focus matte

[Cory Mitchell]

I really don't know if it's possible or not, but I thought, what the hey!

No one really knows how the focus assist works, but I was wondering if the system somehow highlights what's in focus, or what's out of focus, I was wondering if it would be possible to record that highlight and then use it later as a matte for compositing. IE if it highlights everything out of focus (or the opposite) you record that data and then in post drop everything out of focus using that same data?

Is/would this be possible? Create a matte using information from what's in/out of focus?

This is just another idea to do away with green screens (and roto) in certain situations...

Thanks

visionmind

[Obin Olson]

would that not be the coolest thing ever....

[Matthew Rogers]

I really don't know if it's possible or not, but I thought, what the hey!

No one really knows how the focus assist works, but I was wondering if the system somehow highlights what's in focus, or what's out of focus, I was wondering if it would be possible to record that highlight and then use it later as a matte for compositing. IE if it highlights everything out of focus (or the opposite) you record that data and then in post drop everything out of focus using that same data?

Is/would this be possible? Create a matte using information from what's in/out of focus?

This is just another idea to do away with green screens (and roto) in certain situations...

Thanks

visionmind

Uhhh... if it's doing it realtime on the camera, should you not be able to get software that can do the same thing in post? A plugin that could matte out everything that was out of focus....

Maybe I am missing something (you could also have real issues if your DOF was so shallow that you were having issues in keeping everything you needed in focus)

Matthew

[Cory Mitchell]

The problem I see (I'm really not sure) with post is that at that point the software only can analyze the sharpness, while in camera, I believe, the focus information is determined by the lens, therefore that information has to be passed along in metadata or something...

Correct me if I'm wrong, but I think the GY-HD100 (JVC) focus assist highlights stuff in or out of focus (I can't say for sure as I've only heard something about it and never used it) which is what I think would work if it could be recorded.

Like I said, I don't know if it's possible. I don't know if the focus assist system only works at the LCD or viewfinder resolution, or if it could be upscaled sharp enough. But if it would be possible I think it would be very useful, for more than one reason.

thanks

visionmind

[Jochen Schmidt-Hambrock]

The way I read the information on the Focus Assist is that it only provides focus info about one line of pixels, not the whole image.

Jochen

[John Allardice]

Even if it provided information on the whole frame, the most it can do is provide as a sort of "contrast spectrograph", highlighting the areas of increased contrast..ie. detail.
What it would ignore, is areas of low contrast that are in focus, for example, any surface with graduated color would be ignored, whether it was in focus or not

[Johan Malmsten]

Sounds to me like you are after the old "peaking" function... wich just bosts the sharpness-enhancement to a ridiculous level while monitoring. Wich results in an image where the in-focus areas are easily visible (they turn ugly and pixely;)). Never heard of an algorithm that would be able to create alpha data for focused/unfocused areas...

Unless one took the resultant image from the peaking-function and somehow created an algorithm for on the fly roto of it... but hey, "the team" has done magic before... invisible 12:1 compression... ridiculously cheap cine-grade camera... natice online editing of 4k in final cut pro from firewire... I wouldn't be too surpriced if the programming engineers just flicks this feature out just for the fun of it...

Or am I too much of a noob to get into this discussion? ;)

[I Bloom]

Other than the fact that the camera is dealing with data in an uncompressed form, there is no information available to the focus assist that isn't part of the actual image. In other words, the camera is just analysing the image to determine sharpness where the EVF, monitors and your eye cannot resolve it. There is no sense in adding an extra layer of data that could be easily created in post. I would look into some image analysis software for the idea that you have.

However I share your sentiments about wanting to see the focus overlayed on the image instead of in a waveform type display. Actually I'd like both.

IB