I recently bought the Sony Alpha a7. In a bid to get an affordable portrait lens, I rushed to get the Rokinon 85mm f/1.4 only to realize that there is no communication between the camera and lens. Now that I now understand how a manual lens works, I was wondering if there is any adapter of some sort that can help with either controlling the aperture or focus from the camera, or even both?
While that may be true of some lenses (that no electronic connection can be made to the camera), I have seen shops that offer lens modification to allow some high-quality film-era manual-focus lenses to allow their aperture to be controlled and/or to pass aperture info to the camera. I think some even have a chip that somehow identifies the focal length, etc. With modification, some lenses, when focused, trigger the focus magnifier, like the modern Sony/Zeiss manual-focus lenses (e.g. the Zeiss Loxia line). I saw a shop that was doing this for some Contax SLR (and G-series rangefinder) lenses; they had to be the later models that allowed aperture to be set by the camera.
Personally, I love using manual-focus lenses on the Sony A7R. And none of mine have any electronics. You can still push the button to turn on focus magnification and check that important elements are sharp. Once you are used to the process, it’s really not hard, though no adapter or modification will add auto-focus to those lenses.
It would be cool, though, if Sony ever decided to build an auto-focus body (like the Contax AX, where the film plane moved forward and backward to achieve focus). Sony actually already performs a fair bit of sensor movement in their IBIS technology, so it would just be an interesting "next step" to allow some view camera -like rear-standard movements, which could also be further extended to movements designed to achieve focus at some position in the image. That could end up making an A7 -like camera into a system with a body as large as a typical full-frame SLR's, but I think there would be a great market for it, especially for product photography and "trick" videography. (Are you listening, Sony?)