View Full Version : Exposure

24-06-09, 13:33
I know it's second nature to a lot of you guys & gals but I seem to struggle

I always try to shoot aperture priority & sort of understand the basics of DOP & aperture but its exposure I struggle with especially where grass & sky is concerned.
I wonder how many of you bugger about changing from evalutive to partial to spot to centre weighted metering I try to use Evaluative with my centre red dot for focusing often trying to expose on something grey .Is the prefered method with the successful amongst us to use center spot focussing but lock exposure on something neutral or all the AF points assuming these also meter for exposure or am I getting confused here.

Basically I took some photos of a stream surrounded by trees & grass the sky continually blew out if I metered on the sky I had a lovely blue sky the rest was obviously under exposed.

I really don't want to get into filters too much I was using a good quality circular polorazing filter but doubt I was right angles to the sun.It was 7pm ish .
Is it a case of trying to take the impossible photo our are their ways & means.

Basically I would love your views firstly on a good all round setting regarding focusing & metering especially for landscape
Thanks in advance
Cheers Ian

24-06-09, 13:54

You ask "Am I getting confused here?" The answer is "yes". Unless you have the auto-exposure metering locked to the AF point - which you aren't if you're using evaluative - then the AF point used has no relationship to the exposure you achieve. You also say you try and meter off something grey. If you're using evaluative metering, then unless you're filling the frame with a mid grey subject, then it will have very little impact on the exposure. If you're trying to meter from a grey part of the scene, you would have to switch to spot metering and lock the exposure to those settings before recomposing the image as desired.

The problem you describe with the stream and the trees is due to the limitations of the dynamic range of your sensor; it wasn't much better with film, and slide film was/is worse than current dSLR. You have a range of options, none of which are much to do with the metering mode you've used on your camera:
1) Use a neutral density filter to cover the brighter parts of the scene, or
2) Take two images (on a tripod) and blend them together in photoshop, or
3) Take one image in raw format, process the raw image twice to get two different exposures and blend the two immages in photoshop (not as much lattitude as option 2, but better than nothing. Or,
4) Adjust different parts of your single jpeg selectively in photoshop.

Hope this helps.


24-06-09, 17:48
Thanks for your help & advice Duncan I guess I just wondered if there was an easy way or basic settings you tend to use for Landscape in particular.

I guess I didn't put it across very well as I was in a rush at work I realize you can only use the exposure lock button when not in automatic AF points (ie 9 spots) but what does make sense now is being in spot metering rather than evalutive after your explanation thanks.
I saw an article where a guy was trying to replicate I think a sheep in a coal mine the nearest he could come up with was his daughter sat on a grey rock on a dark hillside wearing a very white coat he metered from the rock which helped the overal exposure.
Photoshop & me seem to struggle a bit to be honest levels is about as much as I can muster maybe raw is the way to go .
I've just taken some more sun much higher in the sky results far better.

So after all that what is the prefered exposure mode out of the four hopefully the camera can help or is filters the only option.I thought the polorizer was going to be the answer to my prayers but it didn't help in that situation.as no doubt you could have told me :D

Thanks again any help is gratefully received.

24-06-09, 18:48

The basic problem is that the camera cannot accurately record the full range of tones as your eye sees them under the lighting conditions you describe. Regardless of the camera mode you use, this will be the case. If it's too bright in the sky or too dark in the woods, unless you use a ND filter (to reduce the brightness of the sky) you can have one bit accurately exposed, but not the other. This is a well known problem for wedding photographers where there are black suits and white dresses in the same scene.

You have to tone down the bright bits to get the whole scene to be within the dynamic range capability of your camera. Use an split ND grad filter, placed ONLY over the bright bit of the scene to record detail in the sky.

You could try this:
but if there's no detail there to be recovered, it won't pull something from nothing.

23-10-09, 14:41
I would recommend using bracketing liberally when in doubt. Later when you get home you can select the one you like most. Bracketing will also create an array of frames you can later use for HDR, for example.