Shallow Thoughts : : photo

Writing scripts for your Canon camera with CHDK

On Linux Planet yesterday: an article on how to write scripts for chdk, the Canon Hack Development Kit -- Part 3 in my series on CHDK.

Time-Lapse Photography with your Inexpensive Canon Camera (CHDK p. 3)

I found that CHDK scripting wasn't quite as good as I'd hoped -- some of the functions, especially the aperture and shutter setting, were quite flaky on my A540 so it really didn't work to write a bracketing script. But it's fantastic for simple tasks like time-lapse photography, or taking a series of shots like the Grass Roots Mapping folk do.

If you're at OSCON and you like scripting and photos, check out my session on Thursday afternoon at 4:30: Writing GIMP Plug-ins and Scripts, in which I'll walk through several GIMP scripts in Python and Script-Fu and show some little-known tricks you can do with Python plug-ins.

Tags: photo, writing, programming, mapping, conferences, oscon, speaking
[ 09:31 Jul 21, 2010    More photo | permalink to this entry | comments ]

Article: CHDK part 2

Part 2 of my series on hacking Canon point-and-shoot cameras with CHDK: Turn Your Compact Canon Camera Into a Super-Camera With CHDK, discusses some of CHDK's major features, like RAW image file support, "zebra mode" and on-screen histograms, and custom video modes (ever been annoyed that you can't zoom while shooting a video?)

Perhaps equally important, it discusses how to access these modes and CHDK's other special menus, how to load CHDK automatically whenever you power the camera on, and how to disable it temporarily.

Part 3, yet to come, will discuss how to write CHDK scripts.

Tags: writing, photo
[ 16:27 Jul 08, 2010    More photo | permalink to this entry | comments ]

Article: Customize or Hack your Canon camera with CHDK

My latest Linux Planet article came out a day early: RAW Support (and more) For Your Canon Camera With CHDK.

CHDK is a cool way you can load custom firmware onto a Canon camera. It lets you do all sorts of useful hacks, from saving in RAW format even in cameras that supposedly don't allow that, to getting more control over aperture, shutter speed and other parameters, to writing scripts to control the camera.

I didn't have space for all that in one article, so today's Part 1 simply covers how to install CHDK; Part 2, in two weeks, will discuss some of the great things you can do with CHDK.

Tags: writing, photo
[ 19:02 Jun 23, 2010    More photo | permalink to this entry | comments ]

DSLR Camera Foo

I thought it would never happen ... I've finally joined the Digital SLR world.

Why would it never happen? I enjoyed film SLRs for years ... from the Olympus OM-1 (great little manual camera) I had as a teenager to the Nikkormat EL and Nikon FG I used a decade ago. I only stopped because processing and scanning slides was such a hassle compared to the ease of uploading digital images. So why not a DSLR?

The problem was that when Nikon went digital, they orphaned all their old manual-focus lenses. They're still physically compatible (they'll screw on to the DSLR body), but peeved Nikon DSLR owners inform me (and camera store clerks agree) that the Nikon cameras won't meter with the old lens attached.

I don't mind doing my own focusing (manual focusing is one of the prime advantages of an SLR, not a disadvantage) but having to guess at the exposure setting too? "Oh, just carry a light meter," people say. On a camera that costs over $600? That bothers me.

So I was peeved at Nikon and not about to buy anything from them ... but meanwhile I had all these lenses, and hated to buy some other brand where the lenses wouldn't even screw on. So, no DSLR for me ...

Until I was pouring out my lens-mount frustrations during a camera discussion one night on #gimp and one of the regulars (thanks, Liam!) said "Well then, why don't you just get an adaptor that lets you use Nikon MF lenses on a Canon?"

A what? said I.

Sure enough, there are lots of them on Ebay ... search for canon nikon adaptor or look at Gadget Infinity's "lens adaptor" section. You can even (for a little more money) get a "confirm" lens that lights up the autofocus-confirm points in the viewfinder to tell you when the camera thinks you're in focus.

A few months passed (too busy to do camera research) but eventually I found the time and budget ... and now I have a 5-day-old Canon Rebel Xsi, which indeed takes excellent photos (correctly metered) through my old Nikon AI-mount Sigma 70-300 APO zoom macro. And the 18-55 kit lens (the equivalent of a 29-88 in a 35mm camera) isn't bad either -- a little slow (f/3.5 at the widest) but decently wide at the wide end (in the years of using pocket digicams I'd forgotten how much nicer it is to have a true wide-angle lens) and with a nice close focus for macros at the long end.

Even the autofocus isn't bad -- there are still plenty of times when I need manual, but the Rebel's autofocus is much faster and more accurate than any I'd seen on earlier cameras.

It's such a great feeling to use an SLR again. The morning after the camera arrived, I looked up and saw goldfinches at the feeder just outside the window. I picked up the camera, switched it on, pointed, zoomed, focused and snapped. No worries about whether the camera might have decided to focus on the window, or the window frame, or the tree, or the bush -- just focus and shoot. What a pleasure!

And the best part: this must be a camera made by geeks, because when it has the Nikon lens attached ... it says F00!

Tags: photo
[ 19:59 Sep 02, 2008    More photo | permalink to this entry | comments ]

Dowitcher Photo Published!

I was contacted months ago regarding a photo on my web site asking whether it could be used along with an article on molting patterns in Dowitchers in Birding magazine.

Months went by (print magazines are slow) and I wondered if the plan had been dropped, but last week I heard from the author, Caleb Putnam, and the article is in the current (July/August) issue! Yesterday I received a copy of the magazine and a modest payment. Cool!

Even cooler, the photo is the frontispiece of the article. The author says he's received many comments about how great a shot it is for illustrating molt gaps. That's a pull quote if I ever heard one: "Great shot for illustrating molt gaps."

The article is interesting as well -- I didn't know that molt patterns could identify the two species of dowitcher. Telling long-billed and short-billed dowitchers apart has been beyond my modest birding skills, but perhaps I'll have better luck now. I'll be heading out to Baylands today at lunch to see what the dowitchers are doing ...

Tags: photo
[ 10:49 Aug 25, 2005    More photo | permalink to this entry | comments ]

Musings on photo workshops and classes

Dan's party was last night, including an group which was giving an informal workshop on night photography.

The presentation was a little disappointing, just people showing slides of recent photographs. No discussion of techniques or interesting ideas for night photography, things to try out that night.

It was mildly fun for the couple of us who were Linux users to watch the Windows people fumble with their JASC slideshow program trying to get it to present photos at a reasonable size. Whenever I wonder why I bother to keep maintaining pho, I look at what Windows and Mac people have to go through to look at photos and am amazed all over again.

But strangely, before heading off to Marin yesterday, I did some searching for other linux image viewing programs, to see if they'd solved the window manager problems I've been wrestling with for pho. Amazingly, I couldn't find a single free program in Debian that did what pho does (namely, view a list of images serially, at full size or screen resolution). I had to search for xv source (not in Debian, probably licensing issues), which requires a couple of tweaks to get it to build on linux, and which has the same window management issues pho has. I guess I'll keep maintaining it after all!

After dark we trooped up the hill to photograph lights (Richmond and the Richmond-San Rafael bridge were visible, along with parts of Marin) and wait for moonrise. I took an SLR and the Minolta, and wish I'd taken the Olympus -- nearly everyone else had digital SLRs (Canon) and I wished for something with a decent zoom which would still give me exposure feedback. It's not as if bay area skies can support long star-trail exposures anyway. Moonrise was lovely, a sliver of moon emerging above a thick cloudbank centered over the San Rafael bridge, and growing into a full-sized moon. I hope some of the film photos (on old expired PJM multispeed film!) come out.

Most of the photographers there knew each other from previous classes (I wasn't clear how many are students versus instructors) and most of the group spent the hour before moonrise clustered together taking turns taking the same shot, a person silhouetted against the lights of Richmond while someone else fired a flash from behind the person, back toward the camera, giving an "aura" effect around the silhouette and lighting the nearby grass a bit. Not really knowing anyone, I hung back and instead worked on photos of the various photographers silhouetted against the sky (which may or may not come out; I was shooting from 10 sec to about 3 min, betting on the Marin sky being too bright for longer star trails, but we'll see. One of the other solo shooters was shooting 10 minute exposures and people kept walking into her frame.) Dave shot a few Canon digicam images before the sunset light was completely gone, then the wind got to him and he went back to the house and didn't wait for moonrise.

I'd wondered about maybe taking one of their regular workshops, but this outing was a bit like the couple of other photo workshops I've done: no real instruction or sharing of ideas, basically just a bunch of people wandering around taking photos. If you have specific questions or know the instructors already you might be able to get questions answered, but as a person new to the group, I felt like I'd probably do just as well just going somewhere on my own and taking a lot of photos.

It may be that their multi-day pay workshops involve more instruction, and more feedback the next day on images taken at the workshop. I'm curious about that; the few photo seminars and classes I've taken have also promised feedback afterward, but haven't had much, if any.

Sometimes I think that the ideal format for a photo workshop is an online class: give assignments, then people post their photos a few days or a week later, and everyone discusses them, then you go off to the next assignment with what you learned based on the feedback. The important parts are the discussion and the feedback, not being in the same physical place during the shooting (since not much instruction seems to take place then, for most participants, and if it does it seems to be of the type "everybody line up and take exactly the same photo"). It's hard to do feedback in a several-day workshop at a place like Death Valley when people are shooting film and you can't get it developed quickly enough; a digital camera might be a prerequisite to getting much out of that sort of workshop.

Tags: photo
[ 10:00 Jul 04, 2004    More photo | permalink to this entry | comments ]