The Multi Purpose Rail is one of the most versatile and useful tools for the Photographer, so we'll take a brief look at some of the uses we've found so far:
Single Row Panoramas
To make single row panoramas free from parallax errors, you need to rotate the camera/lens combination about the nodal point of the lens (we'll be explaining this in detail soon in our Panoramic Gear Guide).
To keep your horizons straight across stitched images, you need both a leveling base and a panning base. You can either buy these items separately, or use a tripod head that is designed for such a function, like the Acratech GP (shown above), or the Photo Clam Pro Gold II Easy PQR or Photo Clam Multiflex Geared Head.
Then you need a Multi Purpose Rail with Clamp attached as shown above, so you can offset the camera until the rotation is about the nodal point of the lens. Pictured above is a Hejnar Photo 8" Multi Purpose Rail and Kirk 2.0" Clamp.
Multi Row Panoramas
Like single row panoramas, successful multi-row panoramas also need to be free from parallax errors. To do this you need to be able to rotate the camera/lens about the lenses nodal point both horizontally and vertically. The setup below achieves just that, and allows for full 360° spherical panoramas:
As with the single row panoramas, you need both a leveling base and a panning base. Some tripod heads can serve this function, such as the Acratech GP (shown above), or the Photo Clam Pro Gold II Easy PQR or Photo Clam Multiflex Geared Head.
The rest of the setup consists of three Hejnar Photo 8" Multi Purpose Rails, a Hejnar Photo 90° block, a Hejnar Photo Clamp, and a Really Right Stuff Panning Clamp. We'll detail the specifics of this setup shortly in our Panoramic Gear Guide, but this setup is rock solid and fully Arca compatible. At just over $400 (excluding ball head), its most compelling feature is the fact it also about half the price of similar Arca panoramic solutions from other manufacturers.
Long Lens Support
Controlling vibrations when shooting the super telephoto lenses always poses a challenge, another prime use for a multipurpose rail:
Pictured above are a Hejnar PHOTO G-006D 12" Rail with an Really Right Stuff Lens Support.
Macro photography often requires critical composition. More often than not, being able to slide a rail through a clamp to make small, critical adjustments is a lot easier and faster than repositioning your tripod or other support device.
Pictured above is a Hejnar Photo Rail mounted on a Kirk Window Mount using a Manfrotto 468MG Ballhead.
As a Lens Plate
For larger lenses that have two or more tripod sockets built into the lens foot, a multi purpose rail works perfectly as a lens plate, giving plenty of room to add other accessories (like the flash bracket as shown below).
Pictured above is a Hejnar Photo Rail being used with a Nikon 200-400mm lens on a CB Gimbal. Note the replacement Kirk Foot we used wasn't long enough to allow us to attach the Wimberley Flash Bracket, but adding a multi purpose rail solved the problem.
In The Studio
Want a quick and easy way to put multiple speed lights through an umbrella? Put a clamp on your light-stand and attach some cold shoes to your multi purpose rail as shown below. This allows for much tighter positioning than the more traditional approach of using multiple Justin clamps.
Pictured above is a Kirk Clamp, a Hejnar PHOTO Rail and three cold shoes.
Setting Up Multiple Cameras
Pictured below a multi purpose rail is being used to support two camera setups. This is obviously a more specialized use, as would be a video camera/DSLR combination set up on the same tripod.
A multi purpose rail is one of the most flexible tools you can have when it comes to camera support. Above are just a few of the uses we've found so far, there are plenty more.