Lens options for HPX500 and DOF calculations

[G.P.]

Ok here it goes, another detailed question from me...

I have been looking at 2/3'' lenses for my HPX500's

Digiprimes are just not accessible with my budget, but there are a few others that are. the short list best first:

1) Canon HDEC Primes

2) RED mini primes

3) Fujinon MAF prime lenses

Now the REDs are not out yet, but I have a feeling they will not backfocus properly on a CCD camera, can anyone confirm this?

The Fujinon lenses are only max F2.0 which is too slow for me, so really theres only one option other than digi's and thats the Canon.

Canon HDEC primes are geared for cine use, and have an almost unbelievable T stop of 1.5 (which means the lens F stop is most likely F1.4) that is FASTER than digiprimes. With an Fstop of 1.4 what is the calculation of Depth of Field compared to 35mm lenses?

In other words... I've been told that at F1.6 in 2/3'' world, that is equivalent to F2.8/4 split. So what would an F1.4 be? F2.8 or even faster for 35mm dof??

Does anyone have a mathematical equation they could add to help this? If so with these lenses you really are getting close to 35mm dof wide open. These seem to be math wise, faster than digiprimes. I am not looking for sharpness as much as I am looking for depth and speed.

Anyone with an answer?

 

[Barry_Green]

Depends on what you mean by "35mm" -- are you talking about movie film, or still camera film? They're very different sizes.

In any case, the answer will likely be found in this article:
http://www.dvxuser.com/articles/article.php/21

 

[G.P.]

I mean 35mm academy gate size depth of field

 

[Barry_Green]

A 2/3" camera needs to be opened up about 2.75 stops to match the DOF of a 35mm cinema camera.