EF bayonet

EF bayonet on the Canon EF 28 mm f / 2.8

The Canon EF bayonet is a lens bayonet connection made by Canon. He uses this for his analog and digital SLR cameras of the Canon EOS series. The term EF means Electro-Focus . The bayonet is used for autofocus cameras and almost exclusively for autofocus lenses. Information is transferred between the camera and lens via a serial bus .

The EF-S bayonet is a later special form for digital single lens reflex cameras with the APS-C image format. The S stands for Short-baking , thus a shorter distance between the film plane and the back lens of the objective is meant (but the flange is the same).

EF bayonet

Period

The EF bayonet has been around since March 1987 when it appeared with Canon's first EOS camera, the EOS 650. It replaced the Canon FD bayonet in the following years . The EF lens program only reached the size of the FD program after 1990. By August 2012, Canon had produced 80 million lenses and teleconverters with EF mounts; the 100 millionth lens was produced in April 2014. With more than 80 models, the Canon EF lens series is the largest lens series available on the market. In addition, there are many lenses from other manufacturers.

Emergence

Planning for an autofocus SLR system began at the end of 1981. Right at the beginning, it was decided to create a non-mechanical interface , i.e. a completely new lens connection with exclusively digital information transmission. At the same time, a future professional camera was designed, which later became the EOS-1 . However, development work on this camera did not begin until autumn 1985.

construction

The EF bayonet was a completely new design, it is not compatible with the previous FD bayonet . In contrast to this, it is an inner bayonet that has a larger flange focal length of 44 mm and a larger diameter of 54 mm. The information is transmitted via spring-loaded and gold-plated contacts on the camera and gold-plated contact surfaces on the lens. These contacts are located below the camera's reflective mirror. The transmission is digital, which is why most EF lenses have a built-in microprocessor . In addition, autofocus lenses require a built-in motor for focusing.

The first lenses were equipped with stepper motors, later came particularly quiet ultrasonic motors and ultrasonic ring motors. Newer lenses often allow simple manual intervention in the focusing without having to switch to manual beforehand.

service

The EF bayonet on the camera has a red point on the top, this must be opposite the red point on the lens when attaching it. Then the entire lens is rotated clockwise until it clicks into place. To unlock, a button is pressed which, unlike the last version of the FD bayonet, is on the camera and no longer on the lens.

EF lenses are electrically dimmed, i.e. only if the electrical contacts are connected to those of the camera. An adapter must be used for manual lenses and no data is exchanged between lens and camera. In particular, macro lenses or connections to microscopes or telescopes require EF adapters. The aperture and focus are set manually on the lens. A digital feedback to the camera is not possible.

If the lens is operated in the retro position or the lens has to be removed from the camera while the dimmer button (not available on all EOS cameras) is held down. Then the lens remains dimmed when it is removed.

EF bellows devices are only available from third-party manufacturers. These often also offer a cable connection between the camera and lens. However, these are only required for digital lenses with an EF mount. Manually operated lenses - i.e. without motorized focus and aperture control - do not require a cable connection.

With the exception of a few simple lenses, all EF lenses can be focused manually with a setting ring. This works even if the lens is not connected to the camera. The autofocus mode is switched with a slide switch on the lens. With normal EF lenses, the setting ring is mechanically decoupled when it is set to manual focus and can be moved freely. Lenses with full-time manual focus can also be focused manually when they are switched to autofocus. This allows corrective action to be taken after the camera has focused. The aperture, however, can only be adjusted electronically and on the camera.

The Canon EF-M, a camera with an EF bayonet but without autofocus, which is therefore not called EOS, is dependent on manual focusing. It was in the Canon program for three years from September 1991 onwards, but was of little significance.

Most telephoto lenses have a limitation for the autofocus that can be switched on the lens. Then the focus is not in the entire distance range, but only from 5 m to infinity, for example. This avoids having to focus for a long time if the autofocus does not measure sufficient contrast and therefore traverses the entire area. It also saves energy on the camera's batteries.

In the case of lenses with image stabilization , this can be switched off or its effect profile selected. With Sigma and Tamron lenses, the profile can even be adapted to your own needs with the help of a computer program and assigned to positions C1, C2 etc. on the lens. This setting takes place solely on the lens and not via the camera, so that suitable exposure times must be set manually. That will only change with the Canon EOS-R5, because this camera is built with a stabilizer and therefore has the necessary information in the housing.

Data transfer

The data transfer between the camera and the lens takes place digitally via a serial protocol (SPI). Canon has so far neither published the pin assignment nor the data transfer protocol used. This represents a hurdle, especially for third-party lens manufacturers (see section Compatibility).

The pin assignment determined by reverse engineering reads in the mirror box looking from left to right:

Pin assignment: Canon EF bayonet

Surname	function	comment	image
VBAT	+5.8… 8.4 V for power electronics (AF motor and possibly image stabilizer)	Own all cameras and lenses
LDET	Lens recognition: connected to PGND on the lens, connected to VDD in the camera via pull-up.
PGND	Ground for power electronics
VDD	+5.0 V (+4.5 V in power saving mode) for digital electronics
DCL	serial data from camera to lens (MOSI), OC
DLC	serial data from lens to camera (MISO), OC
LCLK	Clock signal (approx. 77 kHz), generated by the camera (SCLK, CPOL = 1), OC
DGND	Ground for digital electronics
COM1	Pin for signaling tele converters	Available on many L-series lenses as well as some macro lenses
EXT0	Connected to COM1 at: 1.4-fold tele converter Life Size Converter (extension for EF 50 / 2.5 macro for image ratios up to 1: 1)
EXT1	Connected to COM1 at: 1.4-fold tele converter 2-way tele converter

The data are transmitted bidirectionally with the SPI protocol, which is widely used in the microcontroller sector. The data width used is 8 bits.

Image stabilization takes place entirely in the lens, and the stabilizer settings (on / off, mode) are also not transferred to the camera housing. The user himself has to provide for suitable (not too long) exposure times, e.g. B. by using the auto iris with manual time setting.

Register a lens:

• Lens short-circuits pin 2 and pin 3
• The camera then activates VDD
• Objectively identifies itself via the serial bus
• If everything is okay, the camera also switches on VBAT

compatibility

All Canon EF lenses work with all EOS cameras. There are some problems with older third-party lenses because they no longer work with newer cameras. One of the known causes is a reduction in the supply voltage Vdd from 5 to 3.3 V. The problem can only be remedied by changing the electronics of the lens.

Adapter for third-party lens connections

Lenses with the FD bayonet cannot be connected directly, but only via an adapter. Because of the larger flange focal length of the EF bayonet, the lens can then no longer be focused to infinity, so the adapter acts like an intermediate ring . That is why there are also adapters with lenses that are basically teleconverters . In addition to third-party products (often with a single negative lens, which is a moderate image quality results) exists for this the Canon Lens Mount Converter FD-EOS for certain FD telephoto lenses, the focal length is extended to the 1.26-fold and accordingly the light intensity to 2/3 f-stops reduced.

Lenses with the F bayonet , M42 , T2 , Pentax-K bayonet , Yashica / Contax , Leica R or Olympus OM connections can also be connected with an adapter because they have a larger flange focal length . This also applies to some medium format lenses, for example with a P6 bayonet .

With adapted lenses, the aperture and distance must be set manually on the lens.

EF-S bayonet

EF-S bayonet, recognizable by the white - instead of red - position mark under the Canon logo

Comparison of the lens connections EF (left) and EF-S (right), the latter with an additional hard rubber ring

EF-S bayonet of a Canon EOS 550D , with recessed mirror box and the additional white connection marking

The Canon EF-S lens connection is intended for cameras with APS-C sensor size, with a format factor of 1.6 to 35mm format . Except for the lens barrel that protrudes further into the camera, it is identical to the EF bayonet. EF lenses can be connected to all EOS cameras, but EF-S lenses can only be connected to those with an APS-C sensor, although some older APS-C models are also excluded.

Period and meaning

The EF-S bayonet appeared in September 2003 with the Canon EOS 300D . These and all subsequent APS-C format EOS digital cameras can also use EF-S lenses in addition to EF. The previously released EOS digital cameras for this format cannot do this, however, as they are still equipped with the usual EF bayonet. These are the EOS D30, EOS D60 and EOS 10D models .

Cameras with a larger sensor still have the usual EF bayonet, EF-S lenses cannot be used with these cameras. These are the EOS-1D with their APS-H sensor corresponding to the format factor 1.25 (sensor size 28.7 mm × 19.1 mm) and the EOS-1D X , EOS 5D , EOS 6D and their predecessor models (1Ds series and 5D series) all of a small image sensor having (sensor size 35.9 mm × 23.9 mm).

idea

The smaller image format of APS-C cameras also allows for a smaller mirror. An eccentric mirror path when folding the mirror also reduces its space requirement somewhat. As a result, the focal length of the objectives, i.e. the distance between the last lens of the objective and the image plane, can be reduced. For wide-angle lenses and zoom lenses that contain wide-angle focal lengths, this results in structural advantages; they can be made smaller, lighter and more cost-effective.

Corresponding lenses cannot be used on cameras with a larger image format, as they do not leave enough space for the mirror. They are fitted with the EF-S bayonet and cannot be attached to cameras that have the normal EF bayonet. This prevents damage caused by the mirror colliding with the lens barrel.

In addition, lenses with an image circle that is too small cannot be used on a camera with a larger sensor format, which would lead to unexposed (due to vignetting ) or blurred image edges or corners.

The idea of ​​constructing lenses for special cameras with a rear lens reaching unusually far into the mirror box was realized at Canon in 1965 with the FLP 38 mm f / 2.8 for the Canon Pellix . At that time, however, there was no special bayonet that protected against incorrect operation.

The competitors Sony and Nikon do without a special bayonet. For example, Nikon's DX lenses can also be used on FX cameras that vignette at full sensor size, but the firmware of modern DSLR cameras from these manufacturers recognize such lenses and switch (optionally switchable) to an APS-C mode in which only the inner area of ​​the sensor is read, with a loss of approx. 55% of the resolution (corresponding to the smaller number of pixels). The rear lens of APS-C lenses from these manufacturers does not extend further into the mirror box, so that there is no risk of collision with the mirror.

construction

The EF-S lenses are designed for the APS-C image format and have a smaller image circle, so they do not illuminate the full 35mm format. Compared to the large image circle, this enables a simpler and more cost-effective lens construction. The inner part of the lens barrel also protrudes a little further into the camera and ends with a hard rubber ring. When trying to attach the lens to a camera with an EF bayonet, this ring hits the mirror box of the camera and prevents attachment. EF-S cameras have a recessed mirror box to leave room for the lens barrel.

service

Instead of a red circle, EF-S lenses have a white square as a position marker on the lens. A camera with an EF-S connection has two markings, the usual red one at the top of the bayonet for EF lenses and a white one to the right of it at around 1 o'clock for EF-S lenses. As a result, EF-S lenses are not attached with the marking facing up, but turned slightly to the right. If you try to attach EF-S lenses to a camera with a normal EF bayonet, the corresponding white marking on the camera thread is initially missing, and the hard rubber ring of the lens prevents accidental connection and thus prevents the mirror from colliding with the lens.

The EF-S lenses are labeled with the actual focal length. To get the equivalent focal length for the full format (36 mm × 24 mm), it must be multiplied by the format factor 1.6.

Foreign lenses

Third-party lenses for the APS-C format do not use the EF-S bayonet. They always keep the normal distance between the film or sensor plane and the rear lens. If you take photos with these lenses on an EOS camera with a larger sensor, this usually leads to increased vignetting and blurring in the corners of the image. In the case of zoom lenses , this applies at least to the wide-angle part of the focal length range.

EF-S bayonet cameras

Current (in order of appearance, newest first) :

• EOS 90D
• EOS 250D
• EOS 4000D
• EOS 2000D
• EOS 800D / EOS 77D
• EOS 7D Mark II

Expired:

• EOS 7D
• EOS 20D , EOS 30D , EOS 40D , EOS 50D , EOS 60D , EOS 70D , EOS 80D
• EOS 20Da , EOS 60Da
• EOS 300D , EOS 350D , EOS 400D , EOS 450D , EOS 500D , EOS 550D , EOS 600D , EOS 650D , EOS 700D , EOS 750D / EOS 760D , EOS 100D , EOS 200D
• EOS 1000D , EOS 1100D , EOS 1200D , EOS 1300D

Despite Crop 1.6 no EF-S bayonet, but EF bayonet:

• EOS 10D
• EOS D30 , EOS D60

Lenses with EF-S bayonet

EF-S 55-250 mm f / 4-5.6 IS

• EF-S 10-18 mm f / 4.5-5.6 IS STM
• EF-S 10-22 mm f / 3.5-4.5 USM
• EF-S 15-85 mm f / 3.5-5.6 IS USM
• EF-S 17-55mm f / 2.8 IS USM
• EF-S 17-85 mm f / 4-5.6 IS USM
• EF-S 18-55 mm f / 3.5-5.6 IS II
• EF-S 18-55 mm f / 3.5-5.6 IS STM
• EF-S 18-55mm f / 4-5.6 IS STM
• EF-S 18-135 mm f / 3.5-5.6 IS STM
• EF-S 18-135 mm f / 3.5-5.6 IS USM
• EF-S 18-200 mm f / 3.5-5.6 IS
• EF-S 55-250 mm f / 4-5.6 IS STM
• EF-S 24mm f / 2.8 STM
• EF-S 35mm f / 2.8 Macro IS STM
• EF-S 60mm f / 2.8 Macro USM

Canon EF lenses

Fixed focal length

EF 35mm f / 2.0 IS USM

Wide-angle lenses up to 35 mm

• EF 14mm f / 2.8L II USM
• EF 20mm f / 2.8 USM
• EF 24mm f / 1.4L II USM
• EF 24mm f / 2.8 IS USM
• EF 28mm f / 1.8 USM
• EF 28mm f / 2.8 IS USM
• EF 35mm f / 1.4L II USM
• EF 35mm f / 2.0 IS USM

EF 85mm L f / 1.2 USM

Normal lenses to light telephoto lenses from 40 mm to 100 mm

• EF 40mm f / 2.8 STM
• EF 50mm f / 1.2L USM
• EF 50mm f / 1.4 USM
• EF 50mm f / 1.8 STM
• EF 85mm f / 1.2L II USM
• EF 85mm f / 1.4L IS USM
• EF 85mm f / 1.8 USM
• EF 100mm f / 2.0 USM

EF 200mm f / 2.0 L IS USM

Telephoto lenses from 135 mm to 300 mm

• EF 135mm f / 2.0L USM
• EF 200mm f / 2.0L IS USM
• EF 200mm f / 2.8L II USM
• EF 300mm f / 2.8L IS II USM
• EF 300mm f / 4.0L IS USM

Canon EF 400 mm f / 2.8L IS II USM with Canon EOS 1DX

Super telephoto lenses from 400 mm

• EF 400mm f / 2.8L IS II USM
• EF 400 mm f / 4.0 DO IS II USM
• EF 400mm f / 5.6L USM
• EF 500mm f / 4.0L IS II USM
• EF 600mm f / 4.0L IS II USM
• EF 600 mm f / 4L IS III USM
• EF 800mm f / 5.6L IS USM

Zoom lenses

EF 11–24 mm f / 4.0 L USM with Canon EOS 5 DS R

Starting in the super wide-angle range up to 22 mm

• EF 8-15mm f / 4.0L Fisheye USM
• EF 11-24mm f / 4.0L USM
• EF 16-35mm f / 2.8L II USM
• EF 16-35mm f / 2.8L III USM
• EF 16-35mm f / 4.0L IS USM
• EF 17-40mm f / 4.0L USM

EF 24-70mm f / 4 IS

Starting in the wide-angle range between 24 mm and 38 mm

• EF 24-70mm f / 2.8L II USM
• EF 24-70mm f / 4.0L IS USM
• EF 24-105mm f / 4.0L IS II USM
• EF 24-105mm f / 3.5-5.6 IS STM
• EF 28-300mm f / 3.5-5.6L IS USM

Starting in the normal and light telephoto range from 50 mm to 100 mm

EF 100-400mm f4.5-5.6L IS II USM

• EF 70-200mm f / 2.8L USM
• EF 70-200mm f / 2.8L IS III USM
• EF 70-200mm f / 4L USM
• EF 70-200 mm f / 4L IS II USM
• EF 70-300mm f / 4-5.6 IS II USM
• EF 70-300 mm f / 1: 4.0-5.6L IS USM
• EF 75-300 mm f / 4.0-5.6 III
• EF 75-300 mm f / 4.0-5.6 USM III
• EF 100-400 mm f / 4.5-5.6L IS II USM

EF 200-400 mm f / 4.0L IS USM Extender 1.4x

Starting in the telephoto range from 200 mm

• EF 200-400 mm f / 4L IS USM Extender 1.4x

TS-E 17 mm f4.0L

Tilt-and-Shift Lenses

These lenses have electronic aperture transmission, but no autofocus.

• TS-E 17 mm f / 4.0L
• TS-E 24 mm f / 3.5L II
• TS-E 50 mm f / 2.8L Macro
• TS-E 90 mm f / 2.8L Macro
• TS-E 135 mm f / 4L Macro

MP-E65 mm f / 2.8 1–5 × Macro

Macro and magnifying lenses

• EF 50 mm f / 2.5 Compact Macro
• MP-E 65 mm f / 2.8 1-5 × Macro Photo (without autofocus)
• EF 100mm f / 2.8 Macro USM
• EF 100mm f / 2.8L Macro IS USM
• EF 180mm f / 3.5L Macro USM

Individual evidence

1. ↑ Canon Professional Network (CSP): Canon reaches 80 million EF lenses production landmark , August 21, 2012.
2. ↑ Press release from Canon Germany: Top record: Canon interchangeable lens production exceeds 100 million mark ( Memento of the original from May 2, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , April 30, 2014 
3. ^ Photo magazine, September to November 1989, The EOS-1 story
4. ↑ Communication housing - lens , test.de of March 16, 2016, in: Travel zoom lenses: For near and far , accessed on January 8, 2017
5. ↑ Canon Extender EF 1.4x Parts Catalog (PDF) Retrieved on April 5, 2009.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
6. ↑ Canon Extender EF 2.0x Parts Catalog (PDF) Retrieved on April 5, 2009.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
7. ↑ Canon Life Size Converter Parts Catalog (PDF) Retrieved on April 5, 2009.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
8. ↑ Lens technologies: Image Stabilization (IS) , EOS Magazine, accessed August 19, 2020
9. ↑ ^{a b} The new Canon EOS 2000D and EOS 4000D: for a creative introduction to photography. Canon, February 26, 2018, accessed February 26, 2018 . 
10. ↑ ^{a b} Quality first - Canon presents the new DSLR models EOS 77D and EOS 800D. Canon, February 15, 2017, accessed February 15, 2017 . 
11. ↑ ^{a b} https://www.usa.canon.com/internet/portal/us/home/about/newsroom/press-releases/press-release-details/2016/20160217-eos-80d/20160217-eos-80d
12. ↑ http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_60da
13. ↑ Archived copy ( memento of the original dated February 6, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
14. ↑ http://www.canon.de/about_us/press_centre/press_releases/consumer_news/cameras_accessories/distinctive_photography.aspx
15. ↑ Crystal clear even at the shortest distance - the new Canon EF-S 35mm 1: 2.8 Macro IS STM. April 6, 2017. Retrieved April 6, 2017 . 
16. ↑ Archived copy ( Memento of the original from May 14, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
17. ↑ ^{a b c d} Canon USA Expands Its Lens Portfolio With The New Ef 85mm F / 1.4l Is Usm Lens And Their First-Ever Macro Tilt-Shift Lenses. Canon USA, August 29, 2017, accessed August 29, 2017 . 
18. ↑ http://www.canon.de/For_Home/Product_Finder/Cameras/EF_Lenses/Fixed_Focal_Length/EF_400mm_f4_DO_IS_II_USM/index.aspx
19. ↑ http://www.canon.de/For_Home/Product_Finder/Cameras/EF_Lenses/Zoom/EF_11_24mm_f4L_USM/
20. ↑ ^{a b} The Canon EOS 5D Mark IV - for everyone who strives for the perfect picture. Canon, August 25, 2016, accessed August 25, 2016 . 
21. ↑ http://www.canon.de/For_Home/Product_Finder/Cameras/EF_Lenses/Wide_zoom/EF_16-35mm_f4L_IS_USM/
22. ↑ http://www.canon.de/About_Us/Press_Centre/Press_Releases/Consumer_News/
23. ↑ http://www.canon.de/For_Home/Product_Finder/Cameras/EF_Lenses/Standard_Zoom/EF_24-70mm_f4L_IS_USM/
24. ↑ Archived copy ( Memento of the original from October 4, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
25. ↑ ^{a b} http://www.canonrumors.com/canon-officially-discontinues-three-lenses/
26. ↑ http://www.canon.de/For_Home/Product_Finder/Cameras/EF_Lenses/Telephoto_Zoom/EF_70-200mm_f2.8L_USM/
27. ↑ Canon Updates Lineup of EF L-Series Telephoto Zoom Lenses With the Introduction of EF 70-200MM F / 4L II USM and EF 70-200MM F / 2.8L IS II USM. In: canon.de. Canon, June 7, 2018, accessed June 7, 2018 . 
28. ↑ Whisper-quiet, precise and fast: the Canon EF 70-300mm 1: 4-5.6 IS II USM lens with Nano USM AF. Canon, September 15, 2016, accessed September 16, 2016 . 
29. ↑ Archived copy ( memento of the original dated November 14, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 

Web links

• Canon lens compatibility on the Canon site
• Adapter from FD to EOS
• Complete listing of all Canon EF lenses .