The Live Event Producer's Guide to the Sony NEX-FS100

Is There a Right Time for Autofocus?

I've never used autofocus (or any auto features for that matter) on my camcorders, mainly because their sensors are so small that they don't have a very shallow depth of field to begin with. But a large-sensor video camera has a very shallow depth of field when your lens is wide open, so if you want to film with a wide-open iris, I would consider using the phase detection autofocus that the LA-EA2 adapter allows in order to keep my subject in focus more accurately than I could using manual focus.

Autofocus also comes in handy if your lens isn't parfocal; the PDAF autofocus on the LA-EA2 has shown it can quickly snap back into focus during a zoom on NEX models that currently support this adapter.

In-Body IS and Smooth Zooming

In the current Sony Alpha and legacy Minolta AF lens lineup, there are lenses that are parfocal and have fast f/2.8 or f/4.0 maximum apertures, but there are none that also have image stabilization. The Sony Alpha DSLRs that the A-mount lenses are built for stabilize lenses in-body, but the FS100 and the LA-EA1/2 adapters lack in-body stabilization. Fortunately, some Sigmas A-mount lenses have in-lens stabilization but not all are parfocal.

Smooth zooming is also challenging on SLR lenses. Don't expect all SLR lenses to change focal length as smoothly as a camcorder lens. Some are very sticky and this results in herky-jerky zooms.

I've personally chosen to build my kit around A-mount lenses and am pinning a lot of hopes on the LA-EA2 adapter (firmware upgrade coming March 22), but I'll have to wait another few weeks to tell if this gamble pays off. Otherwise, the Conurus Canon adapter does everything I need it to, except for autofocus.

Filming with the FS100

Once you figure out the complicated lens selection options on the FS100, you'll realize that shooting live events on the FS100 has its own challenges. A camera that can pull off a shallow depth of field can be sometimes be too shallow, depending on your subject matter. I often stop-down my lens when my subject is free to move. For conferences, f/2.8 is sometimes too shallow, so I might stop down to f/4.0. For a dance recital, I stop down even further, to f/5.6, in order to have a larger area that is in focus. A variable ND filter then becomes my primary exposure control.

I think it's worth repeating too that using the gain on the FS100 adds much less noise than on a small-sensor camcorder. The FS100 also has a greater exposure lattitude so there is more room for your lighting levels to change before you need to adjust and still get a great image.

Read Shawn Lam's FS100 Zoom Lens Shootout in Winter 2011 EventDVLive.