Digital zoom

Muttondraw

Muttondraw

Well-known member
If you are shooting S35 and you want to record 1080p, you can either window the sensor, or scale in camera. Is that windowing and scaling fixed or you can window any size within the sensor and scale? Obviously you could do this in post but I can see all sorts of situations when it might be preferable to do it in camera.

Martin

To avoid confusion this thread really should have been called "Digital Extender"
 
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Now that I say is quite an idea.

There's plenty of resolution at least to pull of a digital magnification in camera of a factor of 3 (I think) or more in 1080p mode. 2x in 2K.
Of course who knows what that would take on the processing side.

A smooth 'zoom' would requrie interpolation, which doesn't really fit the RED idea. However as just a fized "digital extender" is should work by just skipping "n" pixels.

- Mikko
 
mikkowilson said:
A smooth 'zoom' would requrie interpolation, which doesn't really fit the RED idea. However as just a fized "digital extender" is should work by just skipping "n" pixels.
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There must be interpolation otherwise you wouldn't get from 4K (4096 pixels wide) to 1080p (1920 pixels wide), or from 2k to 1080p. But I was thinking about a variable digital extender rather than an operational zoom. You should be able to scale the image by about 150% (if you are aiming to record at 1080p) before there is any softening at all. Even 200% scaling should be quite acceptable.

Martin
 
Why do you need a zoom? Just walk closer.

j/k :)

I think this would only work for RGB recording, as RAW size is fixed and can not be scaled from a larger sensor area, from what I understand.
 
jlaurili said:
Just walk closer.
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Good point. Alternatively I could just stick the set on roller skates and pull it towards me, then I wouldn't need to get out of my armchair!

jlaurili said:
I think this would only work for RGB recording, as RAW size is fixed and can not be scaled from a larger sensor area, from what I understand.
Click to expand...

I think you may be right. The ideal for RAW capture would be to specify a windowed area while shooting, so it looks right in the viewfinder. This would be stored as metadata and then applied as a crop in Redcine before scaling. The digital extender process would then still be a creative decision made by the camera operator rather than the editor.

Martin
 
Shoot Redcode Raw 4k then resize, crop, zoom, etc in post as much as you like.

Also shooting in windowed 2k (or 720p) mode will magnify the image 2x, so you kind of already have a digital zoom.
 
ZaneIsNumber1 said:
Shoot Redcode Raw 4k then resize, crop, zoom, etc in post as much as you like.

Also shooting in windowed 2k (or 720p) mode will magnify the image 2x, so you kind of already have a digital zoom.
Click to expand...

Yeah. I know it can be done in post, but if I am framing a shot I would prefer to make the decision in camera. I like the idea of it being defined in camera but only as metadata in Redcode Raw 4k.

Martin
 
I sure would like to have windowing based on standard sizes like anamorphic would be nice, with shaded area outside the frame that you can see the audio boom about to fall into your shot, BEFORE it trashes the take!
 
And for the insane times you need 250fps, how about a 1024 window or even an 800x600 window, for super highspeed work!!! oh ya!!! I am telling you it would be used more then you think!

Why rent a crappy industrial vision high-speed system when you can shoot RED with a window on the sensor!
 
I was thinking about that also, and think it would be a great idea for high speed work. Maybe even down to 320x240.

obin said:
And for the insane times you need 250fps, how about a 1024 window or even an 800x600 window, for super highspeed work!!! oh ya!!! I am telling you it would be used more then you think!

Why rent a crappy industrial vision high-speed system when you can shoot RED with a window on the sensor!
Click to expand...
 
Muttondraw said:
Yeah. I know it can be done in post, but if I am framing a shot I would prefer to make the decision in camera. I like the idea of it being defined in camera but only as metadata in Redcode Raw 4k.
Click to expand...

I see what you mean, but odds are that the in camera, real time scaling will not be as good as what can be done in post with good software. Fact is that, with 4k rez, you zoom, crop, chop, etc in post, and it will hold up. So the option is there, but there would be issues of practicality to impliment this in camera. There would be the sudden need for a digital zoom control, etc.

I'm certainly no saying it's a bad idea. I would probably use the function if it was included, but I suspect, out of the box, the options will be full frame 4k or 2k crop.

And I agree with obin. Say a 1k super high speed crop! Not sure what lens would be suitable though.
 
ZaneIsNumber1 said:
I see what you mean, but odds are that the in camera, real time scaling will not be as good as what can be done in post with good software. Fact is that, with 4k rez, you zoom, crop, chop, etc in post, and it will hold up. So the option is there, but there would be issues of practicality to impliment this in camera. There would be the sudden need for a digital zoom control, etc.
Click to expand...

Okay. I don't think I am getting the idea across fully. Mikkowilson hit the nail on the head by saying that the principle is more like a variable digital extender. I think the expression digital zoom is possibly misleading, it implies zooming in shot. While that might be possible it raises all sorts of other issues so I will avoid going there for the point of this argument.

Here is a scenario. You are shooting 35mm Redcode RAW with the intention of recording to 1080p. The longest lens you have is 300mm but you could really do with a 400mm lens for this shot. So you go to the menu and select digital extender and press up. In your viewfinder the picture would gradually get larger along with feedback telling you how many pixels width of the sensor is being represented and what magnification factor you are seeing. When the readout says x1.33 or 133% you would have the equivalent image size that a 400mm lens would give you. You can frame and shoot just as if you were using a longer lens.

On disk the image is NOT necessarily recorded cropped. On disk the full 4K sensor information can still be recorded, but in addition some metadata is included that says this shot should be windowed as specified. The result is that when the footage is put through Redcine the windowing will happen by default unless a decision is made to change it. Effectively the scaling is happening in post but all the framing decisions are being made by the camera operator. Alternatively the shot is recorded with the windowing as specified, again the scaling would happen in Redcine, but this time some advantage could be gained by storing less data.

If instead of Redcode RAW, you decide to record RGB the scaling would then be done in camera. I don't think this would be an issue as this must already happen to get from 4K to 1080p, so there must already be the tools to do high quality interpolation.

I can see all sorts of possibilities with this approach, It would allow you to fake longer focal length shots when you don't have a long enough lens but also all your primes would effectively become variable primes so you could make do with fewer lenses without any significant quality hit (as long as your intention was shooting with the full sensor and outputting at 2K or 1080p). The important thing to remember is that there are pixels to spare so this approach is not like using digital zoom on a camcorder. It could give you considerably better results than using an optical extender. Any enlargement of optical abberations would be swamped by the eventual scaling down to 2k or 1080p, so that shouldn't be an issue.

While all of this could happen in post it would not be the same experience. With the best will in the world you couldn't make the decision to use a 24mm lens and frame it as if it was a 26mm with the intention of cropping it in post. But with a digital extender you could, You would shoot exactly what you see so you could frame accurately safe in the knowledge that your intentions would be interpretted correctly.

Martin
 
I get you now, I was thrown by term 'zoom'. It would be a handy way to exploit the camera's resolution and I would certainly argue for more crop choices than 2x.
 
Thanks Steve. It will be interesting to see how many more reservations get taken in the next 15 hours, bound to be a sprint for the finish.

Martin
 
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