This personal blog comprises whatever I feel like saying on any given day, which often involves topics like new media, journalism, Web technologies, Racket/Scheme/Lisp, Free and open source software, societal issues, cinema film, Boston, frugality, and humor. Many things noted here are solely for the benefit of future Web searchers trying to solve particular esoteric problems, and are not of general interest. This blog is largely insulated from my professional life, and vice-versa. I attempt to provide full disclosure of potential conflicts of interest. My site currently gets over 1000 unique visitors a day.
After drilling for two decades through more than two miles of antarctic ice, Russian scientists are on the verge of entering a vast, dark lake that hasn’t been touched by light for more than 20 million years.
—Marc Kaufman, "Scientists close to entering Vostok, Antarctica’s biggest subglacial lake," Washington Post, 2012-01-27
I used to be a photographer, who got spoiled by gorgeous Canon L lenses, so now that I'm a non-photographer, and permitting myself only a 40D and one cheap-ish lens, I have to find the right cheap-ish lens. I decided that cheap-ish with my expensive tastes probably means a prime. (Yes, among other normal-ish zooms for a 1.6x crop, I've had a then-much-awaited Tamron 17-50/2.8, which overall wasn't bad for the relatively cheap price, except chromatic aberration occasionally got freakishly bad. After trying a few lens models when I was a photographer, I eventually settled on an old Canon 17-35/2.8L, which was acceptable, but is out of my current non-photographer price range, and I doubt I'd be able to find a sharp copy of that lens again.)
Initially, my current one cheap-ish lens is a Canon 50/1.4, which I picked because my most important use was the occasional headshot of a friend, and a fast 50mm prime is both great for portraiture on 1.6x crop prosumer DSLRs, and relatively affordable because it's a normal on the 35mm format camera for which most current 50mm lenses were designed and sold.
However, the 50/1.4 is a bit too long on 1.6x for most purposes other than headshots, such as taking a shot of a group indoors, or as a walkaround lens. Yet it's still too short to be used like a long. So I decided to trade my 50/1.4 in on a 28/1.8 (and let friends deal with their headshots being a bit less flattering). When the 28/1.8 seemed soft on an initial shot just now, I printed out a focus chart, and found that the AF was front-focusing considerably on my 40D. Sadly, both lens and body were bought used, and can't be sent to Canon for free calibration. Sigh.
Think that your own lens is soft, or back/front-focusing? One of the better articles I've seen on the topic is by Roger Cicala, "`This Lens is Soft'...and other Myths." Read this article first, before going to the test charts.
Anyway, I'll have to do a practical test with the 28/1.8, to see whether the front-focusing is noticeable when stopped down a bit. All I know at this point is that, if I need to do any near-macro photography wide-open, I'll have to fine-tune with manual focus.
In some ways, the Internet was better in the '80s.
compare in OpenWRTIf you need the ImageMagick compare program in OpenWRT
10.03.1, but were dismayed to see that package imagemagick-tools
contains only convert and mogrify...
What I did as a stopgap measure was to set up an OpenWRT build tree, make a very simple patch to enable compare, and build a custom imagemagick-tools package.
Note that this change might also cause additional dependencies on
existing OpenWRT library packages. Since this is only a stopgap measure until
ImageMagick compare is packaged properly, I did not bother to
touch the imagemagick-tools metadata.
Incidentally, the OpenWRT build environment is pleasantly easy to use, although slower than I'd expect.
If you need a relatively beefy device supported by OpenWRT, here's a list I distilled the other day:
Model | OpenWRT | Flash | RAM ----------------------+---------+-------+------- Buffalo WZR-HP-AG300H | trunk | 32 MB | 128 MB Netgear WNDR3800 | 10.03.1 | 16 MB | 128 MB Netgear WNDR3700 v2 | 10.03.1 | 16 MB | 64 MB Netgear WNDR3700 v1 | 10.03 | 8 MB | 64 MB
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