All my cameras, 12 – Olympus SP N

November 16, 2012

The Olympus SP N is a 35mm fixed lens rangefinder camera dating from the mid 1970s – an era when almost every camera company had one or more models in this category. Generally the lenses are in the normal focal length range (40 to 50mm), with fast maximum apertures and good image quality. The Olympus has a 42mm f/1.7 lens with excellent image quality. The N is a slight variation on the more common SP model, (just adding a battery test feature as far as I’m aware.) Cameras in this category are an easy and relatively cheap way to get into rangefinder style photography for those who are only familiar with SLR cameras.

Like most classic film cameras it is a simple piece of equipment, particularly in comparison to the complexity of today’s digital cameras. The front panel has a PC socket for firing studio flash. The side of the camera nearest to the PC socket has a dial for setting the film speed on both the ASA (ISO) and DIN scales. The ISO range goes from 25 to 800 in 1/3 of a stop increments. The meter was designed to be powered by a 1.35 v mercury battery. These are no longer made however I have had accurate results using the cheap hearing aid batteries of the same voltage. These are a bit smaller then the old batteries so I put a circle of cable around the battery to hold it in place. Of course you could use a hand held meter but it’s nice to be able to use the camera meter. The meter readout appears in the top of the viewfinder window, where a needle will point to a number on the EV scale between 3 and 17. Based on this reading you would then choose a combination of aperture and shutter speed for correct exposure. How this works in practice is an impressive bit of industrial design. The shutter speed and aperture controls are next to each other on the lens, with a small window displaying the EV number at the far end of the shutter dial. Different combinations will reveal different EV numbers, with the idea being that you choose a combination that gives the same EV number given by the light meter. Even more impressive is that once you get this EV number you can keep it while turning the aperture and shutter dials together to bring up different combinations of aperture and shutter speed while allowing in the same amount of light. For example, if the meter reads EV 10 at 100ISO, f/5.6 at 1/30 will bring up EV 10 on the lens. If I want more depth of field I can turn them together to f/16 at 1/4 which still gives EV 10, or I can move them to f/2 at 1/250 for less depth of field or a faster shutter speed. Hats of to whoever came up with that clever system.

The camera also has an auto exposure setting, which I have never used, as well as a clever auto flash feature that I have used and which works well. For auto flash you need to know the guide number of the flash and relate it to the ISO of the film. The auto flash settings are on the same lens ring as the apertures, so once you turn to the GN section you are getting the camera to choose the aperture. The GN is set according to the flash unit in use and assumes the film is 100 ISO. As you manually focus the lens, the camera takes into account the GN and distance and calculates the correct aperture. This is based on the simple flash formula  GN / distance = aperture; e.g. with a flash with a guide number of 40 (in meters) and a focus distance set to 5 meters the correct aperture is f/8 and the camera will know to select this. If the film ISO is not 100 you could account for this by choosing a different guide number to fool the camera into selecting the correct aperture.

The viewfinder is bright and has the classic rangefinder design of frame lines that show what will be in the photo, along with a generous amount of space outside the lines so the photographer can see what else might be included or excluded to improve the composition. This type of viewing is similar to the framing devices that artists use to determine the composition of a drawing, and is significantly different to SLR through the lens viewing. Having a fixed lens avoids the problem of requiring a mechanism to bring up varying frame lines for changing focal lengths. These older cameras are far from being obsolete or collectors items – if you shoot film and get one of these in good working order they are capable of producing excellent results as well as being enjoyable to use.


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