Once upon a time ... Digital Betacam

[martinnoweck]

if i remember the specs right the chip(s) of a digital betacam camcorder delivers a higher resolution than the resolution recorded on tape. something like camera delivers 1024 x 576 pixels but only 720 x 576 pixels will be recorded on tape (stretched)? anyone who can confirm this?

regards,
martin

 

[hunterrichards]

A lot of SD cameras have higher pixel count chips than they record. Even sony's DSR series have more pixels than they record on tape. I think it just helps make a sharper image without aliasing problems.

 

[Priyesh P.]

it`s called oversampling and as far as I remember the digibetas had a CCD block with a horizontal resolution of 1000 lines, not 1024.

 

[Stephen Williams]

Hi,

The Viper has 3 x 9,200,000 sensors but only outputs 1920 x 1080

Stephen

 

[GlennChan]

1- The lines of resolution spec may be measured funny. And such specs are meaningless without specifying amplitude modulation / what your cutoff is before you say that it doesn't count as resolution. The real story can get a bit more complicated than that if they are employing pixel offset as that could introduce artifacts. And with any sampling system, you have tradeoffs between sharpness/resolution, aliasing, and ringing artifacts.
Some info on sampling issues: http://broadcast-monitors.glennchan.info/scaling-artifacts/scaling-artifacts.htm

(Hmm... just thought of something. Any cheating in the DSP may distort MTF measurements??)

2- The simpler and more useful answer is just to look at the pictures. There are so many theoretical factors (what type of OLPF used, pixel count, pixel offset or no offset, lens, digital signal processing, etc.) that it's hard to characterize all that into a single number, and the numbers may not be particularly useful. So I would just look at the pictures.

Now what you need to keep in mind is that:
A- Perceived sharpness is only influenced a little bit by actual resolution.
B- Best way to measure actual resolution is to see how well you can read small text + pick out fine details (e.g. for HD, you should be able to see pores on closeups).
C- Contrast and edge enhancement tricks make a huge influence on perceived sharpness.
D- Grain has a small effect on perceived sharpness.

http://www.cambridgeincolour.com/tutorials/sharpness.htm

3- If the camera has a 16:9 sensor then things might be a little different.

 

[Benni Diez]

What I can tell is that properly shot DigiBeta looks superior to SD material shot on DV. Also the dynamic range and color depth is far better.
I've made a short film on DigiBeta, shot with a 35mm adapter and treated the material in 10bit throughout post. A lot of people thought is was shot on 35.
It's just that the tape workflow is a bitch nowadays.
I wonder how it would look like with a raw output on the camera. I bet it would still beat a lot of HDV cams, not to mention AVCHD.

 

[Charles Angus]

D-beta can be great, I remember being surprised to learn that Atanarjuat (The Fast Runner) was shot on D-beta. All Arctic exteriors - very demanding environment.