As far as I"m concerned, 1080i is the same thing as 720-60p. So the choice between the two is probably just semantics. If you have the option to shoot 1080-60p, then there's more of a decision to make. And if you shoot 720-30p, you are losing the ability to create identical 1080i footage, if you care about that. Otherwise, I wouldn't worry about it.

>I'm liking 720p for an all around end product, but still shoot 1080.

That's pretty much me as well. Another thing is that if you shoot with a DSLR, there is less moiré and aliasing at 1080p because fewer pixels are being skipped. Also, with the DSLR, zooming while you are shooting is pretty much out of the question because the back focus is off, the iris changes in jumps, and the manual zoom ring isn't really designed for video zooming. A little extra resolution lets you do gentle zooms and pans in post. Since I've started doing this I've really liked how that lets you do things like time a zoom in that ends with a smile or a turn of the head. I suppose I will end up with a 4k camera at some point because I would use this for 1080p HD delivery.

I don't understand that Andy. 1080i is 1080 lines. 720p is 720 lines. Not the same thing.

I'm shooting 1080p at 29.97 fps and downrezzing my final renders to 720p at the same framerate using Handbrake (because of it's slightly superior resizing algorithm). I've downrezzed 1080i to 720p using Handbrake and it's decomb filter and it actually looks pretty good, but I'd still rather shoot progressive if I have that option.

Shooting at 1080p and downrezzing to 720p also gives you a little room for deshaking with Mercalli without losing end resolution.

One thing easily overlooked is generally the same camera shooting progressive compared to interlaced will deliver more vertical resolution. I've found this quite noticeable on the EX1 comparing shooting 1080p25 to 1080i25.

The danger is if you have to deliver interlaced that'll be viewed on a CRT 25p can deliver too much vertical resolution and quite nasty problems with line twitter / aliasing can bite hard. So far I've found 1080p25 pretty safe. I've had major issues with 720p50 though however the content included brick wall with fine horizontal detail. More testing needed I think to compare apples to apples.

Bob.

ah bob....

i failed to even consider 1080p25 vs 1080i25. (which is what the z5 will do).

working on the principle there's probably NO crt's left in my audience, would 25p be better than 25i?

(where's my betasp decks!?)

"working on the principle there's probably NO crt's left in my audience, would 25p be better than 25i?"

I would say yes. Motion rendition may still not be as good however as many HDTVs these days do all manner of magic anyway this seems less of an issue than it used to be. In anycase if you shoot 50i and then de-interlace to get progressive you lose that and you may well be loosing vertical resolution as well.

One other thing, you do lose around 3dB sensitivity shooting P.

Bob.

>One other thing, you do lose around 3dB sensitivity shooting P.

Why is this Bob?

/jerry

"Why is this Bob?"

Because when shooting interlaced the processing includes line pair averaging. This prevents line twitter and reduces vertical resolution but also averages out noise. The last bit means an effective increase in sensitivity.

Bob.

1080i is interlaced, which effectively means that 2 x 540 lines are displayed (one for even and one for uneven lines) at a refresh rate of 25 or 30 frames (depending where you are). 720p is progressive, which means that the full 720 lines are displayed at any time, in a refresh rate of 50 or 60 frames.

When it comes to bandwidth, they are considered identical.

(which is how I understood it...)

Our local OTA tv stations broadcast in 720P and 1080i and they are spectacular with both resolutions with the exception of one 720P channel which "has diminished skills".
It is a touch blurry edged with a touch of "VHS Syndrome". I would suppose it is old equipment rather than path interference. Sony XBR2 tv.
JJK

Nick that was kind of a sloppy post at the end of the day. More specifically, I'm referring to my belief that output on everyone's LCD screens and TV's is always progressive, so if you're shooting 1080i, people are seeing deinterlaced footage with a vertical resolution pretty much equivalent to upsampled 720p.

Bob's points are probably more interesting to contemplate...