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class="Paragraph" HD Downconverts To 4:3

Published : 25th May 2004


I've just had a rather unsettling experience. We shot with a Panasonic Vari-Cam and down converted to 4:3 using a Panasonic deck to Digi-Beta. In the process we seemed to have lost about 10% of our head room. Frames are now uncomfortably tight. The on set monitor was an Astro and a CRT. I was assuming a common top line for down convert (similar to 35mm approach).

Is it common to lose this much picture information in a down convert? The HD source tapes are fine.

Thanks in advance

Nick Hoffman NYC DP



This is one of the reasons it’s so difficult to shoot compromise framing.

Shooting for a letter-box presentation on 4 x 3 television the top of the frame is absolute; you see everything right up to the black bar. Displayed in 16 x 9, you lose some of the top, bottom, and sides. Unfortunately, the only solution seems to be to allow much more headroom than you might like. This is a fact of life we’re all going to have to live with as we enter the age of multiple aspect ratios in common use.

Too wide, too devoid of action on the sides of the frame; what a nightmare!

I don’t believe the down converter is cropping any more of the picture than a 16 x 9 display, but you definitely need to test.

Best regards,
Leo Ticheli
Director/Cinematographer
Birmingham/Atlanta



In the process we seemed to have lost about 10% of our head room.

If I have to downconvert to 4:3, I put on the monitor the usual markers for 4:3, but I assume that this markers are not the "safe" area of a monitor...

It's like viewing a 4:3 monitor with the under scan option.

Pol Turrents (ACTV)
DoP Spain, Barcelona



Nicholas Hoffman wrote :

>I was assuming a common top line for down convert (similar to 35mm >approach). Is it common to lose this much picture information in a down >convert?

You will loose top and bottom info when you go to 4/3. It's the same a shooting DigiBeta and choosing 95 or 90% frame lines.

When shooting for a 4/3 finish, I always adjust my view finder frame lines (top, bottom, and sides) to approximate 95% of transmission. I'm not familiar with the Panasonic, but with my f-900, I consider the side lines generated by the camera when choosing the 4/3 frame lines in the menu as transmission lines, just like a TV ground glass in film, where you have transmission and safe action. I use the horizontal and vertical variable frame line generator to create a "safe action" area in my eyepiece. I then point the camera at a 4/3 chart to adjust the monitor generated side lines to my safe action lines in the VF.

I haven't had any complaints with 95%, but I'd like to hear from anyone who might suggest a different % choice, like 92.5% or even 90%.

Ian Ellis DP
600 op/f-900 owner
Austin TX
512-751-5690
www.texashighdef.com



>You will loose top and bottom info when you go to 4/3. It's the same a >shooting DigiBeta and choosing 95 or 90% frame lines.

Is this why my SD downconverts from HDCam telecine sessions don't line up to the 1.78 Widescreen matte in Final Cut Pro?

If I apply that matte to a HDCam dub, I lose the top and bottom.

Thanks!

David Mallin
Cloudchaser Films
PO Box 170267
San Francisco, CA 94117



Try going into the menu of the 720 deck and choosing a 13x9 output. This will give you all the vertical information and not look letterboxed, in fact I'll bet no one will even notice it's not 4x3. The 4x3 option crops some.

On another topic, I thought the Oscars looked fabulous in HD -- some of the best video I've seen at home in HD.

If any one needs criticism, it's ESPN for filling their HD channel with upconverted and stretched SD for most of their schedule. It looks nasty, and I suppose they think people will think it's HD.

Rod Paul