2011-10-31
Link: A demonstration of an issue with ETTR
This link requires a bit of explanation (if only so that I can remember it later). The person I'm linking to took a standard colour checker test target and took a properly exposed shot then a series at increasing positive exposure compensations (ie, exposing to the right), postprocessed all of the overexposed photos to correctly expose them again, and then cropped strips of the colour targets and stacked the same strips from each exposure. The goal is to clearly see any colour shifts caused by ETTR.
(As he notes, some are deliberately overexposed, going beyond what you should theoretically do with ETTR. Of course they do represent what happens if you accidentally overexpose in the course of trying to do ETTR.)
Part of what I like about this is that it's an experiment that anyone can do (if you have a colour checker test target). Your camera and processing system may well give you different results than his, but either way you'll have learned something interesting.
So: Experiment: ETTR hue shifts and now the revised Experiment: ETTR hue shifts (reformatted).
PS: obviously you should do this test with the camera on a tripod and locked at a single ISO, unless you also want to test the effects of ISO on colour shifts. Although that too may be a useful test, depending on how you're thinking of using ETTR.
2011-08-26
A review of the Filzer dZ4L bike computer
This may be a good bike computer for someone, but it certainly isn't one for me. My experiences with two units have been negative.
My first dZ4L lasted only a few weeks after I bought it; it failed to survive a relatively modest Toronto autumn rain. As far as I can see, this is intrinsic in the design of the computer; the transparent plastic top seems to be simply pressed very firmly on the main unit, not sealed. This is basically tailor made for capillary action around the edges, so once you've got enough water exposure the water starts being drawn up the sides and into the main display area where it mists up the screen and then gets into the electronics. Result: dead unit.
After a year of more or less reliable operation out of the rain, my second dZ4L is now frequently failing to register wheel motion, resulting in either much too low speed readings or a total glitch. This appears to be due to the plastic mount warping (and expanding in the summer heat; hotter weather makes it worse and cooler weather makes it more reliable) so that it no longer firmly holds the computer against the mount contacts. It can simply stop working on its own, plus even small bumps seem quite prone to jarring it just loose enough. Rapping or pressing the computer into the mount can temporarily make it register again, but it's far from reliable and rather frustrating. Trying to use a map case or anything that rests near the mount on the handlebars is troublesome, because it seems very easy for a velcro strap or whatnot to put just enough pressure on the computer or the mount to let things come lose; even a very light touch can be enough.
I find this really unfortunate. The dZ4L's four line display is by far the best information display of any bike computer that I've seen, but a bike computer that periodically glitches out and drastically under-reports speed when I go over even a minor road bump is not a bike computer, it's an unattractive handlebar ornament.
(I may some day put this on the MEC website, where I bought my dZ4L.)