Trip Leader Checklist

One of the things I enjoy doing is leading backpacking trips and other adventures. Along those lines, I created a checklist of the steps needed to prepare for such a trip. Turns our there are a lot. Perhaps this list is useful for you, too. Feedback welcome.

The Worst Error Message in the World

SVN's new merge tracking in version 1.5 is really neat, but it's got a few nasty warts still, one of them being this very opaque error message:

Some revisions have been merged under it that have not been merged into the reintegration target; merge them first, then retry.

Uh... which revisions? Merge what? Huh? @#%^&*@#&$^*@#&^!!!!

Googling this error message yields a bunch of conflicting advice. In my case, this thread was the fix. Use:

svn propget svn:mergeinfo --depth=infinity

at the root of the branch working directory. You should get mergeinfo for only the root ("."). Delete the mergeinfo for all other objects (using svn propdel svn:mergeinfo) and commit.

Note that this is with SVN 1.5.4. I think perhaps it is fixed in 1.5.5???, though problem situations created in <= 1.5.4 will persist.

Focus Charts

Since I was having trouble focusing my manual focus Takumar, I thought I'd check whether my camera was front- or back-focusing, i.e., the focus point was in front of or behind where it was supposed to be.

(This applies even with MF lenses because my camera has "focus confirm", where it uses the autofocus sensors to show when you're in focus, even if you have to turn the focus ring yourself. It's pretty handy when you have a smaller viewfinder and no split prism, as is typical for APS-C DSLRs like my K200d.)

Casual testing using a magazine revealed an apparent front focus of ~10mm on both the Takumar and the modern 18-250 zoom. Yipes! What a bummer when the zoom already needs warranty repair for asymmetric vignetting (see shadow in upper-right corner of previous two posts).

However, use of an actual focus test chart in good light (above) shows that the zoom has no focus problems. It seems to autofocus within +/- 2mm, randomly distributed, which is just fine. The Takumar does have a front focus of ~6mm, but that's easy to compensate for by approaching focus from the far side and backing off slightly after confirm.

Both lenses are plenty sharp, and the Takumar very much so when stopped down. They sure make my point and shoot look like a dog, which is the point I suppose. :)

Project 100, #11.

New Digital Camera... Really This Time!

A little while ago, I blogged about a new digital camera, a Canon SX-10 "bridge camera". Well, I sent it back, deciding that it really was the worst of both worlds rather than the best, and I replaced it with a Pentax K200d, which arrived today -- an entry-level DSLR and one of only two DSLRs on the market that take AA batteries (the other is also a Pentax). It also turns out that I could get an 18-250mm lens (field of view equal to 27-375mm on 35mm) and that I can use Erin's old-school manual focus lenses that were hand-me-downs from her dad (and plus, the image stabilization is in the body, not in the lenses as Canon and Nikon do, so the old lenses are stabilized too). Even though it's a beast at 1.2kg with the 18-250 zoom, I think it's a fit. Yay!

Here's a picture of Jess. 1/8 second, f/1.4, ISO 1600, hand-held with a Takumar SMC 50mm, one of the aforementioned old-school lenses. Given that this was taken in very poor lighting (available light at 11pm) and I'm pretty green at manual focusing, yet it's among the best pics of Jess I've ever seen, I'm pretty pleased.

Choosing a Topographic Map

Outdoor adventures such as hiking, backpacking, and canoeing require topographic maps ("topos" or "topo maps"). It used to be that the only source was paper maps published by the United States Geological Survey (USGS), a government agency. Now, many different vendors republish USGS data. But how do you know which vendors' maps are any good? It is hard to get honest samples from vendors.

Hence, I publish visual reviews of topo maps, so you can decide what works for you.

If you have maps that I haven't reviewed, I would love to include them. E-mail me.

New Digital Camera?

I got a new toy in the mail today, a Canon SX-10 IS. I'm not entirely convinced it's right for me... it's kind of a bizarre bastard child occupying the space between point-and-shoots and full DSLRs. It's three times bigger than my old camera, but 1.5-2 times smaller than a DSLR. It has an extraordinarily versatile lens, 28-560mm (which is fairly wide to huge zoom), and zero-centimeter macro capability (i.e., the subject can touch the glass)... for a DSLR that'd be 3-4 lenses, and at least $2000 and 10 pounds of glass (but higher quality glass, of course).

However, it's way bigger than the P&S that I've been taking on hiking trips so far (36-105mm) and been fairly happy with, and it has the same kind of small, noisy sensor that compact cameras do, and the user interface is rather weird in places. Is the fancy lens worth the extra mass and bulk? I'll contemplate this question over the next few days.

This is a picture of my cat. Believe it or not, it's a 1/2 second exposure, hand-held. Sometimes image-stabilization really kicks ass (click through - it's even reasonably sharp full-size). [Edit 1/5/09 - no, it's actually not very sharp at all.]

Mozilla Developers Hate Saved HTML Manuals

My website, Cyclopath, is written in Flex, Adobe's development environment which produces apps that run in the Flash Player. Needless to say, I occasionally need to reference the Flex documentation, which is HTML. I can browse it either on Adobe's website (slow) or save their zip file and browse it off the hard disk (fast). Guess which I chose?

Anyway, recent versions of Firefox 3 break these docs, because they don't allow different files in the doc package to reference needed JavaScript (because it's in a higher directory), so all the helpful links like "Show Inherited Public Properties" don't work.

And here's the error message that shows up in the error console:

Error: uncaught exception: [Exception... "Security error" code: "1000" nsresult: "0x805303e8 (NS_ERROR_DOM_SECURITY_ERR)" location: "file:///export/scratch/reid/flex3.2.0/doc/langref/asdoc.js Line: 493"]

...impossible to Google. Bah.

Wandering around the Mozilla bug database a little (using, frankly, a lot of expertise that most people don't have) revealed that, in fact, this is by design.

You can turn off the behavior by going to about:config and setting the secret configuration variable security.fileuri.strict_origin_policy to false. Mozilla developers are not interested in making this more obvious and don't believe that anyone other than a web developer needs to change it, despite the large installed base of on-disk HTML user manuals for a variety of things.

I don't fully understand the security reasons for this change. I assume they're sound. But what an absurdly opaque failure mode.

Shame, Mozilla!