For the past month, I've been shooting a project for a client on an HPX300, using the AVC-Intra codec at 1080/30p.
Unfortunately, we now have two simultaneous shoots at two different locations (no way around it due to scheduling constraints), and we only have one HPX300 to work with. There's no room in the budget for a rental, but my producer is suggesting we use our HMC150 for the other shoot.
Not ideal, but suppose I shoot at the maximum bitrate (24 Mbps, correct?) and avoid situations that would magnify the differences between the two cameras (such as lowlight). Would the difference be that discernible? Even if the project's ultimately broadcast in HD?
I don't think there's any compatibility issues - before we edit in FCP 6, everything has to be transcoded into Apple ProRes anyway (this would be true for footage shot on either camera).
I feel like my main concern is, will people be able to tell the difference?
Bring a good monitor to match the looks and make certain you're shooting identical frame rates and resolutions. In SD you'll have a hard time telling the difference but on a good HD monitor you'll see it more.