The HD Camcorder and the Mark IV are two different products with different capabilities and should not be compared. A 1D Mark IV is not the product if you just want to shoot video and connect it to your TV to watch it. There are too many camcorders for it. Most of those dont even shoot progressive.

The Mark IV or for that matter HD video in Canon DSLRs is in news because it gives you the capability that is there in some very expensive film cameras. The majority of professional video cameras in the $20,000 to $80,000+ range have 2/3'' sensors ie. sensor size approximately 8.08mm by 6.6mm with a 11mm diagonal.

The EOS-1D Mark IV’s sensor size is 27.9mm by 18.6mm (33.5mm diagonal). So the 1D Mark IV sensor is about 9.8 times larger than the professional ENG (Electronic News Gathering) camcorders. Since you all know that larger sensor gives a shallow depth of field, the 9.8 time larger sensor size can give you an indication of how good it is.

Apart from Depth of field the EOS-1D Mark IV’s larger sensor size results in amazing low light capability unheard of in the professional ENG cameras. For example in the Sony HDW-F900R CineAlta 24P HDCAM can only shoot at an ISO equivalent of 320. (It costs upwards of 76000 US Dollars).So imagine the ISO 3200 or ISO 6400 of the 1D Mark IV vs ISO 320 of the the Sony F900R. Now you understand why people in the industry are getting excited.

So much so that for the first time, a major network in US had one of their prime time show finale filmed it with a DSLR (5dII).

The Mark IV gives an opportunity to do a film with qualities comparable to such top end equipment used in Hollywood. Ofcourse, you need to pick up accessories, and skills too.

Cheers,
Sabyasachi