The Blackmagic HDMI to SDI converter works fairly well, with some caveats:

1) You must update the firmware to the most current release. Prior to the firmware update, the image from the 5D Mark II (with or without Magic Lantern) would display a black line across the screen, when recording to CF card. The recording was fine, but the black line caused clients (and me) to freak out at first. The firmware update appears to fix this.

2) Despite the product being labeled as having a "+12 Volt" input, it DOES NOT WORK WITH ANTON BAUER DIONIC 90's. Yes, you read that right. Since the voltage of a fully charged Dionic 90 is 16.5V, the Blackmagic simply does not turn on. When the Dionic is nearly drained, with a voltage under 15V, the Blackmagic will power on. But, this makes it almost completely useless as a product you are using with a field monitor remotely. Interestingly enough, it works just fine with a 5V power supply, so under voltage is Ok.

If you need to power it in the field, it works just great with lead acid 12V batteries (which are 13.5V max, usually). So far that has been my solution to using this product in the field with Panasonic 8" and 17" monitors. Just keep this in mind before buying one.

Interesting info.
Thanks!

I have been using the Blackmagic box with success powering via d-tap from an Anton Bauer Dionic 90. The solution is to use a simple voltage regulator (like this one from Radio Shack (http://www.radioshack.com/product/index.jsp?productId=2062600) inline in your power cable. It limits the outgoing voltage to 12v. It does get a bit hot but so far it has performed fine. Down the road I will have more robust voltage regulation set up for it but for the time being, no problems.

My preference is to use the box at the camera and then link to the monitor via HD-SDI cable (or better yet, Camwave) rather than the delicate and length-challenged HDMI. This obviously is a challenge in terms of mounting and power, but I'm working hard on a complete solution now via custom machining and Redrock parts.

What about the AjA HA5 converter (HDMI to HD-SDI)? It has a 5V regulated input. Might be able to power it with a 9V battery? Dunno....

What's the quality of the signal once it's converted to HD-SDI? It's it decent quality? 16:9? Useful for critical focus?

Thanks! :)

Briefly tested the AJA. It appears to be more finicky about the HDMI signal it receives and thus doesn't "like" the output of the Canon DSLR's as much as the Blackmagic. This was anecdotal info so I would be interested to hear other's findings. I needed to move on one vs the other so I went with what was recommended. The AJA is a smaller box which is nice but will require more robust power management if one is using a 12v power source. I would be dubious about using a 9v battery, can't imagine it would power it long enough to be helpful. You don't want it going out on you mid-shot.

Images are indeed useful for critical focus. Of course the image is still letterboxed, but I have been able to blow up the image on the monitor to where it fills the frame and it is still a viewable and focusable image, not nearly as blocky as one might expect. The 7D and 1D do represent an improved version of this over the 5D as we know. The stability of the converted image is quite good.

Looks like Markertek/Switronix has a new device designed to power the AJA converters. Wouldn't this be the solution you guys are looking for to power a HDMI/HD-SDI converter?

Switronix Switronix XP-AJA-5 Ptap to AJA 5v Cable Battery Mounts at Markertek.com (http://www.markertek.com/Expendables/Batteries-Chargers/Battery-Mounts/Switronix/XP-AJA-5.xhtml?utm_source=SWT-XPAJA5&utm_medium=email&utm_campaign=dec15news)

After many requests, the new XP-AJA-5 cable allows users to plug into any battery via V-mount or Gold Mt Plate and power both 12vdc accessories(ie. Monitor, light) as well as an AJA mini converter.

Specifications
Input: DC 11-17v
Output for AJA: DC 5v, 3A
Output for P-Tap: DC 11-17v, Unregulated
Green LED Indication: Power input
Red LED Indication: AJA power output
Length:24"

Compatible with the AJA mini converter units accepting 5v, and AJA 2-Pin connector