Things to do during prep with anamorphic lenses?

Bradley Stearn · July 30, 2016

I'm focus pulling on a short film this week. We are shooting on the Alexa Mini with 2x Kowa Anamorphic lenses. I've worked with anamorphic on a fair few jobs in the past, however I haven't always had the luxury of a prep day. On this short film I have an evening of prep before principle photography begins. I was wondering if I could get some advice on the kind of things I should prep/look out for when shooting on vintage anamorphics?

I'll do the obvious and check the accuracy of focal distances to start with. As far as i'm aware each lens will cast a slightly different colour tint onto the image, how can I test this and compensate during shooting?

We are also going to be using diopters for a few close-up shots in the short film. Any advice on pulling with diopters in front of the lens? Is there an algorithm that can be used to figure out focal distances for different diopter levels? Or is it recommended that I just rely on a monitor for these shots?

Dom Jaeger · July 31, 2016

As far as the diopter question, there was a thread on this not long ago:

http://www.cinematography.com/index.php?showtopic=69473

You can mathematically determine your focus range, but you'll still need to critically focus by eye.

Maybe talk to your DP about colour cast issues, and whether you need to do any extra testing, white balance adjustments etc. (Or someone more experienced in this might chime in).

My only advice as a lens tech would be to remember that vintage anamorphics like the Kowas are rather funky, with curved focus planes and wide open aberrations that can make exact focus pulling a bit tricky, so don't get too hung up about marks lining up perfectly. If you can get a lens tech at the rental house to project the lenses for you, it will be most illuminating. :)