New 20D - exposure meter off 1/2 stop ?

[Sailare]

Hi,
I have taken perhaps 200 shots under all lighting conditions with a variety of lens and notice the cameras wants to overexpose by 1/2 stop under all conditions and lens. I have adjusted it down a 1/2 stop and the pictures look great. Seems to be right on when using flash.


Question - Is there something I can do with a grey or white card to set the meter or do I have to send it back to Canon? This is not an adjustable item in the parameters. Forget it or try to fix it?

Please advise!
Thanks
Sailare

[jimlp]

Hi,
I have taken perhaps 200 shots under all lighting conditions with a variety of lens and notice the cameras wants to overexpose by 1/2 stop under all conditions and lens. I have adjusted it down a 1/2 stop and the pictures look great. Seems to be right on when using flash.


Question - Is there something I can do with a grey or white card to set the meter or do I have to send it back to Canon? This is not an adjustable item in the parameters. Forget it or try to fix it?

Please advise!
Thanks
Sailare

You probably already know this but you cannot shoot digital like you shoot film, I find that I have to be 3 times more careful with my metering with my 20D than I do with my film bodies. The only way to determine if your 20D is defective is to do some sort of tests with a light meter and/or graycard to see if the camera meter is close to the hand held light meter. I think you may just have to pay closer attention to your metering.

[scottbergerphoto]

There are two things you can do to test your in camera meter:

1. Put your camera in P mode and take three pictures in the same lighting: a white card, a grey card, and a black card. Make sure the card fills the viewfinder in each picture. View the pictures in PS or PSE. All three pictures should look exactly the same, middle grey and their histograms should all show a single spike in the middle.

2. Use a handheld spot meter that you know to be working and compare readings with your camera's meter of the same three objects above making sure that you fill the viewfinder with the card when using the camera meter. The hand held and camera meter readings should be the same.
If the above tests show that your camera meter is off, then I suggest you return it to Canon for calibration. The camera meter is arguably the most important part of the camera.
There is no fundamental difference in metering between digital and film cameras.
Regards,
Scott

[daveh]

You probably already know this but you cannot shoot digital like you shoot film, I find that I have to be 3 times more careful with my metering with my 20D than I do with my film bodies.

I'm guessing you mostly shoot print film. I've shot mostly slide film for the last 30 years and didn't feel much of a transition.

[Sailare]

thanks for the replies. At this point it looks like a Canon adjustment.

I have been using a Canon G2 for the last couple of years and it is right on.

I set the G2 on a tripod and aimed it at my light workbench.
ISO 400
evaluative
"0" exposure compensation
AV mode - 3.5 apeture gives a 1/60th shutter

I switched to the D20 on the tripod
ISO 400
evaluative
"0" exposure compesation
AV mode - 3.5 apeture gives a 1/30th shutter

Although I did not expect the meters to indicate exaclty a 1/2 stop difference, it does indicate that D20 is overexposing at "0" compensation.

Not a definitive test, but good enought to confirm my suspicions. Will contact my dealer tomorrow.

[Jesper]

The ISO on digital cameras is not always exactly accurate. It's been a while ago that I had a G3, but one thing that seemed to be well-known at the time was that it was more sensitive than the ISO setting indicated - i.e., ISO 50 on the G3 was more like ISO 80 in reality.

Probably that explains why your G3 at ISO 400 wants a faster shutter speed than your 20D - ISO 400 on the G3 is more sensitive than ISO 400 on the 20D.

Try this: Set your 20D to partial metering and make a test shot of a gray card. If the card is middle gray on the computer (look at the RGB values in Photoshop, for example), the meter works correctly.

[BigRed450]

Comparing a G3 and a 20D is like comparing apples and oranges. I personally would suspect that compared to a light meter you will find that the 20D actually gives the correct reading not the G3.
Even though the G3 is a quality cam and has manual settings it is still just a point and shoot camera and not intended or required to be as acurate as a DSLR.....

[Sailare]

Well,
After only 5 days and 4 calls to Canon tech support regarding the 1/2 stop over exposure, it finally failed completely.

Pressing the shutter down half way gives me a flashing 30 second shutter along with a 3.5 apeture (wide open). (All settings and with different lens)

It does fire and counts off 30 seconds but it's a little more than 1/2 stop over exposure to be sure!

Bummer.... Tech support says its a failure and contact my dealer for a replacement.

Hope this isn't as painful and time consuming as I have read in other posts.

Will let you know the outcome etc.