Partial/Evaluative metering 10D vs. 20D?

Recently, I upgraded and bought a Canon 20D. When I shot with the 10D I found that

partial metering gave me better results than the evaluative metering. I was wondering if

Canon did any improvements with the 20D and if anyone has noticed better exposures

using evaluative metering with the 20D. My flash shots are considerably better with my

20D and the 550EX over the 10D. That's probably more due to E-TTL2 more than

anything though. Also does evaluative metering take into account which focus point is

being used?

"Also does evaluative metering take into account which focus point is being used?"

 

Yes, if you're using AF. The camera biases exposure to the active AF point. Why? It assumes you lock AF on the subject therefore exposure for that point is given priority over other segments of the frame.

 

Incidentally, I get excellent results with Evaluative metering with my 10D. Problems only arise when the scene brightness range exceeded the ability of the sensor to record. So, you must expose for highlights and let the shadows go black. I wish digital sensors had the exposure range of negative film.

Puppy Face, currently CMOS chips are about 8 stops of range, no where near good negative color film never mind B&W. It will be another 10 years before we see 12 stops, the marketing weinies sell Mega Pixels not dynamic range. It would also be nice to see less noise at the higher iso values (I suspect we will see this before we see the DR improved). I wonder if Dynamic Range and noise are coupled, any of you physics / EE geeks out there care to chime in?

I've just laid out almost a thousand dollars on a 10D after weeks of researching what to buy, how come thats the first I've heard of the range of DSLRs being so much less than film? I went digital thinking the learning curve on composition and exposure would be faster but now you're telling me its going to be harder to get the image right?

 

Wait, I need to calm down... it won't be harder, just less room to mess up right? After all, getting the exposure right is the same on any body if you meter or judge the scene right, right?

Digital is less forgiving of exposure error. But on the plus side you can see right away if there is a problem and reshoot. Bracketing is free if your subject allows which helps alot. There are scenes where you will not be able to keep detail in the highlights and shadows. Again if your subject allows you can bracket and composit in PS. Personally I don't find it to be a big problem but then I don't have much experience with film.

Gerry, I thought that the Canon digital cameras were around 5.5 stops or so similar to that

of slide film. 8 stops? That would kinda be an improvement I would think.

 

Anyways, Archie, don't worry about your purchase. It isn't all that bad. Just remember not

to blow your highlights. You can always expose for the highlights and bring the shadow

areas up in Photoshop or combine 2 exposures. Think "Just like shooting slide film".

 

Now to bring this back onto topic... Anyone else have thoughts on the evaluative metering

of the 20D vs the 10D?

"I wish digital sensors had the exposure range of negative film" well they have a bigger dynamic range than tranny and you don't get people complaining that tranny is inferior. Neg film may well have an absolute dynamic range larger than current DSLR's BUT much of this is compressed in the highlight area of the density slope or in the grainy shadow areas and is of little practical value. In practical terms the straight linear nature of the sensor response is greater than the straight line portion of neg film's eposure response. Fuji's new S3 claims to have a very large dynamic range and 22mp backs for med format have over 11 usable stops - way, way bigger than neg. The dynamic range of my 20D is comfortably better than my 300D - I suspect we have not seen the limit. There is however a practical consideration in that the larger the dynamic range the more post processing you need to get all the tones properly seperated to give pleasing contrast and colour saturation.