HPX-170 & Backfocus?

[Bassman2003]

Hello,

I have never used the HVX-200 and am interested in the HPX-170, but I wanted ask a question about the workings of the lens.

In Barry Green's preview of the HPX-170, he mentioned a feature where one could turn the focus ring into the Iris ring.

This is nice, but I wanted to know if the camera operates with a backfocus approach like pro cameras or a non-backfocus approach like a VX-2000?

Mainly I am wondering if while in this manual focus mode the focal plane stays the same through the zoom range?

For example, zoom in, grab focus and the entire zoom range will be in focus at that same focus point.

Thanks

[Barry_Green]

Yes the backfocus stays consistent. Zoom in, focus, zoom out, shoot.

[Bassman2003]

Thanks.

That is good to hear that the camera operates like a removeable lens type of setup.

One other question, when the focus ring is being used as a focus ring, is the iris adjustment fluid or does it have little stop points or gradiations?

[Barry_Green]

The iris ring operates smoothly (no stop points) and the gradations are 1/6-stop increments.

[Bassman2003]

Thanks Barry.

How does the 1/6th stop incriment compare to a broadcast lens?

[Barry_Green]

The brightness changes are extremely small and nearly imperceptible. A full-fledged broadcast lens should have an infinitely variable iris, but that doesn't guarantee that it will have such.

[Bassman2003]

Thanks for all of your help!

[DavidBeier]

Not to sound stupid but why wouldn't the focus stay the same when you zoomed in and then out? I've never known a camera with manual focus that you couldn't pull a critical focus (don't know if my terminology is right, been out of film school for a while).

[Barry_Green]

With interchangeable lenses you have to be meticulous about your backfocus; if the backfocus is not properly critically adjusted then zooming will not hold focus.

With a built-in lens it should never be an issue.

[Bassman2003]

Not to sound stupid but why wouldn't the focus stay the same when you zoomed in and then out? I've never known a camera with manual focus that you couldn't pull a critical focus (don't know if my terminology is right, been out of film school for a while).

As far as I know, and from use, more consumer oriented cameras don't operate with a true backfocus per se.

They operate closer to still cameras, focusing where they are in the zoom range, basically not fully manual.

I just wanted to ask and see how the HPX-170 was setup and if it was more on the pro side of things.

I use DVC-200s right now and enjoy the shooting style of a manual lens.