Modern Classic SLRs Series :
Olympus OM-1(n) - Instruction Manual - Part I


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"...The OM-1 has re-defined a new standard for SLR back in the '70. It created the "compact SLR" concept and changed the course of 35mm SLR development. Despite its ultra compact physical dimensions, it has proven its ability to withstand the extremes of climactic conditions, and the battering by professional photographers on hazardous assignments. Part of the total Olympus OM System, the OM-1 enables you to capture life as it happens, from photomicrography to astrophotography, from photojournalism to portraiture. With its many system components, the OM-1 permits an infinite range of photographic capabilities ... a camera that grows as your needs expand..."

Read this FIRST: There can be many reasons why you are in this site. Regardless whether you are thinking of buying a OM-1 or have already owned one, to ensure you get optimum results from your camera, carefully study this manual. Contents appearing in this site are based on an OM-1MD, thus, some sections in this site may not apply to certain earlier models. However, most of them are just confine to ways of attaching or enabling using of certain system accessories. IF you are not certain which exact OM-1 model are you owning, download this Mini-FAQ (52k) : Credit: Maintained by R. Lee Hawkins & Michael Covington & also a group of dedicated Olympus users on the Net.

Tips: Unless you are very familiar with the OM system, it is always encouraged to | click open a new window | before you attempt to carry on reading these section of User's Manual. If you have problems understanding photographic terms used in this site: Refer to the Glossary of Photography section.

Basic Camera Operations

Mount the Lens.
The OM-1 camera is not available as new anymore. So, chances are high that your OM-1 camera could have come with a lens attached. If it doesn't, these two section are essential for a relatively new OM user. Unlike other camera which has lens release button to unlock the lens to enable detaching, OM bodies have quite a different way to detach a lens, because it would require pressing lens release button which is actually on the lens itself rather on the camera body.

To mount a lens, grasp the lens firmly and align the red dots on the lens flange and the camera mount ring. Turn the lens clockwise until it locks in place.

The lens release button will spring up and you will hear a positive "click" when the lens has been fully engaged.

Caution: Do not apply pressure to the lens release button during the mounting procedure. This will assure proper coupling between the lens and the meter,

Detach the Lens. To detach the lens, press down on the lens release button and turn the lens counter-clockwise. Grasp the lens firmly and remove it from the camera body. The mounting and detaching process is easy and swift, although it may be a little too confusing to a non-OM user as there are a couple of button, manual shutter speed ring grips around. Anyway, with a little pratice, that should not be a problem and in fact, provide very logical operational ease and handling as your left hand is controlling the inner ring of shutter speed, a button for checking depth of field, the next ring with different texture and grip for focusing and the further ring of altering aperture values.

Caution: Protect your lens and camera. Always attach the front and rear lens caps when the lens is removed from the camera to prevent any possibility of damage. Never leave the camera body in direct sunlight with the lens removed. If you plan to store the camera without the lens, the use of a body cap is recommended. mountlens2.jpg

Inserting Battery(ies) The OLYMPUS OM-1 is a mechanical SLR camera. It will still operate even there is no battery(ies) installed inside the camera. The power is confined to power the metering circuit to guide the photographer on exposure information via the match needle display system. It is supplied with a 1.35V mercury battery (JIS H-D type) to power its through-the-lens exposure metering system. It will last approximately one year depending upon use and must be replaced with an Eveready (UCAR) EPX625, Mallory PX625 or equivalent. One of the primary problem with OM-1 is sourcing for replacement of batteries for the mercury cell it was designed to work with.

Note: The exposure meter does not function when the battery is not loaded, is inserted incorrectly or is drained. If the exposure meter needle does not move, remove the battery and load it again, or replace with a new one.

The OM-1 has no energy saving feature and thus you must turn the meter off by sliding the mode selector switch to off position

Warning: Olympus WARNS Alkaline battery cells such as (LR44, A76 etc.) may not be suitable to be used on Olympus OM-1.

Most Silver oxide batteries have voltage of 1.5v and may not fit well in the compartment. Alternative: try Wein lead-air button cells.

Some other issues relate to batteries


When the batteries are drained, or there are none installed in the camera, or if it fails to function normally due to extreme change in temperature, unlike electronic SLR bodies, the mechanical OM-1 body will still operate normally EXCEPT the metering information inside the viewfinder will not be available.


Should the battery be left in the battery chamber for a long period, insufficient contact may occur due to battery leakage. Thus, it is good practice to periodically clean the battery and the contact section in the battery chamber with a soft cloth. If the battery chamber is contaminated with a leaking battery, remove the battery at once and clean the chamber. Before doing so, try to clean and removed any deposits remains inside, esp the clips housed inside the compartment and do a few test shots, but I would strongly suggest you to send for examination of the damage done.


For safety reasons at home. After removal of the cells, remember to keep them away from children. Never attempt to throw them to fire place, it may explode. In any case, the camera is not the cause for any mishap - only the carelessness of its owner. Mercury cells are generally regarded as not environmetal friendly and could cause pollution, handle with care or look for subsitutes.


Battery power falls off in extremely cold temperatures and this may cause the camera's photometric circuit to cease operating. In this situation, use new batteries and protect the camera body from the cold. Note that battery power will be recovered as soon as the temperature becomes normal.


Regardless of whether the camera is switched off or not, the OM-1 always discharges a small amount of electricity and it will drain the power easily if left unattended with the Mode Selector Lever set at "ON" position.

LoadFilm.jpg LoadFilm2.jpg

Film Loading Unlike modern SLRs that would perform auto loading, film advancing and even Auto DX film Indexing, OM-1 would require you to manual do all these process to set p your camera properly to take pictures. The first step is , of cause, loading film roll into the camera. The process can't be more simple:

(1) Pull up on the rewind knob to open the camera back.
(2) Insert a film cartridge in the film chamber.
(3) Push the rewind knob back into its original position.
(4) Draw out the film leader and insert it into one of the slots in the film take-up spool. Make sure the film is aligned between the film guide pins.

operat1.jpg Winding.jpg
(5) Advance the film using the film advance lever. Make sure that the film perforations engage the sprockets on both sides.

Warning: When you pull across the film strip, please note undernealth the film is the shutter curtain, avoid pressing at that zone as indicated.
(6) Close the camera back until it clicks into place.

(7) After closing the cover, fold out the rewind crank and turn it slowly in a clockwise direction until a slight resistance is felt. This will take up any slack in the film.
(8) Turn the lever to the right as far as it will go. The film can be advanced by one frame in a single stroke or in multiple short strokes.

Note: The film will not advance after you've shot the last frame; DO NOT force the lever. Rewind the film.

Exposure/Frame Counter

Each time the film is advanced by the film advance lever, the exposure counter automatically adds one frame to the total. The counter is indexed in even numbers from "S" (start) to 36 and "E" (end). Whenever the camera back is opened, the exposure counter automatically returns to "S".Counter.gif

Film Speed (ASA/ISO) It may take a little while for a non-OM user get used to the location of the ASA/Film Speed setting. It is on top of the camera where usually shutter speed ring is located. It has a film speed dial locking button to prevent accidental shift of film speed setting. In order to change ASA/ISO film speed, first depress the button and turn. The film speed range is a fair ASA 25-1600 by modern standard but should be adequately sufficient for more than general use.

setASA.jpg setASA2.gif

(1) Press the film speed dial release button and turn the film speed dial until the ASA rating for the film being used is opposite the black line engraved on the outer ring of the shutter release button. (2) Release the button making sure that the dial clicks securely into place and does not move.

The Aperture Ring Aperture Ring Another unusual setting of the OM system is the aperture ring, it is situated at the furthest of the extension of the lens. The amount of light allowed to strike the film is represented by "F" numbers (or "F" stops) engraved on the aperture ring.

The higher the F number, the smaller the lens opening (less light).When setting the aperture ring you can use either the click-stop positions or any in-between setting to obtain precise exposure. Note: Almost all lenses in the OM SYSTEM provide fully automatic diaphragm control allowing you to focus and compose your picture with the lens "wide open." The diaphragm will automatically stop down to the preselected F stop at the moment of exposure and immediately reopen when exposure is completed. The advantage is the viewfinder remains bright for focusing and composing.

The manual
Shutter Speed Ring The shutter speed ring is in fact at the lens mount. You change shutter speed settings via two grips at each end of the scales. The only other popular 35mm SLR camera is the Nikon's Nikkormat series models. But the OM models are far superior in all segment than the Nikkormats, but that mid compact Nikon model remained very popular. Basically, both systems were somehow have great resemmblance and could have been evolved from medium format's cameras such as the Hasselblad.

Shutter Speed Ring The length of time that light is allowed to strike the film is controlled by the focal plane shutter. The shutter consists of two opaque "curtains" which travel across the film surface. The coordinated movement of these curtains determine the exposure time for your picture: 1000 indicates 1/1000 of a second and 60 indicates 1/60 of a second. The figure 1 indicates one full second. At B (Bulb) setting the shutter will remain open as long as the shutter release button is held down.

To set the shutter speed turn the shutter speed until the desired speed clicks into place opposite the red index mark on the lens barrel. Set the ring only at click-stop positions as no in-between settings can be used. Exposure Meter and Viewfinder Older cameras would, one way of another, require you to activate a lever in order to turn on or off the camera meter. The Nikon and Canons has theirs either on the shutter release button or using the film advance lever to act as a meter ON/OFF switch. The Olympuses are much more straight forward and easy to understand rather than a "guess-where-is-it" type. But a word of warning, do ensure you have turned the lever to "OFF" position after your shooting sessions. OM-1(To be fair to the Olympus, first SLR camera carried such feature was introduced quite late in seventies) does not provide a energy saving feature and battery will drain off quickly if left at "ON" unattended.

(1) To activate the exposure meter, move the meter switch lever to the "ON" position. The meter is directly coupled to the shutter speed ring, aperture ring and ASA film speed dial. It is also affected by the lens speed and subject brightness. (2) To prolong battery life, return the lever to the "OFF"position when the camera is not in use.

MeterON.jpg Viewinfo.jpg
Viewfinder When the needle swings towards the (+) position, it indicates over-exposure. When it swings towards (-), it indicates under-exposure,

Other than the compact size of the camera, when peep through viewfinder of either a OM-1(n) or OM-2(n) camera can be quite an experience. I don't regard it as extra bright, but it is more than adequate for comfortable viewing and focusing. But the truly amazing experience is its extra-large magnification projected inside th finder. I can conclude only the Pentax has given me such similar experience with their M-class SLR bodies of the mid- '70 or the Program A/Super A of the early '80. The OM-1 was the first of its kind and it was introduced during the early seventies. The magnification ratio is 0.92X at infinity 50mm lens. While the picture view field is an above average 97% which has contributed to such impressive projection.

Focusing and Composing Such comfort presents inside the prism permit easy focusing and composing of pictures. The standard focusing screen used provide a horizontal split image for many general photographic applications. While there are another close to two dozen of specialized screens to cater for your different personal configurations.

<--- In focus.

Look through the viewfinder and turn the focusing ring in either direction until your subject appears sharpest. The split image will be vertically aligned in the central spot of the Focusing Screen or a shimmering effect of the microprism ring around the central spot will disappear when critical focusing has been achieved.

Note: The OM-1 viewfinder shows 97% of the actual picture area for added convenience, when composing your pictures. You can determine the distance between the subject and the film plane by reading the distance scale on the focusing ring after you achieve critical focusing.

<--- Out of focus. The actual distance is indicated opposite the red central index mark on the lens mount ring the white scale indicates this distance in meters and the orange scale indicates this distance in feet.

Note: When smaller maximum aperture lenses are used, the split image tends to 'dim' or 'darken' at one side. You can either consider changing to a plain type or use a faster lens. However, such effect is only confined to casuing difficulty in focusing and has no effect in the final image exposed on film.

Determine Exposure Preselecting the Shutter Speed: Should you wish to select a shutter speed (for example, to stop fast action, eliminate camera shake, etc.):
(1) Turn the shutter speed ring until the desired speed is opposite the red index mark on the camera lens.
Lens Setting.jpg
(2) Look through the viewfinder and turn the aperture ring until the needle lines up in the center of the index, For fine exposure adjustment you can use any intermediate F stop position on the aperture ring. Caution: In case of handheld photography with a 50mm lens, a shutter speed 1/60 sec. or faster is recommended to eliminate the possibility of camera shake.

F-Stop: Should you wish to preselect the F stop (for example, to control depth of field for greater creative impact):

(1) Turn the aperture ring until the desired F stop is opposite the white index mark at the front of the lens barrel.

(2) Look through the viewfinder and rotate the shutter speed ring until the needle lines up as close as possible to the center of the index (click-stop positions!). (3) Make the final exposure adjustment by turning the aperture ring until the needle aligns exactly in the center of the index.

Note: At "B" (Bulb) setting, the shutter speed ring is not coupled with the exposure meter.

Holding Camera in a Correct way: Proper camera handling is important in assuring the sharpest possible pictures. Holding the Camera Horizontally
Keep both elbows close to the body, to steady the camera.

Putting the Camera into Operation The aperture ring, focusing ring and shutter speed ring are so arranged as to enable one-hand operation right up to the moment the shutter is released. Hold your breath at the moment of shutter release, Transport the film advance lever with your right thumb and depress the shutter release button with a slow, steady squeeze using the cushion, not the tip, of your index finger.

Holding the Camera Vertically For vertical shooting, keep one elbow close to your body and press the Camera tightly against your forehead. Note: 1. Steady yourself against any nearby support (such as a tree, fence, or wall) whenever possible. 2. For telephotography, or slow shutter speed photography, it is always recommended that you use some kind of support like a tripod and hold the camera steady with your hands.

Unloading Film: When the entire roll of film has been exposed, rewind the film. (1) Turn the rewind release lever counter-clockwise approx. 90° until the red dot is opposite the "R". (2) Fold out the rewind crank and wind it in the direction of the arrow. When it turns free, the film has been completely rewound back into the cartridge. (3) Open the camera back by pulling up on the rewind crank and remove the film cartridge. Keep camera and film out of direct sunlight.

Note: The rewind release lever will automatically return to the original position with movement of the film advance lever, as when reloading with film.

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Shared Resources: Supplementary articles: TTL Metering, Depth of Field, Shutter Speed & Aperture
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Credit: My old time buddy, Ahmad Ikram, Dr of Rubber Research Institute (RRI), Malaysia who shares the same passion with me and also lending his OM-1n, OM-4 and the Motor Drive 1 to me for preparing some images in this site; Mark Dapoz <>for reminding some broken links; Mr Poon of Foto Poon, Ipoh, Mr Richard, Ampang Park, Mr Lim and Miss Jenny of Foto Edar for their generosity for their OM1(n), OM2n camera and some Zuiko lenses. Mr Hans van Veluwen for mistakenly using some content earlier from his OM website; J Sorensen for providing some useful images to rectify some technical "flaws"; Mr Gen Holst for helping during the early stages of development of this OM site; Mr KKLow for some of his earlier images on the OM-1appeared in this website; Miss Wati and Mirza for helping me to convert this Operation Manual into a HTML format. Mr MCLau for rectifying some mistakes made on the earlier preview sites. Site created 'unfortunately' again with a PowerMac. A personal tribute to the creator of the OM system and also a site dedicated to all the fans of Olympuses and Zuiko Optics worldwide. Some of the content and images appeared in this site were scanned from OM official marketing leaflets, brochures and instruction manual(s) for educational purposes. Olympus is a registered tradename of Olympus Optical Inc., Japan.