Canon Canonet QL 17 GIII

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The Canonet QL 17 GIII is the final, high-end version of Canon's famous Canonet compact rangefinder series of the 60s and 70s. It provides shutter-priority auto-exposure and parallax compensation with its 40mm f/1.7 lens.

Physical description

The camera is small for an autoexposure rangefinder of the time, but very dense, with rounded corners and a black leatherette. The camera came in brushed nickel or solid black, which is more sought after on the antique market. Film advance, exposure counter shutter release, rewind crank and the hot shoe are on the top plate, while the battery check is on the viewfinder eye-piece, and the rewind button, tripod socket and battery compartment are on the bottom plate. All other controls are on the lens body.

Two interesting indicators are seen through small windows on the top rear of the camera: one shows red lines that "flicker" or wiggle when the film is winding properly, and the other indicates the state of the shutter: white means uncocked, red means ready to fire.

Focusing and optics

The coated, house-made lens is, like those of many fixed-lens rangefinders, at the wide end of what might be considered the "normal lens" range, at 40mm. This is actually close to the diagonal of one full frame of 35mm; a good rule of thumb is that a focal length equal to the frame's diagonal approximates the effective field of view of the human eyes (i.e., both eyes minus the peripheral vision area,) which is considered to be the desired field of view for a normal. 40mm at one time was a common figure for the "normal" lens, but 50mm won out for a number of reasons. For one thing, it is said to be easier to make a lens faster than f/2 if it has a focal length in the range of 50mm to 58mm.

The lens is decently fast at f/1.7, competitive with the 1.7, 1.8 and 1.9 of many mid-range SLR lenses of the time, and it is a figure Canon were apparently very proud of, as the camera and two of its predecessors were named after it. The aperture is part of a mechanism that includes the advance lever, the shutter release and the meter, and so behaves rather oddly. If one manually widens the aperture while the camera is un-cocked, nothing appears to happen until the film is advanced, when the diaphragm snaps to the selected aperture. The same is not true of stopping down the aperture while the camera is un-cocked. When the camera is cocked, the aperture may be adjusted in either direction normally. When the camera is set to autoexposure mode, the aperture remains wide open and stops down when the shutter release is pressed. The diaphragm has five blades and so produces noticeably pentagonal bokeh and possibly pentagonal lens flares, when the lens is not at full aperture. Unlike many leaf-shutter cameras, the diaphragm is clearly visible in front of the shutter, rather than behind it.

Focusing is by coincident-image range-finder. The QL17 has a fairly advanced rangefinder, with bright frame-lines that move diagonally down and to the right when the camera is focused in the near-field, to correct for parallax. Also lit by the same window is the meter, which shows the aperture being selected by the autoexposure circuit; curiously, the scale skips f/2, probably to fit an eight-stop range on a small display. The rangefinder spot is fairly large, bright and rectangular, with soft edges, appearing yellow against a rose-tinted image. Some photographers may be bothered by persistent ghost images in the viewfinder, caused by the beam-splitter.

The focus is manipulated by a lever operated by the photographer's left hand. On the other side of the focus ring, there is a distance scale in both meters and feet, moving past a line on the camera face, but no depth-of-field scale. The lens is sharpest at f/4 - f/5.6 [1]. Despite the lack of a depth-of-field scale, there are two dots on the distance scale (one each on each of the two lines) that, intentionally or not, indicates the (approximate or exact) hyperfocal distance at f/8. For daylight street photography, it may be convenient to leave the focus pointing to these marks, in which case everything from 11 feet (at f/8) or 7.3 feet (at f/16) to infinity will be acceptably in focus.


The camera has a conventional, mechanical Copal leaf shutter in a between-lens position. It offers bulb exposure and shutter speeds from 1/4 to 1/500, with X flash sync at any speed. Bulb exposure cannot be selected without depressing a catch on the shutter-speed ring. 1/30 is in blue, unlike the other speeds, presumably to indicate that the photographer should not use it (or any speed below it) without a tripod, as camera shake becomes a problem at this combination of speed and focal length.

Metering and automation

The meter is a CdS cell mounted on the lens, just above the front element, with its own Fresnel condensing lens and a miniature aperture dial which moves with the shutter-speed selector, allowing more or less light to fall on the meter depending on the shutter speed. The camera offers shutter priority autoexposure for film speeds between 25 and 800 ASA, as well as unmetered manual exposure mode; the meter or at least the readout is deactivated when "A" is not selected on the aperture dial. The shutter-priority system bears a resemblance to the system used on the AE-1 five years later, with a very similar meter scale in the viewfinder and the familiar "A" mark on the aperture ring. However, due to the differences between a system SLR with TTL metering and a fixed-lens camera with an exterior-mounted meter, the implementation is different: rather than an electronic system which reads the light cell directly and controls the solenoid that stops down the attached lens, as in the case of the AE-1, the QL17 uses a refined version of the old trapped needle mechanism.

In shutter-priority mode, the meter-selected aperture is indicated in the viewfinder by the meter gauge. Since the metering unit is placed within the filter thread, the camera compensates automatically and perfectly for any filter (assuming the filter is uniform across its width,) because the filter affects the meter in the exact same way that it will affect the film. Pressing the shutter release partway "traps" the needle at its current position and stops down the aperture to the f/stop it indicates.

The camera was designed to use the PX625 mercury battery, no longer available in the US. The circuitry in the camera holds up well against slightly higher voltages, so one may use a PX625A alkaline battery as a drop-in replacement, but this will cause exposure errors at the beginning and end of the battery's life. Anecdotally, this amounts to about a stop-and-a-half of underexposure at the beginning of the battery life, and a stop or so of overexposure at the end. Whether this presents a problem or not depends largely on the film and the level of accuracy desired: while slide film has essentially no latitude and must be exposed correctly, black-and-white film has a large, forgiving exposure latitude, but tonal response does tend to suffer at the extremes of this range. Color negatives are even more forgiving in some ways, with an especially large latitude for overexposure, depending on the film and the skills of the person printing/scanning the film. The end result is that underexposure has a more negative effect on most film than overexposure, so for the first part of the battery's life, the photographer may prefer to compensate by changing the film speed on the camera to about half the box speed, or whatever causes the camera's reading to match an accurate handheld meter. The same need not necessarily be done towards the end of the battery's life, unless slide film is being used. Battery use drops to a minimum when the cap is on, or when the camera is in manual-aperture mode.

The only mechanism that requires a battery is the meter, so the camera may be used manually without a battery.


A dedicated flash unit was sold with this Canonet, the Canolite D, which communicates via a specialized contact in the Canonet's hot shoe, and synchronizes with the camera in autoexposure mode at any shutter speed. There is also a PC socket beneath a spring-loaded plastic cover on the left of the body, near the carrying eyes.

For non-Canolite manual flashes, there are dedicated auto-exposure modes for guide numbers 28, 20 and 14. Guide numbers are calculated from flash intensity and film speed, and dividing the guide number by distance-to-subject yields the proper aperture, while dividing by desired aperture yields the proper distance. The Canonet can automate this process, choosing an aperture based on the rangefinder distance, and refusing to fire if the aperture chosen is out of range. This mode also takes into account ambient light.

Some math may be required to find the closest available guide number for a given flash at a given ASA, as they are typically given as “guide number 14 at ASA (ISO) 100,” for example. The camera takes adjusted guide numbers as inputs, meaning that the photographer, and not the camera, must take the film speed into account here. The Canonet uses guide numbers calculated with the distance part of the equation in meters, so it may function incorrectly if the photographer inputs a guide number for an American-market flash, which will be calculated in feet. The manual gives a very basic conversion chart, but multiplying an American guide number by 0.3 will yield a very close approximation.

Manual exposure for flash is also possible, though of course calculating the aperture will follow much the same process as the guide-number priority mechanism in the camera.

Whether in manual or guide-number priority mode, the camera must be set at 1/30th for bulb flashes (to give the bulb time to reach peak brightness) while electronic flashes, including the Canolite D, sync at any speed. The inclusion of such information in the manual must have seemed somewhat archaic in the 1970’s, but perhaps some photographers were still using bulbs then as some extremely dedicated photographers are today.

Using the guide-number modes drains the battery faster than shutter-speed priority mode, so the camera should always be left in A with the lens cap on, or in manual mode.

QL System

The QL system is a hallmark of Canon's cameras of this era. While by no means unique, it was heavily promoted and is always indicated by a badge on the front of any camera model that features it. It appears on most of the later Canonets (which tend to have QL in the name) and most of Canon's last series of mechanical SLR's, but not on any of Canon's later electronic SLR's such as the New F-1 or the A-series. (However, many of Canon's EOS film SLR's also load themselves in a similar way, but with fully motor-driven film advance).

Simply put, the QL system is a thoroughly-engineered attempt to remedy one of the main shortcomings of 135 format, the frustration of loading the film. In conventional 35mm cameras, the film must be somehow attached to the takeup spool. To do so sometimes involves bending part of the film leader to hook it into a slot. Others, such as the Canon A-series, have a small protrusion in the slot to hook a sprocket hole over. The QL system completely eliminates this need by attaching the film to the spool with friction. The spool has a series of spring-loaded arms with rubber pads that press the film against a curved polished plate as it turns. This plate is hinged to the camera back, so that when the camera is opened, it lifts off of the spool. Consequently, all the photographer needs to do when loading is pull out the leader to a certain mark and close the back.

A particularly nice feature is that it is not necessary to keep releasing the shutter in order to advance the camera to the first frame. The mechanism which prevents the film from advancing when the shutter has not fired is disengaged when the back is opened. The photographer can then repeatedly advance the film until the counter shows "0," and then begin shooting. The advance locks when the counter shows "1" and cannot be advanced from that point on without releasing the shutter.


The QL 17 GIII is considered an excellent camera for the price, both new and resale. It is about two-thirds the weight of a Leica M6, and is said to be much quieter (having a leaf shutter instead of a focal-plane shutter), with street photography often cited as an ideal use. Tellingly, an equivalent f/1.7 normal lens for the bayonet-mount Leicas is liable to be more expensive than the entire Canonet. For these reasons, the QL17 is often recommended as an alternative to higher-priced rangefinder cameras. They can often be found on eBay for as little as $30, and with over a million of the cameras sold, they are fairly common at flea markets and garage sales as well. The Canonet is certainly in the upper tier for fixed-lens rangefinders, and certainly one of the cheapest cameras in that tier. It loads easily, has a bright rangefinder window, and is considered rather good-looking. A photographer used to shutter-priority AE Canons like the slightly later AE-1 will find this camera familiar and usable, although the meter is reversed from the AE-1's, and fans of Canon's lens design will also feel at home with the comparatively fast lens. The camera allows ambient-light hand-held photography indoors with ASA as low as 400.

However, the camera is not without its shortcomings; some have to do with its age, some have to do with ergonomics and some with peculiar design choices. Most examples of the camera are well into their forties; light seals have usually decayed, leading to noticeable light leaks at the bottom of the frame if they are not replaced. Also, the aforementioned battery problems can add some difficulty to using the camera. The camera is uncomfortable to some: In order to have his or her right index finger on the shutter release, the photographer must have the strap lug in the space between the index and middle finger, or else hold the camera between the thumb and index finger, which is not conducive to rapidly advancing the film after taking the picture. There is almost no way to hold the focus lever that does not feel sloppy and imprecise. Additionally, there are three metal controls with hard corners sticking out of the lens body in such a way that the photographer can easily hurt his or her fingers on them while turning the shutter-speed selector past them. The camera has a few design choices that are known to irritate some photographers: those who like a rubber eye cup or who need a diopter will be disappointed to find that there is no way to attach one, as the eyepiece has the battery check built into it and has no groove to attach anything. It must also be said that some photographers might find 40mm to be a non-ideal focal length for a fixed-lens camera. Finally, the lack of a depth-of-field scale can be infuriating to the photographer who is used to having one, especially any photographer who has come to depend on it. This is especially problematic when shooting close shots in low light, as the depth-of-field drops off quickly at low apertures and the photographer may have no idea what will be sharp, aside from the point of focus itself.

Considered with its highlights and weaknesses, the Canonet is not, as some would have us believe, a low budget super-camera that competes directly with interchangeable-lens rangefinders like Leicas (though Canon did compete with Leitz with its other rangefinders). It is, however, a rather remarkable bargain for its price point, being fast, small, somewhat lightweight, feature-packed (if lacking in a few key areas), quiet and attractive.

Technical Specs

  • Type: 35mm Rangefinder camera
  • Manufacturer: Canon Inc. Japan
  • Lens: Canon Lens 40mm f/1.7. 6-element 4-group construction with four newly designed glasses, coated.
  • Filter thread: 48mm.
  • Shutter: Between-the-lens type. Shutter speeds from 1/4 to 1/500 sec. and B.
  • Film Transport: Fast loading with QL system, accidental double-exposure prevention.
  • Metering: CDS cell, powered by PX625 or equivalent. Display in viewfinder.
  • Exposure: Shutter-speed priority, guide-number priority, manual.
  • EV range at ASA 100: 3.5-17 (and to infinity with bulb exposure)
  • Viewfinder: Bright-line type with integrated rangefinder and metered aperture indicator, frame moves to correct Parallax.
  • Focusing: Coincident-image rangefinder.
  • Film Speed: 25-800 ASA
  • Battery: One 1.35V M20 (#625, PX625) mercury battery or modern equivalent.
  • Flash: Hot shoe with proprietary contact for Canolite D, PC socket.
  • Weight: 620g




Canon Cameras