Help with a Spot Meter

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Paul
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Hi,

I have a question with regards to using a spot meter.

I was out taking some pictures and the sky was a bid on the bland side, when I took the picture I kept blowing the sky as the building was a lot darker than the sky.

I remember reading somewhere that to overcome this to use a spot meter and meter on the sky and overexpose by two stops and then recompse on a darker area of the subject..

Is this correct?

If so, how do I set this on the camera? am I best to set to AV, TV or Manual. In either mode how to I set the camera?

I assume that in either mode I meter on the sky using the inbult meter eand then set it to +2 then recompose?

If i use manual mode, do I need to adjeust to exposure or apeture to get the +2, obviously if I am in AV I change the aperture and TV adjust the exposure...

I am just a litte confused.

Hope you can help..

Paul
 
Does your camera not have an exposure lock button? Meter off the sky, press the lock button and recompose.

However, all that will happen is you'll underexpose the building.

edit: actually, I don't think the 400d has a spot meter function...
 
your right about the 400D not having a spot meter, I have borrowed a friends 40D at the moment and I trying to get to grips with it to see if I think its work upgrading my body (prob to a 50D)

Back to the question though, I heard that if you overexpose the sky, then wit will try and keep it the correct colour (same with very white snow and dark subjects int he frame). Also heard this is a good method for weddings (white dresses and black suits)..

Thanks..
 
Dunno, I just check the histogram and use exposure compensation.

Shooting in RAW will give you about a stop of reclaimable detail which unless you've gone mega wrong should be plenty.
 
ok, I do shoot in RAW anyway but ideally I want to get it right so I don't have to edit all the pictures I take..
 
You have found the Dynamic Range limitation of your sensor.

You have three choices to overcome this, you can either meter for your subject to ensure that it is correctly exposed by spot metering from a known tone and then setting your exposure to give that tone (usually best acheived by using manual control) and letting the other tones fall where they will, by taking a number of exposures (bracketing) and combining the exposures in post processing to extend the range of tones beyond what would normally be acheived with a single exposure or by setting your exposure to give an acceptable result from the sky and then using artificial light (strobes, lights etc) to balance the rest of the subject (difficult if large subjects).

Some exposure tips here!
 
Ed has hit on the problem and spot metering will not help that. In fact unless you have a fair bit of experience, a spot meter will often get you into even more trouble.

The reason for this post though is just to say that if you are maybe thinking that spot metering will somehow give you a superior exposure setting, it won't. There is only ever one optimum exposure setting and the different metering patterns and camera modes are just a different way of arriving at the same answer, depending on personal preference. Whatever works for you basically.

With digital, the ultimate way to optimum exposure is to use your favoured metering method, then chimp the LCD and tweak it if necessary. Enable blinkies (over exposure warning) and learn to read the histogram. Use exposure compensation, or switch to manual - again personal preference.

The way to overcome extremes of dynamic range with a bright sky is to use a graduated filter (which also darkens everything else about the grad line of course) maybe a polarising filter is the sky is blue, or try HDR technique (high dynamic range) which is to take two or more images at different exposure seetings and merge them in post processing. That works really well but is tricky with anything that moves between the exposures.
 
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