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Help with exposure requested

PostPosted: Sun Oct 26, 2008 2:39 pm
by tasadam
Gidday. My wife and I both use D200 cameras.
Increasingly my wife has been frustrated by the exposure results she has been getting. The lens she used in these examples is the Nikon 17-35 f2.8
My results are sometimes similar - in these examples I am using my D200 and the Nikon 24-70 f2.8 - expensive glass.
Exif info in the images is intact.
Take this shot for example, from her camera.
Image
This is typical for what she gets when shooting anywhere near a light source.
A similar shot from my camera -
Image
Definitely more light getting into her photo.

Now, another example from my camera.
At normal exposure -
Image


at -2
Image


at -1
Image


at +1
Image


Then with her camera and the 17-35, at exposure bias 0 -
Image


At -1
Image


At -2
Image


Another example from her camera - at bias 0
Image


At bias -1
Image


It is possible for her camera to take reasonable exposure photos -
Image

Here are 3 more, at exposure 0, -.33 and -.66
Image

Image

Image

Now I'm sorry about all these images in this post, but does anyone have any suggestions as to WTF is going on and what we can do to end up with correctly exposed images without having so much washout?

We'd really appreciate some help with this.
It does appear to me that the combination of her camera and the 17-35 does seem to create, ordinarily, an over-exposed image.
I should really try swapping bodies / lenses, also try the Nikon 12-24 glass and see if I can narrow the problem down to whether it is glass, her D200, or just technique.
Hers has a later firmware in it compared to mine - hers is capable of recognizing a WR-3 wnereas mine doesn't have that in the menu. I'm reluctant to flash mine in case it introduces similar exposure quirks.

If it's us, and we need to learn something - great - at least we now have a starting point. Any ideas?

Re: Help with exposure requested

PostPosted: Sun Oct 26, 2008 3:16 pm
by rflower
I have had a look at the photos, and I can see the underlying exif information embedded (I am using firefox, with FxIF addon installed - which allows for the viewing of some EXIF from images on the web - if it is left in the image).

Without this information, I would not be able to make these thoughts / suggestions.

The photos that your wife took, states that the metering mode was Centre Weighted, The information from your camera states Matrix metering mode.

The information from the 2 cameras also states that you were both using aperture priority at F22, and that your wife's shutter speed is slower on all shots than the corresponding photos of yours.

My D80 manual states the following:
Matrix:Camera meters a wide area of the frame and sets exposure according to distribution of brightness, colour, distance etc.
Centre-weighted: Camera meters entire frame, but assigns greatest weight to centre area.

My thoughts are this: Your meter took into account the bright light on the right hand side and reduced the overall shutter speed accordingly. Whatever your wife was focussing on / the centre of the frame was dark, and therefore the centre weighted slowed the shutter speed down slightly. As such, your appear to be in the correct exposure range, and hers are affected by the bright light being over-exposed. Ultimately the computer inside the camera should be making the same decisions (especially with the same model camera), but the cameras have (in this instance) been given slightly different instruction sets before the photo is taken. The computer is making the best decision it can, with the inputs set for it.

Take the two cameras out (with the lenses that you both normally use) and set them to the same settings exactly (including the meter mode). Focus on the same thing. The cameras should meter in the same type of range, and hopefully give similar results. I personally do not know what difference different lenses will make to the returning exposure.

Take one camera out. Set it Aperture priority. Set the aperture as you would like. Choose a few different scenes / areas where the light changes. Take 2 (or 3) shots of each scene. Between each scene, change the metering mode. Look (on the camera or the computer back at home) at a) the different shutter settings that has been used each time and b) the effect that more or less light in each exposure has on the photos taken.

Let us know what your findings are.

Re: Help with exposure requested

PostPosted: Sun Oct 26, 2008 4:59 pm
by gstark
Russell has nailed the likely problem.

rflower wrote:The photos that your wife took, states that the metering mode was Centre Weighted, The information from your camera states Matrix metering mode.


That makes the tests invalid from a scientific(ish) PoV: each camera needs to be used with identical settings for this sort of test to be valid.
There are enough differences in each of the metering modes for that to be a sufficient explanation for what you are seeing. Further, the choice of a focus/exposure point within the VF can also have an effect: this does not seem to have been canvassed in the discussion so far.

While I prefer to use spot metering, with each of the modes, you need to learn how they react, and adjust your shooting style accordingly.

Re: Help with exposure requested

PostPosted: Sun Oct 26, 2008 5:09 pm
by Matt. K
As Gary said...reset both cameras to the factory pre-sets (2 green buttons pressed simultaneously I think). Mount the cameras onto a tripod using the same settings and shoot a broadsheet newspaper page as the target. I would be very surprised if a camera was at fault.