Frequently Asked Questions – Follow focus
Welcome to the frequently asked questions about ARRI Pro Camera Accessories (PCA).
This FAQ pertains to follow focus. Directions given are always from the operator’s point of view. This FAQ supersedes any earlier versions. For questions, suggestions or comments regarding this FAQ, send an email to.
1. Mini Follow Focus MFF-2
From the outside MFF-2 Cine and MFF-2 HD look the same, except of the labeling.
Cine has a gear ratio of 2:1 for cine style lenses
The MFF-2 Cine has a gear ratio of 2:1, which means one turn of the focus knob will result in two turns of the focus gear. This gear ratio is common to all classic follow focus units from ARRI (FF-3, FF-4, etc.) and is traditionally suited to cine lenses such as Ultra Primes, Compact Primes, Alura Zooms, Angenieux Zzooms, etc…
HD has a gear ratio of 1:1 for 2/3” broadcast and still photo lenses
The MFF-2 HD has a slower gear ratio of 1:1. In this case, one turn of the focus knob will result in a single turn of the focus gear. This particular gear ratio might be preferred when using lenses with a short focus throw, where the scale from minimal focus to infinity is so short that a traditional 2:1 ratio could be too direct, lacking in precision. Typical lenses suited to the HD ratio are modern still prime lenses, some ENG zooms, extreme wide-angle lenses or some older designs.
The MFF-2 Cine is the follow-up to the MFF-1. The hard stop knob of the MFF-1 was fixed and could not be removed. With the MFF-2 you now have the choice of three different knobs.
Yes. You have a choice of three different knobs: standard, hard stop and 2-speed.
The Standard Focus Knob is suitable for most situations on set when using lenses with hard stops on the focus scale. A standard focus knob with built-in extension is also available.
The Hard Stop Knob is best used with lenses having no built–in limits, such as most DSLR lenses, because it can create infinity and minimum object distance limits on the knob. This way the in-between focus marks stay true throughout the shoot. The Hard Stop Knob has a smaller footprint than the two other focus knobs, fitting in smaller spaces between matte box and camera body.
The 2-Speed Focus Knob has a built-in user-selectable gear box that can engage a lower “gear-to-focus knob ratio” when desired: e.g. when working on the longer end of a telephoto lens’ focus scale, where a large distance is covered between two focus marks, or when pulling focus during a delicate macro shot. Note that all focus marks remain true regardless of the speed selected. A 2-Speed Focus Knob with built-in extension is also available.
You have the possibility to reverse the lower part of the MFF-2 with just a few modifications – specifically for Nikon and Leica lenses.
ARRI neither offers nor recommends adapters to use Mini Follow Focuses MFF-1 and MFF-2 with 15 mm or 19 mm studio rods. The Mini Follow Focus series is designed for 15 mm LWS Lightweight Support.