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Hasselblad 500 EL/M Adventures

Well, I just finished putting my 500 EL/M together after almost completely taking it apart.

So as usual I went to use it one day and the $150 batteries were dead. It stopped mid-stroke, and I was in the boonies, so I cocked the camera manually to remove the lens. BAD IDEA.

As far as I can tell, that forced something past something, and the result was that the front gear train (which cocks the shutter in the lens) ended up being out of phase with the rest of the camera. I took the whole thing apart, referring to the service manuals, which although detailed are a pain to read as they frequently refer to parts by the part number which may or may not be shown in the adjacent figure.

In any case, after taking the whole thing apart and re-synching it I realized I had also stripped a threaded shaft which threads to a gear connecting the winding motor with the body. Saying “what the hell” and deciding I could easily convert it to a manual in the worst case I epoxied the shaft to the gear, which so far seems to hold up.

But anyway. I should have taken pictures to post, but I didn’t have time to take any. The point of this is that at the time I wrote “My First Post” I couldn’t find the DIN connector used for the electric Hasselblads anywhere. It is a 5-pin DIN, with the pins at 270 degrees (see this link). It turns out some refer to this connector as “240” degrees and I just found out they also refer to it as “60” degrees (denoting the angle between adjacent pins for a total of 240). In short, I found it on Mouser for $2.66.

Cool thing is that I think you may be able to power the camera from there—via external battery pack or AC adapter. Also, I’m going to try to find out how much voltage that thing can take. Seeing as how everything is pulsed in operation, it shouldn’t be a problem to double or even triple the voltage as all there is is a solenoid (to release the camera) and a motor which is controlled via limit switch in on-off fashion.

I’m definitely going to get rid of these damn batteries.

Speaking of taskbar [system tray] clocks

All I wanted was a clock with two timezones shown… and I couldn’t find a free one. Took me months to even find out how these people were writing their great shareware.

Turns out, as I suspected, that the tray clock (at the bottom right of your screen) is not an independent program so it is not possible to replace it by “normal” means. You have to, in short, write a program that waits for messages to be sent to the clock and interpret them in a custom way.

One such free program is TClockEx, which is old and doesn’t look good on top of Windows XP themes. But that’s a minor thing—the gem of it is the help file which explains how the author accomplishes his feat by “subclassing” and “hooking”. In other words, it gives you a bunch of new words to type into Google to find out more and even possibly cool sample programs—this is also how programs that change the look (“window manager”, some may say) of Windows work.

At some point I found a program that would show you all the classes currently open and allow you to change their properties—so you could, for example, change the Start button to say “Idiot” or “I could care less about the task bar clock when I can do this”. If I find it, I will post a link.

Of course I never wrote the new clock program. But one of these days I’m going to mess with it again.

Your alternative to crappy WinZip and buggy WinAce

If at some point in your life you downloaded crap from the Internet you ran across ACE files, or maybe RARs, or whatever. Most people are familiar with WinZip and it’s nagging “buy me” message. I used to use a version of WinAce which would destroy any ZIP file it created that was bigger than 2GB. (By the way, even if the program does it correctly, I don’t recommend you create enormous ZIP’s… divide it into a few pieces at least.)

The solution is 7-Zip. Much like manuals, I refuse to pay for compression software. (Even worse is paying for a custom taskbar clock—idiots.) 7-Zip can pretty much handle them all, and I’ve verified it can create intact ZIP files bigger than 2 GB. I’m adding this to the links at right!

Adding actions such as command prompts to the right click menu

It is handy sometimes to be able to open a command prompt in Windows in a specific directory, especially if you’re writing scripts you just want to run from the command line.

For command prompts it’s easy, as there is a Power Toy called DOSHere[.inf]. But really it’s all about the registry.

Luckily (well, somewhat) you can also do this from Explorer, and it comes in handy for older programs which tend to launch always in whatever directory they are in (or rather the “Start in” folder as defined in the shortcut). One such very useful program is this file renamer. Unlike most programs of this type, I’ve yet to run into a combination of actions I needed to perform that this thing couldn’t do (when it came to renaming files, anyway).

But it was annoying to be looking at the directory containing the files I wanted to rename and having this guy start in its own directory.

You can add a right-click menu item for a program like this easily. Warning: I’ve had my computer hiccup with this done before. In Explorer, go to Tools->Folder Options… and select the File Types tab. After the flashlight gets out of your way, look for a file type called “File Folder”, which should be near the top. Select it, and hit the Advanced button.

Now here’s the kicker: you can create new actions and set a default, but you can’t delete or edit them without manually doing so in the Registry. So, type slow.

Hit the New… button. “Action:” is the text to appear in the menu, and the other text box is the command line to the application. There are some parameters you can type in to pass arguments to programs, but most of the time (or at least for the purposes of having a program start in a particular directory) you don’t need that stuff—but here it is anyway. In the case of both the command prompt (cmd.exe) and the file renamer I mention here, all you need is the path to the executable (I put the full path in just to be safe).

Again, remember to be careful how you type because you can’t change it unless you go into the Registry.

Presumably you can also do this with the “Folder” file type, but you shouldn’t need both. I don’t know what the difference is between the two other than “File Folder” is referred to as “Directory” inside the registry.

After I did this the first time at home I had a problem where suddenly after rebooting when I double-clicked on a directory it would open a new window instead of using the same one, and this was regardless of the option set in the General tab of the Folder Options dialog. Some searching on the internet yielded a Registry snippet corresponding to the original unaltered folder-actions, so I had to delete that entire key in my Registry and merge in this new one. Unfortunately I can’t remember where that is or where I searched for it (which is part of the reason I started this blog).

At my computers at work I added the exact same actions and nothing bad ever happend, except today I pressed enter while having 17 PDF’s selected in a window and it opened 17 instances of 7-Zip.

At home I think my computer is just drunk because in iTunes if I tell it to show me the file a Windows dialog box asking how I want to handle the file type opens up every time, and no matter what I do, after about 5 seconds an explorer window opens with the file shown… I guess it’s time for a fresh clean reinstall (see below). I have it down to about 30 minutes these days.

Moving your user profile in Windows

If you’ve been using computers for a while you may have gotten used to re-installing Windows from scratch every so often because of its self-destructive personality.

For this reason I wanted to find a way to keep all my data files (settings and documents) on a separate partition than the one in which Windows was installed, that way, I could just reformat it and get it over with without having to worry to backup stuff.

Just refusing to put your stuff in “My Documents” isn’t enough because you’ll still lose all your preferences (and in the case of many email programs, all your account information and emails) when you destroy the Windows partition.

There is a place in the registry where the location of a user profile is defined. It is easy to move your profile even if the install of Windows is not clean, but you need at least two users. The profile is not created until the first time you log in, and I find it risky (if not impossible) to move the profile for the user which is currently logged in.

So let’s say you want to move user1’s profile. If you’ve just installed Windows, ensure that you log in with user1, then log out once the hard drive finishes crackling. Now log in as user2 (who must be an administrator) and open up a registry editor.

Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList. You will see some keys with weird numbers. There are some short ones (S-#-#-##), then there should be at least two long ones (S-#-#-##-##########-##########-##########-####), which represent real users (in this case user1 and user2). Click on each one and look at the value of ProfileImagePath to find out which user it actually belongs to. By default this value should be something like %SystemDrive%\Documents and Settings\, where is the name of the user. Change this value for the desired user (user1 in this example) to the desired location, then be sure to take that user’s “Documents and Settings” contents and move them to the new location, and you’re set.

Putting your iTunes library on a portable drive in Windows

Finally, the post about symlinks in Windows and how they come in handy.

Many people out there, including me, have a gazillion MP3’s that would never fit on any iPod no matter how bloated they become. The solution is, of course, to put them on an external drive, so at least you can listen to them wherever there is a computer.

However most media players, including iTunes and Windows Media Player, keep a separate database of all your MP3’s which includes how many times you’ve played each one, your rating, etc. So moving your MP3 files to the portable drive isn’t enough if you care about this information (in the case of iTunes, playlists also get stored in the library so it’s annoying as hell).

By the way, don’t use Windows Media Player; the newest versions seem like they never finish them before they release them. They are full of bugs and you run the risk of screwing up your ID3 tags if you use it to edit them. iTunes sometimes seems like a bloated craphole of “design” for people with tight jeans and dirty t-shirts driving around in automatic Audi A4’s, but it still seems to be the best (haven’t tried Winamp since the 2.x days). Moreover, iTunes has a COM interface so you can write your own programs to overcome its occasional stupidity.

In any case, I wanted to put iTunes’s database on the external drive also so that if I move files around or create playlists it will remember them no matter which computer I used. Of course iTunes doesn’t let you choose where the library is; it is by default in the My Documents\My Music\iTunes directory.

In searching around I found a clever solution where some guy created a symlink from the appropriate directory in Mac OS X to whatever directory he wanted the library to actually be. Very clever indeed, except that symlinks don’t exist in Windows….

According to this and other sources, they have existed since NTFS 5.0 (Windows 2000), they are just not documented and not meant to be used (though Visual Studio 2005 does establish one).

Read the article first. Take all the warnings about the risks of doing this seriously, as Windows has been known to hiccup itself out of coherency for random reasons when you do this type of thing.

I used Junction Link Magic to do it on my computer. You can skip the search it does at the beginning since you are creating the junction link from scratch, but if you are trying to edit one you created previously you will have to wait until it finds it.

Go to the My Documents\My Music\iTunes directory and move the itl and xml files (and whatever else you want; the directory has to be empty at the end) to the new place where you want it to be; in my case it was V:\iTunesLibrary (a directory in my external drive). Then run Junction Link Magic and create a link from My Documents\My Music\iTunes to the new location. I would do this without Explorer (or any programs that are accessing the source folder, including iTunes) open because I tried it and Junction Link Magic will not give an error but will not create the link, either. If it does create the link, you should immediately see it listed in the main window.

Now if any program goes to the My Documents\My Music\iTunes directory (including iTunes, Explorer, command prompts, etc.) it will actually be reading the target location (in my case V:\iTunesLibrary) without even knowing it.

Some notes:

At least in Windows XP and 2003 server, once you plug in a portable drive and change the drive letter to something the OS will remember it for that drive. I usually pick a high-up letter in case I share network drives or add physical drives later, because a byproduct of this “memory” is that if the letter you assign to the portable drive happens to be a network share when you plug it in, the drive will be recognized but you won’t be able to use it until you disconnect the network drive mapping…. This is really annoying with digital cameras.

What happens if you run iTunes without the drive plugged in? Yeah, I was scared, too. But thankfully iTunes just thinks you don’t have permission to access the folder and quits—disaster averted.

You (obviously) have to create the junction link on every computer where you plan on doing this. Luckily it’s per-user so you don’t necessary piss your girlfriend off.

I am not this guy

I know I said my next post would be about symbolic links in Windows, but I must clarify something first.

I did a Google search for “donkeypuss” and ran across donkeypuss.com. I am in no way associated with that, or, rather, he’s not associated with me, depending on who’s blog you like better.

Amazing that we would both find the word donkeypuss appealing. For me, it comes from the fact that donkey was a very funny word once, although it was decided in committee on August 1st, 2002, that any word or phrase “said over and over again starts to sound funny”—such as “chicken soup”. But “the status that [donkey] has become may never be reached by another word ever, but I think it’s time that we start to uncover other words that may one day reach the status of the word `donkey’, like `chicken soup’, or `frozen hamburgers’, or `ingrown male fetuses’, or `dirty socks’, or even `sparkplug’, and maybe if it’s lucky, the word `keyboard’.”

However, “chicken soup” never achieved what “donkey” did. “Tigerpaw” got close.

“Donkeypuss” was a resurrection of “donkey” by adding the suffix “puss”, which is one of those words that old people use cutely while young people think it’s absolutely gross.

My First Post

Hello all.

I’m writing my first post here to explain the links I’ve added to my blog—the ones on the right side of the page. I have found these links to be very useful, so I’m publishing them. Basically, they comprise my favorites list.

First, the pictorial histories of cameras. The three I’ve liked leafing through are the ones for the Hasselblad, Rolleiflex, and Nikon cameras. This guy put together a really nice site and it’s a good starting point if you’re in the market for a used camera and don’t know what you want.

At work I find myself taking lenses apart quite often. An indispensable tool for such work is the spanner wrench, which I was surprised to find is generally very expensive and crappy. Not so at US Camera, where the wrench is finally priced proportional to its cost. I remember spending more than $60 at Edmund Optics to buy one which was a clunky piece of crap. Not only that, but they sent me two left sides, so I can’t get the tips to line up. Since it arrived simply as a bag full or parts I kept thinking I just didn’t know how to put it together until I finally found a picture of it assembled at another website and realized they had messed up. By then it was too late to get a refund.

The link to build a panoramic camera is interesting. I’ve been wanting to turn an old Hasselblad A12 back into a panoramic back by rotating the camera and moving the film simultaneously at the correct speed to get the desired exposure. This is one of the links I ran into early on in the search. This guy went through a lot of trouble to build his. I’m sure mine will be worse, which is why I haven’t even started (well, there are other reasons). Haven’t looked at this link in a while, but there is a reason I bookmarked it.

During the same search period I found this guy who turned a scanner into a camera. Definitely a cool project, though he doesn’t talk much about the math behind it. Admirable that he built it with wood and scraps; I would be complaining about how expensive it is to buy the gears and get everything machined.

The mother of all sites in this respect is Professor Davidhazy’s site. He’s also built scanning and panoramic cameras out of cheapie parts. There is a lot to see at his site; the place Google originally took me is here.

My currently most active project is to replicate the flying insect photography displayed at fotoopa. This Belgian guy does some nice macro photography, but most notably is the photos of insects in flight seen here. And here he documents the early progress of the project. Really amazing!

When I first embarked on this project, I was trying to trigger a 500 EL/M electronically, and ran into this link. (Unfortunately I cannot find the 270-degree DIN connector required to make my own chord.) I measured the delay between a trigger pulse being sent in and the shutter in the lens just opening (with the camera’s mirror locked up and secondary shutter open). I did this by putting a photodiode in the camera cavity and shining a flashlight into the lens (so it measures more or less just when the shutter begins to open). This delay is a disappointing 34 milliseconds or so.

Caltech has a few free books online here. The best solid mechanics text is here. This book has examples that no other text dares to approach, and has the most complete discussion of the full Euler beam equation (used for calculating column buckling loads) I’ve ever seen.

Speaking of solid mechanics, there are some really extensive notes on advanced topics here. I ran into them while trying to do some calculations of strain on curved surfaces. Ended up not using them; they are beyond me really.

If you’re curious about the hoopla of digital photography and why pixel size matters, etc., visit this link, which is excellent with its demos of many technical aspects of digital photography. The discussion of diffraction changed the way I take pictures.

Speaking of diffraction, there is a quick calculator here.

If you’re curious about microscopes and how they work (optical ones anyway) there is a good discussion at Microscopy U. Honestly I hate biology and I’m convinced they made up the term “microscopy” to sund important—have you ever heard of “telescopy”? That’s right. In any case, the site is pretty good, but don’t expect any deep technical stuff; it’s really meant to be pretty.

This one is a gem. On this very ugly page is a lot of information of pertinent camera dimensions—such as the distance between the lens flange and the body on Nikon cameras and the thread size on Compur shutters. If you ever need to build a camera body from scratch for some reason, looking here will ensure that you design it so that the focus range of the lenses is unaffected. Unless of course you want to measure it yourself; I can verify the flange-to-film (register) distance for Nikon is correct.

Now that I’m getting into electronics I have found Discover Circuits to be very useful. Sometimes you run into articles written by frenchies that have mislabeled figures so nothing makes sense, but for the most part, it’s good. Here I learned that the “source” of a MOSFET is ground.

Back to photography for a bit… this site has a lot of exploded diagrams of various camera parts and lenses. I don’t believe in paying for manuals (I think even legally it’s worse than letting people have them for free), and, thankfully, neither do they.

I also have a project to build a digitally-synchronized mechanical clock, which is a phrase I use to feel important about my stepper-motor clock. When I first started, I knew nothing about stepper motors. I hate looking like a fool at C&H but I found this site which explains it all, more or less.

The insect photography project is requiring a source of high voltage and current to actuate the mechanical shutter. So I looked for information on camera flash circuits, which do just that. Hasn’t been too helpful yet, though I kind of know what I need now. But I ran across this site, which is an extensive discussion on flashes and strobes and has information on how to build your own. I wish the diagrams weren’t ASCII-art, but—begars can’t be choosers.

If you’re looking for the index of refraction of stuff, start here. It’s hard to find things like that on the Internet because you run into a lot of stupid middle school physics labs.

T T Lim has some incredible flow visualizations (honestly the videography could have been better, but it’s still amazing). Of note are the videos of vortex rings (smoke rings) crashing into each other. There are some rules that govern the behavior of vortex lines (axis of the vortex) that dictate the behavior after the crash. For starterts, a vortex line cannot end in free space, it must end at a surface or connect to another line, but no “T” intersections are allowed. In other words, no matter what your friends say, they cannot blow a smoke “T” or “W”—only rings. If you have a friend that can blow nice rings, try some experiments, like blowing one at the sharp edge of a ruler, with the ruler perpendicular to the path of the ring and then along the path. Try blowing one through another one, etc.

If you have a lot of data you want to fit to a curve, try zunzun. It’s faster than writing MATLAB scripts. Didn’t work for me, but that wasn’t its fault.

If you’re really into optics and are frustrated by the gap between lens design books and reality, try reading through this. They’ve documented [seemingly] everything about their 90″ telescope. I haven’t read it thoroughly, but glancing through it seemed interesting—I’m saving it for a rainy day.

This article on how to create symbolic links in Windows is the subject of my next post.

Back to astronomy for a bit… if you need a star map, go here—it computes them on the spot.

I’ve been looking for a screwdriver that fits inside a Hasselblad body, and of course, I can’t find one. But this one is hopeful, since you can stick the bits on the end of the handle. I’m going to get one.

If you’re in need of finding out what a covariant derivative is, try this. Though I ended up not using it (just like the solids notes during the strain on a shell thing) of all the descriptions I found it seemed to be the easiest to actually calculate the derivatives with. I’m glad I didn’t have to use it, though, because I still can’t figure it out.

If you’re an old DOS guy, try this on for size. BAT files still exist, and apparently are going strong. Of course you’d probably have a lot less of a headache using Python. That’s what I do to script stuff (running programs, creating specific directory trees, copying files). I used to be lazy and did stuff like that in MATLAB but that’s just dumb. Unfortunately the editor that comes with Python doesn’t have a horizontal scroll bar—probably because they want to force you to break up lines that are too long, which is easy enough to do. I found Python to be really easy to learn from scratch by yourself because the documentation is excellent. It can get a bit confusing because there are several ways to express the same thing, but drudge through it because it’s worth it.

This site goes step by step on how to write a real-time audio processing program in Windows—for example, to do FFT on an incoming signal from the microphone. Haven’t gotten around to using it, but it looks like everything is there.

Testing

I have to put something down.