[quote:1ef30e8279="lpaul"]The first picture actually shows the preen gland, not a wound:
http://en.wikipedia.org/wiki/Preen_gland[/quote]
This is interesting. Here is an extract from Wikipedia that gives further details about how this gland functions.
Among animals, birds spend considerable time preening their feathers. This is done to remove ectoparasites, keep them in good aerodynamic condition, and waterproof them. They use the "preen oil" secreted by the uropygial gland, the dust of powder down, or other means such as dust-bathing or anting. When an oil spill affects penguins, animal conservation that rescue them sometimes dress them in knitted sweaters to stop them from preening and thereby ingesting the mineral oil which is poisonous.
[http://en.wikipedia.org/wiki/Preen] Author: lwingkay Time: 18/01/2008 18:26
Wing,
In both pictures, I have the feeling that vignetting had happened as the corners were abnormally dark. And this will have a significant consequence on the exposure of the heron: overexposure.
In the case of P5100, vignetting is especially obvious at the telephoto end of the zoom range.
Would like to know if vignetting had really happened?
Peter
PS
Having said the above, I must say the details in your shot are something that really inspire me. Author: cwchan Time: 18/01/2008 20:55
Thanks Paul and Peter for supplying the information.
Peter,
Regarding the problem of vignetting, I think you have to accept this fact until someday in the future you find another perfect dc in the market. I have already told that vignetting is very serious in Nikon 8400 as it is a super wide angle DC (equivalent to 24mm to 85mm in 35mm format), especially at its wide end. It becomes less serious from mid-zoom onward and happens again at its longest end.
I don't think, exposure is a big problem nowadays as the meter of most DC measures the centre more that the four corners---basically the exposure is acceptable if you adjust the EVs properly after seeing the result . Please bear in mind, for some subjects, vignetting can be a good thing as it can lead the viewer to focus on the interested part. This is the way that we always do in visual art presentation.:
In my field experience, Fuji F30 & F31 are the best DC for digiscopic photography in terms of less vignetting effect, Nikon P5100 is the second.
Wing Author: cbryan Time: 18/01/2008 23:39
on preening, i've seen in a BBC documentary (the life of birds) that some birds, like the hornbills, use secretion from the gland to give colours to their beaks and feathers which otherwise are monochrome. pretty much like cosmetics for birds. very interesting.
bryan
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