Testing Testing
experiments with photography and other toys. Images Across The Earth focuses on beauty, not technology.

Friday, February 22, 2008

Exposure Comp

This one is for danthro.

Here are shots of the lobster weathervane with the camera set to aperture priority (auto shutter speed), and using exposure compensation.

F 5.6 ... 56 mm ... 1/1000 sec
[no exposure comp]

F 7.1 ... 56 mm ... 1/500 sec
0.67 step exposure comp

F 7.1 ... 60 mm ... 1/320 sec
1.00 step exposure comp

Though the aperture was wide open the first shot was too dark - no detail. Even the sky seems gloomy.

In the second shot I upped the F-stop to increase depth of field. All things being equal the camera would have reduced shutter speed to obtain the same exposure as the first shot
[higher F-stop = smaller aperture, which is a little counterintuitive but Wikipedia provides an explanation].

I didn't want another dark shot, so I set exposure comp to +0.67. This increased the amount of light captured by the camera, showing detail on the lobster and building while still keeping rich colour in the sky.

In the third shot I upped exposure comp once more (my camera does it in steps of a third of a stop) but this time although there was yet more colour in the building the sky and clouds started looking blown out.

All these photos are straight from the camera, simply resized to reduce download time.

I went with the middle shot as my Goldilocks shot - the other two were really used to bracket it and ensure that I calibrated correctly. The composition in the last shot is a little sloppy: if it were a keeper I'd rotate and crop it to remove the lower left distraction.

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