How to control IRIS and focus at the same time with a remote follow focus

[davide sorasio]

Hi everybody, I was wondering how people control the aperture and pull focus during a steadycam shot for example. Is it possible through only one remote? Or I'd be necessary to do so with 2 different motors and and remotes?

Thank you in advance for the help,

Davide

[Evan Walsh]

You would need two motors to pull focus and iris at the same time, you could do it from a single motor driver if it can control 2+ motors at once like the 3 axis systems from Arri, Preston, Cmotion etc. Sometimes an additional hand unit like the Preston single channel will be used for someone else to adjust the iris and the 1st AC will only worry about focus.

[Kyryll Sobolev]

Hi everybody, I was wondering how people control the aperture and pull focus during a steadycam shot for example. Is it possible through only one remote? Or I'd be necessary to do so with 2 different motors and and remotes?

Thank you in advance for the help,

Davide

 

you can control both the focus and the iris motor from one hand unit, if you have a system like one of these industry standards

- preston, using only one motor driver for 2 motors

http://www.prestoncinema.com/products_FIZ-HU3_2014.html

hell, you can even throw a zoom controller on there and a 3rd motor

 

- digital bartech, using 2 motor drivers for 2 motors

http://shop.plcelectronicsolutions.com/kit-bartech-bfd-w-slider-2-fstop-v2-1s-2-m26ves/

 

in reality though, the DP or DIT will handle exposure controller separately

[davide sorasio]

thank you all! What still confuses me is, how can I delegate the iris function to a second unit? Let say I one hand unit for focus, and I want the DP to control the aperture during a shot. I need 2 different hands, but how are they in relationship with each other? Do I need only one motor driver for the preston for example? And how do I make sure each hand controls only one thing? Also I know with the PRESTON FIZ I can use two different hands (The question above still exists BTW), but if I wanted to use a bartek for example, should production rent 2 different hands, motors and receivers etc and run thme independently?

Sorry for the obvious question but I've only worked with the need for pulling focus with BARTEK and EDEN KARAT wireless follow focus.

If anybody could also give a maybe more analitical explanation of how I could make it happpen it'd be great.

Thanks so much in adavance

Edited January 8, 2016 by davide sorasio

[Kyryll Sobolev]

thank you all! What still confuses me is, how can I delegate the iris function to a second unit? Let say I one hand unit for focus, and I want the DP to control the aperture during a shot. I need 2 different hands, but how are they in relationship with each other? Do I need only one motor driver for the preston for example? And how do I make sure each hand controls only one thing? Also I know with the PRESTON FIZ I can use two different hands (The question above still exists BTW), but if I wanted to use a bartek for example, should production rent 2 different hands, motors and receivers etc and run thme independently?

Sorry for the obvious question but I've only worked with the need for pulling focus with BARTEK and EDEN KARAT wireless follow focus.

If anybody could also give a maybe more analitical explanation of how I could make it happpen it'd be great.

Thanks so much in adavance

 

if you use preston, you will have this system

 

- MDR, mounted on the camera (http://prestoncinema.com/images/photos/mdr3_2014.jpg)

it receives the signals for focus, iris, and zoom information from hand units. it also drives the FIZ motors via cables.

 

- your focus puller will do the focus control using the FIZ hand-unit (http://prestoncinema.com/images/photos/hu3_double.jpg)

you can attach a zoom controller to the FIZ HU and it will send the zoom information as well

 

- your DP, or whoever else, will do the iris control via single-channel controller (http://prestoncinema.com/images/photos/news08_05.jpg

 

set the MDR, the hand-unit, and the single-channel controller to one channel, and they will all talk to each other

 

==

 

if you use bartech,

 

- you need to have 2 MDRs for the 2 motors, and 2 hand units

- set focus MDR and focus HU to the same channel, and set iris MDR and iris HU to a separate channel (read bartech's manual, they tell you which channels work best)

 

in this picture you can see a DP using bartech system to control iris motors on 2 different cameras http://www.csc.ca/publications/2015/201509/images/ArticleImage20150902.png

 

==

 

if you want to mix-n-match...

use preston MDR for something, and attach bartech MDR for something else

[davide sorasio]

 

if you use preston, you will have this system

 

- MDR, mounted on the camera (http://prestoncinema.com/images/photos/mdr3_2014.jpg)

it receives the signals for focus, iris, and zoom information from hand units. it also drives the FIZ motors via cables.

 

- your focus puller will do the focus control using the FIZ hand-unit (http://prestoncinema.com/images/photos/hu3_double.jpg)

you can attach a zoom controller to the FIZ HU and it will send the zoom information as well

 

- your DP, or whoever else, will do the iris control via single-channel controller (http://prestoncinema.com/images/photos/news08_05.jpg

 

set the MDR, the hand-unit, and the single-channel controller to one channel, and they will all talk to each other

 

==

 

if you use bartech,

 

- you need to have 2 MDRs for the 2 motors, and 2 hand units

- set focus MDR and focus HU to the same channel, and set iris MDR and iris HU to a separate channel (read bartech's manual, they tell you which channels work best)

 

in this picture you can see a DP using bartech system to control iris motors on 2 different cameras http://www.csc.ca/publications/2015/201509/images/ArticleImage20150902.png

 

==

 

if you want to mix-n-match...

use preston MDR for something, and attach bartech MDR for something else

Thanks a lot! one last doubt I still have after reading the Preston FIZ manual, I do not really understand what the AUX channel in the mode menu is made for. I'm attaching here the screenshot of the page manual because I really cannot figure this out!

In the next page it also tells me that :

"The second function of Custom Mode is to turn off one or more of the HU3 control

channels focus, iris, zoom or auxiliary. This is useful when using the HU3 in combination

with the Focus/Iris or Radio Microforce single channel units. Turning off the HU3 channel

will prevent the motor from changing from the setting of the single channel hand unit to

the setting of the HU3 if the signal from the single channel unit is lost.

Figure 7.4 shows the HU3 zoom channel set to Off, so if the signal from the Radio Micro

Force is lost, the motor will not revert back to the zoom setting of the HU3.

In situations where the lens setting must be controlled only by the single function hand

unit and not the HU3, the corresponding HU3 channel should be set to “Off”.

Zoom Mode"

 

Thanks so much in advance for the help!

[Kyryll Sobolev]

i don't know what the AUX setting is for because i have never used it, and i have not seen anyone else use it

 

from the description i suspect that it is a connector for an external recording device that records lens data to be used by VFX or 3D later

 

custom mode you are asking about is to turn off any of the motor controls by the HU3

 

if you are using an HU3 to control focus, and the DP is using the single-channel controller for iris, you want to turn off the iris control on the HU3. this ensures that the HU3 will not override the single-channel link in case the signal is lost (like if a battery on the DP's controller dies during shot, at least the last stop position is active, but since the link is lost, you don't want the focus puller's HU3 to override it and change the stop accidentally)

Edited January 18, 2016 by Kyryll Sobolev