Ask David Mullen ANYTHING

[David Mullen ASC]

35mm anamorphic, 8-perf 35mm VistaVision, and 5-perf 65mm are all rather similar, depth of field wise -- generally you choose almost double the focal length to match the horizontal view of something shot in 4-perf 35mm spherical, assuming the same aspect ratio is chosen. So you'd use a 40mm lens in anamorphic, VistaVision, or 65mm when you'd normally use a 20mm lens in standard 35mm, and hence you have two stops less effective depth of field when shooting at the same stop and distance to subject. More or less. You can do the math to figure out the exact FOV issues.

Roughly, the horizontal dimensions are:
22mm (standard 35mm sound aperture / RED at 4096)
24mm (Super-35 gate)
44mm (effective for anamorphic due to doubling of view on a 22mm gate)
38mm (VistaVision gate)
52mm (5-perf 65mm gate)
70mm (15-perf IMAX 65mm gate)

[benfilm]

Hi,

Could you discuss multiple-camera setups for feature films: are they used a lot for normal coverage, what are the advantages and drawbacks?

Thank you.

[Esmaile Neissi]

HI david,
sorry for being off topic, what is the defrence of master primes and ultra primes?

[David Mullen ASC]

The main difference is that the Master Primes are one-stop faster than Ultra Primes. They are also a bit sharper with less distortion, have more clarity, but at the expense of being larger and heavier. And more expensive.

[Victor Noir]

Hi David,

This is a question I put in 'off-topic' before realizing it belongs better elsewhere...

I'm three weeks from a shoot in the Arctic Circle... eventually heading to the North Pole as well as Franz Josef island. The shoot will entail a lot of 'icescapes': bergs, snowpacks, water and skies for a conceptual video art piece.

I've been told it's an extremely challenging environment in which to shoot--the extremes of temperature, glare, contrast and gods only know what else can make it ridiculously tough, especially if you don't quite, completely, know what you're doing (and that would be me)...

Any advice on filters, lenses, tips, tricks and incantations would be deeply appreciated.

[David Mullen ASC]

I don't have any extreme weather experience, but I'm sure there are others here on this site that do. Main issues I deal with when it gets really cold (I did an HD feature in St. Petersburg, Russia, in December once...) are keeping batteries warm and allowing lenses to acclimate, otherwise they can fog up.

[Tom Lowe]

To David or anyone here. A couple of high school-level photo class level questions here...

Say I have a nice 10-second exposure of a night sky at f/1.4 ISO1600. If I put an f/2.8 lens on the same camera, same ISO, how long will my exposure have to be in order to get the exact same amount of light to the sensor?

Will an f/1.4 lens let in double the amount of light as an f/2.8, or is there some other calculation?

Also, in terms of exposure times, is ISO1600 exactly twice as "fast" as ISO800? Meaning, if I got a nice 2-second expsoure at ISO800, could I switch to ISO1600 and cut that exposure time to exactly 1 second?

[Pawel Achtel]

To David or anyone here. A couple of high school-level photo class level questions here...

Say I have a nice 10-second exposure of a night sky at f/1.4 ISO1600. If I put an f/2.8 lens on the same camera, same ISO, how long will my exposure have to be in order to get the exact same amount of light to the sensor?

Will an f/1.4 lens let in double the amount of light as an f/2.8, or is there some other calculation?

Also, in terms of exposure times, is ISO1600 exactly twice as "fast" as ISO800? Meaning, if I got a nice 2-second expsoure at ISO800, could I switch to ISO1600 and cut that exposure time to exactly 1 second?

Tom, you have 2 stops between f/1.4 and f/2.8, not one. So, you need 4 times as long exposure time (or sensitivity).

Edit: this may help: http://en.wikipedia.org/wiki/F-number

[Tom Lowe]

Thank you, my friend.

What about ISO speed? Is it literally proportional? ISO400 is twice as "fast" as ISO200?

[Pawel Achtel]

Thank you, my friend.

What about ISO speed? Is it literally proportional? ISO400 is twice as "fast" as ISO200?

Yes, Tom.