Combining 1080i and 720p shots.

karapetkov

karapetkov

Well-known member
Hello everyone,

I'm new to this forum but I already got a lot of good info here. :bath:
Now, what is my problem.

I'm going to shoot a short soon and I'm going to use the HVX200.

I plan to shoot most of it in 1080\25p [PAL version].

But there are a few shots that require subtle slow-motion, which is available only in the 720p mode.

And here's what I plan to do:

Shoot the slow-mo in 720p and then up-rez in editing to match the 1080 ones.

My question is would there be a noticeable "jump" between the normal-play 1080 shots and the up-rezzed slow-mo 720 shots.

Would this work or I better shoot the whole thing in 720p?

Sorry if this has been discussed before, I couldn't find such topics.

Thanks in advance.
 
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1080 and 720 can intercut well, the most important thing is maintaining consistent scene file settings as required.

But how will you deliver? Is there any point in shooting 1080? It might indeed be easier to shoot everything in 720.
 
The biggest determining factor, as to whether the resolution change will be noticeable or not, would be the visual content of the shots themselves.

I'd say you would have no prblems in switching to 720 if all of the shots (going from 1080 to 720 and back) do not consist of a great deal of inorganic details that are completely in focus. Differences in resolution seem to be more forgiving in organic subjects such as people and animals, but tend to show up more in fine patterns, print or details in clothing. As long as your composition is not full of little flags that point out the changes in fine details you should be okay.

Also, shots with a shallow depth of field, giving a blurred background, will usually work well toward elimating any percieved loss in resolution in anything other than the subject(s) that are in focus.

Changing angles and choosing different focal points with the shots as you switch the resolution will also help in eliminating anything noticeable in the viewers mind.

With a little foresight and planning you should be able to pull it off without noticeable issues.
 
Well,

The slow-mo shots are two, actually:

1. Slow STEADICAM IN [DOLLY IN] shot closing on the protagonist's face [intensifying his emotional state].

Only the man will be in focus, while the background consists of the walls of a subway station - mostly grey, no particular detail and blurred out.

2. This one is more complicated - crane shot of the same man, standing on the edge of a very tall building [shot from the roof]. In the background we see the sunset, a large city park and some blocks around it. In the end of the shot, we see also tiny people and different details on the ground below. Apart of the man, everything else should be in focus, too. Lots of details and a complicated composition. This shot concerns me the most and it is also the most important of the short.

I consider the 1080 option because, if the short results to be good, maybe I could find funding to make a transfer to film. And in this case, 1080 is the preferred option, right?

As far as I understand, the 1080 mode on the HVX actually stores true progressive 1080 footage in the limitation of the DVCPRO HD codec.

And later in post, this footage can be reconstructed back to become true 1080p\25p footage. All this without loss of quality.

The camera fits the progressive footage to the limits of the container [DVCPRO HD codec].

Please correct me if I'm wrong.
 
I think you are correct on all accounts.

Perhaps you can shoot the scene, or do a similar test shoot, both ways and see how the 720p fairs against the 1080i that's reconstructed in post.

If it's an absolute must that you overcrank for slo-mo, you will need to shoot 1080 30pa, reconstruct the footage into a 24p project and slow the footage speed down in the NLE timeline in order to match the overcranking effect of shooting 720 24p at 60fps. I read where Barry Green said that you need to slow the footage down 40 % but I do not know if that is from within a 30p project or a 24p project.

The benefit of shooting 1080 will be slightly better resolution in details but the tradeoff will be a slow-mo created through some frame blending I believe.

I don't have any real world experience with this but obviously shooting the overcranked scenes at 720p would be easiest and smoothest.

You might try asking Barry green if he knows the real world resolution tradeoffs between overcranking at 720p vs 1080 overcranking constructed on the timeline. Perhaps the frame blending would cancel out the benefit of shooting at 1080 and make 720p the obvious choice.

The bottom line is that I would suggest you take advice from someone who has gone beyond theory and really has done some testing and actual comparisons.
 
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Maybe we should shoot these shots in both 720p and 1080i and see later what we can do in post.

A bit of extra work though, especially the crane shot.

OK, thank you guys for the feedback.

I'll consult with my DoP on the matter and then try to contact Mr. Green.

I'll post the short here, when it's finished (hopefully) :smile:.
 
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