Matthew Perks runs one of our favorite DIY channels on Youtube called DIY Perks. He recently published an exciting project for a view camera system based on a large size episcope lens creating what he refers to as a DIY “35mm f/0.4” lens.
Episcope lens for Photography
Episcope lenses (part of what is known as opaque projectors) were created to project images of book pages, drawings, etc. They were used by artists but also for lectures and discourses.
The lens had to be huge to cover the physical object it needed to project which makes it ideal for the project Perks had in mind. The idea was simple to use the episcope lens to capture an image but not as a direct camera lens but by capturing the light that falls on a surface.
Perks camera design is both simple and familiar (for those who worked with view cameras before) but also innovative in some crucial points as well shall see.
The first stage is choosing the metirial that will be used to project the image onto. Perks choose a diffusion paper and placed it betwen two sheets of acrylic to make it rigid (it is possible that using optical glass or even no glass at all but some sort of holder or even a thin layer of hard diffusion would actually be better for this task from an optical viewpoint).
The next steps had to do with building the view camera system, something Perks did very well using 3D printing and some aluminum parts and profiles. The bellow system was a bit more complex and actually involved a motorized bellow system which can move the entire huge bellow system closing and opening it for focusing.
The biggest innovation of Perks design is probably the inclusion of two fresnel lenses one in front of the diffusion frame and one behind it to focus as much of the light from the lens into the camera. This is certainly an ingenious solution and the result is a much brighter image with far less vignette (although we can not wonder how much better this could have been with actual proper computer optical design and quality glass fresnel elements – but that would obviously make no sense for a low budget DIY project of this type).
The result of this DIY project is honestly amazing. When shooting a subject a few meters away you can still get tramendous amount of background blur – something that is completely impossible even with the fastest commercial lenses on the market.
The lens itself is also quite wide (35mm equivalent according to Perks) which creates an even more interesting result of a wide field look but with a lot of separation creating a very three-dimensional feeling.
From Perks’ video – a comparison between a smartphone, FF 35mm f/1.8 and the new Episcope lens camera system
Some readers have mentioned that Perk’s design is actually very similar to old wet plate and cyanotype photography camera systems of the 19th and early 20th century but of course with some modern touch-ups and video capabilities of actual modern cameras.
We would not be too surprised if this idea will appear in some form on a future set of some Hollywood production for static scenes which require a great deal of background separation and a unique look and maybe it will even be picked up by one of the very few medium/large format manufacturers which are still around.