Scarlet X Data Sheet

[Thomas Kruesselmann]

Thanks so much for this. Incredibly helpful.

 

[J Davis]

I consider that the quoted statement above is not correct. (might be a bed choice of words you used)
I actually believe (until proven differently that FF 50mm f1.2 prime and APS-C lens 17-55/2.8 when set to 50mm give a different FOV. At first this might be confusing. But...

hey man ... its been discussed to death on here and dvxuser and the same discussion always turns up whenever there is a thread that has the phrase crop factors in it. There are minor, very minor inconsistencies with field of view because of the physical nature of constructing lenses but these inconsistencies don't detract from the fact that a 50mm is a 50mm is a 50mm no matter whether is a full frame prime, an aps-c zoom or even a micro four thirds 50mm. The only difference is the size of the image circle and therefore the size of sensors that they can cover. Its the sensor size that changes the field of view - not the focal length.

 

[SeanBrown]

Best thread ever!

 

[Leonard Caspari]

How about a 2,5K Super 16mm mode?
I think this would cater the indie market quite nicely. Lower data rates and such and a Super 16mm look (which some people might actually prefer).

While we're at the topic. Is it physically actually possible to mount a Super 16mm lens to the Scarlet X? Or will it result in backfocus issues?
My expertise in that area is limited at best.

 

[Phil Holland]

David Rasberry has pointed out that the 2k crop factor was a bit off. I have since corrected that. Thanks David!

Its the sensor size that changes the field of view - not the focal length.

Correct. The lens properties don't change in any way, but the field of view or cone of vision available to the shooter has been reduced because of the smaller the sensor size on a given focal length. It's literally cropped off, hence crop factor.

 

[Marko Hocevar]

Its the sensor size that changes the field of view - not the focal length.

David Rasberry has pointed out that the 2k crop factor was a bit off. I have since corrected that. Thanks David!
Correct. The lens properties don't change in any way, but the field of view or cone of vision available to the shooter has been reduced because of the smaller the sensor size on a given focal length. It's literally cropped off, hence crop factor.

Above is not correct (at best not complete) by any strech of meaning.
FOV is according to mathematical and physical laws dependent on BOTH the sensor size and focal length used during recording. (I'm not talking about only one lens but multiple lenses)
Of course this difference in our expressing of FOV could be semantics due to different starting points in the thought process.

For example I consider this as a correct way of expressing the FOV laws:
1. I have only one prime lens of i.e. 50mm and I could record on Scarlet in different windowed/cropped modes.
2. Only the (active) size of the sensor is changing the field of view, not the focal lenth

Stating only sentence 2. without the 1. is not correct because someone reading it could be led to believe that whatever focal length he uses (20mm or 80mm) he would always get the same FOV as long he always shoots at i.e. 4K.

If we forget about the sensors I still believe that APS-C 50mm lens (diagonal FOV 30°) has a considerably different FOV than FF35mm 50mm lens (diagonal FOV 47°) (i.e. if we project them on the piece of paper.)
Of course if you use a sensor that is smaller than the projected image of APS-C lens, then the recording from APS-C sensor will show the same FOV for the FF35mm and APS-C 50mm lens.
The other way around, if you use a sensor (FF35mm) bigger than the projected image of APS-C lens, then the recording from FF35mm sensor will show wider FOV for the FF35mm than for APS-C 50mm lens. (difference will be due to vignetting)

Phil, sorry to sort of derail your effort. I'm actually just "learning in-depth" the FOV facts and would like someone to confirm or dismiss (with valid arguments) my thoughts on this.
Anyway thanks for your efforts - you prompted me to demystify (to myself) the crop/FOV theme.

 

[Phil Holland]

Okay. Time to simplify all of this. I'll be adding the following graphic below to the head of this thread as I want to clarify any confusion going on regarding crop factors and their effect on FOV with the same lens.

This graphic shows different sensor sizes/Red Scarlet X Recording Formats with an aspect ratio of 1.9:1 captured with a 50mm lens. I've calculated the approximate field of view of a 50mm lens on a FF35 sensor cropped to 1.9:1 (Red's sensor standard for Scarlet X), which is 44.3 and not 47 due to the 3:2 aspect ratio. I've added the calculated FOV and the "equivalent" lens that you'd use on a full frame (8-perf) to emulate that frame if shot from the same distance.

It should be noted that all of this is approximate based on a single lens measurement and single focal length. Manufacturers often drift a bit in terms of what the actual focal length of a lens is. There are several 40mm lenses out there that are closer to 41mm and 43mm.

Hope that helps.

****Edit I should also add that the Data Sheet has been updated to reflect the crop factor 3.24x for 2K. Make sure you refresh or download the new one.

 

[Carter Cammack]

I'd like to nominate Phil for a raise. Any second?

 

[PatrickW]

That is awesome Phil. I "get it" now.

 

[Mark Pavy]

Hi Phil, I thought I had it until you added this on the 1st page referring to the Gas Mask man with the orange flower.

"For instance if you wanted to shoot this same frame 4k at 80mm and then capture some slow motion 2k from the same spot you'd use an 162mm lens, which would likely only exist in a zoom."

Maybe I read it wrong.

 

[Jason DeSimone]

Thanks so much for this!

 

[Phil Holland]

Hi Phil, I thought I had it until you added this on the 1st page referring to the Gas Mask man with the orange flower.

"For instance if you wanted to shoot this same frame 4k at 80mm and then capture some slow motion 2k from the same spot you'd use an 162mm lens, which would likely only exist in a zoom."

Maybe I read it wrong.

Doh. Here I go and try to simplify and I bust out a mistake. It should read:

For instance if you wanted to shoot some slow motion at 2k with a 50mm lens and then capture some 24fps at 4k with the same frame you would use a 162mm lens, which would likely only exist in a zoom.

 

[Mark Pavy]

Phew, I thought I had it all arse about face there for a minute lol

 

[Michael Dalton]

Awsome phil thanks!!!

Any chance you can do a chart for crop sensor lens APS-C shooting in 3k or 2k. Would love to know the chart so if I need to scale down for higher frame rates, I can know the comparative lens in 4k.

This will be great for maintaining a wider frame at the lower resolutions.

 

[Bob Pierce]

So, if you wanted to shoot 3K with your Scarlet, the Tokina 11-16 would give you the equivalent to a 22mm wide (in FF35 terms). Not too bad, really.

 

[J Davis]

Awsome phil thanks!!!

Any chance you can do a chart for crop sensor lens APS-C shooting in 3k or 2k. Would love to know the chart so if I need to scale down for higher frame rates, I can know the comparative lens in 4k.

This will be great for maintaining a wider frame at the lower resolutions.

bingo !!!!!! finally someone gets it and is not relating everything back to the full frame stills world

For referencing field of view (fov) back to 4k I use 4k, 3k, 2k and 1k as my multipliers and dividers
4 is double 2 so 50mm on 4k is the same fov as 25mm on 2k
Similarly 1/4 of 50mm is 12.5 so 50mm on 4k is the same fov as 12.5mm on 1k
And then 37.5mm at 3k etc.. etc ..

 

[Phil Holland]

Awsome phil thanks!!!

Any chance you can do a chart for crop sensor lens APS-C shooting in 3k or 2k. Would love to know the chart so if I need to scale down for higher frame rates, I can know the comparative lens in 4k.

This will be great for maintaining a wider frame at the lower resolutions.

There's a chance that I'd do that. If I did I'd probably include more standard cinema focal lengths and the widest you could go on the rectilinear side currently.

Here you go:

bingo !!!!!! finally someone gets it and is not relating everything back to the full frame stills world

I think the global thing to keep in mind that this is relative to a what your "full frame" capture is per camera. For instance, those shooting full frame on an EPIC they would base the 1.0x multiplier on the APS-H sized sensor. For Scarlet X we would want one based on APS-C, which is useful and why I created the above image. Down the line, when the larger RED sensors get deployed we'll have to do this again. When Red releases their FF35 (VistaVision) sized sensor the Data Sheet will still be valid and preferred by those who have that as a base focal length multiplier.

 

[Jarred Land]

Phil.. you are a legend. This is incredible. You have earned yourself a favor. use it wisely

Man I love stuff like this.

Thanks.

 

[Ketch Rossi]

Nice work in deed Phil...

Not that I ever used and or really care for it, but Boy do I get asked a lot every were... Now I just show it to them ha ha... THANKS!!

 

[J Davis]

I think the global thing to keep in mind that this is relative to a what your "full frame" capture is per camera. For instance, those shooting full frame on an EPIC they would base the 1.0x multiplier on the APS-H sized sensor. For Scarlet X we would want one based on APS-C, which is useful and why I created the above image. Down the line, when the larger RED sensors get deployed we'll have to do this again. When Red releases their FF35 (VistaVision) sized sensor the Data Sheet will still be valid and preferred by those who have that as a base focal length multiplier.

I totally agree, which was my point, the original chart's crop factors only held relevance to those shooting video on a 5D, which is not the norm. I think your new chart will clear up a lot of confusion and help many people.
edit:
so long as anyone doesn't misread it as equivalent fov's, because ... it reads backwards ?
because 4k at 50mm is equivalent fov to 2k at 25mm (your chart says 4k 25mm, 2k 50mm)