Noobie question about metering

PoleStar

Hi guys, recently enough bought a eos 400d and have mainly been using aperture or shutter prioriy to compose a shot and let the camera do the rest.

Have been trying to use manual a bit more. From reading the first few pages of Understanding Exposure (bought on recommendation from people here and a great buy! Thanks to all those who said to get it!), his shot seems to begin with either choosing a shutter speed or aperture to get the shot he wants, then meter usually off the sky it seems by pointing camera at sky and seeing what aperture/shutter speed is indicated on camera, setting it to that then composing the shot and taking it.

2 questions popped into my head. Number one, how do you know what to point at with your camera to meter, is it the brightest part of your scene or what. And 2 is, whats the difference between metering and setting the shutter/aperture manually and just setting the camera to aperture/shutter priority and letting the camera set it automatically. As surely since you are metering with the camera, for example when you have set aperture manually to set depth of field, and then setting the shutter speed manually based on eg metering off the sky, that this is the same as putting the camera in aperture priority mode, setting the aperture and shooting and let the camera choose shutter speed?

Sorry if my question is a bit long winded!

PS any PSP users out there or is it all photoshop!

City-Exile

That question can have a few answers.
It really depends on what you want in your picture.
For example, if you wanted a sunset, you should meter off the sky just above the sun, but not including the sun.
If you include the sun, the rest of the shot will be very dark.

beans

I think I'll try and answer this, only because it was one of the things that had me scratching my head for a good while when I was starting out with my SLR.

As surely since you... for example set aperture manually to set depth of field, and then setting the shutter speed manually based on eg metering off the sky, that this is the same as putting the camera in aperture priority mode, setting the aperture and shooting and let the camera choose shutter speed?

It is indeed. If you were going to choose the same shutter speed as recommended by your meter, then there would be no difference at all. Certain scenes this would be fine for, but others you would want to break away from this suggestion.

In the below shot, I was looking up at the bright midday sky through a skylight in a fairly dark room. I looked up, saw the little kid, and thought there was potential for a shot. The meter would be trying to even out the exposure as much as possible, to get as much of what's in the shot exposed correctly. I didn't want this - rather, I wanted to expose for the kid's face, or for any skin tone in that light. This is the level of brightness that I wanted, so I quickened the shutter speed from what the meter was telling me.



This had the effect of blowing out the skylight, way overexposed, but got the skin-tones just right. The rest of the intermediate bright areas fell in line with this. Had I just set aperture, and let the camera choose the best average for the scene, I would have lost a lot of detail in the mid-areas.

Meter for what you want to pull the most detail from. If I wanted to meter for this scene, I would have been able to fill my viewfinder with hand and this would have given me a good exposure for skin-tones - then used this exposure setting for the scene as a whole.

Rambling answer in hindsight, I hope it helps a bit

PoleStar

No your reply is kinda gettin me closer to knowing a bit more.

So meter for what you want first and then setting exposre for this instead of letting camera choose.

I will get there eventually!

If shooting skin against a white background , for example then its prob ok to le camera choose, with a dark background, manually meter off skin tones and then take shot, yes?

PS I ask this as I want to get some good shots of family (baby on the way!). If anyone has any recommendations for good portrait or baby photography books let me know! I would love to shoot shots in my own home with simple backgrounds eg wall or sheet and take good shots or on bed for example with baby.

City-Exile

What lens will you be using?
If you get a shallow depth of field, you can use a neutral backgound & have it blurred. A few metres of white material should do the trick.
Meter off the skin, set the shutter accordingly.

PoleStar

Will be using a 50mm 1.8, should the subject be a good distance from the background.

And will a sheet do?

And also, in these cases, is it best to use something plain white or something darker

Thanks!

beans

Totally down to your own sense of aesthetics, the white background will tend to force your meter to underexpose non-white things slightly in my experience though.

If you use the 1.8 at it's wider apertures you'll have a nice soft background, should help isolate baby faces and whatnot. You'll have to let us see what you get

Paulw

Using f/1.8 will give you a very very tight area of focus. It will give you a good background blur though.

JMcL

PoleStar wrote: »

If shooting skin against a white background , for example then its prob ok to le camera choose, with a dark background, manually meter off skin tones and then take shot, yes?

No, you should meter for the skin tones in both cases, otherwise you'll under/overexpose respectively. The camera's meter is only interested in seeing and "average" 18% grey tone - lots of bright and dark areas fool it.

Also, if you're taking meter readings from bright things like the sky, if you meter so that the exposure indicator is in the center, you'll be underexposed - you need to compensate by setting exposure so that the indicator is maybe anything up to about 2 stops overexposed, depending on how bright the thing you're metering from is.

One good tip from that book is to 'calibrate' the palm of your hand, ie figure what exposure should be set to to correctly expose your hand, then you're guaranteed to have something accurate to meter from wherever you go, and if you don't, then metering is the least of your worries anyway

bman

Sorry to be digging this one up from the depths but I don't fully understand this "metering stuff" . Why would you meter of the blue sky when what you should be metering off is an 18% grey object?

Also, does metering of the sky apply if your shooting an outdoor shot, but there is no sky included in the photo?

I've just got through Understanding Exposure but I still find this hard to understand. Maybe I need to read that section again. The rest of the book was very good in general although I thought he didn't go into ISO very much. Thanks to the people here for advising it.

JMcL

bman wrote: »

Sorry to be digging this one up from the depths but I don't fully understand this "metering stuff" . Why would you meter of the blue sky when what you should be metering off is an 18% grey object?

You don't necessarily always have an 18% grey object to meter from (green grass is actually pretty close though if you have any). The sky is most probably going to be the brightest thing in the scene, and therefore most prone to blowing out the highlights, so you want to meter to prevent this from happening. Obviously it depends on the circumstances.

bman wrote: »

Also, does metering of the sky apply if your shooting an outdoor shot, but there is no sky included in the photo?

No, meter from something that has about the same tonality as 18% grey (eg the aforementioned green grass), or your hand as described in the book. With experience you'll get better at recognising good things to meter from, so my advice would be to learn how to use the histogram (I'm making the assumption you're digital here) to see what the exposure is really like, and adjust if necessary.

the_manchine

Was about to post a question about histograms but googled it instead and came up with this:
http://www.kenrockwell.com/tech/histograms.htm

This guys site has some useful info on it even if it's a bit scattered. If you're pretty green (like me) have a read of "How to Drive your Camera" in the How-To section.

JMcL

the_manchine wrote: »

Was about to post a question about histograms but googled it instead and came up with this:
http://www.kenrockwell.com/tech/histograms.htm

This guys site has some useful info on it even if it's a bit scattered. If you're pretty green (like me) have a read of "How to Drive your Camera" in the How-To section.

Just don't take everything Rockwell says as gospel, he's a bit controversial to say the least. Luminous Landscape has some excellent articles in the tutorials and understanding section, though he doesn't seem to be adding (m)any new ones recently unfortunately

bman

Histrograms seem to be the way to go so. I'm still not 100% on metering so I'll probably take the photo a few times and try to get most of the pixels towards the centre of the histrogram (unless I'm looking to under/overexpose). Cheers for the help.