EVERYTHING YOU WANTED TO KNOW ABOUT HD BUT WERE AFRAID TO ASK...

What is 2K and 4K resolution?

Video people think of resolution in horizontal lines. The standard definition (SD) TV you have at home is made up of 525 horizontal lines. Of the 525 lines, only 480 lines are picture area.

On a computer, a SD frame is composed of dots or pixels. There is a pixel for each horizontal line (480) and each line is made up of 720 pixels. A SD frame is therefore 720 by 480 pixels (720x480).

Panasonic HD is composed of 720 lines, each line being made of 1280 pixels (1280x720).

The Sony F/900’s image is made up of 1080 horizontal lines, over twice the resolution of SD. That’s 1920 by 1080 pixels (1920x1080).

Since Digital Intermediates became so popular, film people like to talk about resolution in terms of the number pixels that make up each line, so the Sony's 1920 pixels is basically 2K resolution.


What is High Definition?
This is a trick question. It seems everything is being called HD.

Basically any image that has more than the 525 lines of SD is being called HD. There is one HD format that has only 480 lines, but because it's 60 frames per second it's called HD.
Is HDV really HD?

The people using these "prosumer" cameras claim they are shooting HD. But what are they laying to tape? I could transfer an old VHS tape to 4K resolution. Would that make it a great picture?

Most HDV cameras have chips that are a quarter of the size of "Broadcast" cameras, don't have the signal processing and the lenses aren’t the best. What do you want for $5000 bucks?

You can use data rate as a measure of quality. HDV has a data rate of 25 mbps. The Panasonic HPX-500 can record up to 100 mbps. The Sony HDW-F900/3 has a data rate of 158 mbps (140 mbps video only)! Trying to compare the $70,000 Sony F-900/3 Cine Alta with $30,000 of Fuji glass to a $5000 HDV camera is like comparing apples to oranges. Or apricots to pumpkins.


What is 24p?

"24" denotes the frame rate and "p" stands for progressive scan.

SD is composed of 30 frames per second (fps), made from 2 interlaced fields (60 fields per second). Each field contains half the lines that makes up a frame, one field containing the odd lines and one field the even lines. When you see the letter "i" the frames are made up of 2 interlaced fields.

Progressive scan has all the picture information in one frame. This is the way a film camera records the image. The computer screen you're looking at now is progressive. You will see a "p" to denote a progressive frame.

Film is usually shot at 24 fps. Unlike a regular NTSC video camera, the HDW-F900 can shoot at 24 fps progressive. We would say it's shooting 24p.

In addition, the F900 can also operate at 60i, 59.94i, 30p, 29.97p, 50i, 25p, and 23.98p (Why the frame rates with decimals? Time code issues, which is explained below).

Now that you know about lines, frame rates and interlaced and progressive, let's put it all together. The CBS and NBC networks have elected to adopt a 1080/60i HD format. ABC chose 720/60p. And Fox chose 480/60p. So you tell me, which one is "HD"?

What is 3:2 pull down?

As you now know, NTSC video is 30 fps. Film and 24p video is 24 fps. That's a difference of 6 frames per second. When you transfer 24 fps to 30fps, you must repeat some frames to make up the other 6 frames. 3:2 pull down describes how they are repeated.

What are all the numbers with decimals like 23.98p and 29.97p?

If you are transferring directly to film and editing on film, use the 30p, 25p and 24p frame rates. In all other cases you would shoot at the decimal numbers. If you are editing in video at any point you want to use 23.98p or 29.97p.

Decades ago, when NTSC TV's went from B&W to color, engineers added something to the video signal to carry the color information. This made the signal slightly longer than 60 fields per second.

Of course, this caused time problems. To make up the difference engineers created a time code that dropped a number now and then. This is called drop frame time code and the old time code became non-drop.

What does this have to do with frame rates? If you are going to downcovert at anytime to video, you want to shoot with one of the decimal number rates so that you will not have problems with time code and audio sync.

You may note that 25p is the only frame rate without a decimal number. The 25p is for transfer to PAL and that Europeon video standard does not have the same TC issues.

All you really need to know is that want to shoot 24p, make sure you really shoot 23.98p

HD VS. FILM

Most people know the advantages to shooting HD instead of film, but here’s a reminder…

Cost...

A case of HD tape costs about $400 bucks.
The same 500 minutes of 35mm raw stock is over $25,000!

Then, pay for developing, telecine and syncing of 45,000 feet of film. On a 90 minute film, 45,000' is less than a 5:1 shooting ratio. Shoot 10:1 and your costs double.

Tape is cheap. And with tapeless formats like P2, there’s no raw stock costs at all.

Don't let fear of the budget get in the way of quality...
Every time you roll camera you're spending money. There's nothing like a foot and a half of 35mm film going through the gate every second to increase the stress level on the set.

This can effect a producer/director's decision on another take and ultimately the actor's performance. Sometimes it seems the best performance by the actors is during the rehearsal.

Don't miss that moment. Tape is cheap, so you can shoot the rehearsals without breaking the budget.

Instant dailies...

HD offers one advantage that film can never offer: WYSIWYG (wiz-e-wig): What you see is what you get. You can see exactly what you're getting immediately. There's no waiting for dailies to come back from the lab to see if you got what you wanted.

If you shoot film, you know the problems: Hair in the gate. Film chip in the gate. Lab problems or mistakes. Overexposure because the A/C opened the iris for focusing and forgot tore-stopfor the shot. Or opened the "wrong" side of the mag. Light leaks from untaped magazines. Light flashes caused by static electricity in the magazine. Camera jams. I've personally seen all of this happen on film projects.

And throw away that low resolution, flickering video tap. Imagine if you could see exactly what you're getting, and then be able to play back the shot immediately. Full color and resolution playback. That's what you get with HD.

Faster...

The shooting process is faster. You don't reload every 10 minutes and with 50 minute loads, you don't re-load as often or worry about run-outs, even during the longest takes.

The camera was designed to use variable focal length (zoom) lenses. You don't spend valuable production time swapping primes. Fuji zoom lenses are fast: They shoot wide open at f2, which means you don't need as much light, which again, means faster shooting.

And because you can see exactly what you're getting on the monitor, shoot in practical lighting situations with confidence.

It seems every shot as a computer screen or TV monitor in the frame. In film, you would need all the monitors in the shot to be running 24 frame video. With the HD camera, Clear Scan syncs up the camera to a monitor with a flick of a switch. Again, HD is just faster.

Simply put, I can shoot faster.

And you’re in post faster. With the P2 tapeless cards you can be editing on set on a lap top two minutes after taking the shot. You could literally shoot, edit and distribute on the web from anywhere on a lap top before you could drive a can of film to the lab.

THINGS TO THINK ABOUT...
Your final product is only as good as the image you started with...

This is especially true if the show is going to end up on DVD or the internet. So much production isn’t for broadcast. The quality shows.

Clients ask me why shoot HD if it's just going to NTSC? For the same reason you shoot 35mm. The better image you start with, the better the final project will look.

As more consumers buy 60” flat screen T.V.'s, it becomes imperative to make the best image possible. And if you're shooting a project that is going to be projected, HD is the only way to go.

Is any of the footage you're shooting for a current project going to be used in the future? And I'm not talking about the distant future. Some countries, like England, will only accept product shot in the 16X9 format. Re-formatting a production is terribly expensive, especially if graphics are involved.

Over 50% of all production is now shooting HD. Are you?
 
 

Copyright 2002-2006 Donley Films, Newport Beach California. All rights reserved.
Dan Donley

  Last Updated 10/30/07