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03-09-2010, 09:13 AM   #16
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QuoteOriginally posted by Wheatfield Quote
To be fair, Jeff, the pictures of the dog happens to be one of the rare occasions when spot metering without input from the photographer will work and the other two exposure methods would fall down. The dog is somewhat darker than mid gray, causing the meter to call for more exposure.
If you had a fawn coloured Golden Retriever, your results would not have been so fortuitous.
I understand that and probably could have explained myself a little better.. Actually the dog is black. So black in fact it's difficult to get a decent shot of him with any type of metering.

The setting he's in goes from almost pure black (the dog) to pure white (the house). Well, off white anyway. Very brightly lit. I think we can agree that's one of the most difficult shooting situations. Something regardless of metering is going to be overexposed or underexposed. Were I using a film camera with B&W film (which I still do), I would have metered the dog and stopped down a couple steps to make sure that's how he looked on the final print. Some times I'll do the same thing with digital. There isn't a lot of (easy) chance in film/wet printing processing to correct it. With digital I can apply some curve masking to get everything in the shot properly exposed. Had I metered the cinder block behind the dog, it would have been more like the matrix shot.

What I was trying to demonstrate, with the photos, is the different behaviors between the 3 metering types (in auto exposure). I'm not trying to push anyone one way or the other. Spot works for me, even in a case of your fawn or GR, I could still pull things around enough to get things where they need to be. I could also look for a mid(ish) grey tone and expose for that. Spot metering allows me to dictate what I have to work with. If I were taking a picture of a partly cloudy sky (for the sake of having the sky the main interest in the photo) I would expose for the darker grey spots in the clouds. I've just become so accustomed to using it, that I know how to control the outcome with it.



03-09-2010, 01:27 PM   #17
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Much of the time, it doesn't make a huge difference what metering mode the camera is using. If the dynamic range of the scene is fairly "normal"—no extremes of both bright AND dark—then all three modes will meter the scene with pretty similar, sometimes identical, results. Consider the following examples. I'm shooting a mud dauber's nest on my front porch. Behind me, the sun is shining brightly in the front yard, but the porch is entirely shaded and the dynamic range of the scene is pretty limited. Changing the metering mode didn't produce a change in the recommended settings for exposure:





Now, I simply turn around and face the front yard. I'm shooting with my feet in the same spot, just facing the other direction, toward the bright day sky. I focus and meter on a tree in my yard. NOW there's a significant contrast between the bright sky and the darker tree, and the choice of metering mode makes a big difference.

This first shot was taken with matrix metering:



The overall result is pretty good. The sky in particular is a deep blue—bluer than in reality, but it's attractive.

Now, spot metering:



Whoa! Much of the sky is now completely blown out, and even the tree seems overexposed, because it is. The tree is dark. It's supposed to BE dark. But the meter wants to make it middle gray, so it overexposes it. This is clearly no good.

Here's center-weighted metering:



Interestingly, in this scene, center-weighted metering = spot metering, because the center-weighted area is all tree, so expanding the metered area doesn't really make a difference. So this stinks, too.

Of the three shots so far, it's clear that the first one—with matrix metering—is the best right out of the camera, and the one that will most likely be able to be improved in post. The blown highlights in the second and third photos can't be recovered. (I didn't try and some improvement might be possible. But not enough.)


*

But I'm not done.

If you want to make things easy on yourself, shoot in P mode, put the meter into matrix mode, and trust the camera to get things right. It will do an okay job, most of the time. Shooting this way, you'll seldom blow a shot completely, at least as far as the exposure is concerned.

But if you want to learn to do better than okay, then, no matter what metering mode or exposure mode you use, you really have to learn how to LOOK at the scene in front of you and evaluate it in your own head. If I'm shooting in available light (i.e. no flash), I always try to look at the scene and ask myself these questions:
  1. Is the dynamic range (DR) narrow, "normal" or wide? I don't usually try to calculate the DR in terms of stops. I can guess pretty well, but as a practical matter, the question for me is simply, will the DR fit entirely within the camera's grasp (about 5 stops) or not?
  2. If the DR is narrow, I simply LOOK to see if the scene is mostly light or mostly dark, and adjust the EC accordingly (for example, +1 for a bright scene, -1 for a dark scene). On the other hand, if the DR is wide—if there are very bright brights AND very dark darks—what part of the scene do I most want to expose properly?
  3. Once I decide what part of the scene matters most to me in terms of exposure, I also try to guess what its weight is in the scene, that is, is that key area a small part of what I see in the finder (like, say, a small dark bird on a branch surrounded by a lot of bright sky) or is it a large part of the scene (say, a canoe on a lake with trees in the background and some very bright sky occupying a bit of the shot above the trees)?

And then I apply some exposure compensation, as required. If I am shooting in P (or Av or Tv) mode, I dial it in using the +/- button. If I'm in M, as I am most of the time nowadays, I want the meter's exposure reading to show + or - some amount. If you're using an auto-exposure mode (P, Av or Tv), you bias the meter. If you are shooting in M, you bias your reading of the meter. Same result.

Now, I think you HAVE to work this way. The meter is just a tool and you want to use it, rather than vice versa. The reason your brain is so important here is simple: Unlike your brain, the meter has no idea what the hell it's looking at. The meter doesn't know the difference between brightly lit fresh snow and a coal cellar. When you reckon the EC needed to capture the scene correctly, all you're really doing is telling the camera, "This is snow: It's SUPPOSED to be bright white," or "This is a litter of black puppies: they are SUPPOSED to be dark."

Which is what I did when I took the last shot of the boring tree in my boring front yard: I cut the shutter speed in half (from 1/750th sec to 1/350th sec). Here's the result:



This is the best of the four exposures of the tree. NOTE CAREFULLY that it doesn't LOOK as good right out of the camera as the first one. It looks a bit washed out. That's okay. For one thing, it's a more accurate representation of what I actually saw. Even more important, there are no blown significant highlights here and the exposure is pushed just about to the right edge of the histogram, where I want my raw captures to be. This shot can be processed more effectively than the first one.

*

Using matrix metering is a way of letting the camera do some of the compensating for you. That's why I use matrix most of the time. I still have to look at the scene and think about possible EC one way or the other, but with matrix, the camera has already done some of the balancing for me, so I don't have to adjust quite as much as I would if I were shooting center-weighted and certainly not as much as if I were shooting in spot metering mode. Using my tree examples, I applied 1 stop EC in my reading of the meter for the last matrix metered shot. If I'd been shooting in center-weighted, I'd have had to apply TWO stops EC to achieve the same result, because, if the fourth shot is right, then the center-weighted result earlier (tree pic #3) was wrong by two stops.

Still, with every shot, I LOOK first, think for a half a second, and then (in M) move my shutter or aperture settings a bit one way or the other so that the meter is where I think it should be. I've never made a study of this, but I will venture to say that, when I shoot in matrix exposure mode, I seldom need to adjust the metered result by more than 1 stop.

And I hasten to add that this particular picture is just one example, and it's one that favors matrix mode (because there's no difference in result here between spot and center-weighted modes). I like matrix. Works for me. But honestly, it doesn't matter, so long as you know what you're doing. A lot of excellent photographers use center-weighted. Perhaps there are a few people out there who use spot metering routinely. Whatever works, is fine.

*

So bottom line, there are two skills here.

First, know what your meter does. If you understand what it's doing, you can probably use any metering mode and get similar results.

Second, LOOK at the scene and decide for yourself what EC is called for, so you can keep your whites white and your blacks black.

If you practice just a little, you'll soon be able to set the exposure compensation (or read your meter in M) properly, the first time. It's not terribly difficult. We're not talking about the zone system here! But if you don't like the result when you look at it on the display screen, simply make another quick adjustment and shoot again.

Will
03-09-2010, 09:47 PM   #18
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QuoteOriginally posted by JeffJS Quote
The camera is pointed at the same spot on all 3. The dog's face.
By cropping the image and putting the dog's face NOT in the center, it makes any analysis of the metering results difficult. We don't know what was in the whole image. For instance in the spot meter version, it looks like it would have been metering the light wall and screwing up the exposure - according to your photo. However, when you explain that it was centered on the black part, it makes all the difference, and perfect sense.

Oh, and the only time I used spot was accidentally - though fortunately it worked out as the center of the images were fairly medium-toned. I use matrix as I have a slightly better result than center after a bit of testing..
03-09-2010, 10:41 PM   #19
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FWIW, I'd have meter that shot by metering off a part of the ground that is in the same light as the dog, then applying a stop or so of compensation because I don't want the dog to read as being quite as black as it would otherwise be. Using this method, it really wouldn't matter what mode I was in - but I find center weighted most convenient overall.

03-10-2010, 06:50 AM   #20
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Thank you all for the help especially Will thx for that detailed explanation.
What i use to do before was multi segment and then take a look at the picture and use the Exp compensation + or -.. Good to know i was on the right track.
03-10-2010, 09:21 AM   #21
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In the March issue of Outdoor Photographer, there is an article beginning on page 50 that I plan on using. It is an interesting way of looking at metering and applying the zone system to the in camera meter. Here is an extremely brief extract of the way they do it. It strikes me as a way of handling metering that will give the best exposure possible.
  1. Choose a small area of the picture that is the brightest tone you want to keep detail in. The article used a waterfall in bright sun.
  2. Spot meter that area and
  3. Add two stops (+2.0) to the exposure.
The converse is
  1. Choose a small area of the picture that is the darkest tone you want to keep detail in.
  2. Spot meter that area and
  3. Under expose by two stops.
This strikes me as a simple way to accurately expose the scene for the results I want, and one that is both quicker in camera than shoot, chimp, adjust and quicker than bracketing when it comes to post processing.

It comes to mind that when I happen upon a scene with more than five stops between the darkest and lightest areas when I want to preserve detail in both that I could take two exposures, one using each of the above, and run them through a Shadow and Highlight process such as Photomatix.
03-10-2010, 02:58 PM   #22
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A standard?

Choosing And Using Metering Patterns
In general, choose patterns using these
rules of thumb:

Matrix: (patterned) When the light
comes from over your shoulder onto the
scene. When contrast is not excessive
(very deep shadows) and when there is a
fairly even distribution of light and dark
throughout the scene.

Center-Weighted: (When used
in conjunction with exposure lock);
highly directional light; bright light that
dominates a portion of the frame, but is
not necessarily the main subject (such
as landscape with bright sky and darker
ground); to control bright highlights that
do not dominate the scene but that have
a profound influence on exposure. When
scene contrast is high.

Spot: When the main subject falls within
its own shadow; when you want to control
and saturate highlights. When scene
contrast is high. When you want to saturate
a specific area within the frame.

source: Digital Photography
03-10-2010, 03:07 PM   #23
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QuoteOriginally posted by Clicker Quote
Choosing And Using Metering Patterns
In general, choose patterns using these rules of thumb:....
sourceigital Photography
I don't disagree with the details here, exactly. It's more that I disagree with the whole idea of changing the meter constantly. The key to success isn't using the specific metering mode that best suits your scene. The key to success is knowing how to use whatever mode you're using.

In The Hot Shoe Diaries, Joe MacNally confesses that he leaves the camera on matrix metering all the time. On the other hand, I have talked to more than one good photographer who claims to use nothing but spot metering. And center-weighted is also very common, perhaps the most commonly used mode. As long as you get the results you want, it doesn't matter at all. And you CAN get the same results from any metering mode, if you know what you're doing.

Thinking about changing metering modes just seems like a waste of time to me, and furthermore, potentially confusing. It's better to get good at working one way, and stick with it. I have given the college try—indeed, the grad school try—to using hyperprogram mode (P), but I found that I could never get away from M entirely, and not just when shooting flash. So I'm back to using M full time. There are disadvantages, and they are even fairly significant. But in the long run it's easier to get comfortable with one way of working and stick with that.

My 2 cents, anyway.

Will

03-10-2010, 07:47 PM   #24
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QuoteOriginally posted by rustynail925 Quote
What i use to do before was multi segment and then take a look at the picture and use the Exp compensation + or -.. Good to know i was on the right track.
Lots of good advice above, especially Will & Albert & Clicker. And yes, you're on the right track: find what works for you and tweak it. I've used center-weighted on various cameras (or hand-held meters) for decades. Also the trick of reading off something that's nearer middle-gray-intensity than the (contrasty) subject, like the ground or my sleeve. Now with digicams, we can just chimp the shot and adjust as needed -- or, bracketing is free!

I'm close to two years on my K20D now, and I've stuck pretty much with center-weighted the whole time. But it doesn't hurt to get out of a rut. So today I tried the Zone System trick, which came out pretty much like the method Albert cited just above. His magazine method: spot read the darkest or brightest points in the picture, and adjust by 2EV. The Zone method: spot read the darkest AND brightest points, and set the exposure midway between.

So I put a FA100-300 lens on my K20D, set to Av mode and f/5.6, and looked off my back porch into dark evergreen trees and bright snow. The snow wasn't directly sun-lit, but it was pretty bright anyway. I spot-read the snow: 1/350 sec. I spot-read the darkest point I could in the trees and shadows: 1/30 sec. I got to the midway number by mentally multiplying and dividing by two: half of 350 is about 180, twice 20 is 60; half of 180 is 90, twice 60 is 120. Midway is 105, and the closest I can get is thus 1/90 sec -- which is -2EV from the brightest reading, just as Albert's method suggests. And 1/125 is +2EV from the darkest.

In the shot at 1/90 sec, the shadows showed detail and the highlights weren't blown. If I hadn't been tired and cold (excuses, excuses!) and had thought of doing a REAL test, I'd have shot again at 1/125 sec; and then switched to center-weighted, read off my middle-grey sleeve, and tried that exposure; and then switched to matrix, and shot again. But the Zone System trick worked; and center-reading off gray works; and test-shooting and chimping and adjusting works. Whatever works. WHATEVER WORKS!!
03-10-2010, 08:26 PM   #25
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Like many posters here have suggested, spot metering gives you finer degree of control over the metering a particular spot/point - but if you use it incorrectly, it can clip some highlights. It is also very tricky to use as it depends where your focus point is set; this is very similar to using a Manual focus lens (which is either center weigh or spot).

In most situations, multi-segment metering provides relatively correct exposure, however, in high contrast situation or situations where you need high degree of accuracy on the exposure of focused point (area), you will need spot or center weigh). Therefore, I do not leave the metering in "spot" mode.
03-10-2010, 08:45 PM   #26
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QuoteOriginally posted by RioRico Quote
I'm close to two years on my K20D now, and I've stuck pretty much with center-weighted the whole time. But it doesn't hurt to get out of a rut.
Yeah, I think I change my methods occasionally just for the heck of it. I'm pretty sure this isn't illegal.


QuoteQuote:
So today I tried the Zone System trick, which came out pretty much like the method Albert cited just above. His magazine method: spot read the darkest or brightest points in the picture, and adjust by 2EV. The Zone method: spot read the darkest AND brightest points, and set the exposure midway between.
Well, I have never claimed to understand the zone system really. But I have three books on it here and I'm pretty sure there's more to it than that. :-)


QuoteQuote:
Whatever works. WHATEVER WORKS!!
Amen, brother.

Will
03-10-2010, 09:53 PM   #27
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The RioRico Zoned-Out Exposure Trick

QuoteOriginally posted by WMBP Quote
Well, I have never claimed to understand the zone system really. But I have three books on it here and I'm pretty sure there's more to it than that. :-)
What, you want me to pontificate even MORE here? A real masochist, eh?

Anyway, there are more Zone Systems than I can shake a meter at. Most are more complicated than I have time for. So let's call this the RioRico Zoned-Out Perfect Exposure Method (C) (TM) (patent applied for) and be sure to pay me royalties whenever you use it, which should be often.

1) Spot-meter the brightest point
2) Spot-meter the darkest point
3) If possible, set exposure midway
4) For more shadow detail, go +1/2EV
5) For more highlight detail, go -1/2EV
6) Bracket bracket bracket, just to CYA
03-10-2010, 09:56 PM   #28
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QuoteOriginally posted by WMBP Quote
Well, I have never claimed to understand the zone system really. But I have three books on it here and I'm pretty sure there's more to it than that. :-)
Will
Will, grab a copy of the Outdoor Photographer March 2010 issue, and read it - it's short enough to read at the magazine rack if you don't have the money for it. They took the concept developed by Ansel and the f/64 group, and applied it to a 5 stop dynamic range as provided by our sensors, then simplified it so that a dummy like me could actually use it!
03-10-2010, 09:58 PM   #29
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QuoteOriginally posted by RioRico Quote
6) Bracket bracket bracket, just to CYA
There you go. There's a method I can put my faith in!
03-10-2010, 10:01 PM   #30
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QuoteOriginally posted by Canada_Rockies Quote
Will, grab a copy of the Outdoor Photographer March 2010 issue, and read it - it's short enough to read at the magazine rack if you don't have the money for it. They took the concept developed by Ansel and the f/64 group, and applied it to a 5 stop dynamic range as provided by our sensors, then simplified it so that a dummy like me could actually use it!

Thanks. I have not seen that issue around here. Maybe my subscription expired and I didn't notice. Is THIS the article?

The Digital Zone System - Outdoor Photographer | OutdoorPhotographer.com

Will
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