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Old Feb 10, 2008, 3:15 PM   #1
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Up till recently I have been using either centre weighted or spot metering with the Pentax K10D.

On the suggestion of a professional of a bird group I did latest wildlife shoot using multi-segment metering. ( After editing it also retains EXIF details !!!)

Here is a shot of an aviary bird seldom seen @ the middle of the day. A Nankeen Night Heron.

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Old Feb 10, 2008, 6:17 PM   #2
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Hi Ian,

First, let me compliment you on this shot -- it's well done! -- And certainly of a subject that I don't get to see, which is always good.

Matrix metering certainly worked for you here, but there are a lot of situations while birding where it wouldn't be as appropriate. One extreme example would be a white bird in direct sunlight in front of foliage that's in deep shadow where the bird does not fill the majority of the frame. Matrix metering will generally allow some significant portion of the white to blow out, erasing any detail.

Something that I do with every new body that I get is to find the boundaries of the metered areas for the different modes.

1. Set up a lamp with just a bare low wattage bulb in the middle of a decent sized room. You want the bulb at least a couple of feet away from the background wall so it illuminates the wall pretty evenly.

2. Set the ISO to a specific speed, use Aperture Priority mode to keep the aperture constant. Don't use any Ev compensation, and don't change any of these settings.

3. Start with matrix metering, half press and hold the shutter with the bulb in the center of the frame and allow the cam to lock focus, then pan slowly to each side, watching for any changes to the shutter speed. As long as the bulb is in the frame, the shutter speed won't change too much. Take a shot with the bulb in the center and towards the edge of the frame.

4. Switch to center weighted and repeat the procedure. You'll see that the shutter speed gets significantly longer as the bulb leaves the center quarter or third of the frame. Note the difference. Again take shots with the bulb at the center and edge of the frame.

5. Switch to spot metering (choose the center spot) and repeat the procedure. You'll see a more significant lengthening of the shutter speed, and it happens more rapidly than it did with center weighted metering. Again take shots with the bulb in the center and at the edge of the frame.

With both the center weighted and spot modes, try to remember where the bulb is located in the frame when the shutter speed starts to change. Now you know roughly the coverage and actual location of the metering sensors that make the difference in those modes.

You should also see from the shots you took that matrix metering doesn't expose the bulb well -- it's probably pretty much blown out at both the center and at the side. Center weighted does a bit better exposing the bulb when the bulb is centered, and worse when it's off to the side, and the bulb should be best exposed with spot metering with the bulb in the center, and overexposed the worst when it's at the side.

This will give you a very graphic illustration of how the metering works in each mode. Matrix averages the entire frame, Center weighted also averages but, biases the exposure significantly to the central portion of the frame, and spot only meters the very center of the frame. I'm sure that you already knew this, but this shows how much a difference there is between the modes.

BTW, if you set the bulb up in front of a patterned background, then use the center focus point, you can also find the approximate size and location of the focus sensor there. Knowing this can help prevent the "bird out of focus but the branches behind in focus" problem since the red focus indicator that lights up in the viewfinder is significantly smaller than, and doesn't always exactly match the location of the actual sensor.

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Old Feb 10, 2008, 7:04 PM   #3
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Interesting topic, I really have not played with these options much. Does the camera meter at the same time it focuses or when you press the shutter button. In other words, if I am using spot metering and spot focus, half press to get focus, then recompose will it base the metering off of the spot I focused on or the center spot after I have recomposed?

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Old Feb 10, 2008, 8:33 PM   #4
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Great Question and response so far.

Over the last year, I have toggled between the segmented and spot metering. I started out with the segmented as a default. In reading some posting from Harriet, I tried spot metering as a horse practice. I really did not like the results. Obviously the horse was dark brown with a dark saddle, and I have returned to the segmented as a default - probably due to my inexperience here, to quickly determine the overall cirmcumstances of the shot and make an approperiate selection.

On shooting the moon - yes use spot. When I was in the Navy, I always used spot since the antennas that I was taking pictures of, were essentially the only item of interest - the rest of the shot was just there as background.

old habits die hard.....

... by the way - a really nice image - I like the setting!
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Old Feb 10, 2008, 11:17 PM   #5
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Tim - it depends on how you have your camera set up. The default is that the exposure is not locked at the same time as the focus, so if you half press to lock focus, then recompose to take the shot, the camera will continue to meter as you recompose (discovered this while taking sunsets). You can change this by changing the AE-L with AF locked option under the custom menu (it's the same for both the K100 and the K10). I keep thinking about setting this to "yes" because so often that's what I want to do (with flowers and such), but haven't actually tried using it. If I think I'll get an incorrect exposure, I'll just use the AE-L button to lock it. Does anyone use this option?

Another, related setting is the Link AF Point and AE setting. I'm not sure I totally understand this option and what it does - the book says its for use only when using multi-segment metering - it links the exposure and AF point in the focusing area during multi-segment metering. - I'll have to play with that just to understand what it does, and why it would be different than not linking them.

I find I'm using multi-segment metering more with the wide angle - the types of pictures I tend to take with it aren't like flowers etc. where I want a specific subject metered correctly and the rest isn't important. It really does depend on what type of picture you are taking - one of the reasons why I love having the K10's selection dial, rather than going into the K100's menu to change it.
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Old Feb 12, 2008, 2:04 PM   #6
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Thanks everyone for feedback on metering.

Scott: Appreciate detailed metering trial system. Have not got round to trying it yet but have it saved for a quiet evening.

Cheers: Ian Mc
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