Abstract: An FAQ for the Canon EOS system

Photography - Canon EOS, digital, nature



* Pellicle mirror enables continuous viewing, even during exposure for the ultimate in "decisive moment" action and news photography.

* Built-in, high-speed motor drive for continuous shooting at up to 10 frames per second!

* Wide range of professional features including high-speed five-point autofocus, multiple metering patterns, five auto exposure modes, silent rewind and much more.

* Ultra-fast six-millisecond shutter release delay.

* Fully compatible with Canon EOS system EF lenses, Speedlites and other EOS accessories.


Taking the professional photographer to the next level, the Canon EOS-1N RS is a specially-developed camera designed to meet the needs of photojournalism, sports and scientific photography where precision and high speed is essential.


Containing almost all of the features of Canon's flagship EOS-1N, this model features a pellicle mirror which eliminates the flipping of the mirror as the shutter is released. This results in several dramatic differences for the professional photographer:

* The photographer is able to view the exact moment of exposure, or the "decisive moment" -- a critical factor in sports and photojournalism, as well as in scientific photography.

* Because the mirror doesn't move, the time to advance the film is significantly reduced, enabling shooting speeds up to an incredible 10 frames per second!

* This design also enables an ultra-fast six millisecond shutter release delay, significantly faster than a conventional 35mm SLR

* Because the camera's vibration is significantly reduced as the result of this design, it is ideal for scientific applications where high magnification is required, such as photomicroscopy, photomacrography, and astronomy. And for engineering applications such as motion analysis.

* The photographer can view the precise moment of flash exposure and immediately verify synchronization -- an important aspect when using multiple lighting. In addition, when using slow shutter speeds, any motion as a result of hand shake can be detected.

The presence of the pellicle mirror imposes some limitations: since shooting is done through the mirror, there is a light loss of approximately 2/3 stop. Also, since twice as much light goes to the film as to the focusing screen, the viewfinder image is slightly darker than normal. However, in-camera metering automatically compensates for the light loss, and a specially-designed laser-matte screen provides an amazingly bright view.

Last but not least, the EOS-1N RS pellicle mirror features a hard-coated titanium oxide surface that's resistant to scratching and can be cleaned when necessary by a qualified technician.


Unlike the EOS-1N, which permits film advance speeds up to 6 frames per second by adding the optional Power Drive Booster E1, the EOS-1N RS features a built-in motor drive which can provide three different modes: RS, continuous and single frame advance.

The RS mode enables shooting at up to 10 frames per second. This speed enables sequence photography far beyond the capabilities of conventional SLRs, making the EOS-1N RS the camera of choice for fast-moving sports action such as skiing, surfing, motorsports, etc., as well as scientific photography including motion analysis.

With framing rates this fast, there are some limitations. For instance, the lens remains stopped down during the shooting sequence, thereby eliminating AI Servo predictive AF. Despite this, One Shot AF and manual focusing continue to operate, providing significant control over this crucial camera function. Also, Automatic Exposure Bracketing (AEB) which enables the photographer to automatically bracket exposures up to +/- 3 stops in 1/2 or 1/3-step increments, is unavailable.

When AI Servo or AEB are essential, they are accessible at up to five or six frames per second respectively in the continuous advance mode, as well as during single frame shooting.

The RS mode offers one other key feature -- ultra-fast 6 millisecond shutter release. The camera completes all pre-exposure preparations (such as AF, metering, and aperture drive) when the shutter is pressed halfway, so that shutter release is all that remains when the button is fully depressed. It's this attribute which enables timing control so precise that it becomes easier than ever before to capture peak action, like the ball on the bat or a race car filling the frame. By comparison, conventional SLRs feature release time delays from 40 to 200 milliseconds, making precise shutter timing virtually impossible.


The Canon EOS-1N RS is packed with features demanded by professional photographers. These include:

The Canon AIM System, a sophisticated integration of focusing, exposure and flash control designed to interface with the photographer. It uses a 16-zone SPC (silicon photocell sensor), and during evaluative metering, takes readings from each zone. The readings are compared with pre-defined algorithms to determine optimum exposure settings. The five central zones are also the locations of the camera's five-point autofocus system, accomplishing high-precision metering according to subject position. Thus, autofocus and metering can work together to ensure optimum results. For flash photography with EOS Speedlites, the multi-zone TTL flash metering sensor is also linked to the five focusing points, enhancing flash exposure accuracy for the main subject by evaluating its position.

An advanced Multi-BASIS (Base Stored Image Sensor) AF detection mechanism links a series of 5 focusing points to a microprocessor-controlled program that can automatically select a subject or track movement from point to point. Additionally, the photographer can take charge and select individual focusing points at will, with a choice of several control layouts according to personal preference and shooting style.

A wide variety of metering patterns enables sophisticated photographers and novices alike to achieve the precise exposure desired. The 16-zone metering sensor located above the viewfinder eyepiece provides a choice of evaluative, center-weighted average, partial and spot metering. Another metering cell is placed directly on the BASIS AF sensor, for 2.3% fine spot metering.

During evaluative metering, the camera's main CPU compares luminance readings from the entire scene, with the active focusing point taken as the central zone. This method enables the camera to recognize a broad range of lighting situations, including difficult ones such as backlighting. The evaluative metering system then applies automatic exposure compensation as required for optimum results in real time, providing amazing accuracy in fast-moving situations.

Other metering modes, including center-weighted average metering, 9% central-area partial metering, 3.5% spot metering linked to the focusing points, and 2.3% central-area fine-spot metering, leave the matter of exposure compensation completely up to the photographer, and are ideal for the experienced shooter when time is available for setting the exposure ahead of time. Most of these metering patterns are not linked to the focusing points, making it possible to focus on one area and take meter readings from another.

For flash photography, the EOS-1N RS is compatible with all current EOS system Speedlites and dedicated flash accessories. Flash metering features include a three-zone TTL flash sensor, built-in flash exposure compensation and flash output reduction control. When A-TTL and TTL flash exposure are combined with autofocus, the active focusing point controls flash exposure for improved accuracy with off-center subjects. Unlike other systems, Canon's multi-zone flash exposure control works in real time, eliminating the need to lock focus and recompose. This can often become crucial with live subjects, capturing peak expression while maintaining full autofocus and auto-exposure performance at all times. Flash synchronization speeds up to 1/250th second extend fill-flash range while minimizing "ghosting" in bright light situations as well.

The EOS-1N RS provides a choice of exposure modes, including Intelligent Program AE, Shutter & Aperture Priority, A-TTL and TTL automatic flash exposure, plus full manual control and bulb mode. Exposure overrides are comprised of AE lock, all-mode AEB (Automatic Exposure Bracketing), and multiple exposure.

While the Canon EOS-1N RS offers an incredible variety of features, even greater control is possible through a rich selection of custom functions. This enables the photographer to preset 14 custom operations, including:


CF1: Automatic film rewind operation
0: High-speed automatic rewind
1: Automatic rewind prohibited (Pressing film rewind button activates
high-speed rewind)
2: Silent (low-speed) automatic rewind
3: Automatic rewind prohibited (Pressing rewind button activates silent
Useful Situations:
This function is useful for situations in which silence is required--for
example in a quiet theater or at a pro golf tournament--where the sudden
noise of a camera's rewind would cause disruption.

CF2: Film leader position after rewinding
0: Rewinds film leader fully into cartridge
1: Leaves the film leader outside the cartridge after rewinding
Useful Situations:
This function is useful for individuals or news agencies who do their
own film processing. The film leader is left outside the cartridge after
the film is rewound automatically or in mid-roll.

CF3: Film  speed setting
0: Film speed automatically set according to DX code
1: Film speed set manually (DX code is ignored.)
Useful Situations:
This option is for photographers who shoot film at ISO settings 
determined from their own tests. Setting this function frees the 
photographer from having to change the film speed every time a new roll 
is loaded.

CF4: AF activation
0: Autofocus starts when the shutter button is pressed halfway. Exposure
is locked when the AE lock button is pressed.
1: Autofocus starts when the AE lock button is pressed. Exposure is
locked when the shutter button is pressed halfway.
2: Autofocus starts when the shutter button is pressed. Autofocus is
temporarily suspended when the AE lock button is pressed. (AE lock is
not available when "2" is set.)
Useful Situations:
4-1. This option lets the photographer carry out metering and autofocusing
4-2. For sports photography using focus prediction in AI Servo AF mode,
this option lets the photographer temporarily stop the focus.

CF5: Shutter speed and aperture value setting method in manual exposure
0: Shutter speed set by main dial. Aperture set by quick control dial
or by combined operation of exposure compensation button and main dial.
1: Aperture set by main dial. Shutter speed set by quick control dial
or by combined operation of exposure compensation button and main dial.
Useful Situations:
When making manual exposure adjustments, this function lets the 
photographer choose whether to use the main dial for adjusting the 
shutter speed or aperture value. This option is convenient for studio 
flash photography where the shutter speed is kept constant while the 
aperture is frequently varied to alter depth of field and exposure.

CF6: Increment used for setting shutter speed and aperture values, as
well as exposure compensation and flash exposure compensation amounts.
0: Shutter speed, aperture value and all exposure compensation amounts
set in 1/3-step increments
1: Shutter speeds and aperture values set in 1-stop increments, and
all exposure compensation amounts set in 1/3-step increments
2: Shutter speed, aperture value and all exposure compensation amounts
set in 1/2-step increments
Useful Situations:
This function lets the photographer input shutter speed and aperture
settings in any increment that he or she is used to. 1/2-step exposure
compensation amounts are also possible, providing wide flexibility to
suit various shooting styles.

CF7: Electronic manual focusing after AF completion or failure
0: Manual focusing is possible. (This function works only with lenses
equipped with a manual focusing ring.)
1: Manual focusing is prohibited. (Manual focusing is possible by setting the
lens' focus mode switch to "M."
Useful Situations:
This option disables the manual focusing capability of the electronic
ring provided on many USM L-series lenses, eliminating the possibility
of accidentally turning the ring and shifting the focus after AF is

Compatible lenses:
EF28-80/2.8-4L USM, EF50/1.0L USM,EF85/1.2L USM, EF200/1.8L USM,EF300/2.8L USM,
EF400/2.8L USM, EF500/4.5L USM, EF600/4L USM, EF1200/5.6L USM

CF8: Evaluative metering operation
0: Evaluative metering
1: Center-weighted average metering (The LCD panel still shows the evaluative
metering symbol.)
Useful Situations:
Setting this function to center-weighted average metering provides the
photographer with a predictable metering pattern for determining 
exposure. This is useful for experienced photographers who have over 
many years developed an ability to accurately determine exposure 
combining average metering and exposure compensation.

CF9: AEB exposure sequence
0: Under/Correct/Over
1: Under/Correct/Over
2: Correct/Under/Over
3: Correct/Under/Over
(0 and 2: AEB operation is canceled when main switch is set to L, lens
is exchanged, film is replaced or rewound, bulb exposure mode is set,
flash charge completion is detected, or the clear button is pressed.)
(1 and 3: AEB operation is not canceled when main switch is set to L,
lens is exchanged, or film is replaced or rewound. Also, in this mode,
the user can activate AEB by pressing the AF mode and shooting mode

Useful Situations:
2,3: These settings change the bracket sequence to "Correct/under/over,"
which is useful when shooting live subjects or changing scenes where
the first shot will most likely capture the best expression or 
1,3: These setting are useful for photographers who frequently use AEB,
because it prevents AEB from being canceled every time the main switch
is set to L, lens is exchanged, or film is rewound or exchanged. Also,
in this mode, the user can activate AEB without having to open the 
camera's palm door.

CF10: Focusing point superimposed on focusing screen
0: Focusing point superimposed in red
1: Superimpose prohibited
Useful Situations:
This option is for users who are annoyed by the AF frame illumination
in the viewfinder. as well as for those who frequently use manual 
focusing to adjust the final focus.

CF11: Focusing point selection method
0: Focusing point selector and main dial
1: Exposure compensation button and main dial
2: Independent operation of quick control dial or exposure compensation
button and main dial.
Useful Situations:
0,1: This option makes it possible to match the EOS-1N's button operation
to the photographer's existing camera (EOS-1 or EOS A2/E).
2: This option lets the user track the subject with the focusing point
in real time by operating the quick control dial, which is useful when
tracking a moving subject using focus prediction control in AI Servo

CF12: Autofocus Beeper Control
0: Silent in-focus confirmation (Viewfinder display only)
1: Audible in-focus confirmation (One Shot AF and manual focus only)
Useful Situations:
This function replaces the EOS-1N's beeper setting, which is eliminated on the
EOS-1N RS due to the RS mode setting on the camera's main switch. Also, it
replaces the EOS-1N's mirror lock feature, which is unnecessary on the EOS-1N

CF13: Focusing point and spot metering
0: Fine spot metering in center of image area
1: Spot metering linked to the manually selected focusing point
Useful Situations:
This function links spot metering to the manually selected focusing
point, allowing the user to spot meter the subject without changing
the framing of the scene.

CF14: Flash output control
0: Automatic flash output reduction control activated
1: Automatic flash output reduction control prohibited
Useful Situations:
This function prevents underexposure of strongly backlit subjects during
fill-in flash photography with Canon EOS Speedlites, and is also recommended
when applying user-set flash exposure compensation.


The priority when developing the EOS-1N and EOS-1N RS was to design a body and control layout that enable the photographer to act swiftly. Thus, an emphasis was placed on comfort, simplicity and precise placement of key controls. The smoothly contoured body fits naturally into the hand, and the layout of the three main controls -- the shutter release, main electronic input dial and Quick Control dial -- is such that they can be operated easily with the right hand while looking through the viewfinder. The right side grip is covered with rubber and synthetic leather to prevent slipping.

As important as ease of use is reliability, and here too Canon took special care when designing the EOS-1N & RS. The central body and chassis are made of diecast aluminum surrounded with a glass-fiber reinforced polycarbonate resin carefully selected for maximum strength and light weight. Resistance to moisture and dust is equal to that of the Canon EOS-1 through use of similar gaskets and seals. There are special water drains for the input dial assembly and the Power Booster E1 attachment area. All shutter blades are coated with a water-repellent lubricant. Reliability is further improved through use of double terminals for all important electrical contacts.

The EOS-1N & RS have been thoroughly tested in blazing heat, frigid cold, and high humidity, proving over and over that it meets our standards for professional reliability. Flawless operation is confirmed from -20 degrees C to 45 degrees C (-4F to +113F), and to 85% humidity, based on our standard test method.


The EOS-1N & RS employ a new shutter unit featuring a top speed of 1/8000th sec., a maximum flash sync speed of 1/250th sec., and ultra-high precision. What's more, by reducing the weight and load of the shutter blades with the use of carbon fiber and duralumin materials, durability has been further enhanced. In the case of the EOS-1N RS, shutter operation is further modified by utilizing a design which places both shutter curtains in front of the film gate when the camera is at rest. This dual layer improves light-blocking capability, and is required by the pellicle mirror design.

Feature Comparison: EOS-1N RS vs. EOS-1N/PDB E1 and EOS A2/A2E

Category                              EOS-1N RS EOS-1N/PDB E1 EOS A2/E
Diecast aluminum mirror box, 
heavy-duty body construction          Yes          Yes        No
(coverplate fully sealed)             Yes          Yes        No
Gold-plated double electrical 
contacts (DX, grip section)           Yes          Yes        No
Built-in pop-up flash                 No           No         Yes

AF focusing area (# of points)        || + ||(5)   || + ||(5) || + || (5)
Automatic focusing point selection    Yes          Yes        Yes
Manual focusing point selection       Yes          Yes        Yes
Eye Controlled Focus                  No           No         Yes (A2E)
AF Working Range (EV, ISO 100)        0 to 18      0 to 18    0 to 18

Evaluative metering/# of zones        Yes/16       Yes/16     Yes/16
Center-weighted average metering      Yes          Yes        Yes
Partial metering/%                    Yes/9%       Yes/9%     No
Spot metering linked to focusing 
points (3.5%)                         Yes          Yes        Yes
Fine spot metering (2.3%)             Yes          Yes        No
A-TTL/TTL flash metering (type)       multi-zone   multi-zone multi-zone

Shutter speed range                   1/8000 ~ 30 sec. (ALL)
Maximum X-sync shutter speed          1/250        1/250      1/200
Manual shutter speed/aperture 
value increment (EV)                  0.3/0.5/1.0  0.3/0.5/1.0  0.5
Exposure compensation/AEB step 
amount                               +/-3 steps, +/-3 steps, +/-2 steps,
                                      0.3/0.5 EV  0.3/0.5 EV  0.5 EV
Flash exposure compensation step 
amount                               +/-3 steps, +/-3 steps, +/-2 steps,
                                      0.3/0.5 EV  0.3/0.5 EV  0.5 EV

Maximum Winding Speed, One-shot AF    10.0         6.0*       5.0
Maximum Winding Speed, AI Servo AF    5.0          5.0*       3.0
Rewind Noise Level 
[High Speed/Low Speed], (dB)          59/48        59/48      50/42
*with Power Drive Booster E1

Superimposed display                  Yes          Yes        Yes
Fine spot metering mark               Yes          Yes        No
Remaining frame count indicator       Yes          Yes        No
Manual metering indicator             Scale        Scale      +/-
Variable-dioptric correction 
eyepiece/dpt range                    Yes/-3~+1    Yes/-3~+1   A2/
Built-in eyepiece shutter             Yes          Yes        No  
Viewfinder coverage 
(% of actual picture area)            100%         100%   92% V x 94% H

Custom Functions 
(Multiple Choice/Number)              Yes/14       No/14      No/16
Independent DOF preview button        Yes          Yes        No
Mirror Lock (maximum delay)           Yes/30 sec   Yes/unlimited Yes/2 sec
Width (mm/in)                         161/6.3      161/6.3    154/6.1
Height (mm/in)                        155.9/6.1    155.9/6.1  121/4.8
Depth (mm/in)                         78/3.1       78/3.1     75/3.0
Weight (gr/oz)                        1,300/45.5   1,310/45.9 665/23.5

EOS-1N RS Specifications


Type: 35mm focal plane shutter SLR (Single-Lens Reflex) camera with multi-point autofocus, auto exposure and built-in high-speed motor drive. Lens Mount: Canon EF Mount (fully electronic signal transfer system). Usable Lenses: Canon EF Lenses Viewfinder: Fixed eye-level pentaprism. Gives approx. 100% vertical and horizontal coverage of actual picture area and 0.72x magnification with 50mm lens at infinity at standard diopter (-1). Focusing Screen (standard): Ec-R Bright Laser-matte screen with fine spot metering area mark. (Eight optional interchangeable screens are available, but must be changed by qualified technician.) Dioptric Adjustment: -3 to +1 dpt Eyepoint: 20mm Shutter: Vertical-travel focal plane shutter, all speeds electronically controlled. Shutter Speeds: 1/8000~30 sec. (in 1/3, 1/2 or 1 step increments) and bulb. Maximum X-sync speed: 1/250 sec. Mirror: Fixed pellicle mirror (Mirror blockage: None to 1200mm f/5.6). AUTOFOCUS AF Control System: TTL-CT-SIR (Secondary Image Registration) phase detection type using multi-BASIS (Base Stored Image Sensor). Focusing Point Selection: Selected automatically by camera or manually by user. Focusing Modes: (1) One-shot AF (2) AI Servo AF (3) Manual focusing AF Working Range: EV 0~18 (ISO 100). AF Auxiliary Light: Specified Canon Speedlites automatically project light through an ultra-bright LED (peak sensitivity: 700nm) when required. EXPOSURE CONTROL Light Metering: TTL full-aperture metering using a 16-zone SPC (silicon photocell). Five metering modes available: evaluative metering (corresponds to 5 focusing points), partial metering (covers approx. 9% of the central picture area), fine spot metering (covers approx. 2.3% of central-picture area), spot metering (covers approx. 3.5% of the picture area at each AF frame position) and center-weighted average metering. Metering Range: Evaluative and partial metering: EV 1~20. Fine spot metering: EV 3~20. (At normal temperature with 50mm f/1.4 lens at ISO 100). Usable film speeds: ISO 6-6400 (ISO 25-5000 when automatically set by DX code) Shooting Modes: 1. Intelligent Program AE with variable shift 2. Shutter-priority AE 3. Aperture-priority AE 4. A-TTL and TTL program flash AE 5. Manual 6. Bulb. Exposure Compensation: (1) AEB: +/-3 steps in 1/3 or 1/2 step increments, repeatable. (2) Manual compensation: +/-3 steps in 1/3 step increments, by independent operation of quick control dial or combination of exposure compensation button + main dial; can be used together with AEB. AE Lock: (1) Auto AE lock: AE lock occurs simultaneously with AF completion in One-shot AF mode with evaluative metering. (2) Manual AE lock: Possible in all AE modes by pressing AE lock button. Depth-of-Field Preview: Possible in all exposure modes, by operation of independent depth-of-field preview button. FILM TRANSPORT Film Loading: Automatic. Film automatically advances to first frame when back cover is closed. Film Wind: Three modes available: Single frame, low-speed continuous exposure, and high-speed continuous exposure. Maximum Film Winding Speed: (shutter speed: 1/250 sec. or faster) One-shot AF/Manual Focus AI Servo AF --------------------------------------------------------------- High-speed RS Mode approx. 10 fps Not Available Low-speed RS Mode approx. 3 fps Not Available High-speed Continuous approx. 6 fps Approx. 5 fps Low-speed Continuous approx. 3 fps Approx. 2.5 fps Shooting Capacity: (with 24-exp. film) Battery type Temperature AA-size lithium AA-size Alkaline Ni-Cd Pack E1 ------------------------------------------------------------------ Normal (20C/68F) 250 (165) rolls 100 (65) rolls 65 (45) rolls Low (-20C/-4F) 90 (60) rolls 6 (4) rolls 45 (30) rolls Values in parentheses are for 36-exp. film Power Source: Eight AA-size alkaline batteries, AA-size lithium batteries, AA-size NiCd batteries or NiCd Pack E1. Film Rewind: Automatic at end of roll. Two rewinding speeds available: Silent and High-speed. (Maximum rewind speed with 24 exposure roll: approx. 4.5 sec. Rewind noise: High-speed mode: 59 dB; Silent mode: 48 dB.) Mid-roll rewind possible. Battery Check: By pressing the battery check button; battery level shown in four-step display in the LCD panel. OTHER Custom Functions: 14 custom functions available. Flash Contacts: Direct contact at accessory shoe and PC socket (JIS-B type). Simultaneous use is possible. Remote Control: 3-pin remote control socket provided. Data Display: In viewfinder and LCD panel. Multiple Exposures: Up to 9 exposures can be pre-set. Automatically clears upon completion. Self-timer: Electronically controlled with 2- or 10-second delay, selectable; Camera Back: Interchangeable with the optionally available Command Back E1. SIZE Dimensions: 161 (W) x 155.9 (H) x 78 (D) mm 6-5/16" (W) x 6-1/8" (H) x 3-1/16" (D) Weight: 1,300 gr/45.5 oz (body only, without batteries) 1,500 gr/52.5 oz. with 8 AA-size alkaline batteries.

© Copyright Bob Atkins All Rights Reserved