Turns out the FEA I’ve been doing with Solidworks 2007 was based on some mis-information. I was using Cosmos Express (the simple/beginner’s FEA tool in SW2007) and once I realized that I needed some sort of saftey factor on my parts, suddenly I couldn’t make anything strong enough to hold the 300lbs that the spring would be pulling inside each arm segment. I decided to look at some different materials than 6061-T6, and that’s when I found that SW’s material library had the yield strength of 6061 @ 8000psi. Wikipedia and ALCOA list it as a yeild strength of “over 35,000PSI” (http://en.wikipedia.org/wiki/6061_aluminum) which is quite a big difference! Now that I made that change in SW, suddenly all my parts are more than strong enough.
I also re-designed my spring holding apparatus- I’m running 5 steel springs of a smaller diameter to get enough range of motion, and hold enough weight. The upside is that I can also run 4 if I find that it’s way too strong for my camera, or I can run just 1 for very light weights.
Seems like Canon will not be coming out with any sort of firmware upgrade to get 24P out of the 5DMkII. It also seems like RED is pushing back it’s promised deadlines (which they also promised not to stick to, so it’s hard to blame them).
This makes me really want to think more seriously about the 5DmkII for video. There are now workarounds for all the main shooting issues (manual f-stop – twist the lens, or use manual nikons, manual ISO with * button to lock it down, manual shutter speed - http://www.vimeo.com/2425650). They might not be pretty, but they work. The only real stumbling block is the 30P shooting mode. If I can just convince myself that the 30P isn’t so bad, then I’d jump on the bandwagon. The upsides are many- most importantly, big sensor, and great low-light performance. Now instead of obsessively reading Reduser.net (which replaced my obsessive reading of DVXuser.net) I can read http://www.5dfix.com/ and other 5D sites.
For run-n-gun documentary work, it looks just amazing- you could get away with just a few lights (or none at all with some natural light), a small audio kit, and you’re good to go. You could fly a very light stabilizer rig to help with the handling issues- Here’s some footage from switzerland- http://www.bildblog.ch/canon-5d-mk2-expedition/ they are just using a hand-held glidecam, it’s not perfect, but it’s not too bad for being so damn portable.
Come on canon, or hackers! make my day.