View Full Version : HDV compression artifacts and the bokah from 35mm lenses...


Lonnie Bell
June 13th, 2007, 06:42 AM
Hi all,
So, I'm watching A1 footage and other HDV postings, and is it just me, or do physics support my conclusion - but I think that HDV artifacting is less when 35mm adapters are used...

1. Is this because: if someone's using an adapter they're more apt to compose/light/pan/tilt the shot with more care?

2. Or is it the physics behind it... is the bokah (out of focus areas) produced, with it's blurry circular structures, easier on HDV, and perhaps producing less artifacting...

Besides the obvious depth of field, I think the bokah is a primary reason to use these adapters - as I hate compression artifacts.
Anyone else notice this and what's your take on this...

Thanks,
Lonnie

Jerome Marot
June 13th, 2007, 10:31 AM
The unsharp parts of the image have less high-frequency components and are thus easier to compress, leaving more bits for the sharp parts of the image.

So yes: images with shallow depth of field are easier to compress.

Lonnie Bell
June 13th, 2007, 10:49 AM
Jerome - you are one sharp noodle!
...and no, not just because you confirmed
my suspicions - Big Thanks!

Lonnie