Manual exposure...

kelly1

Hello all,

I got into a discussion on another thread about the merits of using manual exposure and my opinion at the time was that for general shooting, it's best to let the camera decide the exposure. Afterall there's enought to think about when taking a shot without adding exposure into the mix.

But I'm coming around to the idea that manual may be best especially since it's not as difficult as I thought it would be - just spin the wheel to adjust shutter speed while looking looking at the meter through the viewfinder.

Do most of you seasoned experts recommend manual? Does it slow you down or maybe you forget to check the exposure resulting in badly exposed shots?

Regards,
Noel.

DaireQuinlan

But why bother, If you're just using the in-camera metering and matching up with whatever the camera has metered as the correct exposure then you're just doing exactly what the camera is doing anyway, only more slowly.
There are times when I switch to manual, but only if I know that the camera is going to screw it up. Otherwise its all aperture priority with exposure compensation when necessary.

pullandbang

/\ /\ As he said

Aperture priority 99% of the time and manual if there's a lot of sky for example and the camera is going to overexpose it.

magicbastarder

what daire said.

pixbyjohn

I have used manual a lot, like you I tend to use the on camera exposure meter to setup the shutter speed for a given aperture setting. It also allows me to over or under expose as I needfor a given situation. But I use aperture priority mostly when I am out and about. I set the aperture I feel I need and the camera looks after the shutter speed for me. All in all once you get a good photo it really doesn't matter which settings you use I think.

kelly1

DaireQuinlan wrote: »

But why bother, If you're just using the in-camera metering and matching up with whatever the camera has metered as the correct exposure then you're just doing exactly what the camera is doing anyway, only more slowly.
There are times when I switch to manual, but only if I know that the camera is going to screw it up. Otherwise its all aperture priority with exposure compensation when necessary.

Apparently a lot a pros shoot exclusively in manual mode. It's bound to be good for consistent exposure eg. playing at a football match where one team is wearing black and the other white. Not sure who gave me that example, I thought it was you!

You only need to change the exposure when the lighting condition change and it takes very little time to have a quick squint at the meter.

Does anyone here advocate manual?

magicbastarder

there are certain conditions where manual makes sense, but i find they're less common than situations where aperture priority is the easier option.

Paulw

I'd shoot manual about 90% of the time, and aperture priority 9% (the other 1% would be me experimenting).

With manual, I can control both aperture and shutter speed. There are times, with harsh light/shadows, when the camera will like to set a shutter speed higher or lower than what I personally want. There are times when I don't care about blown highlights or backgrounds.

Obviously, this is all just personal taste, but for the vast majority of cases, I shoot manual.

PopeBuckfastXVI

I shoot manual now, I was aperture priority for a long while, but I shoot manual to allow me more accurate metering, especially with focus and metering having the same button on my camera (unless using back button focus), I may want my point of focus over or under exposed, or at the very least not be 18% grey. I do forget to adjust sometimes though, and over or under expose the first shot in a given situation, but that'd be about it.

Once you set your exposure correctly for the situation then you don't need to worry about a big white or black thing passing through the frame and flucking up your exposure too - leads to consistency.

I wouldn't tell anyone else they should use manual, but if it works for you, then why not.

DaireQuinlan

kelly1 wrote: »

Apparently a lot a pros shoot exclusively in manual mode. It's bound to be good for consistent exposure eg. playing at a football match where one team is wearing black and the other white. Not sure who gave me that example, I thought it was you!

I think it was Paulw, as below Yeah there are certainly situations where it might make more sense. Pauls is one, another is if you're (for example) shooting landscape and you spot meter various parts of the scene, decide what you want exposed correctly and work out your exposure that way, aka Adams and the zone method for example. Charybdis I think brought that up the last time.
For 99% of usage though the matrix meter in your camera (presuming that you have some modern digital body) is probably smarter than you are in working out what to shoot at. The trick is in knowing when it's not.
I tend to have to resort to exposure compensation a lot more when I'm shooting with something that only has CW metering. And of course I have a pile of cameras that have no meter at all, that require me to use an external meter. In that case it's generally just incident metering I use and transfer the settings across after making whatever adjustments I think neccessary.

squareballoon

I shoot manual 95% of the time now too because I prefer to decide for myself how to expose each shot. I would use AV if I was chasing children around outside.

charybdis

There really isn't much point though if you're using evaluative/matrix metering or similar and just centring the needle before you shoot.

As I have mentioned before, I've pretty much switched to using manual mode and spot metering 100% of the time, not necessarily because I think it's guaranteed to give me better results, but as an exercise in self discipline. I'm very happy working in this way though, it's really cemented my understanding of complex metering/exposure and my camera's dynamic range. It's quite quick to do when you know what you're doing; identifying key tones before you even raise the camera and then placing them where you want on the meter's scale, adjusting their relative placement if you're in a situation with unusual lighting or you have a lot of opportunity for exposure latitude in the highlights that you can pull back in post, and taking the shot. I usually try and keep key shadow detail above -2, skin tones at around +1 (depending on the light), and try and reign in any important highlights below +2. The whole process only takes a few seconds from raising the camera to your eye and hitting the shutter release.

I have also tried taking a photograph of a scene in manual/spot and then taking a second photograph with the same framing in aperture priority with the same aperture value and in evaluative metering mode in order to compare the decisions of the camera with my own; in a surprisingly large number of situations, the camera and I more-or-less agree (the camera will sometimes pick a slightly wonky shutter speed or an unnecessarily high or low ISO, but the exposure value is very similar to the one I chose), but when our opinions are divergent, my choice is the one I prefer.

It's also very satisfying to be able to look at a scene and start thinking about the relative tones present in the scene and where you'd like to place them in your photograph. Much like all the learning about photography technique I've done, this is satisfying not just because you can articulate the image you want when confronted with a new situation, but because you learn to see new situations in terms of how you can represent them. I am firmly of the opinion that learning to control the camera for the purposes of capturing what you see requires you to learn to see in new ways.

Morrisseeee

100% manual..........everything..........I like to be in control !! Then I've no choice as I mainly use old manual lenses, and as Daire said I usually meter the brightest/darkest area of a scene and then compensate/experiment. I find centre-weighted metering works best (for me).

kelly1

charybdis wrote: »

There really isn't much point though if you're using evaluative/matrix metering or similar and just centring the needle before you shoot........

Thanks Charydis, your reply was very informative.

I personally use Aperture priority and, a lot of the time, but not always; spot metering.

That said, I'm not the most competent person with Manual, so...

Borderfox

Saturday I used aperture priority (very sunny and shutter priority meant a small f-stop) but Sunday I used shutter priority. Taking pictures of showjumping to sell on site so all in jpeg with +2/3 overexpose. Indoors I use manual a lot, mostly use a lightmeter to find out the levels and shoot accordingly

PCPhoto

squareballoon wrote: »

I shoot manual 95% of the time now too because I prefer to decide for myself how to expose each shot. I would use AV if I was chasing children around outside.

ahem ..... do their parents know ? ...do you regularly "chase children" ?

jpb1974

If it's available on the camera I'm using then I tend to roll with Aperture Priority with Exposure Compensation when necessary.

Doesn't really matter what you use so long as the photos are exposed the way you want them. With digital cameras a quick chimp and review of the histogram will tell you quite a bit.

kelly1

Thanks for all the inputs. I'm going to give the manual a whirl for a while and see how it goes.

swingking

I always use Manual exposure except when I know I'm looking for a fast shot involving action or street. Also I expose using the spot metering system and always try to take my readings from an area of neutral tonal range, ie. something grey

Barname

you are all wasting too many keystrokes fighting

lets do it old school, behind the bike shed after school.

youllneverknow

depends if the day is dark or dull ill expose it more myself to brighten it up abit but most the time i let it do it its self

smelltheglove

I use manual 100% of the time, no matter what! I decided to push myself a ling time ago and do an under lit boxing fight in manual only to keep the pressure on, I feel I work better under pressure, and since that day I have pretty much forgotten about any other settings! Even family snaps are manual!

Mensch Maschine

Suprised at how many don't use Manual more often. I use manual 100% of the time. I usually set the ISO for the start of a session, the the speed and mainly change the aperture accordingly. I like to have control of my depth of field.

Having shot manual pretty much from the start, I can guess the right aperture etc very quickly.

AnCatDubh

You need to think about what it is you are trying to do/shoot. Modes are there for a reason and the reason is generally to help the photographer for particular situations.

There are horses (modes) for courses (situations).

In the only book by Scott Kelby that i've read (well, i've read parts); I did note that he said, if he's finished shooting with purpose ie. an assignment or that he is just moving from one place to another he will set the camera and shoot in "P" mode (which of course I deduced means "professional" mode and is reserved for professionals; p = professional right? :rolleyes:). His rationale as stated was if he saw something that he wanted to shoot in an instant as he moved from one location to another, he wasn't going to have time to think about what mode, settings would he choose, the professional mode would do that all for him. And he backed it up with a particular image of an open top car which pulled up in front of him and then took off and he snapped it, processed it, and made a truck load of money out of it.

Personally, whatever the mood takes me and it depends on what i'm trying to shoot.

Anyhow, if we are real purists we should all set our cameras into B mode all of the time (b=brilliant results right?) and work it out like real photographers (Take that Mr. Kelby ).

Mensch Maschine

Good points. I must explore the rest of my camera more. I feel I got into a little comfort trap when theres more that can be done.

CabanSail

I do tend to shoot mostly in P but vary the Modes & other functions according to the situation that is presented. I have done my "apprenticeship" and have used cameras long before any of the fancy modes were around. You had no choice other than Manual, and it wasn't called Manual then it was just a camera.

Personally I think it's more important to understand exposure, regardless of which mode you use. When I am in P Mode I look down in the viewfind & it will feed me the relevant exposure information (Aperture, Shutter Speed & ISO) and so I can make a decision & alter things as required. If I want a larger/smaller DOF then I quickly scroll through the EV equivalents on the back dial. Likewise if I want faster or slower shutter speeds. If I then want to over or under expose then that is available on the front dial of the camera. So without moving my eye away from the viewfinder I have a lot of control over the image, this does me for most situations. I will select other modes & functions when they are required.

magicbastarder

i think the short answer is do what you find most comfortable. moving to M is not necessarily going to make your shots better, and could even make them worse, at least in the short term. if it helps you understand light better, fire away.

Thecageyone

On my old fuji bridge cam I was using manual 100% of the time. I just wanted to get it into my head. It done me good, when I got the dslr I already felt comfortable with manual controls.

I tend to start in Aperture priority, but I'll always check the image right away and adjust in manual from there. I find the cam gets it very wrong at times, especially, as already mentioned, with very bright skies. It's the best mode for quick shooting. Manual is better with a bit of fiddling.

P mode is almost Auto is it not? Only you can control the ISO? or it was on my fuji at least.

Mountainsandh

That's so interesting ! I'm just trying to self-teach bits and pieces, and not part of a club, so all the experienced photographers comments are really useful.
I learned to use the Manual control on my old Fujifilm Finepix, it was miles better than the preset modes, and I just felt I was learning more. I'm not a bit logical or "maths" minded, so for me understanding exposure is an ongoing process... and experimenting with fully manual mode really helps.
I saw someone mentioning they checked in AP what settings the cameras chose and then replicated in Manual, but I tried it and it annoyed me actually. I'm not under pressure to take good pics straight away, just doing this for fun, so I prefer to go manual and get it wrong sometimes. As it happens I get it wrong a lot of the times, most of my pics are underexposed, but when I do give it a bit more thought and time, I get it right sometimes, and then aren't I proud ?
I sort of know now though, the kind of shutter speeds and aperture I like best (and Iso) in the situations I take most of my shots.

The comments in this thread really are shaking me up to learn how to use metering though, that's an area I've barely explored, and exposure compensation too. Have had DSLR since Christmas and not read manual yet .

gbee

kelly1 wrote: »

Hello all, my opinion at the time was that for general shooting, it's best to let the camera decide the exposure. Regards,
Noel.

Yes, a lot of the time this is fine, especially with changing weather and or in the sports arena when the subject may get very close to one at times.

However, if one wants to practice true manual exposures one really needs and incident light meter.

The camera meter is fooled by white or black clothing and does not function well in dull overcast conditions. So we all get used to using the +/- compensation, but, especially for those really tricky situations and dull days a handheld incident light meter is the way to go.

You'll be surprised at the subtle differences that a 1/2 stops makes etc.

magicbastarder

Mountainsandh wrote: »

The comments in this thread really are shaking me up to learn how to use metering though, that's an area I've barely explored, and exposure compensation too. Have had DSLR since Christmas and not read manual yet .

the manual will probably not be very good about explaining the concept of exposure; it will probably just explain the exposure functions on the camera.

magicbastarder

gbee wrote: »

However, if one wants to practice true manual exposures one really needs and incident light meter.

one of the handy things about the hasselblad is that the shutter speed ring and aperture ring are adjacent and lock together - so once you select an exposure, you can twiddle the ring and it carries the two rings together in such a way that the exposure remains constant. probably only possible in leaf shutter cameras.

CabanSail

magicbastarder wrote: »

one of the handy things about the hasselblad is that the shutter speed ring and aperture ring are adjacent and lock together - so once you select an exposure, you can twiddle the ring and it carries the two rings together in such a way that the exposure remains constant. probably only possible in leaf shutter cameras.

I have an old Nikon lens sort of like that. I will soon dig it out of storage. It is called a Flash Coupling Lens. It was used before the days of Auto Flashes & it would lock the Aperture Ring together with the Focus Ring. These were set for the Guide Number for the Flash & Film Speed. It was a nifty little lens.

gbee

magicbastarder wrote: »

one of the handy things about the hasselblad is that the shutter speed ring and aperture ring are adjacent.

Loved mine, once I understood it, ƒ/11 ~ ƒ/2.8 in an instant

DaireQuinlan

CabanSail wrote: »

I have an old Nikon lens sort of like that. I will soon dig it out of storage. It is called a Flash Coupling Lens. It was used before the days of Auto Flashes & it would lock the Aperture Ring together with the Focus Ring. These were set for the Guide Number for the Flash & Film Speed. It was a nifty little lens.

The 45mm GN ? I've been trying to get my hands on one of them for ages. They're inclined to go for silly money for what they are though. I think the FM3A 45mm lens which was optically the same pushed up the prices of the older AIS version as well. They were pretty neat though. I think it was actually the focus ring that was linked to the aperture though, right ? So as you focused closer the aperture would close up more ?

-edit- ah, yeah, what you said

charybdis

magicbastarder wrote: »

one of the handy things about the hasselblad is that the shutter speed ring and aperture ring are adjacent and lock together - so once you select an exposure, you can twiddle the ring and it carries the two rings together in such a way that the exposure remains constant. probably only possible in leaf shutter cameras.

There are fixed-lens rangefinders from the 70's that have their exposure controls laid out in a similar way (albeit without an actual locking mechanism). It is amazing to me how you can get a crash course in exposure just by looking at the lens barrel; certainly a far cry from spinning a dial on a DSLR and watching (seemingly arbitrary) numbers change on an LCD.

gbee wrote: »

Yes, a lot of the time this is fine, especially with changing weather and or in the sports arena when the subject may get very close to one at times.

However, if one wants to practice true manual exposures one really needs and incident light meter.

The camera meter is fooled by white or black clothing and does not function well in dull overcast conditions. So we all get used to using the +/- compensation, but, especially for those really tricky situations and dull days a handheld incident light meter is the way to go.

You'll be surprised at the subtle differences that a 1/2 stops makes etc.

I don't think an incident meter is ideal in all cases. The only situation in which I'd imagine an incident meter is clearly preferable is with complex strobe setups, otherwise I don't see why it's preferable to a spot meter.

gbee

charybdis wrote: »

The only situation in which I'd imagine an incident meter is clearly preferable is with complex strobe setups, otherwise I don't see why it's preferable to a spot meter.

Stobes are easy @ except for the first time.

If you want to go spot meter ~ I'd be inherently in agreement with you.

But, from my experience, I've not had accurate enough camera based spot metering since the OM-4. Since digital, getting the exposure right is as crucial as when using slide film.

My DSLRs Olympus E10; Nikon D1x; Canon 1DMKIII, Canon 5D and a few in between ~ I was never happy with their inbuilt spot metering ~ but applying an incident reading from my Sekonic L-358 was quick, easy and accurate [obviously where the on-board would have difficulty as mentioned].

And I was severely tempted to get theSekonic L-758DR for its spot metering prowess, sure, can't argue against the spot.

magicbastarder

the only camera i really use spot metering on is my OM4Ti; i've not really figured it out on the new camera (which has an instruction manual an inch thick, and my usual method of ignoring the manual is not proving too fruitful so far).

the spot is easiest when you've something close to 18% grey (or something you want to come out at that anyway) you can meter from. otherwise you're into averaging out, and that's not 100 miles away from matrix metering, from what i understand of matrix metering.

DaireQuinlan

magicbastarder wrote: »

the only camera i really use spot metering on is my OM4Ti; i've not really figured it out on the new camera (which has an instruction manual an inch thick, and my usual method of ignoring the manual is not proving too fruitful so far).

Is the OM4Ti the one that you can make a bunch of different spot readings and then compare them ? Or average them or something ? That's a pretty useful metering system so long as you're aware of the the potential gotchas of reflective metering and you've got the time to do it I guess.

Matrix meters are pretty smart at this stage. Particularly the colour ones. The big array ones basically do a really low res sampling of the entire scene. They then compare it to some internal database they have of similar shooting situations and hand back the ideal metering to use in that situation. Of course their idea and your idea of 'ideal' might not necessarily match up ...

magicbastarder

yep, it can take up to eight spot readings and average them out. you can also point it at part of the scene and tell the meter that it's a highlight or a shadow, iirc - i've never used that functionality.

Mountainsandh

magicbastarder wrote: »

the manual will probably not be very good about explaining the concept of exposure; it will probably just explain the exposure functions on the camera.

I know magicbastarder, Google is my friend .
I was just thinking of that little meter thingy (exposure compensation, in increments ?), and how I only seem to be able to access it in Aperture Priority, can't get it in the fully Manual mode... but maybe I can, and I just need to read the b%$$dy thing (it's a Pentax K-x I have if anybody has one):(.

charybdis

DaireQuinlan wrote: »

Is the OM4Ti the one that you can make a bunch of different spot readings and then compare them ? Or average them or something ? That's a pretty useful metering system so long as you're aware of the the potential gotchas of reflective metering and you've got the time to do it I guess.

Matrix meters are pretty smart at this stage. Particularly the colour ones. The big array ones basically do a really low res sampling of the entire scene. They then compare it to some internal database they have of similar shooting situations and hand back the ideal metering to use in that situation. Of course their idea and your idea of 'ideal' might not necessarily match up ...

The evaluative/matrix metering systems are really advanced and work remarkably well in most cases, but when you don't have the luxury of the latitude of negative film and are working with digital highlight shoulders and potential for noisy shadows it's often beneficial to expose as carefully as possible.

Mountainsandh wrote: »

I know magicbastarder, Google is my friend .
I was just thinking of that little meter thingy (exposure compensation, in increments ?), and how I only seem to be able to access it in Aperture Priority, can't get it in the fully Manual mode... but maybe I can, and I just need to read the b%$$dy thing (it's a Pentax K-x I have if anybody has one):(.

Exposure compensation has no meaning in manual mode, it only makes sense in terms of an auto exposure mode (like aperture priority) because all it does is tell your camera to change the exposure by a given amount from whatever the metered value is; in manual mode you set the exposure manually so the camera cannot apply any kind of compensation because it has no control over the exposure. When using manual mode, you should pay attention to what your meter is telling you when you meter off different things and adjust your exposure parameters accordingly.

gbee

charybdis wrote: »

Exposure compensation has no meaning in manual mode,.

Whilst your explanation is correct, compensation is still used in manual mode. IE, in snow scenes you'd like +1 or +2. Albeit that you have to apply this manually to the shutter and aperture as it won't be applied automatically.

But if you use the manual settings and use the manul meter reading [in camera] it will react the same way as in automatic mode [obviously cameras differ and some only allow spot in manual] but in this snow scene the manul exposure [without compensation] will result in a darker image, the same as could be expected from the auto modes ~ with reference again to the way various auto mode work, and their auto cut off points.

Naturally manual mode releases the full potential of any camera.

Will23

i see i lot of the more experienced users go with aperture priority... any thoughts on shutter priority?!

comments on pro and cons welcomed, thanks!

Will

charybdis

gbee wrote: »

Whilst your explanation is correct, compensation is still used in manual mode. IE, in snow scenes you'd like +1 or +2. Albeit that you have to apply this manually to the shutter and aperture as it won't be applied automatically.

But if you use the manual settings and use the manul meter reading [in camera] it will react the same way as in automatic mode [obviously cameras differ and some only allow spot in manual] but in this snow scene the manul exposure [without compensation] will result in a darker image, the same as could be expected from the auto modes ~ with reference again to the way various auto mode work, and their auto cut off points.

Naturally manual mode releases the full potential of any camera.

I'm not sure if you mean that you have a camera that you can dial in exposure compensation for use with metered manual mode that will bias the meter by the specified amount or if you mean that you have to mentally account for an exposure bias when choosing your exposure settings when using manual mode. I didn't think any camera had an exposure compensation setting that could be used in manual mode; if one did, I'd assume it'd be confusing and counterproductive. In your example of shooting in snow, I understand why exposure compensation would be desirable when using an auto mode, but I don't see why it'd help when you're using manual exposure and can place the snow tones where you want on an exposure scale.

magicbastarder

Will23 wrote: »

i see i lot of the more experienced users go with aperture priority... any thoughts on shutter priority?!

most of the time, unless i'm worried about camera shake, the aperture has more of an impact on the end result than the shutter speed. so it's the latter i'd want to control. you'll probably find that sports photographers would have more use of shutter priority, if they're concerned about freezing the action.

Will23

thanks magicb..

i kinda felt as much, just bought an AE-1 and am wondering should i have gone for an A1 or AV-1 altogether!

Will.

Mountainsandh

charybdis wrote: »

I'm not sure if you mean that you have a camera that you can dial in exposure compensation for use with metered manual mode that will bias the meter by the specified amount or if you mean that you have to mentally account for an exposure bias when choosing your exposure settings when using manual mode. I didn't think any camera had an exposure compensation setting that could be used in manual mode; if one did, I'd assume it'd be confusing and counterproductive. In your example of shooting in snow, I understand why exposure compensation would be desirable when using an auto mode, but I don't see why it'd help when you're using manual exposure and can place the snow tones where you want on an exposure scale.

Thanks Charybdis and Gbee, the comments help even though as I said, I'm a newbie, and have never tried looking at the meter on my camera, or metering for a particular area, but I know I need to try/learn that... I've been like a dog sort of sniffing the air to guess what exposure I need.:(

AnCatDubh

Thecageyone wrote: »

P mode is almost Auto is it not? Only you can control the ISO? or it was on my fuji at least.

A qualified yes to the above. Auto with overrides may be a better descriptor. Each camera / brand may handle P mode differently whilst Av or Tv should be reasonably standard across camera / brands (at least in their intent).

Generally, P mode will take a best guess on any given situation. Depending on your camera it may allow you to configure where that 'best guess' should be. Where it normally differs (at least in what i've seen on my Pentax bodies) from Auto or 'green' mode is;

a) it will allow you alter the shutter or aperture settings using the front and rear dial controls which is what Cabansail refers to previously.
In this respect, I guess you could use it as a very quick way of switching between aperture and shutter priority (no mode-dial change), as when you select one of the two (front or rear dials - aperture/shutter values), the camera automatically works out the other parameter.

If you look at it in the view finder and for example think "heck that shutter speed will never work, i need at least 1/250" you can go to shutter priority in an instant using the front dial. With Auto you simply don't. You allow the camera decide everything. So "Auto" may decide that you need to shoot everything at f1.4 in low light situations to get as much light in there as possible where you might actually want to steady your camera and go for longer shutter speed instead and more depth of field.

P mode may suggest f1.4 to achieve a decent shutter speed but you can quickly override that if you decide to.

b) you can set the iso as you've described although on the Pentax I can do that in Auto too (not sure the rationale for that)

c) you get greater control over the use of flash, again in "Auto" you may find yourself limited. On the Pentax you go from 2 options in Auto to 6 options in P Mode.

d) I'd guess the next one will be camera dependent but on the Pentax I can tell it (using the custom menu) what to give priority to - Normal, Shutter, Aperture, or a sweet little option that I didn't even know I had which is to read information from the lens and use the sweetest spot it can as per the lens profile.

There's probably more depending on camera. Remember all of the above will be camera dependent.

charybdis

Mountainsandh wrote: »

Thanks Charybdis and Gbee, the comments help even though as I said, I'm a newbie, and have never tried looking at the meter on my camera, or metering for a particular area, but I know I need to try/learn that... I've been like a dog sort of sniffing the air to guess what exposure I need.:(

Metering is something anyone interested in controlling exposure should know. The first thing to understand is that there are different metering modes: evaluative/matrix metering reads a number of values in the scene and compares that data to a database in the camera in order to decide what exposure parameters best match the situation you're in; centre-weighted average metering returns exposure parameters that will try and render what occupies the middle bulk of the frame as an averaged middle grey tone; spot metering is similar to centre-weighted average metering in that it returns exposure parameters that will render what is in a certain area of the frame as an averaged middle grey tone except the area it looks at is very small, typically just a small spot in the centre of the frame (hence the name). There are other metering modes, but once your understand the differences between these three, you should be able to understand any metering mode.

In the non-evaluative/matrix metering modes, your camera treats what it is looking at as what's known as "middle grey"; this is a medium grey tone that's neither very bright or very dark. This behaviour can be good because your meter treats what it is looking at as middle grey and will try and expose it so that it isn't very dark or very bright; this can be bad because the world and everything in it isn't middle grey and sometimes things are very dark or very bright.

As I said earlier in the thread, I'll typically try and put skin tones at +1; this means if I'm taking a photograph of a person with average caucasian skin in consistent light I'll spot meter off their face and overexpose what the meter is telling me by 1 stop. This is because I want this person's face to appear lighter than middle grey because that's how it looks, the camera doesn't know this though, so if I was to spot meter off the person's face and use the exposure recommended by the camera without adjustment the person's face would appear darker in the photograph because the camera would have treated it as if it was middle grey.

I also understand that anything that is between +2 & +3 on my meter's scale is going to appear in the photograph to be very bright or even pure white; similarly, I know that anything between -2 & -3 on my meter's scale is going to appear to be very dark or even pure black. With this in mind, I can make decisions about how I want to expose based on where different values I've metered rest on the meter's scale; I may have to slightly overexpose my image in order to keep detail in shadows I want there to be detail in to prevent them from turning to pure black, or I may have to slightly underexpose to retain detail in highlights where needed to prevent them from turning to pure white. Working like this may require you to massage your camera a little more when shooting, but the result is far more control over how your images appear and, with practice, an intuitive ability to look at scenes and be able to think about how you might expose it to look like it should .

From the link to your Flickr stream in your signature, it looks like you're using a Pentax K-x. From what I've read, Pentax cameras seem to be pretty great for this kind of work as they offer several metering modes (including spot) and Pentax's cool green button that I'm very jealous of and wish more manufacturers would adopt.

I previously wrote a little about understanding metering and exposure here and here.