DIY HMI pt 3

After even more research, I’ve decided to retrofit one of my Lowel Omni fixtures with a 70W HQI bulb.

~$86 for the bulb – Iwasaki EYE Color Arc MTD70/D #56227 which is4000 lumens, 6000hrs, 6500K 92CRI.  the bulb is 120mm wide, so it’ll have to go at a 45 degree angle in the square fixture.  The specs say it has an up to 15min restrike time, but I’m betting it’ll be more like 5mins, like the other Iwasaki HQI bulb that I have in my soft box.  Here are the specs for the bulb- http://www.eyelighting.com/tb/MH/ColorArc/EQS-N-52-78-56227.pdf

~$98.43 for the ballast- 120v-277v input – electronic ballast for 70W bulb

~$5 for a lamp holder for this bulb

I ordered 1 bulb, 1 balast, and one lamp holder from Steve from Dyna-Brite Lighting in Tuscon (Phone:  1-520-882-4404).  I’ll have to do a bit of metal work to get everything inside the fixture, and then will need to make some special cables to connect the light to the ballast, and ballast to the wall.

If it works, then I’ll have an openface/spot/flood adjustable Lowell Omni that puts out ~ 300W worth of light (in Tungsten terms) and pulls 70W from the wall.  Not to shabby for a hair/rim light.

 

DIY HMI continues

Started doing more research on a small HMI I can use for a hair light.  Looks like there are several 200W HMIs on the market- by Arri, Joker, Frezzi to name a few.  The Frezzi is $3500 for a hot-restrike unit that includes pelican case, soft box, filters, barn doors, and ballast.  Similar unit from Arri that also includes a DC ballast costs $5200.  Wow.  This is for a single 200W HMI (puts out about 600W worth of light compared to a tungsten) in a fresnel housing, with accessories- but wow!  That’s not cheap.

Turns out they all seem to use the same bulb- Phillips 200W MSR HR HMI bulb.  Bulbs cost around $120 from Barndoor Lighting. The bulb has a GZY 9.5 base, and is 80mm (3.2″) tall.

Further research lead me to find only 1 compatible ballast for this bulb-  made in Germany.  Schiederwerk EVG 2-20 ballast  roughly – $380, then you also need an ignitor - HZG 8-25 (Hot Restrike!), part number 32 058 1000. Ignitor – $95.  The US distributor is Jeffrey Van Etten @ Professional Lamps jfsales@plilamps.com

So we’re at $600 for bulb, ballast, and ignitor.  You still need a fixture, a box for the ballast (it’s a circuit board) and cabling.  

If you can get away without hot-restrike, then things get a lot cheaper.  Coollights has CDM (similar tech to HMI) bulbs 150W in an Arri knockoff shell with a nice ballast and cable for $460 or so.  Takes 5 minutes to warm up, but is cheap, bright, and apparently well made.  

Food for thought.  Don’t know if a doubling in price is worth it for hot-restrike (one could get a similar arri knock off for $270, and replace the guts with an HMI and build a ballast box- but I bet you’re still near $1000 or more when done- but you’d have a pretty sweet 200W HMI for $1000, which isn’t all that bad.

FEA follys

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.

Canon 5DMkII makes me want to accept 30P

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.

24fps prayer

So I just read this post on ProVideoCoalition by Adam Wilt- and honestly, I couldn’t disagree more.

He basicly is saying that he can’t wait for the day when we are all shooting and delivering 60P content, and that 24P is an ugly holdover from a past era and should be done away with.

While there are some technologies that I agree with this concept on – my pal Aaron brought up the B&W viewfinders on ENG cameras.  I mean seriously, I don’t see any advantage to them, and you could always turn the color off on your COLOR viewfinder to get the same look…

But I don’t see 24P going away ANY time soon, nor do I want it to.  I like my videos to look good, and to me, what looks good IS 24P.  Maybe someday some future generations of filmmakers will start a new film movement that makes 60P cool, but for now, they are not the films that look good to the VAST majority of filmmakers, and audiences (and I’m talking about audiences that can tell the difference).  For the people who can’t tell the difference- who cares?!  

You know what, let’s stop using oil paint because you can get a more life-like and detailed image with inkjet or an airbrush or something!  That’s a great idea.  Lets see how many oil painters and collectors want to make that change. 

 

There’s my first rant on my first blog.  Whoopie.

Video/Film Sensor Size Chart

After looking these up on wikipedia too many times, I decided to make just one chart that lists all the sensors size of the various DSLR, and video cameras out there, or coming soon.  I actually never understood that Super 35 (s35 on this chart) is the size of regular 35mm movie camera film, and is significantly smaller than full frame 35mm film.  I didn’t even go down below 1/2″ sensor size, because it’s just too depressing to see how small the sensor is on my HVX200.
Sensor Size Chart

Nebtek HD70

After spending a LONG time hemming and hawing, comparing the various options for HD on-camera monitors:

Carrion (amazing picture, great price, but heavy and larger size)
Panasonic (very nice, but equally very expensive)
Marshal 7″ (not bad at all, not very bright, heavy)
Totevision (questionable build quality, so/so picture)
IKAN 8000HD (crap picture, all plastic, very cheap, not really fair comparison)
Varicam/Swit (garbage)

I finally bit the bullet and bought a Nebtek HD70 for on-camera monitoring (and for future use in my yet un-built stabilizer). The picture is AWESOME- heads and toes above the Marshal 7″. It’s bright, and with a hood, works fine even in full sun-shine. They have an edge enhance mode that really makes pulling focus in a 85mm f1.4 nikon a snap. It has underscan, blue gun, bars, and various PAR modes (though I pretty much only use 16:9. There are multiple holes for tripod mount plates, or for other attachment methods, so it should work great on a stabilizer. The power and video i/o are in the back, and can be turned so they point sideways. It runs on 12v, or 7.2v through a smaller connector. It’s got an all metal case, feels quite tough, and has BNCs w/ loop-through. I paid just under $2k for it.

Now the bad-
I got it with the Panasonic battery adaptor (I have an HVX200) and my non-panasonic brand batteries didn’t work until I added a few strips of gaff tape to the battery mount to ensure contact with the electrical connectors. Nebtek said that both the adaptor and the off-brand batteries are made from molds of the panasonic items, and they use those molds far past when they should- thus the parts don’t always fit right. I’m not very happy with that answer, but with the tape it seems to work just fine.

It eats batteries pretty quickly, I’m using 5600mah units, and I get about 2 hours of use out of them. Not so great when they take ages to recharge. So I might be looking into a different battery option. Not sure yet. Price and weight of AB or IDX system is daunting.

Finally, when my camera is in HD mode, if I am WAY overexposing the frame, the monitor will freak out and think there is no video signal. It’s not really a big deal, since you’d never actually shoot with those settings, but it’s annoying when you are setting iris, or moving into a brighter area and you loose your picture till you dial back the iris. I guess I could look at it like a “feature” It’s lake a hard stop for when you blow 100+ IRE. Nebtek support has been good, and is working with me on this, so it’s still unresolved.

Home Built Steadicam

I lurked on HBS (homebuiltstabilizers.com) for years before getting up the gumption to try my own build. Now nearly 6 months later, I’m still planning things out. I’ve reverse engineered the Steadicam G50 arm, and am going to try that as my first shot. Why not eh?! If it works, I’ll be stoked. What’s more likely, is that I’ll learn a lot about machining, and use those skills to make some simpler items.


Here is one of my CAD drawings of the G50 arm mechanism. If I understand it correctly, (from reading the patent) I think that the red parts work as a cam to reduce the spring force as the arm booms to it’s maximum height- which makes certain the arm doesn’t lock up, or bump at the top. At the same time, it also lessens the force of the spring at the bottom of the motion- I’m not sure why this is, and might try to make a prototype to figure it out.

DIY Kinoflo

My first DIY lights- I bought some electronic ballast flourescent fixtures at Home Despot, then added some daylight balanced, high CRI T12 bulbs. Finally for the 2-bulb fixtures, I added some EMT pipe clamps to attach to lightstands, and for the 4-bulb, I bolted 2 fixtures together and added a 6″ baby plate on the back to attach to a mafer clamp on top of a light stand.

They work well, but they are kinda heavy, and hard to transport without risking breaking the bulbs.