Table of Contents
Fujinon Cabrio ZK 19-90mm T2.9
Summary
FUJINON ZK4.7×19 is a standard zoom lens with a frequently-used focal length covering from 19 to 90mm.Thanks to the detachable servo drive unit on the ZK series, the lens can be operated in the same manner as a traditional broadcast ENG-Style lens and accessories. Furthermore, with the servo drive unit removed, traditional cinema manual, or external cine motors for zooming and focusing operation is also available for all models of this series. With the latest optical simulation technology and high precision large diameter aspherical elements, it has achieved both high optical performance and a lightweight compact body of 2.85kg. Thanks to high resolution from the center to corner, high image quality without image distortion will be exhibited on the large screens of movie theaters.
Tech Specs
| Manufacturer | Fujinon |
| Series | Cabrio |
| Model | ZK |
| Focal Length | 19-90mm |
| Max Aperture | T2.9 |
| Min Aperture | T22 |
| Format | Super 35 |
| Image Circle | 31.5mm |
| Minimum Focus | 34 in. |
| Focus Rotation | 200 |
| Iris Blades | 9 |
| Optical Design | 24/16 |
| Squeeze | none |
| Front Diameter | 114mm |
| Filter Thread | 111mm* |
| Focus/Zoom Rod | 3mm |
| Native Mount | PL |
| Data Protocol | LDS, Cooke /i |
| Length | 8.8 in. |
| Weight | 2767 g |
| Body Telescope | none |
| Body Material | Aluminum |
| Focus Drive | Servo |
| Iris Drive | Servo |
| Zoom Drive | Servo |
History
Country of Origin: Japan
Release Date: -
Launch Price: -
Design Revisions: Version 2 (see notes)
Service
This section restricted to Duclos Staff users.
Known Issues:
1. Version 1 (old style) has less accessible optical adjustments than Version 2. Centering/field may be on best effort basis depending on the lens.
2. oil buildup on element in front optics. oil seeps form the housing holding this element. elements must be removed form housing and all housings and elements must be cleaned to fully remove oil form seeping however it can reoccur due to grease used and construction of lens.
3. zoom drifts when vertical. this is typical and would not happen if servo unit is installed. We can re-lube the zoom heavier to prevent this (mostly) but this may affect the performance of the servo unit when it is re-installed.
4. Due to the proximity of the iris ring/iris pin access window/iris blade assembly, oil leeching/migration to the iris blades from iris lubrication is common.
Service Manual: Disassembly/Re-assembly
Screws: Fujinon
Full CLA: 18-20 hrs.
Type I (old): Fujinon above 19-90, servo says SAF, S/N on FER
Type II (new): 19-90 above Fujinon, servo says SAFB, S/N on iris ring
iris only: 3 hrs.
slip focus scale: 1 hr.
remove beauty ring, FER (lifts off towards front), and nitotape holding scale to focus cam (mark before removing focus scale completely)
C/A front optics only: 4 hrs.
+ 4 hrs when cleaning front optics to remove oil residue in focus optics. this includes cleaning the optical focus housings and threads of oil as well.
Adjust zoom curve:
0.003“ is about 75 microns, I think the mid range spec for the 1st gen 19-90 was about 30 microns. I would try overhauling the zoom cam first (cleaning/changing grease and rollers) and try to bring down this error. If unsuccessful there are spacer washers under the first zoom cell that can be changed. On our collimator if the error is positive we add spacer thickness, if negative we subtract.
Re-installing and initializing servo:
https://www.youtube.com/watch?v=weizqXDKuP0
back focus ring adjustment: 1-3 hrs.
Servo Notes:
Focus returns to center of scale when in servo mode and powered with the power bank:
“Servo focus on all of our handheld lenses work in positional mode only. Input a specific voltage and the focus will move to a specific point. Our zoom works in speed mode, the more voltage you apply the faster the zoom will move. When there is no control plugged into the focus, the gear ring will move to its center position when in servo mode (this is the zero-voltage point).”
Iris not reaching end to end: This could be many things, try the following…
Maybe the gain (sensitivity) is too low. Adjust the iris sensitivity pot (see attached diagram for location). Too much gain can result in hunting/chattering of the iris gear ring. If this did not fix it try the next step.
loosen the iris gear backlash slightly, this adjustment has always been a little sensitive. Mark the screwhead. The adjustment is spring loaded inside the drive unit for the iris motor and encoder assembly. If this does not fix the issue turn the screw back to original position.
If the top two suggestions do not work, I would replace the iris motor and check movement. If the new motor didn't solve the issue, then I would change the ribbon cables, then the PCB.
…end of Staff section
Notes
*Q: What are the main differences between V1 and V2 of Cabrio 19-90mm? (source: Fujinon's website, 2023)
While both Versions of 19-90 have a 114mm outside front barrel diameter, V2 has a 111mm filter thread and V1 has a 112.5mm filter thread, resulting in a doubling of the housing thickness. This change was made due to the thinner front ring being more prone to damage. New version front barrels for V1 Cabrios are available from Fujifilm Optical Devices service centers at a charge. The serial number on V1 is also located on the front rings whereas the serial number on V2 is located on the zoom ring. When looking at the factory model number of Cabrio 19-90, V2 includes a “B” at the end (ZK4.7×19-SAFB). In terms of optics, lens performance is in many ways a matter of personal subjectivity. Some optical adjustments were made to improve Cabrio 19-90 V2; however, the differences in optical performance between the two versions can be difficult to perceive when looking at real-world moving pictures, as compared to high-end lens bench/test equipment.
Version 1: SAF. “Fujinon” in white located above “19-90” in green.
Version 2: SAFB. “19-90” in white located above “Fujinon” in green.