow my advice above and check the result.

Ya, I am going to Laurence Photo first thing in the morning and buying a standard focus screen. Seeing how its about 4am, first thing will turn into about noon

After some LV shots I could see right away that the camera was exposing correctly through LV and when I went back through the VF it under exposed again.

I am going to grab the correct focus screen from Laurence photo tomorrow.

I would still like to know if anyone has any idea what this screen is.


-Eric-