P or I (NOT for broadcast)?

[VideoMaker]

I sort of hijacked the P or I for broadcast thread with my more general questions about progressive vs interlace. So I'm starting this new thread to toss out some beliefs I have accumulated regarding P & I, frame rate, etc. and the HMC150. I'm hoping to generate some fruitful discussion on these points. Specifically do you agree, or disagree with any/all of these. If you disagree, tell us why.

1. ALWAYS SHOOT PROGRESSIVE - Unless required (e.g., for broadcast) I never shoot interlaced, always progressive. I believe dealing with interlaced creates too many problems when adding fxs, color correction, scaling, etc.

2. PREFER 720P60 TO 1080P30 - I believe I have read here that 720p is the HMC150's sweet spot for general shooting, and 60P would be preferred for any fast motion scenes, or when there may be a need for slow motion in post.

3. PREFER 1080P to 720P WHEN SHOOTING CHROMAKEY because there is more color information available (is this true, and if so, why?).

4. PREFER 24P WHEN SHOOTING LOW LIGHT because the 1/48 frame rate permits more light (but increases motion blur).

5. ALWAYS SHOOT 24P WHEN FILM-LIKE CADENCE IS DESIRED.

What about exceptions to these? For example, if you were shooting a fast action football game, would you prefer to shoot 1080i60 instead of 720p60? If so, why?

 

[Barry_Green]

1. Agree
2. I prefer 720/60p over 1080/60i, but wouldn't compare 1080/30p to 720/60p. I prefer 1080/30p over 720/30p.
3. Definitely true. 1080p records about 10-15% more luminance, but 125% more chroma samples, so the ratio of chroma sampling to luma sampling skyrockets when using 1080p.
4. Yes, if you're aiming for a slower shutter speed. If you set the shutter slower than 1/60 on 60p or 60i, you'll cut your frame rate in half anyway.
5. Definitely.

 

[VideoMaker]

Barry, can I infer from your response that you would prefer 1080p24 over 720p24. If so, is it that 720p is no longer the sweet spot at lower frame rates (i.e., not bumping into ceiling with 1080p)? Also, for those cases where my target delivery is DVD, is there any preference difference between 720p and 1080p?

 

[Barry_Green]

I would definitely always take 1080/24p over 720/24p whenever offered the choice. For DVD delivery, it depends on the look you want -- if you want the "live" look, I'd definitely use 720/60p over 1080/60i for DVD. And if you want the "film" look, for DVD, you can pretty much use either. By the time it gets down to DVD, I doubt anyone will be able to tell the difference as to whether it was originated on 720 or 1080. 1080 has a lot higher percentage of chroma samples to luma detail, but DVD is 4:2:0 anyway, so ... 720p would be overkill for DVD. But if you ever intend a blu-ray or other high-def release, I'd rather have a 1080p master to fall back on, than a 720p master.