The angle of view that we obtain with most cameras when using a “standard” focal length is often not wide enough.  So we put on a wide-angle lens.  This will give us the horizontal (or alternatively vertical!) spread that we require, but we are often disappointed to see in our pictures vast areas of boring foreground or sky.  What we need on these occasions is a panoramic format.  Fortunately, the large frame size of Medium Format cameras is excellent for the taking of panoramic images.

Alternative solutions, such as the Russian Horizon/Horizont cameras, use 35mm film and a rotating 28mm lens that gives an enormous horizontal angle of view of 120°.  These cameras produce negatives or slides that are 24mm high × 58mm wide (a format ratio of 2.41:1).  This will normally give you 21 images on a 36-exposure film, or 15 images on a 24-exposure film.

Dramatic images can be produced with these cameras (and I enjoy using one!), but there are a number of limitations:

• the swinging lens introduces very obvious barrel distortion to most images (straight lines become very pronounced curves), and considerable ingenuity is required at the composition stage to mask or eliminate this problem
• in practice, it is also necessary to hold the camera exactly horizontal, with the horizon running right through the middle of the image, exactly half way up, unless you want a deeply-curved horizon
• it is of course not possible to change lenses with these cameras
• the Horizon/Horizont is are not suitable for fast-moving objects, as even at the fastest shutter speed, the lens takes several seconds to expose the whole frame
• in consequence, flash photography is not possible with these cameras, either
• it is not possible to focus the lens on the Horizon/Horizont; the lens depth of field includes infinity.  To get closer objects in focus, it is necessary to stop down the lens substantially.  This makes most interior shots impossible, unless a tripod is used and a very slow speed, which prevents including people in the shot.
• there is no B setting on the shutter (nor would that be possible), so exposures longer than the camera’s slowest shutter speed cannot be made.

(The Hasselblad Xpan uses lenses that do not rotate, and will give you the wider 24mm × 65mm format, but you will be limited to just three (extremely expensive!) lenses, and you are likely to find that buying projectors for this format is difficult and also extremely expensive.)

With the Pentacon Six, the widest horizontal angle obtainable is 112°, using the Zodiak Fish-Eye lens – not significantly different from the 120° of the Horizon/Horizont.  This lens does of course introduce distortion, but as you will be using a cropped area from the centre of the frame, this will in most cases not be obvious.  The commonly-available 45mm lenses will give a horizontal angle of view of approximately 65°, which will be more than adequate for most occasions, and of course there are versions of this lens with a shift capability, if required. 

Telephoto panoramics
Of course, sometimes a panoramic format is required for a picture of a more distant subject, and any lens up to the 1000mm mirror lens can be used.  In fact some of my favourite panoramic shots were taken of lions that were not in cages, for which I used the 500mm Pentacon lens poking through the open (!) window of a stationary car.