Clear formulae to calculate FOV

How to calculate FOV

I need formulae to know following 4 elements.

1. What's standard? and on what standard is it calculated.
2. FOV in MFT BMCC with NikonF to MFT adapter?
3. FOV in MFT BMCC with canon ef to MFT adapter?
4. FOV in MFT BMCC with metabones speedbooster?

How to calculate FOV

I need formulae to know following 4 elements.

1. What's standard? and on what standard is it calculated.
2. FOV in MFT BMCC with NikonF to MFT adapter?
3. FOV in MFT BMCC with canon ef to MFT adapter?
4. FOV in MFT BMCC with metabones speedbooster?

1. Sorry, Luc, but this request might be better if you told us what you want to use as a standard lens on what camera. Then the rest is easy to provide. People who come from the stills world use 50mm generally as their standard lens on a full-frame 135 film camera with a 36mm wide image like the digital sensor in the Canon 5D. People from the cinema world of yesterday use the Academy 35mm standard for film which is very close to the sensor size of the BMPC4K. More recently, Super 35mm film has become a cinema standard including for these digital times. What is your choice of standard?

2 & 3 are identical.
4. Adjust 2 & 3 by 0.71

Rick Lang
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Sry Ric, new to things. I'm not from stills world. I'm now directly entering into motion world.

Well let me take latest standard for digital cinema Super 35 film.

Lens for reference be : 50mm, 35mm and 85mm. (Thinking of Rokinon Cine lens)


1. Explanation and Formula for FOV in BMCC MFT camera with NikonF to MFT adapter?

2. Explanation and Formula for FOV in BMCC MFT camera with metabones speedbooster?

Luc, all of my FOV questions get answered with two links:

http://www.abelcine.com/fov/
http://bmpcc.rubenkremer.nl

Sry Ric, new to things. I'm not from stills world. I'm now directly entering into motion world.

Well let me take latest standard for digital cinema Super 35 film.

Lens for reference be : 50mm, 35mm and 85mm. (Thinking of Rokinon Cine lens)


1. Explanation and Formula for FOV in BMCC MFT camera with NikonF to MFT adapter?

2. Explanation and Formula for FOV in BMCC MFT camera with metabones speedbooster?

35mm
35mm lens on a S35 sensor has a horizontal angle of view of 39.2 degrees and a frame height of 4' with a subject at a distance of 10'

35mm lens on a BMCC MFT sensor has a horizontal angle of view of 25.5 degrees and a frame height of 2.5' with a subject at a distance of 10'

35mm lens on a BMCC MFT sensor with Metabones Speed Booster has a horizontal angle of view of about 35.1 degrees and a frame height of 3.6' with a subject at a distance of 10'


50mm
50mm lens on a S35 sensor has a horizontal angle of view of 28 degrees and a frame height of 2.8' with a subject at a distance of 10'

50mm lens on a BMCC MFT sensor has a horizontal angle of view of 18 degrees and a frame height of 1.8' with a subject at a distance of 10'

50mm lens on a BMCC MFT sensor with Metabones Speed Booster has a horizontal angle of view of about 25.1 degrees and a frame height of about 2.5' with a subject at a distance of 10'

85 mm
85mm lens on a S35 sensor has a horizontal angle of view of 16.7 degrees and a frame height of 1.6' with a subject at a distance of 10'

85mm lens on a BMCC MFT sensor has a horizontal angle of view of 10.6 degrees and a frame height of about 1.0' with a subject at a distance of 10'

85mm lens on a BMCC MFT sensor with Metabones Speed Booster has a horizontal angle of view of about 15 degrees and a frame height of 1.5' with a subject at a distance of 10'

You can see the effect of the Metabones Speed Boost is that the apparent focal length is reduced almost as if you were on a S35 sensor. Actually it is virtually identical to a Canon APS-C sensor which is a little smaller than S35. Where this is interesting is that the BMPC4K sensor is actually smaller than S35 and APS-C so you actually end up with a wider frame using the MSB on the BMCC MFT! And you gain a full stop of aperture.

If you are confused by my statement that the BMPC4K has a smaller sensor than S35, I forgive you. The BMPC4K sensor is nearly identical in width to the Academy 35mm film size which was a precursor of S35. You can hear Grant Petty referring to it as a 35mm size sensor at NAB 2013 and that's what he means, Academy 35, not Super 35mm film. BMD Marketing has it wrong and I've pointed it out several times but Marketing continues to use the S35 term because it sounds better. In defense of this behaviour, other companies have done the same thing too so always wise to look at the actual active sensor size and not promotional copy.


Rick Lang
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35mm
35mm lens on a S35 sensor has a horizontal angle of view of 39.2 degrees and a frame height of 4' with a subject at a distance of 10'

35mm lens on a BMCC MFT sensor has a horizontal angle of view of 25.5 degrees and a frame height of 2.5' with a subject at a distance of 10'

35mm lens on a BMCC MFT sensor with Metabones Speed Booster has a horizontal angle of view of about 35.1 degrees and a frame height of 3.6' with a subject at a distance of 10'

Thanks a lott rick for the detailed post...

Well, one more Q.

What is a Constant number I should multiply with 35mm lens on a S35 sensor to know following

1. What mm lens it would become on bmcc mft with nikon adapter?
2. What mm lens it would become on bmcc mft with metabones speed booster?
3. What mm lens it would become on other standard sensors?

35mm
35mm lens on a S35 sensor has a horizontal angle of view of 39.2 degrees and a frame height of 4' with a subject at a distance of 10'

35mm lens on a BMCC MFT sensor has a horizontal angle of view of 25.5 degrees and a frame height of 2.5' with a subject at a distance of 10'

35mm lens on a BMCC MFT sensor with Metabones Speed Booster has a horizontal angle of view of about 35.1 degrees and a frame height of 3.6' with a subject at a distance of 10'

Thanks a lott rick for the detailed post...

Well, one more Q.

What is a Constant number I should multiply with 35mm lens on a S35 sensor to know following

1. What mm lens it would become on bmcc mft with nikon adapter?
2. What mm lens it would become on bmcc mft with metabones speed booster?
3. What mm lens it would become on other standard sensors?

If you mount a 35mm lens normally on a S35 sensor or film camera, you would likely refer to that as a 'normal' lens in that it sees things roughly the way our eye sees. But I've heard some people consider a slightly longer lens as their normal lens so each person may have their own references.

The 35mm lens on a typical S35 sensor has a horizontal angle of view of 39.2 degrees and at a distance of 10', the vertical frame will be 4' if the sensor has a 16:9 aspect ratio like the BMD cameras and others. Call that your standard measure with a crop of 1x.

1. That 35mm lens mounted on the BMCC MFT would be almost a 1.6x crop (1.57x) and it would have an angle of view of about 25 degrees and a vertical frame of 2.5' as if it was a 55mm lens on the S35 camera.

2. That 35mm lens on the BMCC MFT with Metabones Speed Booster would be almost a 1.12x crop and have its apparent focal length reduced to almost that of a 25mm lens with a 35 degree angle of view, a frame height of 3.6' at a distance of 10' and look wider than a 40mm lens on that S35 camera.

3a. That 35mm lens on the BMPC4K would be approximately a 1.17x crop compared to S35 (people will usually say 1.2x and that is close enough) and it would have an angle of view of almost 34 degrees and a vertical frame of 3.4' as if it was a little longer than a 40mm lens on S35.

3b. That 35mm on a true micro four thirds sensor has a crop of 1.4 compared to S35 and would be close to the mid-point between the values in 1 and 3a so roughly an angle of view of 30 degrees, a frame height of about 3' and look wider than a 50mm lens S35.


Rick Lang
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Thanks a lot Rick...