This is a small addendum to my earlier post.
I suggested earlier that learning your camera in manual (M) mode is "best." I was serious, but I know that M scares a lot of people. That's
why there is a P mode, and an Auto mode, and all the kiddie modes (on the K100D -- their absence from the K10D is one of the things that shows it's a camera for serious photographers). Anyway, I want to add a note about M, and try to explain when you should use it and when you might prefer instead to use shutter-priority or aperture-priority.
If you want to take good photos and to be able to take credit for those photos, then you should want to take control of the camera, to be in charge. But to take control, you need to understand what control means, what is being controlled, what the variables are, why you should do this rather than that.
Now, if you shoot in M mode, you are in control, of everything, at least everything relating to exposure.
Understanding the meter in M mode
So, is M hard? Nah. All you really need to do is learn how to read the camera's light meter. When you look through the viewfinder, you can see the light meter's "opinion" as to whether you're properly exposing the shot or not. I don't recall what this looks like on the K100D, but I think it looks like it looks on the K10D, which is sort of like this:
. . . . ||||
^ ^ ^ ^ I ^ ^ ^ ^
- . . . . . . . +
Hope that comes out. You should see a series of ^ markers (on the K10D they're actually small bars) marking off one-stop increments. This is the scale. Above that, you've got the meter reading, represented in tall bars (actually, thick bars on the K10D). On the scale, there's a mark in the middle representing zero or the nominally correct exposure. The bars above the scale are always either on the left side of zero (indicating underexposure), or the right side (indicating overexposure), or there is just one bar right on zero, in which case the camera thinks you're nailed the exposure on the head. In the example above, there are three red bars to the right of zero, indicating a one and one-half stop overexposure.
I should mention that the meter looks a bit different in some cameras. On my *ist DS, for example, all I get is a number: "1.5" means that the camera thinks I'm about to overexpose the shot by one and a half stops; "-1.0" means I'm underexposing by one stop; and "0" means the camera thinks I've accidentally done something right.
How to respond to the meter
Once you know how to read the meter, the only thing left is knowing how to respond to its suggestions. If the meter indicates that you're overexposing the photo by one stop, then, um, do something to limit the amount of light that's going to make it to the sensor -- or make the sensor less sensitive. I recommend that beginners keep their cameras set so that everything is in half-stop (rather than one-third stop) increments. If you've got your camera set to use half-stop increments, and you're overexposed by one and a half stops, you have these two basic options:
- Increase the shutter speed by three clicks (each click represents half a stop). For example, if your starting shutter speed is 1/90th sec, turn it one click to 1/125th sec, a second click to 1/180th sec, and a third click to 1/250th sec. Do this if you think you've got the aperture set properly for the depth of field that you desire.
- Close or "stop down" the aperture three clicks. For example, if your starting aperture was f/4, move the aperture dial one click to f/4.5, a second click to f/5.6, and a third click to f/6.7. Do this if you've got the shutter speed set properly to freeze the action or stabilize the camera as you desire.
Each time you turn one of the dials by one click, you ought to see a change in the meter reading. If you started 1.5 stops overexposed, and you stop the aperture down from f/4 to f/4.5, the meter should look like this:
. . . . |||
^ ^ ^ ^ I ^ ^ ^ ^
- . . . . . . . +
You could also mess with the ISO, but again, I recommend that beginners think in terms of shutter and aperture almost exclusively. For one thing, you have a lot more control over those settings than you have over the ISO, and for another thing, you will almost always want to keep the ISO as low as possible. I recommend that you try to set the ISO somewhere reasonable and
leave it there. What's reasonable? If you're outdoors in bright sun, set it as low as it will go. Indoors, if you have no other ideas, set it to ISO 400. Note that, if you start at ISO 400 and you're one and a half stops over-exposed, well, you can't take the ISO down one and a half stops on a K100D, since that would be 100, and the K100D only goes down to 200.
Finally, you can use any combination of changes to shutter speed and aperture that results in a one and one-half stop change. For example, you could move the shutter from 1/90th sec to 1/180th sec (one stop) and change the aperture from f4 to f/4.5 (half a stop). But I don't do this a lot. I usually start by thinking about what is most important to me in this exposure -- depth of field or something else. Unless I'm shooting sports or I'm shooting with a long telephoto lens, it's usually depth of field, which means I'll set my aperture first, then I'll read the meter and adjust the shutter.
And that's all there is to it!
Of course, I'm lying a little bit. Okay, I'm lying a lot. Saying that's all there is to good photography or even to good exposure is a little bit like saying to a piano student, "Well, Beethoven wrote a C#, and here's C#, so just put your finger here and press down and voila! You're playing a Beethoven sonata!" If you're learning the piano, hitting the right keys is the basic idea -- but then there's all that other nasty stuff, like tempo, and volume, and articulation and musicality and such. Getting back to your camera, anybody can learn to read the exposure meter, and how to move the shutter and aperture dials to get the exposure meter to give a thumbs up. Seriously, this isn't rocket science. If my dog had an opposable thumb, she could learn to do this. But yes, there is more to taking good photos than this: like knowing what metering mode to use and why, what part of the scene to meter on, how to recognize the 547,812 different types of scenes that the meter can't actually meter very well and what to do about them, etc.
But it is useful -- and I dare say, encouraging -- to remember that the meter that the camera uses in M mode is the same one it's using in P mode. The difference is that in M mode, you get the credit for moving the e-dials. Nominally correct exposure, exposure that makes the camera's meter happy, doesn't mean
good exposure, and it certainly doesn't mean a good photo. But it's a start, an important start.
Doesn't M require math?
Yes, M requires math. You must know how to count to three, four, sometimes as high as five or six to use manual mode successfully. Beyond that, there's very little math required.
But what about those f-stop numbers? Don't you have to memorize them? And the shutter speeds, too?
Well, you
will memorize them soon enough. It might help you remember the f-stops if you realize that they consist of two series of numbers
1, 2, 4, 8, 16, 32
1.4, 2.8, 5.6, 11, 22
with the second series dove-tailed into the first series. These are the basic f-stops:
1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
You'll figure out soon enough that doubling the main part of the f-stop number actually means a
two-stop difference in exposure, while doubling the shutter speed or the ISO = simply a one-stop change in exposure.
As I say, you'll learn this quickly enough without effort. But you don't really need to know or remember any of this to be able to use M. Just look at the meter, count how many half-stops off "correct" your exposure is, and move the e-dials that many clicks in the right direction. Heck, if you have trouble counting to three or four, don't count -- just look at the meter.
The only thing that you really do need to understand to be able to use manual mode is that the f-stop values are fractions, so that the bigger the number below, the smaller the aperture: f/16 is like 1/16, where f/4 is like 1/4. One quarter is bigger than one-sixteenth. To make the aperture smaller or narrower, make the divisor part of the f-stop bigger. Actually, I think this is the hardest part for beginners. And it should not take you more than about thirty minutes to get over this speed bump. You just have to decide it's important.
I'm still scared of M! Why can't I use Tv or Av?
Okay, you can use Tv or Av if you want to. You don't even have to feel bad about it. I don't know very many pros that use P often (or ever). But lots of pros use Tv or Av.
Since there's nothing you can do in Tv or Av that you can't do in M, why would you bother with Tv or Av? Because when you're shooting in manual mode, you have to think about three things at once -- reading the meter, and adjusting the shutter and/or the aperture. In Tv or Av mode, on the other hand, you don't have to think about the meter, which isn't even displayed; and you don't have to think about one of the other things -- in shutter priority, you don't have to think about the aperture, and vice versa. The meter isn't there in Tv and Av because it's useless: it would always show a correct exposure. That's the whole point. You dial in a shutter speed, and the camera automatically sets the aperture for a correct exposure. Or you dial in an aperture, and the camera automatically sets the shutter speed for a correct exposure. Anyway, shooting in Tv or Av, you basically only have to think about one thing.
The advantage of Tv and Av to everybody, including experienced photographers, is that they're quicker and easier than M. This doesn't matter if you have time -- even a second or two -- to think about every exposure. When you get good at M, you will respond more quickly than you ever thought possible. But if you're shooting lots of candids in low light, or you're shooting sports, it may be easier to set one thing or the other and let the camera handle the rest. This frees you up to think about other things like composing your shot nicely.
EV: Exposure compensation
Since you've got my permission to use Tv or Av, I suppose I should wrap up this dissertation with a comment on exposure compensation, especially since this will take us back around to the value of using M mode.
The camera's light meter always wants to get a balanced exposure. I like to call this the Goldilocks effect: the meter doesn't want the photo to be too bright or too dark, it always wants the light to be
just right. If the overall scene is really bright, the meter will suggest that you stop down to make it look like it was not really bright. If it's rather dark, the meter will suggest letting more light in to make it look like there actually was plenty of light. If you take nominally correct exposures for a few weeks and study your photos, you will learn fairly quickly that the camera's meter sometimes makes a bad recommendation -- no, not just sometimes, but often. If you are photographing snow, the camera will want to make it look sort of gray rather than white. If you're photographing men in dark suits, the camera's meter will suggest settings that make the suits look lighter. If you want your snow to stay white and the dark suits to stay dark, you'll need to compensate by telling the camera to overexpose or underexpose by a stop or so. For snow, that +1 EV produces a nominal overexposure, overexposure according to the meter. But the resulting photo is not actually overexposed, it is correctly exposed, according to the ultimate judge of correctness, which is our eyes. Snow should look like snow.
So if you shoot in Tv or Av, you have to be aware of the times when something in the scene is going to throw the meter off the scent in one direction or the other, and you adjust using the exposure compensation (EV or +/-) button-dial. If you have a good reason to be using Tv or Av mode, then dialing in an EV value may make sense.
But notice what you're doing at this point. You're asking the camera's meter to lie to you, and you're telling it precisely what sort of lie to tell. Or putting it less metaphorically, you're overriding the meter.
Well, heck, if you're going to start doing that sort of thing, then you should give up on Tv and Av and go back to M. The point of Tv and Av is supposed to be that they're easy. As soon as you are sophisticated enough to know how to override the meter in those modes, then you might as well go back to reality, learn to take the camera's meter reading simply as a suggestion, and then set your aperture and shutter speed to their true values. If you work in M, and you set the aperture to f/4 and the shutter to 1/250th sec, those are the settings. When you see them in the EXIF info for your photo, you know those settings are the true settings used for the exposure. But if you shoot, say, in Av mode, and set the aperture to f/4, and you dial in one click EV (ask the camera to overexpose one-half stop), and the EXIF info tells you the shutter speed was 1/250th sec, and the EV = 0.5, what does that mean? Does it mean that the shutter speed was really 1/350th sec?
So the bottom line is: M mode is actually the easiest mode on the camera to understand, because using M is like reading your own handwriting. Of course, you have to learn to write before you can read your own handwriting. But once you do learn to write, next thing you know, you're composing verses, and if you keep that up for long, you might one day find that you've written a real poem.
Have fun.
Will