Scarlet Cinema DOF?

[David Rasberry]

To end the questions about DOF why not take the 7D and shoot something to show it?

Before I can I need to ask about something that I'm too tired to wrap my head around just now.
The 7D is 1.6 crop of a 5D FF sensor. Now, the canon lenses equals the number on the FF sensors and 18mm on a FF sensor is 18mm.
On the 7D with a 1.6x sensor it equals to 28mm. This is the number that is the widest on the Scarlet fixed.
Now, what does 28mm T2.4 on a 2/3 sensor equals to on a canon 7D? Is it correct to shoot 18mm (FF sensor) at 5.0? Will that give the correct image; 28mm 2/3 sensor at T2.4?
If I'm to test how the image will look (in terms of DOF and focal length) how should I set up my 7D?

The difference in apparent DOF corrected for FOV is about 2 to 2-1/2 f stops. You would shoot the 7D at about 1/2 way between f4-f5.6 to simulate Scarlet at f2.4 maximum aperture for the same field of view.

 

[David Mullen ASC]

To end the questions about DOF why not take the 7D and shoot something to show it?

Before I can I need to ask about something that I'm too tired to wrap my head around just now.
The 7D is 1.6 crop of a 5D FF sensor. Now, the canon lenses equals the number on the FF sensors and 18mm on a FF sensor is 18mm.
On the 7D with a 1.6x sensor it equals to 28mm. This is the number that is the widest on the Scarlet fixed.

Now, what does 28mm T2.4 on a 2/3 sensor equals to on a canon 7D? Is it correct to shoot 18mm (FF sensor) at 5.0? Will that give the correct image; 28mm 2/3 sensor at T2.4?

If I'm to test how the image will look (in terms of DOF and focal length) how should I set up my 7D?

I think you are just confusing yourself. The 18mm Canon lens is still an 18mm lens whether it is put onto a FF35 5D or an APS-C 7D. It does not become a 28mm on the 7D. It just looks similar to a 28mm on a 5D in terms of field of view. But the focal length does not change when the lens is put on different cameras with different sized sensors.

I believe the wide-end of the fixed Scarlet is the equivalent view of the 18mm on a 7D (35mm cine / Super-35 / APS-C) or a 28mm on a 5D (I don't have a calculator). There is a 2.5X crop factor between 2/3" and Super-35. The crop factor is also more or less the depth of field difference in f-stops due to the focal length differences needed to achieve the same field of view. So once you match distance, shot size, and field of view between the 2/3" camera and the 35mm cine camera (Scarlet versus 7D) then you'd have to close down the f-stop by 2.5-stops to match depth of field.

So basically don't worry about what focal length you test on the 7D, just shoot different focal lengths and shot sizes but with the lens closed down by 2.5-stops to see what you'd get depth of field wise compared to shooting on the Scarlet with the same images in terms of field of view. If f/2.4 is about a half-stop open from f/2.8, then you'd be shooting your 7D tests at about f/5.6 to get a similar depth of field as with shooting on the Scarlet at f/2.4.

 

[Jesper Sichlau]

I believe the wide-end of the fixed Scarlet is the equivalent view of the 18mm on a 7D (35mm cine / Super-35 / APS-C) or a 28mm on a 5D (I don't have a calculator). There is a 2.5X crop factor between 2/3" and Super-35. The crop factor is also more or less the depth of field difference in f-stops due to the focal length differences needed to achieve the same field of view. So once you match distance, shot size, and field of view between the 2/3" camera and the 35mm cine camera (Scarlet versus 7D) then you'd have to close down the f-stop by 2.5-stops to match depth of field.

I've tried the f/5.6 on a APS-C sized camera, and it really does give a great depth of field. So people shouldn't worry about that factor, or at least wait till they see what the camera can deliver, to worry about it. It will be nice when the camera finally hits the market so all these threads won't appear so frequently (and Daivd can get a little more sparetime.)