Whats the difference between them. I always wonder about it. How much percent of the viewfinder at the center (for center weighted metering ) and that for spot metering is used. Well, it might depend on which model you are looking at. But on an average it should be fairly same. Is spot metering related to the other focussing points other than the center point.

Thanks

-- sajeev (chack74@yahoo.co.in), March 21, 2002

Answers

Sajeev, you might also be confused by partial metering. Only the EOS 3, 1n and 1v cameras have "true" spot meters. The other cameras have partial metering available. Both spot and partial use a certain percentage of coverage either at the center focusing point or the active focusing point (you have to set partial/spot metering to the active point using a command function: the default is the center point).

Spot metering is just smaller partial metering: the camera makes its metering decision based only on what it sees on and around the focusing point (and does not consider anything else in the frame).

The other mode you mention is center-weighted--don't forget that it is called center-weighted AVERAGE, which means that the exposure reading is taken for the entire frame but biased (weighted) for the center. So spot/partial and center-weighted average are very different.

The best way to figure out the coverage for the metering modes (in addition to reading the published specs on the cameras) is to check the meter values when you point the camera a light bulb. You can see for practical purposes how the camera makes its decisions.

Don't forget that often times, depending on the circumstances, the different metering modes can produce identical aperture/shutter values and that even when they vary by a stop or two you won't see a difference in prints (you will see a difference in slides).

-- Preston Merchant (merchant@speakeasy.org), March 21, 2002.

thanks preston. i always used to get confused with center-weighted metering and spot metering. i think now i can make better use of center-weighted and partial metering.

-- sajeev (chack74@yahoo.co.in), March 21, 2002.

I don't have much use for center-weighted average. The other metering mode on my Elan 7 is Evaluative Zone metering, which usually produces an excellent result as it considers all the elements of the frame.

I use partial metering for low-light work (where it is essential) and for flash and portrait shots.

My all-manual Olympus OM-1 has only center-weighted, so I have come to learn its limitations and be happy with it on that camera. But with the Elan, center-weighted seems unnecessary.

Which camera do you use, Sajeev?

-- Preston Merchant (merchant@speakeasy.org), March 21, 2002.

Just to correct Preston there, the EOS 5 also has a spot meter.

A spot meter looks at a tiny spot (less than 5%) in the centre of the frame (or linked to active focus point). A partial meter is the same but covers a larger area in the middle of the frame (about 9- 10%). Centre weighted expands this further, taking most of the frame into account, with more emphasis placed on the central area. Evaluative takes the entire frame into account, but decides for itself which parts are more or less important.

-- Isaac Sibson (isibson@hotmail.com), March 21, 2002.

Thanks for the correction, Isaac.

Sajeev, I agree about the difficulty of changing modes with your camera. I used one for a while and then upgraded. Being able to change metering modes without changing shooting modes is important. But knowing what I know now, I wouldn't have a problem.

-- Preston Merchant (merchant@speakeasy.org), March 21, 2002.

Having used manual focus Nikons for 25 years before switching to the EOS system, I feel very comfortable using center weighted metering. It is my normal mode. I will sometimes use spot metering of alternate mid-toned areas and then set my exposure manually. Most of the time, I use center weighted metering and compensate for brightness. I hardly ever use the evaluative metering.

It's really a personal choice as to what metering mode you use. At one time, using Tri-X black and white film, I never metered anything and almost always got the exposure right. It was simply because I was shooting between five and twenty rolls of that film a day and I knew what it did under just about all lighting conditions. Now that I'm shooting only slides, I rely much more on metering.

-- Lee (Leemarthakiri@sport.rr.com), March 21, 2002.