Exposure and Contrast

Started Jun 20, 2011 | Discussions thread
bobn2 Forum Pro • Posts: 50,583
Re: Exposure and Contrast

MaryGierth wrote:

bobn2 wrote:

MaryGierth wrote:

bobn2 wrote:

I was rather thinking of this advice you gave to the OP:

'The overexposure is due to the fact that because so much of the scene is dark the exposure settings are based on trying to properly expose (brighten up) the background rather than the face of the girl. (Based on these results I assume you are using evaluative metering.) As far as what you can do - try to fill the frame with more of her face. You can also try using center weighted or spot metering (metering on the face).'
To which he replied

'I have not had good luck using spot metering, as i tend to either underexpose or blow out background if im metering on a face'
and you said

'If you spot meter on her face which is very fair skinned you will need some positive exposure compensation possibly +1. This will prevent underexposure and if the background is dark you won't blow it out. '

Yes, that is what I wrote in response to the OP's issue.

Exactly, so, this is not simple advice, it is moving well into the 'black art' territory. You need to spot meter off the face to get 'correct' exposure, but even that isn't good enough, you need to judge whether or not it's a very fair skinned face and give a +1, presumably a dark skinned face would be -1EC. Basically, trying to use exposure to adjust output image density is a fools errand, unless you really have to.

Now apparently what you meant to say was 'put it in LV, wave it around a bit and when you like what you see hit AE lock'

No I didn't intend to say that to the OP. I commented on metering and LV in response to your post about the black hole of metering or how ever you put it.

black art, I said, or meant to say.

Well, I think rather you might have an advice problem. For a start when you recompose, the exposure is likely to change substantially from the one where you hit the 'AE lock' button,

Yes, but other parts of the image are, and they may, or may not be important to what you're trying to do - blown highlights in the background, and actually, specular highlights on the subject, too. View it from a different angle, they will change. One of the perils of reflected light metering.

If you were happy with how the main subject is exposed when you locked it, it doesn't matter that the camera's meter would choose a different setting for the recomposed scene. The main subject is properly exposed in the sense that it appears the way you want it to when you locked it.

See above

When I spot meter I do take into account other parts of the image - significant blown highlights or blacks.

Still less simple

If the exposure works for the subject but not other important parts of the image you have to adjust the exposure or you have to change the lighting (move the subject, use flash for example).

And still less, and again leading to a photograph that isn't necessarily the one you wanted.

for a second, what you see on the rear LCD has a habit of not looking exactly the same as it does on a big screen or in a print (even with one of these fancy new high res LCD's)

The lcd is a guide and most everyone knows from experience that the image will look diff on the computer, in print, or on tv.

So, not quite as straightforward as watching TV, eh? Extrapolate what teh TV migh be like if it was a cinema screen.

third, what you are seeing in LV is th JPEG

Which is what I think the OP is shooting and asking about.

despite this?:
I shoot Raw and use Aperture 3 on my mac.
Not sure that's a well founded assumption.

Or alternatively, give it the biggest exposure you can without blowing the highlights, then process it to give the results that you want. The 'best' exposure is always the largest exposure you can get,

I've never heard this before. If you are trying to say expose to the right and then post process - ok, that will work in many situations. But here you have someone who does not want to spend much time in front of the computer.

according to your wrong assumption. He would probably not have chosen to shoot raw, and probbaly not have gone for a Mac if that was the case.

So I am not sure how this advice helps him in an image number 2 scenario to get better color contrast and saturation on his subject if he is not going to pp.

I would suggest it helps by encouraging him to use Aperture 3 to get the results he wants on a nice big Mac screen, rather than messing around with 3 inch LCD in bright sunlight.

subject to your own pictorial constraints (DOF, lens sharpness, motion blur). That way exposure is subservient to what you're trying to achieve, not the other way round (i.e. because you can't get 'correct' exposure easily with this photo, take a different photo, which is what your advice says)

The way I read the Op's question - he's is looking for better color, contrast and saturation in his main subject. He doesn't want to pp. I think the best way to do that is to shoot the subject differently. Alternatively you could try other exposure settings as discussed in the posts on metering or shooting in manual mode. You could also pp but the OP is specifically looking to get better results out of the camera. So I think the most relevant advice in this thread is that which deals with how to shoot not how to process.

The OP's subsequent answers would seem to deny that he doesn't want to PP (actually just P), since he shoots raw. The way I read the OP's question is that he has been sucked into all this gobbledygook talked about correct exposure, and hasn't realised that it is much simple and more direct to get the results that he wants in processing, rather than trying to hit the right part of an S-curve in the in--camera processing that he isn't using.

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