This is something that comes up a lot and I get many questions about. In part because I designed the MTF B4 to Canon, FZ and E-Mount adapters. Budget adapters that allow you to use a 2/3″ B4 ENG lens on a Super 35mm sensor by using the lenses 2x extender or on a center crop sensor without the 2x.
The question is… what will the pictures look like?
The answer is… it depends on the lens.
Not a very helpful answer perhaps, but that’s the truth of it. Different lenses perform very differently. For a start I would say forget 4K. At best these lenses are suitable for HD and you want to have a great HD lens if you want good HD pictures.
But what about the “look” of the images? My experience is that if you put a wide range ENG zoom on a S35mm camera the look that you get can be best described as “2/3″ ENG look with maybe shallow depth of field”. Lets face it, ENG lenses are full of compromises. To get those great big zoom ranges with par-focal focus there are a lot of glass elements in those lenses. Lot’s of elements means lots of places where CA and flare can occur. The end result is often a lowering of contrast and color fringing on hard edges, the very same look that we are used to seeing on 2/3″ cameras. Typical cine or DSLR lenses tend to have simpler optical designs. Prime lenses are normally sharper and show better contrast with less flare than zooms due to there simpler internal design.
So don’t expect to put a typical B4 ENG lens on your S35mm camcorder and still have that crisp, high contrast digital cinema look. Of course B4 zooms are handy for the ability to zoom in and out through huge ranges while holding focus. So an adapter and lens may well make your S35mm camera more versatile. But if you want the best possible images stick to cine style lenses, DSLR lenses or zooms designed for S35.