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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Field of view factor for 4K to 3K, 2K?

Just trying to wrap my head around this, couldn't you compensate for the FOV by moving back a few feet? The lens characteristic doesn't change, a 50 is a 50, but by moving back to match what a 50mm FOV would look like on 35mm wouldn't you be getting the same result on a Red One?
 
Isaac Brody said:
By moving back to match what a 50mm FOV would look like on 35mm wouldn't you be getting the same result?
Click to expand...

No. Even if it is possible to move the camera to compensate (and it isn't always even possible), the perspective and background are different. It's only when such compositional elements are not important for the shot that it does not matter.
 
Isaac Brody said:
Just trying to wrap my head around this, couldn't you compensate for the FOV by moving back a few feet? The lens characteristic doesn't change, a 50 is a 50, but by moving back to match what a 50mm FOV would look like on 35mm wouldn't you be getting the same result on a Red One?
Click to expand...

If you are talking about shooting in 4K mode on the RED ONE and backing up on a 50mm lens to match the FOV of a 35mm lens on the RED ONE in the same 4K mode, then yes, you could match the view but not the optical perspective created by the shorter focal length.

Same goes for the situation where you have a 35mm lens on the camera in 4K mode and you switch to 2K windowed mode, cutting the FOV in half -- backing up may restore the view, but the lens perspective will be different compared to not backing up and switching to a 17.5mm lens instead in 2K mode.

Which is basically what Daniel said...

Now if you're talking about something more minor, like the FOV of a 50mm lens on a Super-35 camera versus the RED ONE in 4K mode, which is more like 35mm Academy in width, yes, probably you could just compensate by moving the camera a little.
 
- and, you may not want to shoot a close up with a 25mm lens on a RED at 4k, but do it with a 40 or 50, because people are less attractive when shot up close with wide angle lenses. And I think most DPs will tell you they generally stick to a specific focal length for most of a picture to maintain that specific perspective that has been mentioned. They are more likely to move the camera than swap lenses or zoom.
 
Does anyone know if the 3K sensor surface area on the RED One equates to the same surface area on the new 2/3 interchangeable scarlet?
ie Scarlet 2/3 has a pixel size of 5.4 microns?

If this is the case, then (please check my maths) using the 2.33 multiplier for 3K that Jason mentioned in post two, a 2/3 interchangeable scarlet with PL mount and 23mm 35mm still lens would be the same FOV as 50mm on an R1 shooting 4K?
 
Daniel Browning said:
No, 3.04 microns.
Click to expand...

So 3.04 / 5.4 = 0.563 ratio difference

original 2.33 multiplier / 0.563 ratio difference = 4.1385 multiplier

50mm / 4.1385 = 12.1
50 mm FOV = roughly 12mm FOV?

EDIT:
doesn't matter. with that much a difference between the each of two 3K surface areas it almost
negates any practical use of 35mm nikons on a 2/3 scarlet to get a regular FOV. (fisheye ~= 50mm)
 
J Davis said:
So 3.04 / 5.4 = 0.563 ratio difference

original 2.33 multiplier / 0.563 ratio difference = 4.1385 multiplier

50mm / 4.1385 = 12.1
50 mm FOV = roughly 12mm FOV?
Click to expand...

All that matters for field of view is sensor size; pixel size and resolution are not a factor. For example, all of the following have the exact same 40-degree horizontal angle of view:

  • 50.0mm on Epic FF35: no lookaround, sensor is 36mm wide, 6K.
  • 41.7mm on Scarlet S35: no lookaround, 30mm (wider than Super-35), 5K.
  • 37.5mm on Scarlet S35: a possible tweener format, 27mm wide, 4.5K.
  • 33.9mm on Scarlet S35: matching RED ONE, 24.4mm wide, 4K.
  • 33.9mm on RED ONE: no lookaround, 24.4mm wide, 4.5K
  • 30.9mm on RED ONE: with lookaround, 22.2mm wide, 4K
  • 23.1mm on RED ONE: 3K mode, 16.65mm wide, 3K
  • 15.4mm on RED ONE: 2K mode, 11.1mm wide, 2K
  • 14.0mm on Scarlet 2/3": no lookaround, 10.1mm wide, 3K
  • 12.5mm on Scarlet 2/3": some lookaround, 9.0mm wide, 2.7K

The lookaround and recordable area may be different when the new cameras are released, but the above is my best guess.

For another example, the following have the exact same horizontal field of view, depth of field, diffraction, total amount of light falling on the sensor, and the same open iris diameter:

  • 6.5mm f/1.8 on Scarlet 2/3" 10.1mm width
  • 14.5mm f/4.0 on RED ONE (recordable area only)
  • 15.5mm f/4.3 on RED ONE (including lookaround)
  • 16.0mm f/4.4 on EPIC S35 (using only 24.89mm, like Super 35 film)
  • 19.3mm f/5.3 on EPIC S35 (full 30mm width)
  • 22.8mm f/6.3 on EPIC FF35
  • 36.0mm f/10 on EPIC 645
  • 108mm f/30 on EPIC 617

J Davis said:
Doesn't matter. With that much a difference between the each of two 3K surface areas it almost
negates any practical use of 35mm nikons on a 2/3 scarlet to get a regular FOV.
Click to expand...

Yes. Super wide angle S35 lenses (e.g. 14mm) become normals on Scarlet 2/3", and super wide angle FF35 lenses (e.g. 24mm) become telephoto on Scarlet 2/3".

FWIW, the crop factor between RED ONE 3K and Scarlet 2/3" is about 1.65X, which is similar to the crop factor between FF35 and RED ONE 4K.

Hope that helps.
 
Yes, thank you Daniel, immense help.
I thought of another thing – the resolving power of the lens, seeing that it is such a small portion of the image circle that is used, would also be reduced would it not ?
(thereby making a lot of the pixels on the 2/3 sensor redundant)
 
J Davis said:
I thought of another thing – the resolving power of the lens, seeing that it is such a small portion of the image circle that is used, would also be reduced would it not ?
Click to expand...

The short version is: yes.

The long version is a little more complex. Some FF35 lenses (especially super tele and macro) will certainly have enough resolution for 3 micron pixels, but the MTF (contrast) will probably be lower than a lens specifically made for 2/3".

For an example you can look at the EF lenses people are using on the XL-H1, which has approximately 3 micron pixels as well (IIRC), but a much smaller sensor. Another way to look at is to think about how many teleconverters can be put on the lens before it yields no improvement in detail.
 
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