johnridley: (Calvin vs Bike)
johnridley ([personal profile] johnridley) wrote2007-05-24 07:44 am
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Coyote sighting

I see rabbits and hawks every day, woodchucks, possum, buzzards and raccoon once a week or so, and a couple of times, fox. But for some reason, though I know they're around and have heard them, I have only seen coyote around here from a distance.
OK, this photo is from a distance too; he bolted from the bushes at the side of the road and stopped probably only 30 feet away when I first saw him as I rode past, but he was probably 300+ feet away by the time I snapped this photo. For some reason, coyote are nervous about weird people wearing fluorescent lime colored shirts looping back and stopping on the road and pointing things at them; they tend to run off.


100% crop @ 6x zoom from a 7MP camera set to ISO 400 to try to get the fastest shutter I could (I feel grain is better than blur if I have to choose).

[identity profile] kevinnickerson.livejournal.com 2007-05-25 06:13 pm (UTC)(link)
Isn't 100% crop the same as zero picture?

[identity profile] johnridley.livejournal.com 2007-05-25 07:55 pm (UTC)(link)
Hmm, not sure. What I meant is that I cropped it down and the result is not resized, just cropped. 1:1 pixels. I'd just seen that terminology a lot on dpreview when people were posting highly cropped samples, like just a face in a crowd to demonstrate the resolution of a lens or something.

[identity profile] kevinnickerson.livejournal.com 2007-05-25 08:22 pm (UTC)(link)
Hm, if that's the way they use the phrase ok, but to me a 50% crop would mean I discarded half of the photo. 75% would discard 3/4 of the photo, and you can see where this is going. Cropping to me says nothing about resampling.

Interestingly ImageMagick thinks a percent crop takes that percentage of the linear dimensions, not area, and is what you keep, not what you discard.
convert -crop 50% in.jpg out.jpg
gives out-0.jpg .. out-3.jpg where each out*.jpg is 1/4 of the original image. That makes
convert -crop 100% in.jpg out.jpg
basically a no-op.

This is useful information. I have some huge images I meant to chop up, but thought I had to work out all the math, so I hadn't.