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View Full Version : Deep Focus... mmhmmm



Kholi
05-03-2009, 12:24 PM
The sort of topic that the majority may not care about, but it's completely relevant to the general discussion. It's completely fine to want and need deep focus at times, it's a great option to have especially in documentary environments.

Good news for those who might want to do event shooting and need deep focus:

1600 ISO and F22 with the kit lens is still rather palpable @ 36" of screen real-estate and 42" of screen real estate. Just did some random deep focus stuff outside and in the bathroom and it's pretty darn clean.

I'm thinking this might be a good way to save the compression as well for moving material.

Here's why: if the compression doesn't have to deal with the intricacies of "soft focused" areas, then does it have a lighter workload? As well, with passing foreground objects they might break up a bit less?

I'm going to experiment with this today with the car mount in 1080 and 720, Grabbing deep focus at various focal lengths in moving situations and semi-static to see what happens.

This adds another notch to the GH-1's versatility belt. And one that I welcome, albeit the major draw is DOF and FOV control in a tiny package, there's nothin' wrong with some good ol' deep focus!

Ruzo
05-03-2009, 12:37 PM
Wouldn't "soft-focused" areas have less details for the compression to deal with?

Kholi
05-03-2009, 12:42 PM
It depends. I'd think that soft focused areas have more or equal to because of the gradations between areas. Blending details within blur or trying to capture that information.

Waiting for more thoughts on this though.

mattsand
05-03-2009, 12:52 PM
not an easy question. blurry areas are easier to compress since they contain less frequencies, many coeffs will become zero even before quantization, but they are also much more vulnerable to compression artifacts since out eyes are much more sensitive to lower frequencies. most compression schemes are built on the very idea that high frequency data doesn't have to be very exact and can thus be quantized more. given a fixed datarate though i'd say a blurry image should have less artifacts than a sharp one.

/matt

Kholi
05-03-2009, 12:59 PM
Thanks for the input, Matt. Is it worth testing out? In 1080/24 it constantly looks to me that the out of focus areas go to hell WAY before anything in focus does. That's what lead me to want to try it out.

I guess it's not so straight forward, though.

Guess this could all be better if the data rate was fixed instead of variable.

DvxHerb
05-03-2009, 01:05 PM
I'm curious / frightened to see what was the subject of your deep focus bathroom experiments. :happy:

Kholi
05-03-2009, 01:05 PM
LOL. It's just a plant and a fish, and some candles that were there. There's a lot of light in any bathroom because of the confined space and bounce. I usually do a lot of light testing in there when I don't want to break out my own lights/cfls.

Rakesh Jacob
05-03-2009, 01:09 PM
"Just did some random deep focus stuff in the bathroom"

You've got my attention!

Kholi
05-03-2009, 01:11 PM
Oi... I'm not even gonna edit that post. Just so you guys can have fun with it. LoL

Kholi
05-03-2009, 02:32 PM
Okay, so deep focus didn't help the 1080/24 Compression breaking to pieces under just about any motion beyond a very slow/light pan.

However, I can surely confirm that 720/60P holds up EXTREMELY well deep focused and shallow under vibrations and movement at the same time.

Just pausing on a very large LCD I can't see much more than a smudge here or there where the compression fails to net detail, otherwise it's incredibly solid and quite exciting to see this deep focused image.

I'll compiles some vehicle stuff to post as soon as I get back to FCP. Won't be a lot of it, but at least it'll put some minds at rest about motion and how to deal with it.

squig
05-03-2009, 03:24 PM
Deep focus? Are you smokin crack again Kholi?

Kholi
05-03-2009, 03:31 PM
There's absolutely NOTHING wrong with Deep Focused composition. And it certainly bares validity in a video world.

Steadicam work will greatly benefit from Deep Focus, will it not?

And it puts the camera in a realm where you can use it for similar work that you would use the HVX200A/HPX170 for, where you don't have TIME to fiddle with focus constantly.

Please do not think that the niche dictates the mass, because this shallow focus groove is ONLY a niche within a massive machine that rarely ever cares or sees the need for it.

A lot of the times all you REALLY need on an HVX200A is a Wide Angle adapter. That does PLENTY good in a narrative environment as well.