Raven Crop factor?

[Ron Michaels]

Doing my searches, I seem to be getting mixed responses as to what exactly the crop factor is for the raven at 4.5k? Rental company says 1.87 which I'm sure is referring to 4k, red calculator says 1.66, some forums say it's 1.76... Anyone have a definitive answer? FF35

Thanks agin,
Ron

 

[Phil Holland]

What format is your "hero" format to crop from? S35? FF35? etc...

This can help either way:

http://phfx.com/tools/formatCompare/

 

[Ron Michaels]

Lol FF35, thanks.

 

[Aaron Lochert]

Doing my searches, I seem to be getting mixed responses as to what exactly the crop factor is for the raven at 4.5k? Rental company says 1.87 which I'm sure is referring to 4k, red calculator says 1.66, some forums say it's 1.76... Anyone have a definitive answer? FF35

Thanks agin,
Ron

When talking crop factor, there's several variables at play. It all comes from how you define crop factor and how you define your "hero" format as Phil says.

Full frame 35 format is 36mm x 24mm (diagonal: 43.27mm), but that's a 3:2 format for stills, it doesn't quite equate to shooting video. If you're shooting video on a DSLR, that means shooting 16:9, so then you're looking at 36mm x 20.25mm (diagonal: 41.3mm). So this first variable is deciding which of these two formats to compare to.

Raven's full sensor is 23.04mm x 10.8mm (diagonal: 25.5mm), which is a 4.5K 2.1:1 aspect ratio format. This full sensor readout is called "4.5K FF" but it is not the same as another Dragon camera in 4.5K FF. Any other Dragon camera at 4.5K FF is reading a 23.04mm x 12.06mm (diagonal 26.01mm) area off the sensor. The Raven sensor isn't as tall, which affects the vertical dimension as well as the diagonal. So this is yet another variable.

And the third variable is defining crop factor: horizontal, vertical, or diagonal. So you've gotta watch out with these online calculators. Neither Red's nor Phil's calculators have a Raven-specific calculation. The happy accident with Phil's is that he calculates a horizontal crop factor, which is the same dimension for both Raven and other Dragon cameras at 4.5K FF.

For Raven 4.5K FF:

Horizontal crop factor FF35 (both 3:2 and 16:9) to Raven 4.5K FF: 36/23.04 = 1.56

Vertical crop factor FF35 (3:2) to Raven 4.5K FF: 24/10.8 = 2.22

Vertical crop factor FF35 (16:9) to Raven 4.5K FF: 20.25/10.8 = 1.88

Diagonal crop factor FF35 (3:2) to Raven 4.5K FF: 43.27/25.5 = 1.70

Diagonal crop factor FF35 (16:9) to Raven 4.5K FF: 41.3/25.5= 1.62

For other Dragon cameras @ 4.5K FF:

Horizontal crop factor FF35 (both 3:2 and 16:9) to Dragon 4.5K FF: 36/23.04 = 1.56

Vertical crop factor FF35 (3:2) to Dragon 4.5K FF: 24/12.06 = 1.99

Vertical crop factor FF35 (16:9) to Dragon 4.5K FF: 20.25/12.06 = 1.68

Diagonal crop factor FF35 (3:2) to Dragon 4.5K FF: 43.27/26.01 = 1.66 <--- this is what the Red.com calculator is doing, which is incorrect for Raven.

Diagonal crop factor FF35 (16:9) to Dragon 4.5K FF: 41.3/26.01= 1.59

So there you have it. It's easy to calculate on your own (one dimension on format 1 divided by the same dimension on format 2), just gotta make sure all your inputted dimensions are correct.

Definitive enough?

 

[Björn Benckert]

speak Height/Width mm is the only thing making sense. As both sensor sizes and aspect ratio vari and the FF35 / vista vision frame size is something that has an aspect ratio we most likly will not see on sensors and also something that will in a couple of years be considered a small sensor. So why not just talk about sensor size in terms of size and not in relation to something else. Nobody called 70mm cropfactor minus 2...