I have a penchant for vintage lenses and more particular vintage soft focus lenses. My collection has been growing and I enjoy exploring the pictorial possibilities and creating art with this vintage glass.
In most cases I use a large format camera to shoot with these soft focus and other vintage lenses but I've adopted a select number of these for use on Medium Frame digital camera as this fits my workflow well. In my particular case this is a Mamiya 645 AFD II for travel or the Phase One 645DF in studio in combination with a Leaf Aptus 10 digital back. The latter covers 36 x 56mm and yields 56 megapixels in a 1:1.55 format.
Adopting a barrel soft focus lens involves mounting the lens on a suitable helicoid for manual focusing and fabricating a method to fasten the lens to the said helicoid at the proper lens-to-film-plane distance. The helicoid in turn has to fit the lens mount of the camera ... of course ...
Not necessarily an easy task but there's however a fairly, be it somewhat expensive, solution. There'a a popular (discontinued) helicoid on the market from Asahi for the Pentax 67 camera. The Pentax 67 camera lens-mount-to-film-plane is the largest of all popular film cameras. This a good start as it gives me a lot of room to work with. Adaptors for the Pentax 67 lens mount to any other imaginable film camera are available. I have an adaptor for the Mamiya 645 and an adaptor for the Nikon F mount. As such I can uses any lens configured through this method for my Mamiya/Phase One also on one of the many Nikon 35mm or "full frame" cameras in my toolbox.
Mounting the lens itself is easily done using a Pentax 67 body cap fitting the Asahi Helicoid. The body caps are made from a resilient machinable plastic and work quite well. A Pentax 67 macro tube system is used to properly space the lens from the actually film plane. Alternatively a macro-bellows set-up could be used. The macro extension tubes make for a very portable solution and one can stack them theoretically at infinitum.
Below is an image of my growing number of lenses adopted as such for MF camera/digital back use. Also shown is an adaptor to mount the Pentax 67 body cap to a Linhof Technika IV camera. This adaptor can in turn be adapted to my Sinar view camera. With a Phase One sliding back on the SInar, I can use the Leaf Aptus digital back with a tilt, shift and swing options from either view camera.
Lenses in above image, left to right, top and down:
Where possible I adjust the lens spacing for infinite focus. For the longer focal lengths I often forego infinite focus as we're dealing with soft focus lenses and it really doesn't matter to me if the horizon at infinite is perfectly sharp. Actually, I prefer soft.
In following blog posts I'll be demonstrating the results of a select number of lenses I've repurposed using the above method in the hope that this is a stimulus for fellow photographers to share their efforts.