When you get down to it, mirrorless cameras are really just portable computers with a couple of screens, a sensor and a lens mount.
More and more of the business of the camera is implemented in software, and that software is becoming somewhat commodified. (Indeed some mirrorless cameras use versions of Linux or Android, making them open source projects as well.)
One of the quirks of the mirrorless world is that unlike some DSLRs, they tend to be able to function quite well in what Sony calls a lens-off situation, where there is no electronic coupling between the camera body and the lens.
They can usually perform metering and simple autoexposure modes without knowing anything about the attached lens. And — partly because of their other application as video cameras — they generally offer some visual aids for manual focussing, such as focus peaking.
And that means we can use lens adapters.
Almost all micro-four-thirds, APS-C and full-frame mirrorless cameras can make use of almost all SLR and rangefinder lenses ever made. This is because the flange focal distance — crudely the gap between the surface of the sensor and the front face of the lens mount — of mirrorless cameras is much shorter than even that of a Leica rangefinder.
As long as there’s enough difference between the flange focal distance of the lens mount you wish to adapt and that of the camera you wish to adapt it to, you have enough room to put in place at least a simple metal tube adapter that can connect the two and fix them the right distance apart. It’s even possible to adapt between the mounts of some mirrorless cameras, with mount adapters as thin as 2mm.
These adapters can be surprisingly complete, particularly for Sony mirrorless due to its short (18mm) flange focal distance and its open specification (and/or easily-reverse-engineered) mount. The more room there is for the adapter to work with, the more room to adapt functions both mechanically and electronically. There are adapters that can provide autofocus and auto aperture control for many donor mounts and many host cameras.
There are even mounts with additional glass elements in them that can reduce the size of the image produced by a lens, to allow a full-frame field of view on a smaller APS-C camera, or a medium format field of view on full frame.
There are mount adapters for old lens mounts such as the DKL/Deckel mount for the Kodak Retina. With careful exposure choices, vintage lenses bring much of their vintage feel to modern sensors.
But more than this, we can mount any lens that can be connected to the camera via a light-tight tube, using a bellows or helicoid. With such an adapter a lens need not have its own focus mechanism. There’s an ecosystem of low cost M42-mount adapter plates and helicoids to help.
So with the mirrorless world, we have small general-purpose cameras that can also function as quasi-digital backs. The accessories market reflects this.
At the high end, Arca-Swiss have adapted their Universalis line to effectively provide a digital technical rig. Cambo’s excellent Actus series can adapt almost any lens to any mirrorless camera without losing infinity focus. Novoflex has a simpler high quality interchangeable-mount tilt/shift bellows and a partnership with Schneider to provide a 90mm digital technical lens adapted for the purpose.
But why use tilt/shift in the first place? What is that good for in the modern age? And what to do if your budget doesn’t stretch to these amazing pieces of kit?
In the next few posts I will outline why I’ve begun to explore tilt/shift technical photography, and do a show-and-tell about some DIY experimentation.