What is the purpose of ARRI's pre-marked rings? arri pre-marked-rings By Hugo Noire on 1/10/20, 7:18 PM • 553 views Hello everyone! I'm just getting started in the world of cinema (aspiring to become a focus puller one day) and wanted to understand what is the purpose of ARRI's pre-marked rings? Nothing in the WCU-4 manual, nothing under the description of the pre-marked rings, etc. :( Could anyone help shed some light on this for me please? Clemens Hönig On 1/10/20, 8:41 PM Hi Hugo, Welcome to the forum! Without the pre-marked rings, you would mark each plain ring, with the exact same values and markers as the current lens. So each focus ring would fit to a certain lens. The pre-marked rings allow you to automatically match a certain ring to many different lenses. To enable this, you need to create the lens data, which means teaching the system, which position of the motor fits to which position on the lens. Once you have the lens data, you can match the pre-marked ring to the lens, because the system knows, where the motor position for each lens value is and where these values are on the pre-marked rings. This has two main advantages: 1. You can use the same ring for many different lenses. 2. By using the same rings, you can train your muscle memory, as the pull between a certain distance will be the same, no matter which lens you are on. Hope that makes sense to you. Best, Clemens
Hugo Noire On 1/10/20, 10:09 PM Fantastic reply, thank you very much Clemens! Explains it perfectly well! My follow up question is then how do you know which pre-marked ring to use as there are different versions (3ft6in, 20in, 8in, etc.) Thanks for your help!
Clemens Hönig On 1/10/20, 10:19 PM You would choose the one, which is closest to the close focus of the lens. However, if the close focus does not match exactly to the ring, you might loose either a little travel on the lens or on the ring.
Rafael del Campo On 1/11/20, 6:06 AM That is. Also has some advantage. Per example when you are working with Premarked focus rings, the infinity for perfect on end of the knob travel, this si very helpful for lenses with travel after infinity. That is a space than don’t have real use, it’s designed for can make focus when the zoom or lens mount is uncolimated and don’t lost the infinity. With Premarked ring you can use the real travel el the focus ring and don’t pull wrong after infinity mark. Other advantage is than if you have a lens set mapped with LDA file, and stored on SD card with you, you don’t need re-mark the rings each time when you use that lens. Basically you have all rings marked and perfect fitted for all lenses if you have the correct LDA, this is a big time saved when you go to projects without camera test and you star the day shooting without time for check all. Daryl Nah On 1/11/20, 4:37 PM Hi would just like to ask something related with the premark disc which i noticed/discovered. And if you guys could clarify? using CPRO ONE - You mentioned to take the ones with the close focus of the lens, so at least you have the full range of the lens without having it stop half-way for eg, (Lens 50mm, min 12inch, but if you use 3.6inch disc, lens will stop at 3.6feet). I noticed in general, some of the pre-marked disc markings dun seem to match in line with the lens at certain distance range especially when not using pre-marked ones Closest to its focus if you know what i mean? is it common? - The other was i was at rental house, they had 3 x Cooke S5/i sets, bought over the few years(older one and recent ones). Mapped One set, but tried to use on the other set, it didn't match. So ended up having to map a new set of files for that model though they are identical. Thanks! Rozemarijn On 1/11/20, 10:06 PM Hi Daryl, the lenses seem the same but they are actually know for being all different when you create lensfiles. The cookes. You can load a lensfile and modify it, and save it with the correct serial number to save some time with creating. Your other question, i dont quiet understand....help me out a little with and example.
Daryl Nah On 1/12/20, 2:02 AM Hi Roze thanks like example I use a 35mm lens, with premarked 12inch, the marking on the disc and the lens match (3feet on lens, 3 feet on marking disc) but if use like 18 inch disc...you turn the marking disc to 3 feet, on the same lens, the lens will drift to like 2.9inch for example.
Rafael del Campo On 1/11/20, 9:59 PM The LDA file has serial number, and that LDA fit perfect only for that lens, you can use a file for any lens if you want. Usually fit too for other but the system it’s designed for use one file by lens. You can copy the created file and modify for fit perfect on a new lens, saving time of mapping. That is very good when you are using macro lenses all day for not macro shoots and you can use the Premarked for lost the close travel and feel it like a normal lens. Some AC than has the “muscle memory” for anamorphic (the anamorphic is usual all lens set with the same close focus) use a Premarked focus ring when shoot on spherical for feel all lenses with the same close focus About use Premarked ring with less travel than lens travel, effective the lens stop in ring mark losting travel on lens. fizornot On 1/12/20, 3:01 AM The greatest benefits of lens mapping are you can use the ring that is most appropriate for the shot , and your marks stay the same when you switch lenses ( assuming the camera and subject are in the same place ). For example, if you are pulling on a long lens with a minimum focus of 2’ but the subject will never comes closer than 6’ you can spread out the marks by using the 3’6” ring on the wcu4 . This makes the pull less twitchy.