metering mode

**Yisehaq** · 10-28-2008, 11:17 AM

Explain some theory for me please. That is on how to use metering modes. Let me start from what I know about metering mode (spot, partial,evaluative,center weighed)all Canon I think.
Spot metering is fine with me I think. If I shoot something dark I close the Av down either one stop or two and white will be the reverse (18% gray scale thing) because one can measure small area.
My questions is can you use same priciple with other modes? How can that work say for evaluative and center (as it calculates the whole field of vision).

I would in fact appreciate if I can here a podcast on it.

Anyways, I am sitting tight with my pen and paper.

**baddness** · 10-28-2008, 11:55 AM

I hope you get an answer because I have been wanting to know this as well.

**Travis** · 10-28-2008, 01:16 PM

I'm not sure what is unclear to you.... seems like you have the principle down...

Assuming using AP (AV)

Spot meter - measures a very small (about 3%) of your frame and suggests an appropriate shutter speed to correctly expose the 3% portion it is measuring

Center Weighted meter - measures about 60% of the frame and suggests an appropriate shutter speed. Center Weighted will also give small consideration the exposure value outside of the center area.

Matrix (evaluative) meter - measures the entire frame and compares the reading with several thousand algorithms preprogrammed into your camera. It then suggests an appropriate shutter speed based on a matching algorithm.

Matrix will nail about 90% percent(or more) of your general imaging but can be fooled in high contrast scenes. It doesn't know what part of the high contrast image you want to expose. Center weighted (and spot) allow you to instruct the camera to expose a desired area. Just be aware this can have consequence to the rest of the image. For example, you may spot meter the eye of person, and the resulting exposure will have a well exposed eye. However, the sky might be completely blown out, or shadows completely underexposed. You as the artist have to decide what is important. Matrix metering would pull in the sky and give you a more even image (except the eye would be slightly under exposed). You could dodge the eyes in pp though.

Each metering mode is a tool. They are all good, and you have to decide which tool is more applicable for the job. If shooting in a priority mode you are able to make exposure compensation adjustments to fine tune your result. If shooting manual then you decide the under/over exposure based on the meter.