WCU-4 Manual T-stop information input

Mon Jan 22, 2018 2:00 am

Hi,

Would it be possible to manually input t-stop into the WCU-4 handset without having to use a motor or Lens data encoder? It's really helpful to have the depth of field read out on the handset but I don't want to have to buy a lens data encoder and add more bits to the camera.

Nick
Nick Forster
 
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Re: WCU-4 Manual T-stop information input

Tue Feb 13, 2018 11:06 pm

I would love that feature....
xanoramix
 
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Re: WCU-4 Manual T-stop information input

Wed Feb 14, 2018 10:47 am

Hello,

if you use LDS lenses, you get the informations on the WCU-4 without Motor or lens data encoder.
When you use LDA files, you need the magnetic encoder values from the Motors or LDE-1 to get the scale informations/position of the lens.

best regards
Gernot
Gernot Füllsack
 
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Location: Vienna

Re: WCU-4 Manual T-stop information input

Wed Feb 28, 2018 12:05 pm

Hi Gernot,

I know its a different system, but it works on a Preston. When you select a lens (essentially the same as a LDA file) and if you have programmed the iris, but don't have the iris motor connected, the iris data still comes through relative to the position of the slider control on the handset. This way if you match the iris position on the handset to what the DOP has set on the lens then the DOF readings work with the Light Ranger system. Very handy and it would be nice if the same thing could with with the Arri system.

Regards,
Ben R
nzben
 
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Re: WCU-4 Manual T-stop information input

Thu Mar 01, 2018 5:19 pm

Dear Ben,

well, that's possible because Preston doesn't make cameras... they only have so much sorces to gather the data.

For us this system is not precise enough: imagine you would set a value on the hand unit (f5.6) but have a lens set to f2.8.
f5.6, the inaccurate value, would be fed into the metadata. LDS is camera-centric, the values al origin within the LDS core in the camera or UMC unit.

Best,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
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Location: Munich, Germany

Re: WCU-4 Manual T-stop information input

Fri Mar 02, 2018 8:02 am

I understand that Jan.

In this case I'm looking at it from the perspective as a tool for the AC. If there is an iris motor on the camera or the lens is LDS, then I get the information I need. If there isn't an iris motor on the camera (in the case of non-LDS lenses), then there obviously isn't a desire on the production for the metadata for that lens axis to be captured and used, but it would still be useful to me on set.

In my experience even when the LDS or LDA data is captured in most cases it isn't used by post production - surprisingly even on large VFX driven projects.

BR
nzben
 
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Joined: Sun Jan 22, 2017 12:56 pm

Re: WCU-4 Manual T-stop information input

Fri Mar 02, 2018 10:35 am

Hey Ben,

if there's no motor and no LDS, there's a gap to bridge - that is why we invented the Lens Data Encoder (a motor-like thing, without any drive).

If the lens data is not used - well that is because of inexperience with the workflow I guess.
Because if you've set up your part correctly (what one can assume since you are interested in accurate data on the WCU-4) - it is all there - automatically in every file recorded.

Postproduction only needs to extract the data.
Do you know why they don't use the data?

I would like to encourage you to spread the word: prodcutions don't need to take money in their hands to make use of that data.

A further read here: LDS FAQ

Cheers,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
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Location: Munich, Germany

Re: WCU-4 Manual T-stop information input

Fri Mar 02, 2018 9:21 pm

Jan, PM me if you want.
nzben
 
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Joined: Sun Jan 22, 2017 12:56 pm

Re: WCU-4 Manual T-stop information input

Fri Jun 01, 2018 5:45 am

I'll jump in on this with a resounding YES PLEASE! We all know how the systems work. But we would like the ability to manually set the iris info on the wcu-4 using ANY lens and have the depth of field readout occur just like if the iris motor was on and was mapped. Possible or not?

I don't think you'd find an ac working who thinks this is this is a bad idea. Quite the contrary.

The argument about the post metadata being wrong if the iris is actually set differently by accident is only valid in a small percentage of overall production, simply because most don't use it, and that's operator error if it's set differently anyway, just like anything else. So there is theory and reality. There is a TON of day in and out use where only one motor is used, and this would be an amazing feature.
jakecamera
 
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Re: WCU-4 Manual T-stop information input

Sat Jun 02, 2018 10:05 am

What would be great, but probably not possible, would be a motor setting to switch an Iris motor between Servo & Manual.

BUT

I suppose you could always mount an Iris motor, calibrate it to the iris. THEN disengage it from the barrel so the motor's gear spins freely when you use the slider. This way your DP is free to adjust stop, and you can just match it on your slider for your DoF readout.
JonBowerbank
 
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