Muddying the anamorphic waters (Revised and Part 2)...

[Stephen van Vuuren]

The original page has one shot revised:

http://www.sevensmilingsharks.com/mu...anamorphic.htm

I've added a new page with shots Barry Green once again has generously provided.

http://www.sevensmilingsharks.com/mu...amorphic_2.htm

Notice how much sharper letterbox and stretch is at 5.6 than anamorphic, whereas the greater DOF at f16 keeps the anamorphic in better focus.

Which tells me the issue is with focusing not softness.

[Joe Russ]

very interesting test...it sort of makes the anamorphic adapater a blessing and a curse at the same time....one thing i was curious about....the letterbox images...if you look at the thistles of the tree, it almost looks like interlacing...i was curious what this is from, is it from thin detail mode on the camera, or were you filming in an interlaced mode or was it not completely reverted to progressive in vegas...

the main reason im asking is im thinking about buying the camera but i wont be able to afford the anamorphic adapter for a while but will still be making wide (cropping/stretching to anamorphic in post) aspect ratio movies. so it becomes important when i stretch the image that there not be visual artifacts (such as interlacing or whatever that effect is) other then the softness of stretching the image slightly.....

[Glenn Gipson]

Is it me? But I don't see how LB mode causes the camera to loose 100 lines of resolution? In fact, LB mode almost seems to be wider then the adapter, in some shots. Where is the 100 lines of loss with LB mode?

[Stephen van Vuuren]

Per Interlacing - Barry is having some issue with some shots appearing interlaced. Not sure why yet.

But the LB mode is clearly not looking horrible, either in this grabs or the full-rez motion clips I've looked at. I actually think the thin mode is what is helping the letterbox stretch better. It gets slightly soft, but even on wide shots, quite acceptable.

[Boyd Ostroff]

I really don't know much about the DVX-100, but these comparison images are similar to tests I made with some other cameras. The "interlacing" you mention is the result of stretching the image vertically.

When an image is letterboxed to 16:9 it uses the full 720 horizontal pixels, just the same as normal 4:3 video. But it only uses 360 vertical lines. In other words, there's a 60x720 black area above the image and a 60x720 black area below it. So you have "thrown away" 120 of the 480 available scan lines. This results in 120/480 = 25% loss of vertical resolution compared to the anamorphic adaptor which uses all 480.

The "interlaced" look occurs when you stretch those 360 lines back up to 480 in order to create an anamorphic 16:9 image which will display properly on a widescreen TV.

For a graphic example, look at this blowup from a test I shot with letterboxed 16:9 on the Sony VX-2000 vs the native widescreen PDX-10.

[Stephen van Vuuren]

Boyd:

We are talking about two different kinds of interlacing. Yes, the stretched images have some artifacts, but we were getting actual half field lines only visiible (and quite noticable) on moving objects. The one dramatic example Barry replaced by going back to the original footage.