Tuesday, August 11, 2009

photography 201 - exposure metering

I'm sort of embarrassed to admit I didn't know what the heck exposure metering was until recently. I thought I knew most of my camera's bells and whistles by now, but since I didn't read the owner's manual cover to cover, I guess there are some (ok many) things I missed. But I can't be the only one, right? So without further ado, let's talk exposure metering.

First off, let me clarify that I'm talking about in-camera exposure metering. I am not, however, talking about your various camera modes - this is photo 201, so we're taking it to the next level. Check your owner's manual to locate where your exposure metering control is located - on my Nikon D200 it's located near the viewfinder on the right hand side (the button that says "AE-L" and "AF-L"):

http://www.digitalreview.ca/cams/pics/NikonD200_back.jpg

Exposure metering determines how the image sensor will respond when a photo is taken. By understanding your options for exposure metering, you will get better exposure for your more challenging shots - shots with tricky lighting conditions. Generally speaking, there are 3 types of exposure modes: (1) center-weighted, (2) matrix or multi-segment mode, and (3) spot.

Center-weighted metering is just as it sounds - the metering focuses on the amount of light in the center of the frame, and sets the exposure accordingly. For example, if the center of your image is a white wedding dress, but the surrounding scene is dark foliage, center-weighted metering will exposure your shot based on the brightness of the white wedding dress. Center-weighted metering can be good for portraits, but many articles I read were not too fond of this metering setting. Take that for what's it's worth...

Matrix metering incorporates various calculations of the lighting throughout your image to achieve the proper exposure. Matrix metering is a more detailed approach to exposure than center-weighted metering. Most websites I perused for this post suggested you use matrix metering most of the time.

Spot metering is similar to center-weighted in that it focuses on the center of the image, but spot metering focuses on a very small portion of the overall image (which varies camera to camera). Spot metering is best for high contrast shots, like this one:

(photo courtesy of Planet Neil)

The lighting varies greatly in this image - spot metering will set the image sensor for the proper exposure of the men in the brightest part of the image.

Consider exposure metering an added boost to getting proper exposure in your photos. Any questions/comments - you know where to find me...

2 comments:

Patti Spada August 12, 2009 at 9:34 AM  

AAAHHH! I know what you mean! I, too, feel like I figured out this setting way later than I should have...but once I did, it changed my life. Ok, at least my camera life. I actually leave mine in spot metering most of the time - I find that if it's off, exposure wise, it's usually 'off' by less, and is more fixable in photoshop than other mode's metering errors. (Did that make sense?)

Glad I'm not the only one :)

Mel August 16, 2009 at 4:09 AM  

Thanks for this!