Still confused about lens cropping factors . . .

[tj williams]

Rob Stuart n all:

1. I thought it was possible to use the whole sensor with 35mm lenses to capture 2K raw?

2. If using the Nikon lenses intended for the digital cameras the target is smaller than for standard 35mm lenses, will this vignette in 35mm acquisition?

[Evin Grant]

35mm still format is 36x24mm, APS-C or Nikon DX is 23.7x15.5mm Red is 24.4x13.7mm in 2540P, 22.2x12.6 in 4k RAW, and 11.1x6.3mm in 2k RAW.
Here's a table that might help.

36x24mm = 35mm Still (Nikon F6, Canon 1DsMII, 5D)
23.7x15.5mm = APS-C, Nikon DX (Nikon D2x, Canon 30D)
24.4x13.7mm = Red full sensor 2540P Uncompressed out only.
22.2x12.6mm = Red 4k RAW windowed Redcode 4K RAW, 1080 & 720 RGB.
11.1x6.3mm = Red 2k RAW Windowed, 1080 & 720 RGB.

[tj williams]

Thanks Evin that was quick. So I'm OK unless for some really odd reason I decide I must use my digital Nikon lenses to output2540P uncompressed to a big raid!!!

You know I did't really think this through before but this means that the field of view on a 25mm prime will not be exactly like what I would see in academy aperature? since academy is 22mm by 16mm RED will record slightly less height and a couple of more mm of width? Now will we be able to scale what we capture. So that for instance in recording for 185/1 movie dist. I can scale to the projector size of 21 by 11 mm? or other sizes? for instance 235... which?

Is there an explanation of what overscan we will see around the picture going to disk on the 720 monitor/lcd I can't seem to find that info. Just that there is some? So will we adjust among several frame lines. What are they?


1. I thought it was possible to use the whole sensor with 35mm lenses to capture 2K raw CAN I????

[Steven Parker]

tj - 1. I thought it was possible to use the whole sensor with 35mm lenses to capture 2K raw CAN I????

I thought so too, but it seems no:

http://red.com/formatoptions.htm

Only S16 size image area is listed for 2K accquisition

So I think for me it's accquire at 4K RAW and scale in Redcine to 2K/1080/etc

Well, 4K RedCode RAW, not uncompressed...

It's been coming for a while, but now we shooters really will be involved in post!

[Evin Grant]

You can always use a smaller windoow from a 35mm optic.

[Ralph Oshiro]

. . . I thought it was possible to use the whole sensor with 35mm lenses to capture 2K raw . . . I think for me it's accquire at 4K RAW and scale in Redcine to 2K/1080/etc.

I had the same questions, and I THINK I finally have it figured out . . . well, I'm going to commit a minor crime here and cross-post this from another thread I had already posted it in. This is actually more an attempt to clarify my previous questions/assumptions mentioned in this thread. I don't know if anyone had error-checked my conclusions, but this is what I FINALLY figured out, with help from the other members here. This is the only post where I was able to define for myself, the acquisition resolution vis-a-vis, their respective cropping factors vis-a-vis, their respective maximum frame rates vis-a-vis, their respective acquisition bitstreams (RAW vs. RGB), all within the constraints of being able to record using the on-board RED-DRIVE . . .

My personal acquisition recipe [revised]:

A. STANDARD 24fps PHOTOGRAPHY:

1. Acquire 4K REDCODE RAW at 24fps, using the full 4K sensor area, using Nikkor 35mm still lenses [which effect a x1.62 cropping factor], taking full advantage of 35mm cine-sized, depth-of-field characteristics, and record to the on-board RED-DRIVE. Rescale the 4K REDCODE RAW image in REDCINE down to 1080p, and crop to desired aspect ratio [e.g. 2.35:1].

B. HIGH-SPEED 60-120fps PHOTOGRAPHY:

OPTION 1: Acquire 4K REDCODE RGB, at up to 60fps, using the full 4K sensor area, using Nikkor 35mm still lenses [which effect a x1.62 cropping factor], using the in-camera scaling to achieve a 1080p image (while still taking full advantage of 35mm cine-sized, depth-of-field characterisitics, but limiting your post-processing options), and record to the on-board RED-DRIVE.

OPTION 2: Acquire 2K REDCODE RAW, using the windowed 2K sensor area, at up to 60fps, using Nikkor 35mm still lenses [which now effects a x3.24 cropping factor in 2K], using the in-camera scaling to achieve a 1080p image (sacrificing your 35mm cine-sized depth-of-field characteristics, but still retaining all the benefits of RAW acquisition for later post-processing in REDCINE), and record to the on-board RED-DRIVE.

OPTION 3: Acquire 2K REDCODE RGB, using the windowed 2K sensor area, at up to 120fps, using Nikkor 35mm still lenses [which again, now effects a x3.24 cropping factor in 2K], using the in-camera scaling to achieve a 720p image (sacrificing your 35mm cine-sized depth-of-field characteristics, and limiting your post-processing options), and record to the on-board RED-DRIVE. Rescale back up to 1080p in REDCINE.

If anyone can spot any errors here, please post your reply here! Thanks!

[Evin Grant]

B. HIGH-SPEED 60-120fps PHOTOGRAPHY:
OPTION 1: Acquire 4K REDCODE RGB, at up to 60fps, using Nikkor 35mm still lenses [which effect a x1.62 cropping factor], using the in-camera scaling to achieve a 2K image (while still taking full advantage of 35mm cine-sized, depth-of-field characterisitics, but limiting your post-processing options), and record to the on-board RED-DRIVE.

There is no data to support this posibility. I believe the 60 fps at 2K onboard is dependant on the 2k S16 windowing. You will need to use the uncompressed out to record anything faster than 30 fps using the whole 35mm sized sensor. At least as far as I can tell.

[Steven Parker]

You can always use a smaller windoow from a 35mm optic.

Evin, sorry if I haven't quite got it yet, but can you explain how to use a smaller window if the lens is covering the full active area of the sensor?

Sounds like in-camera resizing...

[Ralph Oshiro]

There is no data to support this posibility. I believe the 60 fps at 2K onboard is dependant on the 2k S16 windowing. You will need to use the uncompressed out to record anything faster than 30 fps using the whole 35mm sized sensor. At least as far as I can tell.

Oh. Thanks, Evin. Yeah, I don't know if any of this is correct. I took this information from a post by another member. I hope he doesn't mind me cross-posting it here:

Ralph, if your end result is to be 1080p, you CAN shoot the Academy 35 sensor area, preserving 35mm DoF, at 60fps and record on-board at 1080p60 REDCODE RGB. You don't need to window the sensor for 60fps. If you window the sensor, you can record 120fps on-board, but only at 720p REDCODE RGB. You would need to up-scale this in post to cut into a 1080p programme, but I think I would look ok.

[Evin Grant]

Evin, sorry if I haven't quite got it yet, but can you explain how to use a smaller window if the lens is covering the full active area of the sensor?

Sounds like in-camera resizing...

It's windowing, in other words just using the part of the sensor you need. Like the high speed crop mode on the Nikon D2x. CMOS sensors can address their photosites individualy so you can use the center portion only so the data can be read twice as often, hence the 120 fps capability in 2K.