35mm Adapter Buyer's Guide

People are always chasing the illusive film look with video cameras, looking for ways to mimic the look and feel of film. When 24p video popped onto the market a decade ago, it was a big deal, and brought the video world a bit closer to mimicking the look of film on a small budget. Besides the 24 frame per second movement, film also has a much shallower depth of field than video. In film, having this kind of control over focus is often used to draw the viewer's attention to certain parts of the frame and away from others. A major pitfall of video has always been sensor sizes, which are physically much smaller than a frame of 35mm, resulting in a huge depth of field and just about everything always being somewhat in focus. Yet, another weakness in the prosumer video market is that most camera models often have a fixed zoom lens, forcing the user to work within the constraints of the manufacturer's lens. A solution to both these problems is to add a 35mm adapter to your camera.

In a 35mm adapter, there is a piece of ground glass that resides between the mount of the adapter and the lens of your camera. This ground glass becomes the focus point for your camera. The lens you place on the adapter projects an image onto this glass as if it were a frame of 35mm film. With the adapter connected, you are filming a projected image off the ground glass. The area of the ground glass is much larger than the size of the sensor in your video camera, so the image on the glass has much less depth of field, giving you more control and bringing you a lot closer to the film look.

In 35mm adapters the ground glass often moves in order to simulate a film grain look and to minimize the presence of the ground glass texture in your image. There are four types of movement, static, vibrating, spinning and off-center spinning. In static adapters the ground glass doesn't move, making it easier to film at higher shutter speeds but increasing the likelihood that you will see the texture of the glass in your image.

In vibrating adapters, the ground glass moves quickly back and forth to soften the appearance of the ground glass texture and simulate grain. While this technique works well, technically there would be a fraction of time each second that your image is out of focus due to the shifting of the plane, but you would be hard pressed to actually see it. Sometimes this can make shooting at higher shutter speeds difficult.

In spinning adapters, the glass remains on the same plane so it doesn't phase out of focus at a point like in a vibrating system. The circular plane spins to soften the glass texture and give the hint of a film grain. An off-center spinning glass works in the same way, but reduces the glass texture even more and more importantly promotes even light transmission.

If you hold up a bare lens near your eye and look through, you'll notice that the image is upside down. That upside down image is what is going to be projected onto the ground glass of your adapter, meaning that in some cases you will be seeing an upside down image in your camera. Most adapters offer an accessory to flip the image right side up. Basically, a prism goes between the ground glass and the camera to right the image. Letus and P + S Technik sell their adapters as one piece with the image correction built in. Redrock, Cinevate, and Shoot35 offer an additional accessory to correct this. If you find yourself lacking this accessory, some cameras have the option of flipping an upside down image for previewing it correctly. Other times you would have to set up an external monitor, mounted upside down to assist in framing. Always remember, that if you record an upside down image you will have to spend time flipping all your footage during editing.