# Real/virtual camera matching

#### hdace

##### Melancholy&MysteryStreet
I hope someone can shed some light. Recently shot a live action film with lots of blue screen to composite backgrounds. We used a RED Gemini. Its sensor is 30.7 x 16.2 mm (well 18, but we didn't use all of the top & bottom - 5120 x 3000 for full sensor, but we were filming in 5120 x 2700). We had a Zeiss 35mm canon mount prime lens for most shots, usually around F-stop 2.2.

I assumed there would be an obvious formula banging around the internet somewhere that would tell me how to convert all this data into a Frame setting on the Camera Properties window. Or tell me what the FOV should be. I'm finding it all too confusing. I've eye-balled it and it looks to me like the Frame should be 0.8 inches and the FOV should be 57.71º x 32.42º. But I can never get it to match quite right.

Is there some way of working this out mathematically?

Thanks! --Hal

#### Thomas Leitner

##### Member
I hope someone can shed some light. Recently shot a live action film with lots of blue screen to composite backgrounds. We used a RED Gemini. Its sensor is 30.7 x 16.2 mm (well 18, but we didn't use all of the top & bottom - 5120 x 3000 for full sensor, but we were filming in 5120 x 2700). We had a Zeiss 35mm canon mount prime lens for most shots, usually around F-stop 2.2.

I assumed there would be an obvious formula banging around the internet somewhere that would tell me how to convert all this data into a Frame setting on the Camera Properties window. Or tell me what the FOV should be. I'm finding it all too confusing. I've eye-balled it and it looks to me like the Frame should be 0.8 inches and the FOV should be 57.71º x 32.42º. But I can never get it to match quite right.

Is there some way of working this out mathematically?

Thanks! --Hal

No formula needed: "Frame" in Camera Properties means the hight of the sensor (16,2mm or 0,6378 inches). After setting the frame hight set your focal lengh to 35mm (this should give you a FOV of 47,39° x 26,06°).

ciao
Thomas

#### hdace

##### Melancholy&MysteryStreet
Thanks!

Nowhere in the LW guide or anywhere on the internet does it say those simple words: "Frame" means hight of sensor. Wouldn't life be easier if simple facts were stated now and then?