Lens Mapping on Preston HU3

Lens Mapping on Preston HU3

Hey All, Nick from Talamas here, and in today’s post I will be showing you how to map a lens with the Preston HU3. We map all lenses in our inventory as well as sub-hired lenses.

  • In the main menu of the HU3, you’re going to want to scroll down to the “Lens” option, and hit choose.

  • Select “All Lenses” and then the Manufacturer, In this case I’ll be mapping our new 80mm Atlas Orion 2x anamorphic lens, and since Atlas isn’t listed will select “Other”.

  • Choose whether you’re working on a prime or zoom lens, then select “New Lens”.


  • Now is the time to enter lens specific information such as focal length (in this case 80mm), the last 3 digits of the serial number, important for dealing with multiple sets of the same lenses, and if you’d like to add a note, which is useful to separate different lens sets from the same manufacturer (with this lens I added the note “ORION”).

  • Once you have all that info in the system and your rig is all set up, you’re ready to start mapping.

  • Select the lens you just created, then “Edit Lens”, and either “Calibrate Focus” or “Calibrate Iris”.

  • We will start with Focus, once selected the HU3 will ask you to set the lens to infinity, depending on your orientation to lens you may need to reverse the direction on the MDR.

  • Once infinity is set, the HU3 will ask you to set close focus, it will automatically go to 2’ but in the case of the Atlas Orion the first labeled focus mark is 3’. Therefore we just set the lens to 3’ and scroll using the “Down” button on the HU3 until it reads 3’.

  • Once your close focus is set, the HU3 will determine 10 marks that need to be set within the range from CF to Infinity. Then it's as easy as moving the lens to that mark and hitting “Next”.

    • Pro Tip: I have the lens rigged on our Gecko Cam projector because it is at eye level when I’m sitting, it’s important to have a consistent head position when setting your marks to get the best accuracy. You can use any camera and tripod combination to get the right height for you.

  • If you get to a point where the HU3 has a mark that isn’t labeled on the lens, just go to the next nearest labeled mark and use the direction buttons on the HU3 to that point.

    • For example in the photo below, the HU3 wants me to go to 9’6”, however that mark does not exist on the lens, so I can either got to 9’ or 10’ on the HU3 to set my next mark. Don’t try and guess where 9’6” would fall on the lens, as that will throw of the accuracy of your map file.

  • Once all 10 points have been set, the focus should be completely calibrated and you can move on to the Iris.

  • Iris calibration is much quicker as you only set two points, the widest aperture, and the narrowest aperture.

  • When setting the widest aperture it’s important to note that only the standard stops are available to choose, if you’re lens starts on a in-between stop, move to the first selectable stop on the HU3.

    • For example, if I had a lens that's widest stop was T1.8, I shouldn’t just set T1.4 as T1.8, you should adjust the slider so the lens matches with the next selectable stop which is most likely T2 or T2.8. This isn’t as important if you’re using the HU3 alone, but becomes very important if you plan the pair the HU3 with a Preston Light Ranger.

    • Once you set your Minium T-stop and Max T-stop your lens is now completely mapped and the file is automatically saved to the internal memory of the HU3.

    • The HU3 can internally store 256 lens files, but with the addition of the Preston Bluetooth Module, and the Preston Cinema Systems App you can store and manage as many lens as you’d like, and also keep your HU3 firmware up to date on your mobile device.

  • Once your lens is completely mapped any you are ready to use it on set you can choose between 5 pre-marked focus rings that are included with your FIZ kit. Rings A (9”), B (1’6”), C (2’), D (3’), and E (6’) are based on Close Focus markings.

  • From the Main menu, scroll down to “Lens” and select the “Ring” option at the bottom, the select which ring will work best for you.

  • In the example of the 80mm Atlas Orion, the minimum marked close focus distance is 3’ so if I want the full range of the ring I would choose ring “D”. However if I knew for a certain scene or shot I didn’t have to focus any closer then say 6’ I could choose ring “E” which would set a minimum limit on the HU3.

Thanks for following along, and if you would like to rent the Preston FI+Z system, or have any questions about mapping lenses please feel free to reach out to me or any of our Rental Account Managers.