Posts by David Hood
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For getting sense of the effect of raw, here is an image I toned fairly aggressively in photoshop with curves. Now, to my eye, there is actually not a lot in it at this stage, but looking at the histogram of the top image (8 bit colour jpg version) you can see the histogram has gotten gaps in it compared to the bottom version (16 bit colour psd but in reality my old camera only does 10 bit colour in raw). This has not effected things much at this stage, but if I was to go on making other changes on top of this the effect of the gaps would gadually add up. So, not much effect if you are only changing a picture by a little, but it can add up.
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Capture: Two Tone, in reply to Lilith __,
The amount of compression in a standard camera jpg is minimal
It is not really the compression where the differences are- If you know you are going to be adjusting the tones in the picture, the raw image has much more tone information in it than a jpg, so you can do much stretching a small tone range over a big distance as your are just bringing out hidden differences normally to small to see. That said, an awful lot of the above is predicated on the software you are using to read in the image being able to deal with the depth of tone information in its internally saved format- if when you read the raw in it is effectively being converted to a jpg then raw will not gain you much (except for tone shifts you are doing as part of the import process).
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A couple from the walk to work. I have found that with my trusty old Canon S3IS, if I set the camera to black and white, the preview window shows greyscale and it saves a jpg processed by the Camera, but running the CHDK added firmware set to save as RAW (processing to DNG on the camera) the DNG version is full colour I can process later being a bit more selective.
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I also habitually underexpose because detail is better recorded in dark areas than bright on my camera.
HSL conversions on computer basically work by plugging each of the sensor values into a formula. The controversial part is the L, where there are different ways of calculating lightness just like there are different conversions to greyscale. A lot of L conversions (and greyscale ones) heavily favour the green sensor information as humans are most sensitive to that part of the spectrum (so are 60% to 70% green with most of the rest being the red). -
As a Herald columnist, I for one feel it is clear Martha Corey should be hanged for witchcraft. I mean, sure their are allegations that this charge is caused by Thomas Putman reaching out for land, but what kind of a country are we coming to if we are not prepared to act without thinking on the accusations of a small band of fevered hysterics.
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Building site
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I will also post my admiration of the Rangitoto.
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Chris, some phones you can adjust the point the are basing the brightness of the photo on. If your phone can do that, try targeting the black (or at least dark) of the pan handle, or conversely the brightest spot in the picture.
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Old marble work, Dunedin North Cemetery
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Pond, Dunedin Botanic Gardens
