What is a rangefinder?
An anamorphic rangefinder is a set of two achromat diopters in reverse polarity. You can then achieve focus for the entire setup by varying the distance between those two diopters. In close focus, the diopters are at their maximum distance apart, and at infinity, they are right next to each other.
Popular rangefinders for anamorphic lenes include:
With our Isco Micro single focus anamorphic kit, you can calibrate your infinity point and then just single focus with the rangefinder. See this article for more details on how to calibrate a single focus anamorphic kit. Because of this, we can calibrate the infinity focus to a point other than infinity, and the rangefinder will now focus from that point inwards. By bringing your infinity point in, you are also bringing your close focus point.
It is essentially the same principle of using a diopter on a front filter thread– except that we have the ability to change the power of that diopter, or eliminate the diopter effect altogether.
Now you would lose your ability to focus further than whatever point you have set as your infinity point. So to return to infinity, you must recalibrate your anamorphic and prime lens back to infinity. But if you know your focal range on a certain shot, you can achieve macro focus with a rangefinder without having to use diopters.
If you have found this article interesting and are further interested adding anamorphic to your toolbox as a cinematographer, please visit our anamorphic lens store for demos and examples. We have spent several years collecting, modifying, and testing anamorphic lenses to weed through the junk, make needed modifications, and assemble ready-to-shoot packages.
If you are interested in learning more on working with anamorphic lenses and DSLR, please check out our anamorphic tutorial blog for more anamorphic tips and tutorials!