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12-12-2008, 07:31 AM   #1
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Killer exposure bracketing idea

In general the exposure may be calculated by checking the light entering the lens and this may be successful, but has many limitations. Olympus had a good idea in their film cameras of measuring the light reflected back from the film plane in real time. It strikes me that digital cameras are in the unique position of knowing exactly how much light has fallen on the sensor real time and could react very quicky to that.

Anyway moving on slightly from that, immediately after the picture is taken, unlike a film camera, the taken picture can be immediately analyzed by the camera itself. In fact it will quite happily show you a preview of the picture with big red flashing blobs to tell you that it is overexposed.

I think Pentax (or any other digital manufacturer) could use an exposure bracketing method based on the results of the taken picture. Call it 'auto correct' for example. You switch on 'auto correct' and take a picture. Actually, the one shutter press causes 2 pictures to be taken, the second one adjusted in exposure according to the level of blown highlights in the first. It shouldn't take the camera long to analyse how many pixels are pure white and take another picture at a changed shutter speed (or changed ISO etc). This process could be repeated if necessary, taking a third picture based on the results of the second.
It could work for underexposure as well - zero pixels in pure white means increase the exposure.

The chances of the second picture being good are very high and rather than a random half a stop each way type of bracketing, this would be based on the actual taken picture, so when my K10D overexposes by 2 stops on one of my manual lenses, it could immediately correct for that. This only needs a firmware update to achieve.

Is this a new idea or have any of the camera manufacturers already done this?
I think it could be a killer feature only bettered by actually getting the exposure right in the first place!!

12-14-2008, 03:53 AM   #2
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"Olympus had a good idea in their film cameras of measuring the light reflected back from the film plane in real time."
AFAIR Pentax LX have that metering system.

Write Your idea to Pentax, I wonder if if they use it, will they even say "thank You"
12-14-2008, 05:31 AM   #3
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Yep LX all the way, great for long low light stuff, you know 30 secs plus stuff.
12-14-2008, 06:17 AM   #4
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Sorry to rain on your parade, but they most likely do that already.


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