Interlaced footage on a cinema screen

[Ryan K]

It's my understanding, from what I hear from an editor chum, that if were to shoot footage at, say, 70i it would manifest unseemly lines when digitally projected onto a cinema screen. I'll be shooting a short on HD in the not too distant future which will be projected as such and some of the stuff will have to be shot beyond the camera's progressive scan capabilities as interlaced footage.

 

Now, is he talking out of his arse? Does anyone have any experience in this field?

[David Mullen ASC]

It's my understanding, from what I hear from an editor chum, that if were to shoot footage at, say, 70i it would manifest unseemly lines when digitally projected onto a cinema screen. 

Now, is he talking out of his arse? 

<{POST_SNAPBACK}>

 

If he said "70i" he is... there is no such thing. Maybe he meant 60i.

 

When interlaced-scan photography is converted to whole frames for transfer to film or progressive scan presentations, you get a phenomenon called "jaggies", a sawtoothed edge to moving objects since they occupied a different place in each of the two fields. If you combine this with shooting on a video format with a fewer number of scan lines to begin with like standard def video, on a big screen it is fairly noticeable (as opposed to viewing on a small progressive-scan monitor.)