Much better understanding of metering modes

[TMR Design]

Last night I really got to see how different metering modes can drastically affect exposure.
I am currently shooting trading cards for eBay using my A620 and a lightbox. The cards are 3.5" x 2.5 inches and I shoot each card centered on the base of the lightbox, which is a piece of white foam board measuring 30" x 20". The camera is about 18" from the card which keeps it out of Macro mode by the slightest amount and I am at full telephoto.
I was experimenting with the metering modes and I thought I would try Spot metering, thinking that I want to meter off the centrally located card and not the white background. When I would focus and have the camera meter the shot I noticed that the AF point was getting a correct exposure but all around the sides and edges of the card were being blown out and changing shutter speed or exposure did nothing. It was obvious that the camera could not meter the entire card correctly using Spot metering. When I switched to Center weighted it was better but Evaluative was undoubtedly what I needed to be using. As soon as I switched to evaluative the enitre shot had the correct exposure and nothing was being blown out.
This was the first time I've ever really seen such a good demonstration on why to choose one mode over another. I always unnderstood them and at times selected one based on the shot but never got a good sense of what was best in given situations.

Having said that, can someone give me specific examples of when and why you would use a particular metering mode and how the wrong mode would adversely affect the shot?

[inthedeck]

Maybe you could post the 'samples' that you shot...to give people an idea of the difference? Might be a little more helpful...

[TMR Design]

Maybe you could post the 'samples' that you shot...to give people an idea of the difference? Might be a little more helpful...


I will actually do that this afternoon. Good idea.

[Cindi]

I've never totally understood when to use them either so I would love to hear some input as well. Thanks for taking the time to do this Robert.

[Stefan A]

I used partial (the smallest) metering recently when I was photographing a live band.

Stefan

[TMR Design]

Hi Stefan,

Did you compare partial to evaluative and make a decision based on results or was it just a guess and it worked out?

I am trying to determine how to intelligently know what is the correct method of metering before I shoot rather than waiting to see the results.

[TMR Design]

I just took these pictures. The first one was using Evaluative metering and the second was Spot metering. With no other adjustments made on the camera this was the result.

[Cindi]

Hmmmm, I'm thinking I need to start experimenting more so I can better understand all the settings. There is a definite difference in your 2 shots!

[TMR Design]

Hi Cindi. Pretty interesting and surprising huh? I was shocked. Since each card is slightly different it did not show up in the first hundred or so cards I shot. Then all of a sudden I saw that this card was really blown out in the LCD so I took a couple of shots and reviewed them on the computer. Everything was shot in Av mode using f/5.0 and shutter speeds varied between about 1/80 and 1/200 and I dropped the ISO to 100.

The examples are crops but each one is surrounded by white foam board with the card taking up most of the frame.

This makes me now wonder about some of the shots I've taken outside and whether my metering mode selection was appropriate.

[3drcpilot]

I do coins on the Bay and switched to a black background and spot metering. Yet in macro I use no zoom. I try to keep as much of the background out of the shot.
It really helps on toned pieces with lots of vivid colors.
Black background and spot metering (http://members.cox.net/audiesplace/Copy%20of%201883CCrevEB.jpg)

Yet some coins are in a white holder, and then evaluate is the better choice.
white background, eval meter, different lights (http://members.cox.net/audiesplace/1834%2050C%20NGC%20MS62%20obv.jpg)

[spur]

Robert, the photos where you show the difference is what I would expect because the spot metering would have metered the very dark center of the card so it tried to make the center 18% grey. Of the first 100 or so that it did not cause a problem, were they lighter in the center? Center weighted would also have given more weight to the dark part of the card and less to the white border. That's why the person holding the camera is what makes a great or only fair photo. Knowing when to use each mode is part of the ART of photography. It would seem that last night you took another big step in your photography, many people would just blame the camera for messing up. You learned that your brain is better than the one in the camera. I'm looking forward to your different shots, they should be very instructive to the rest of us.

[Stefan A]

Actually, I did no experimenting to decide. Some of the the guys over at the performing arts forum use spot metering for all their live concert shots. So I just figured that's the way to go. Makes sense though. I would rather not have the extremely dark, or the extremely bright backrounds from a rock concert influencing the exposure of the subject.

Stefan