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08-08-2010, 08:55 AM   #1
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Exposure Question

Hi guys

Just got back from China where I "tested" my new K7. Must say I'm generally happy with it.

I do have one question.

When taking pictures where the background is "relatively darker" than the subject, but I want the subject to the side of the frame, how can I focus on the subject, but have a slightly longer exposure to capture a bit more of the dark area?

I've (now that I think about it) not tried manual focus.

I have tried changing aperture and trying various parameters on the thing.

Sorry for the really noob question, and I have checked the manual. This seems more a technique question

08-08-2010, 08:59 AM   #2
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If I understand you correctly you want to meter more into the dark.
Point the camera there, then hit the AE-L button (exposure lock), then move to your subject.
08-08-2010, 09:19 AM   #3
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... or EV up (if You want metering to be something between).
08-08-2010, 10:17 PM   #4
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Thanks blende8

Tiltman, can you please explain?

Right now what I do is if part of the photo is overexposed I try to Photoshop fix it, but that's not always ok. Underexposed parts are a bit easier to lighten up.

08-09-2010, 12:22 AM   #5
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Something will have to give in any one given high-contrast exposure - either you meter for the shadow detail, blowing out the highlights, or you meter for the highlights, losing some shadow detail.

You can bracket and try HDR, but that can have variable results depending on the software.
Generally, I'd suggest exposing enough to get all the shadow detail (that's needed) and try and salvage the highlights you want by recovery in PP.
08-10-2010, 01:05 AM   #6
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Thanks guys, appreciate the quick responses.
08-10-2010, 01:59 AM   #7
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As Wieland explained, Auto Exposure Lock is one way.
Ev adjustment and HDR are two others.
Then there is spot metering as well.

Let me explain a little more on this subject.
In general the camera will measure the entire field of view and adjust it's exposure to the total average.
There are a number of situations where that does not work for you:

1. Back light.
You are facing the light, the total light taken in by the camera in average is high.
The exposure will be set to short, giving dark subjects.
You get sillouette like subjects.
Sometimes, this is just what you want.

2. The total dynamic range of the picture is too wide for the camera to handle.
The field of view contains both light and dark areas.
Te picture holds both dark shadows without details and blown out light areas without any details.

3. Low light.
In dark situations, you may want to capture the atmosphere of the scene, however your camera compensates for the low light by taking a very long exposure.
The camera over exposes. Your picture becomes too bright. Loosing the effect.

So, what tools do you have available for handling these situation?
You have several....

1. Back light:
- Spot metering.
Put the camera in spot metering, meter the subject.
If the subject is not in the middle of the picture, use AEL (see below)
Take the photo.
- Auto Exposure Lock. (AEL button)
Compose (zoom in, point the camera) so that you "only" see the subject in the view finder.
Press the AEL button until the beep (there is a * on the display now)
Recompose as you wish, focus, take the photo.
- Flash.
You can use the on camera or a loose flash to "fill in" the picture.
By adding light from the camera on to the subject, you will see the subject *and* the background clearly.
This only works on short distances (few meters) a flash can cover.
- Compensate manually.
Overexpose manually using the Ev compensation button.
Press the [+/-] button while turning the rear wheel to add +1 Ev up till +2 Ev.
Now the camera will overexpose by 1 or 2 stops on whatever amount of light it measures.

Remember, if you put your camera in digital preview mode, you can always take a test shot by clockwise turning the power button and see what the exposure is doing for you.

2. Dynamic range is to small:
- Use HDR (High Dynamic Range) pictures.
Here only HDR is the only sort of real solution.
There are 2 options:
a. In camera (read the manual).
b. Using software (Photoshop, Photomatix, others) and exposure bracketing.
The general idea behind HDR is to take multiple pictures, from underexposed to over exposed, combine them into one with all details.
HDR is a topic with many tweaking options, except when you use the in camera function.
There is a lot to read on this subject.
- Make a deliberate choice on what subject is to be exposed right.
Use the techniques mentioned under Back Light, directed at your subject of choice.

3. Low light.
Here the same techniques as in Back Light can be applied. See above.
The only thing to consider here is to avoid Auto ISO.
If the camera encounters low light in Auto ISO mode, it generally will max the ISO value in the set range.
This will increase the noise level in the dark areas, of which you may intentionally have a lot.
So, select the ISO value manually to ISO 100 - 400 max.
Use the ISO button on top of the camera and the rear wheel to select the ISO value of your choice.
You can select Auto ISO again by pressing the ISO button and the Green button at the same time.

Hope this helps you....

- Bert
08-10-2010, 02:16 AM   #8
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Assuming you are shooting JPEGs, on the K7 there are a couple of features without going into HDR shots where you take multiple exposures and merge them into one using external software or the HDR function in the camera.

there are 2 specific functions, shadow detail protect and highlight protect, which work to extend the dynamic range of the photo within a single exposure.

Within a normal scene, the camera records full detail within a range of about +/- 2 1/2 stops either side of the metering point (5 stops total) you can increase this range a little by reducing contrast in the settings, but this is only about an extra stop of dynamic range

Highlight and shadow protect functions each work independantly on the upper half or lower half of the dynamic range to add about another stop to each side, fiving much more dynamic range than is normally possible.

this function is only on the K7 (to the best of my knowledge)

you can achieve the same in a photo editor, using RAW, but this is done in camera.

You should, as a matter of course, be adjusting contrast, white balance etc as a function of the overall scene lighting and practice will help in this regard

08-13-2010, 01:12 AM   #9
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Thanks guys, wonderful information. I obviously had not prepared enough before my trip to China, though I did take some nice ones (the ones that didn't need this kind of stuff).
08-13-2010, 08:04 AM   #10
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Can you select the focus point on the the one side or another, instead of the center? If not, add some EV, focus on your subject and recompose.

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