Olympus OM-1: The SLR Game Changer

A late-production example of the diminutive OM-1 MD with even later-production OM Zuiko 50/1.8

  Updated May 21, 2021

  Game Changer. An overused phrase nowadays to be sure, but when applied appropriately it conveys an unmistakable break with the past and an opening up of previously unthought-of possibilities. So it was with the Bobby Orr of SLRs - what came to be called the Olympus OM-1. Bobby Orr??? It's like this, eh. Like Bobby Orr totally changed hockey forever, eh. Like, before Bobby Orr, defensemen didn't lead the rush, eh, or score more than 21 goals a season, eh (he did so for 7 consecutive years, topping out at 46 in 1975), or like score more than 60 points in a season, eh (he scored over 100 for 6 straight years, winning two scoring titles along the way, something no defenseman has done before or since). Or win MVP, eh (three years consecutively, only one other defenseman has won MVP once in the last 50 years). Or win Best Defenseman in the league like eight times in row, eh. And he did all that on like, one knee, eh (his left knee was first seriously injured in his second year in the NHL and he would have 13 or 14 surgeries on it over the course of his career). But his effect on the game was far more pronounced than just the record books. Offensively-minded defensemen (paradox, anyone? ;-)) became indispensable in hockey. Arena construction went nuts in New England as thousands of kids were turned on to hockey by "numbah foah, Bawbee Oah". He turned casual or non-fans into hockey lifers. GAME. CHANGER. In the same era, the Olympus OM-1 did likewise for 35mm SLRs. In this article we will concentrate mostly on the features, operation, and handling of the OM-1 and how it changed the SLR landscape and 35mm photography forever.

  An Auspicious Debut 

    At its unveiling in July 1972 (after five years in development), Olympus designated the camera M-1, after its chief designer, Yoshihisa Maitani. And the entire system to be built around it was to be the M-System. That was all hunky dory until Leitz saw it at Photokina in September of that year, threw a hissy fit, and protested that only they had the right to use the "M" designation for their interchangeable lens 35mm rangefinder and viewfinder cameras such as the M1 (note the lack of a hyphen). It didn't matter that a single letter could not actually be trademarked nor that Olympus was applying this to an S...L...R. Of course, Leica had been dealing with Japanese copycatting for well over 30 years by this point, so their oversensitivity shouldn't have come as a surprise. To rub a little more salt in the wound, they had been taking a royal butt-kicking as far as sales went for nigh-on a decade now from these same manufacturers, particularly when it came to SLRs ;-). 

   Anyhoo, rather than waste time arguing with the wound-up Wetzlarians, Olympus simply acquiesced and renamed the system "OM" on the spot (examples of which started to appear in early-1973) and it seems that they told Leitz that there had only been 5,000 M-1s produced and that they would destroy the rest of the top plates with the M-1 embossing ;-). This feather-unruffling worked, even if the truth was stretched a bit. Olympus had put a lot into M-1 production and they were not about to just trash a bunch of perfectly good parts. So they used up their existing supplies and reserved most of the M-1s for sale in Asia and could still sell 5,000 M-1s in Europe without incurring any further ire from Leitz (remember, this was pre-Internet and globalization was still a twinkle in the eye). M-1 production extended until at least February 1973 (ascertained by date-codes under the film door pressure plates).

    Whether called M-1 or OM-1, the result was still the same: the camera was the talk of the industry and Olympus proceeded to absolutely bury Leitz when it came to sales (surprise, surprise), which came to approximately 1.5 million copies before the camera was updated as the OM-1N in 1979. For comparison, total Leica SLR production from 1964 - 2009 was around 488,000 (for 13 separate models). And as for their vaunted M-series, Leitz managed to produce just under 52,000 Leica M4, M4-2, M5, and MDa models combined from 1972 - 79. So, Olympus didn't make out too bad with their nice-guy attitude :-). The irony in all of this was Maitani-san's affection for Leica, as his personal camera had been a Leica IIIf, and it was the compact, dense nature of that body and its lenses which inspired his approach to designing a better SLR. For some lemon juice in the papercut for Leitz (who renamed themselves Leica after their most famous product in 1986), we now know that about 52,000 Olympus M-1s (oh my, the irony no longer drips, it is a torrent ;-)) did manage to escape into the wild before the nomenclature change took effect :-o.

    The OM-1 was intended for professional and advanced amateur use. It was tested for 100,000 shutter actuations (equivalent to the Nikon F & F2 and Canon F-1) in conditions ranging from -20 to +50 Celsius (-4 to +122 Fahrenheit), while reducing weight to 740 grams (26.1 oz) with a 50/1.4 lens mounted versus 1,185 grams (41.8 oz) for the Nikon F Photomic FTN and 1,180 grams (41.6 oz) for the Canon F-1 with their respective 50/1.4 lenses mounted. Initially, the Nikon and Canon models had the advantage of attaching an accessory Motor Drive, but Olympus rectified this in 1974 with the introduction of the OM-1MD (initially, a sticker was added to the front of the camera with a permanent smaller inset plate soon replacing the sticker). 

  Features Unique to the OM-1 Upon Its Introduction

    Aside from the obvious downsizing and weight-reduction from standard SLRs of the day, the OM-1 introduced some other elemental changes to SLR design that were soon emulated by its competitors:

• Air-Dampened Mirror - Vibration caused by the movement of the mirror out of the light path to the film was a long-standing bugaboo for the SLR. Until the OM-1 came along, dampening of this vibration was left to a skinny foam bumper on most SLRs. Along with the miniaturization of a multitude of other components, one of the most inspired innovations by Olympus was a miniature shock absorber that utilized an air-piston/cylinder combination to absorb much of the energy produced by the swinging mirror. Air-dampers soon were popping up on all sorts of other SLRs due to their efficacy in reducing the effects of mirror-slap in pictures below 1/125 sec. shutter speeds.
• Viewfinder - Average SLR viewfinders in 1972 showed the subject from 0.8 - 0.85x magnification with a 50mm lens focused at infinity. And showed 90 - 94% of the actual area that would be rendered on film. Nikon prided themselves on having a 100% area viewfinder @ 0.8x magnification on the F & F2. With the OM-1, Olympus took the approach of more magnification (0.92x) with 97% coverage, just a tick behind the top-flight Nikons. All other things being equal, more magnification contributes the most to ease of manual focusing with an SLR. The bump from 0.8x to 0.92x is noticeable. They coupled this with a wider angle of view than normal to provide the best overall viewfinder experience among SLRs at the time, and it could be argued, of all time. Olympus was also one of the first SLR makers to adopt silver prism coatings versus the aluminum-based prism coatings used by most of their competitors. They paired this with the first multicoated reflex mirror to achieve a 70%-brighter viewfinder than the industry norm. Again, this set off a spate of bigger, brighter viewfinders among the other manufacturers.
• Interchangeable Focusing Screens (IFS) - It was a truth universally acknowledged, that a professional-calibre SLR must have user-interchangeable viewfinders & focusing screens. Interchangeable viewfinders necessitate adding more structure, and therefore bulk and weight, to an SLR. Maitani was having none of that, so he exhorted his team to find an alternative that would still allow for the interchanging of focusing screens while retaining the overall strength advantage and size & weight savings of a fixed prism finder. In another first, they came up with a swing-down latching frame that was accessed through the lens mount and that could be opened with a small tweezer which also served to allow the user to grab a tab on the exposed focusing screen (you do not want to get your grubby fingerprints all over the screen ;-)) for removal and then do the same in reverse with the replacement screen, all in a matter of seconds. Olympus also deleted the standard condenser section of an SLR focusing screen and compensated for this by curving the bottom surface of the pentaprism. This allowed them to substantially reduce the thickness of the screen. The combination of these efforts and the elimination of the integrated frame-on-screen approach used by other manufacturers saved weight on the order of 88% (14 grams, which was a lot when you worked for Maitani ;-)). Olympus' solution for interchangeable focusing screens became the industry standard (Contax RTS/II/III, Pentax MX, all enthusiast Nikons from the FE forward, all enthusiast Canons from the AE-1 Program forward, all professional and enthusiast Canon EOS bodies, and all professional Minolta Maxxum/Dynax bodies to mention a few) and is still used on the latest professional and prosumer DSLRs. Even Nikon gave in with the F6, their final professional film SLR ;-). 
• Lens Size and DOF Preview - Having the lightest and most compact SLR would be of marginal benefit if the lenses were not matched for it. Overall balance and handling would have suffered if Olympus had just left it at that. And here was another far reaching innovation: size and weight-reduction of the entire OM lens system. OM lens lengths and weights ranged from  20 - 30% less than their rivals in 1972. This set off a flurry of weight and size reduction amongst the other Japanese lens makers that extended into the mid-1980s. Until the Pentax SMC-M series of lenses first started appearing in 1976, you could guarantee that Olympus would have the smallest and lightest lens for a given focal length/maximum aperture value (and even then, they were always in the mix). The OM team also decided to incorporate the depth-of-field preview system into the lenses rather than the body. While this was nothing new, it allowed for one less control to take up precious space in the OM-1's very dense internal layout and also had the added benefit of making any future manual focus OM bodies DOF-preview-capable. 
• Motor Drive - The 5 frames per second (fps) performance of the OM-1MD without mirror lock-up (MLU) was without peer among mainstream professional or enthusiast cameras at its introduction and was only matched by the Pentax MX (1976) and Canon A-1 (1978) throughout the remainder of the 1970's (the Nikon F & Canon F-1 topped out at 3 fps, and the Minolta XK Motor & Nikon F2 at 3.5 fps without MLU). Sure, both Nikon and Canon came out with special high-speed versions of the F, F2 and F-1, but these were reserved solely for professional photojournalists covering the Olympic Games. Such hi-strung beasts lacked exposure meters, automatic aperture stop-down capability, and resorted to MLU (Nikon F) or a fixed pellicle-style mirror (Canon F-1 & Nikon F2 MD100) to achieve 7, 9, and 10 fps, respectively. And they were ridiculously bulky and heavy with double the power requirements (16 or 20 AAs) of the standard versions. 

  Layout and Handling
  
    At a casual first glance from the front, the OM-1 (apart from its size) does not appear to differ much from traditional SLRs as far as control layout is concerned. There is the familiar dial to the left of the film advance lever, with the rewind knob and self-timer lever also in their common locations. But as soon as you hold the camera in your hands and gaze down upon the top deck, you are immediately struck by the strangest set of shutter speed markings from 25 - 1600, with 25, 50, 100, 200, 400, 800, and 1600 marked in yellow on the dial. What the hey?! Then you see three letters on the inside circumference of the dial "A...S...A". Aha! So it's not a shutter speed dial at all...it's the film speed dial (ASA was the precursor to ISO). Almost simultaneously, your left middle finger and thumb have cradled the aperture ring. You now glance at it and...what's that? B, 1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000? Have you woken up in some Salvador Dali-themed photographer's nightmare?? Nope, welcome to the shutter speed ring ;-). Want to make a guess for the aperture ring's location? Too late, your left index finger has already found it. So what gives?    

ASA (ISO) Film Speed Dial

Shutter Speed, Focus, & Aperture Rings

​   We have a couple of things to unpack here: 1) optimization of internal space, and 2) Maitani's favored technique for photography.

1. The internal right side of then-current SLRs was customarily crowded with mechanisms for the meter needle, shutter speed control, and film advance. In order to increase flexibility, Maitani elected to move the shutter speed control closer to the actual shutter workings located in the bottom of the body. Doing so concurrently freed up space to place the ASA dial directly above the galvanometer for the meter, further improving modularity. This contributed more than anything else to the width-reduction of the OM-1 over its contemporaries (as much as 12mm or 7/16"). 
2. In Maitani's own words: "In my style of photography, while supporting the lens you can focus, check the depth of field, and change the shutter speed. That's quite an improvement I think." This left-hand-centric control philosophy meant that the right index finger was always on the shutter button in order to capture the "decisive moment". And don't forget that his Leica experience had conditioned him to having the aperture ring at the front of the lens, too. In the interests of ultimate responsiveness, Maitani even went so far as to veto any sort of shutter release locking mechanism, which did not please all magazine testers: "When the camera went on sale, the camera magazines pointed this out and severely criticized it. The counter-argument I wrote then was that you might waste a frame because there's no shutter lock, but in my experience sometimes you don't get two chances to take a photo. You miss that unexpected photo opportunity. Whatever camera I'm carrying, I prefer to have the shutter ready to fire immediately." (I cannot fault his reasoning on that :-)). This also keeps one from developing the habit of leaving the shutter cocked when the camera is returned to its bag, and thus decreasing the lifespan of the springs used to activate the mechanical shutter. 

   The location of the film rewind release was another variation from the norm, being easily activated by the right index finger on the front of the camera, instead of fumbling around on the bottom or having to remove a "Never-ready" case to access it. While downsizing was a basic tenet, a deliberate effort was made to keep control sizes as large or even larger than the full-size competition.  

   If you are coming from a traditional Japanese SLR, the OM-1 definitely takes some getting used to. But if you are willing to stick with it and use it the way its designer intended, operation soon becomes instinctive. Yes, there is no display of the set shutter speed or aperture value in the viewfinder, but as your muscle memory builds you begin to intuitively sense the settings. For example, with the two opposed shutter ring gripping surfaces at 3 and 9 o'clock, you know that the shutter speed is set at 1/30 sec. The DOF preview button on the lens falls right into the curve of your left middle finger. The OM-1 rewards repetition. 
 
    The OM Zuiko focusing ring rubber is one of the grippiest in vintage SLRdom. Olympus developed a fine-grained diamond-pyramidal pattern that grabs your fingertips more securely, with less pressure required, than any other rubber-gripped series of lenses in my experience. As far as the feel of the other controls goes, everything has a feeling of solidity and quality, with maybe the film advance being the only thing that can feel a bit rough compared to such gems as Minolta XEs or XDs, but this can depend a lot on the condition of the particular copy and whether it needs a CLA (clean, lube, adjust). 

  Impact on the Industry

   At a time when the overall sales of fully-mechanical, manual exposure SLRs were beginning to fall as electronically-controlled Auto Exposure (AE) models were taking off, the OM-1 bucked that trend, averaging sales of nearly 200,000 per year until it received a light refresh to become the OM-1N in 1979. It would continue to be produced in that form until 1987, making for a very successful 15-year run. Olympus positioned it perfectly in the marketplace, with its pricing far below the Canon, Minolta, and Nikon professional models and right in line with their enthusiast-level SLRs, while offering a feature-set distinctly weighted to the pro side. For example, in 1977, Competitive Camera of NYC had the OM-1 with 50/1.4 Zuiko (740 grams/26 oz) priced at $1,135 USD (inflation-adjusted to 2021, as are all prices in this article), with the Motor Drive 1/M.18V Battery Grip & Holder adding $1,445 and 610 grams (21.5 oz) including 12 AA batteries. Compare that to:

• Canon's top amateur mechanical model, the full-size FTbN w/ FD 50/1.4 ($1,115 USD), which had no provision for motor drive or IFS, and weighed 1055 grams (37 oz). The Canon F-1 w/ FD 50/1.4 came in at $1,855 USD and 1085 grams (38 oz) as the 50/1.4 had been given a 45 gram weight reduction in 1973 following the introduction of the OM-1 (hmmm...I wonder why? ;-)). The Motor Drive for the F-1 added another $1,465 and 920 grams (32 oz) including 10 AA batteries. 
• Minolta's top amateur mechanical model, the SRT-202/SRT-303b/SR-505 w/ MD-Rokkor 50/1.4, which also had no motor drive or IFS and weighed 945 grams (33 oz), cost $1,075 USD. The professional XK/X-1 w/ 50/1.4 MD-Rokkor bumped the weight to 1140 grams (40 oz) in non-motorized form for a cool $2,165 USD, nearly double the OM-1 & 50/1.4 combo. And the XK Motor version with lens and batteries would pulverize the scales and your bank account to the tune of 1895 grams (67 oz) and $5,260 USD.
• Nikon's FM was their brand-new top amateur mechanical model in 1977, obviously designed after the OM-1 came on the scene and it showed: its 845 gram weight with the also-new 50/1.4 AI Nikkor was at least getting closer to the OM-1 than Canon's and Minolta's end-of-life full-size amateur models. The FM did have a more modern vertical shutter, but with the same speed range as the OM-1, and a faster-acting gallium photodiode (GPD) meter, but no IFS or independent MLU (the mirror did swing up and lock when the self-timer was activated). These were not massive advantages by any stretch. But you had to pay $450 USD more for the Nikon combo. The FM's accessory MD-11 motor drive topped out at 3.5 fps (versus 5 for the OM-1's) and tacked on another $680 USD and 600 grams (21 oz) with 8 AA batteries for a combined total of $2,265 USD versus the $2,580 USD for the OM-1 w/ 50/1.4 & Motor Drive combo. And here comes the big one...the F2A w/ 50/1.4: $2,290 @ 1085 grams (38 oz); and add another $2,330 to spin your film with the MD-2 at 3.5 fps without MLU while adding another 840 grams (30 oz) of weight. So you could buy two OM-1s for the price of a single F2A :-). And add a motor drive for $900 USD less than the Nikon MD-2...while saving 575 grams (20 oz) of weight per body/motor drive combo. For pros used to carrying at least two or three bodies at a time, that started to add up quickly, in terms of dollars and slipped discs ;-). 
• Pentax' MX of 1976 was the most direct response to the success of the OM-1 from any manufacturer. Pentax basically said, "we will do whatever it takes to match or beat the OM-1 in every specification". The MX undercut the Olympus by 0.5mm (0.020") in width and height (let me know if you can feel that difference in hand ;-)), was 2.5mm shorter with a 50/1.4 lens mounted and weighed exactly the same configured as such, while shaving 15 grams off of the Olympus as a body only. Pentax sacrificed MLU to achieve this, while using a GPD meter and a basically-identical shutter configuration. They bumped the viewfinder to 0.97x @ 95% coverage (at the cost of eye relief) with full shutter and aperture information in the viewfinder along with an LED meter readout. They adopted the IFS system with 8 screen choices available, the air damper for the mirror, a motor drive system that gave (gasp!) 5 fps with a very familiar grip configuration including a vertical battery pack that held 12 AAs and weighed 663 grams (ooh, missed the OM Motor Drive 1 with Grip by 53 grams) ;-). The top and bottom plates on the MX are some of the thinnest you'll find on a vintage SLR illustrating the lengths Pentax went to in order to compete with Olympus. And last but not least, Pentax introduced an entirely new line of SMC-M lenses, only a year after they had introduced an entirely new line of SMC Pentax lenses. And they went ballistic in their efforts to reduce size and weight knocking up to 50% of the weight from some optics. In many cases, Pentax accomplished this by simplifying the optical formulas of these lenses (glass is the heaviest component in a lens, after all ;-)). This obsession with weight reduction did exact a toll, however. For just one example, the SMC Pentax 20/4 weighed 300 grams (10.6 oz) with 12 elements, the SMC-M version dropped to 150 grams (5.3 oz) and 8 elements. There was no way that Pentax would be able to maintain the same overall optical performance with such a reduction in the number of elements. They obviously felt the tradeoff was acceptable, though, as the OM Zuiko 21/3.5 sported 7 elements and came in at 180 grams (6.3 oz) and that was their real target with the SMC-M lenses. The MX w/ SMC-M 50/1.4 sold for $1,215 USD at Competitive Camera in 1977, just above the OM-1 combo. The Motor Drive MX/Battery Grip M added $1,300 USD to that, which made it a virtual wash if you chose to equip your OM-1 or MX with a proper motor drive. 

    Even more than the sales success, it was cases like the Pentax MX that drove home the impact the OM-1 had on the SLR business. By the end of the 1970s, Olympus had pushed their way into the top echelon of Japanese SLR makers, expanding the long-standing "Big 4" into a "Big 5". Bodies and lens lineups throughout the industry were put on diets. The full-size SLR was dead.   

  The OM-1 Today

    By the time the OM-1N came along in 1979, electronic SLRs had really taken over as far as market share was concerned. Olympus' own OM-2, introduced in 1975, was another success for the company. Even more noticeable was the runaway ascendancy of consumer-targeted electronic SLRs, following the introduction of the Canon AE-1 in 1976. Olympus added their OM-10 to the consumer cornucopia in 1978. The OM-1N found itself superseded in the lineup by the OM-3, Olympus' final pro mechanical SLR offering in 1983, but remained in production until 1987 with the last remnants selling through 1988 for $710 USD (remember that is inflation-adjusted) with a 50/1.4 lens. That was the price of surviving into the Auto Focus (AF) era. Many an OM-1 was relegated to an attic, basement, or closet, pushed aside by all-automatic point & shoots (my Dad referred to them as PhDs - Push here Dummy ;-)), or the latest whiz-bang polycarbonate pretender to the throne. There have been both benefits and consequences from the banishment of these beauties for decades. The benefits being that many low-mileage OM-1s (especially OM-1Ns) are still around, needing only a bit of love to resuscitate them.

   The biggest problem encountered by potential OM-1(N) (and OM-2(N)) buyers nowadays is the de-silvering of the pentaprism due to deterioration of the foam that Olympus used to "protect" the prism from outside damage. While most full-size SLRs had relied on a rather large air gap between the prism and the outer housing to provide a buffer zone from impacts to prevent prism breakage, with the OM-1 that was out of the question in their desire to reduce bulk. So, their solution was to pack the much-smaller gap with foam to provide a similar level of protection. Which worked fine...until the chemical process of the degradation of the foam would eat the silver coating of the prism. This shows up as grey, green, or black patches in the viewfinder or kind of a wispy or shimmery effect, particularly in the bottom half of the viewfinder. If you are looking at obtaining an OM-1, your first order of business should be to evaluate the viewfinder. Even if it looks good, be prepared to have any existing foam removed (you can DIY or have this done by a repair tech) as it will just be a matter of time before deterioration sets in. Interestingly, on OM-1 bodies with seven-digit serial numbers roughly between 111xxxx - 163xxxx, the foam was deleted from the factory according to John Hermanson, a long-time factory-trained Olympus technician (check out his website www.zuiko.com). With the start of OM-1N production, the foam returned, so you will definitely want to make sure it is removed if you get one. In practice, the foam offered little in the way of additional protection, so you really lose nothing by getting rid of it. Of course, replacement prisms are long-gone now, so the only way to replace a corroded one is to find a donor OM body with a good prism ​(the same prism was also used on the OM-10, OM-20/OM-G, OM-30/OM-F, and OM-40/OM-PC and they are to be preferred for replacements as none of the consumer models used the foam, according to John) and make the transfer. Here is a video for DIY foam removal: 

    Aside from the foam, the OM-1N or late-production OM-1 bodies are to be preferred. Olympus made 19 internal improvements from the M-1 to the MD version and 15 more over the remainder of OM-1MD production to the OM-1N's debut. The most noticeable changes to the OM-1N were the inclusion of a flash ready & correct flash exposure LED indicator in the viewfinder and a subtly reshaped film advance lever & rewind release button. Other additions included: contacts for databacks, and modified springs in the film door to hold the film cartridge in place more securely. Obviously, your best chance of finding a good prism will be with a late OM-1 and if flash operation is not a big deal for you, you will get nearly all of the other internal improvements that came with the OM-1N.

   The next issue to be aware of with any OM-1 (or OM-2) is failure of the film to advance completely to the next frame. This stems from a need for a proper CLA of the film advance mechanism. It uses a clutch system that will fail to engage fully if it has suffered contamination or excessive wear. Really, budgeting for a complete CLA is the course of wisdom if you want to get the most enjoyment and life out of any vintage SLR. The OM-1 was designed to be serviced and repaired, it was not throwaway. So a CLA is always worth it, in my mind.

   Another problem that can be addressed while a CLA is being performed is the meter circuit, which was designed for the 1.35V 625 mercury cell that has been banned for a long time now. A Schottky diode can be installed into the power chain that will properly adjust the voltage for use with the current 1.55V SR44/357 silver oxide cell (with an o-ring installed around its circumference to center it properly in the battery chamber). John Hermanson includes this modification with his standard OM-1 CLA service. An alternative is to use the MR-9 battery adapter (around $30 - $40 USD, nowadays) that uses the smaller 386 silver oxide cell to power the meter. This adapter had a diode integrated in its construction to achieve the same effect as the conversion. The drawback being that the 386 cell has less capacity than the 357 and will thus not last as long. 

   Other than those few niggles, the OM-1 remains one of the finest mechanical SLRs ever to be produced. The combination of compactness, light weight, rugged build, superb viewfinder, responsive controls, and the extensive OM system of lenses and accessories make it a great candidate for beginner or connoisseur, alike. SLRs were never the same after the OM-1, and if that doesn't make it a Game Changer, I guess I don't know what does :-).

  References:

    OM-1 @ https://www.olympus-global.com
    Special Lecture - the OM-1  - the XA Series @ https://www.olympus-global.com
    The Olympus M-1 Information Page @ http://olympus.dementix.org
    Olympus OM System - Concepts and Overview @ http://olympus.dementix.org
    Various Olympus Brochures @ www.pacificrimcamera.com
    Camtech Photo Services @ www.zuiko.com
    Leica M Serial #s @ https://cameraquest.com/mtype.htm
    Leica R-system cameras @ https://www.apotelyt.com/camera-line/leica-r-system
    Bobby Orr Statistics @ https://www.hockey-reference.com/players/o/orrbo01.html