Hi All

This is George Mathew again. This time my questions are about Partial metering of EOS Rebel 2000.

1. Does this Partial metering is same as the standard Spot metering? I read some where that it is just a name difference and Canon call it as Partial metering in its low priced EOS Cameras? Is it true or there any technical differences between the two?

2. Which is better, a small spot metering area or a wider spot metering area? For example, Rebel 2000 has 9.5% of the view finder as a partial metering area and some other camera has 3.5%.

3. Canon Rebel 2000 manual says it has 3 types of metering. 1. Evaluative 2. Partial and 3. Center weighted. It also says Camera sets the metering mode to Partial when the AE lock is used. At the same time it says that camera uses Center weighted when it is in mode "M". Does it mean that Partial metering cannot be used in mode "M". What is the metering used when we have the camera setting in mode "M" and AE lock is on? Is it partial or Center weighted? Does the AE lock override the Center weighted setting to Partial in mode "M"?

4. According to manual once the AE lock is pressed, it stays for 4 seconds or till we turn the dial. I read in a book that to find out the normal exposure of the subject, with AE lock feature, compose the subject by keep pressing the AE Lock button. Is it required? What happens when we reframe and focus another subject or area while the AE lock is on(which was done for a different area or subject)?

Thanks in advance for your help!

Regards George

-- George Mathew (george_mathew2k@yahoo.com), December 19, 2001

Answers

Hi, George.

1. Partial metering and spot metering are slightly different. Spot metering uses a smaller percentage of the zone in the viewfinder, a smaller “spot” from which to determine the exposure. Partial metering can vary from camera to camera (by percentage of coverage) as you note; spot metering is more refined than partial metering. Usually only higher-end cameras have a true spot meter. Everything else offers some fraction of partial.

2. As for which is better, it just depends on the situation. Spot or partial (either one) will serve you well when trying to shoot in low-light or high-contrast situations, or just when you need to concentrate on one component of the frame. When taking portraits, for example, you might partial meter the subject’s face and not worry that some of the background might be blown out. You probably wouldn’t notice much different between spot and partial, except in an extreme case. You WILL notice a difference between them and the zone evaluative setting.

3. The Rebel 2000 doesn’t let you choose among the three metering types in all modes, as it defaults to one or the others accordingly. It does get confusing about overriding. The MAGIC LANTERN GUIDE to the Rebel 2000 can help you sort all this out. It is a clearer and fuller treatment of the workings of the camera than the Canon manual. The book is easy to find--Amazon, wherever . . .

4. AE lock saves the meter reading when you press the button, so that the exposure indication will not change when you recompose. That AE lock “memory” lasts for 4 seconds (for some reason). If you want to find the “normal” exposure reading for your recomposition, pressing AE lock again probably turns it off so the camera will take new reading.

If you are just getting used to your Rebel, I wouldn’t worry too much about AE lock. In 98% of the pictures you’ll take, evaluative or partial metering will produce the correct result, and if you are shooting print film (as opposed to slides), your lab will make minor adjustments.

Good luck!

Preston

-- Preston Merchant (merchant@speakeasy.org), December 19, 2001.

Hey George,

In regards to: "...it says that camera uses Center weighted when it is in mode "M". Does it mean that Partial metering cannot be used in mode "M"."

I don't own a Rebel 2000, but I have 2 EOS cameras that use the same type of non-selectable metering patterns. In the EOS 10S and IX, M mode uses a center weighted pattern. However, when I press the (*) partial metering button the pattern narrows to the partial meter pattern as in any of the other Creative Zone modes. I suspect the Rebel 2000 is the same.

It's easy to test if this is true for your camera. While in M mode, point it at a scene of mixed tonal values, e.g., very light and very dark areas, and adjust the exposure. Next, press the partial metering button and see if the exposure is plus or minus. The center weighted pattern tends to averages the values for a good overall exposure. The partial reading will often vary due to a smaller image sample that may contain predominantly light or dark areas.

-- Puppy Face (doggieface@aol.com), December 19, 2001.

i did this experiment to understand how metering works. i have EOS 300 which is same as EOS Rebel 2000. at night i switched on the light and used "M" mode to get a correct exposure. the central focussing point was one the light. so i got a shutter speed of 1/350 seconds which is ofcourse quite high at night. when i pressed the partial metering button the shutter speed reduced to 1/125 sec for correct exposure. this was done before the shutter button was pressed halfway (i.e. before AE lock). i did similar experiment with "Av" and "Tv" mode and find that the shutter speed increased from 1/60 sec to 1/125 sec i.e. same as shown by the "M" mode. the shutter speed was increased for "Av" and "Tv" mode because the default metering is "Evaluative" which takes the light in whole viewfinder for getting EV, while in "Partial" and "Center Metered Averaging" metering the light near the center (with different percentage depending on which of these two metering is used) is used. finally you have to decide what kind of metering you need depending on the subject you are shooting. for instance, for landscape photography "Evaluative" metering would be a better choice, for close up and portrait photography "Partial" or "Center Metered Averaging" would be better.

-- sajeev (chack74@yahoo.co.in), December 20, 2001.

Hi All

Thanks a lot for your answers! It was very helpfull for me. I am now learning about spot metering from a book called "Confused Photographer's Guide to On Camera Spot Metering" by Bahman Farzad. It is good book. He suggests to take a reference tone and find out the normal exposure using on camera spot meter. Then based on a tone ruler (Black, Dark Gray, Medium Gray(18%), Light Gray and White) he asks to override the camera setting either + 1, +2 or -1, -2 or leave as it is. Now my question is how practical is this procedure? Is it the same way a skilled photographer take the pictures? I know that this is out of this forum subject. But still as a continuation of my previous question on EOS, some one please reply.

Is it possible for the owners of this forum to eliminate postings that comes from people like Alfie? I am sure that it is going to create a very bad impression about this forum among the new comers. Think about a person who come here for the first time and read one of his postings!

Do some thing immediately!

Thanks George

-- George Mathew (george_mathew2k@yahoo.com), December 20, 2001.

If you had a reason to believe that your spot meter were inaccurate, you could test it against a grey card and then make adjustments in future photographs. But you probably wouldn’t need to. Spot meters are supposed to calibrated against 18% grey; the trick is learning to use them properly, which means finding the best “spot” in your composition to take the meter reading. That’s a subjective decision-- different photographers would do it differently.

Like the folks said in the other posts, dark shadows and bright snow (or any other extreme of light or color temperature) can fool any meter, so you may have to experiment.

The theoretical “skilled photographer” you mention (and you should count yourself as one) would rely on the meter but would also know its limitations. Try shooting for a while in manual mode, letting the camera alert you when you are over- or underexposing. Use one type of film, like ASA 400 black and white. Get a feel for what meter readings are indicated in certain situations. It won’t be long before you are able to guess correctly. When your eyes and judgment are good, you’ll know when the meter is being fooled. Or you may discover situations in which it may be better to intentionally underexpose (as in a silhouette) or overexpose (capturing detail in a dark room).

Good luck!

-- Preston Merchant (merchant@speakeasy.org), December 20, 2001.