What do the letters FD and EF mean?

[Bill Neiswender]

What do these letters mean on a lens description like FD and EF and which is used on the XTI?

 

[Phoenix96]

FD and EF are the lens mount types. FD was Canon's older lens mount style, used on cameras like the F-1 and AE-1 (among many others). FD is not known to stand for anything.

EF is the newer lens mount, introduced with the Canon EOS cameras in 1987. EF stands for "Electro-Focus".

Your Rebel XTi has an EF-S lens mount. EF-S lens mounts can take any EF lens, but also EF-S lenses which are designed specifically for use with "cropped sensor" digital SLRs like the Digital Rebel and 20D/30D/40D.

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phoenix96
http://www.milham.org

 

[CityLights]

What do these letters mean on a lens description like FD and EF and
which is used on the XTI?

http://www.canon.com/camera-museum/camera/lens/f_lens.html

--
CityLights
http://www.pbase.com/citylights/favorites
http://www.pbase.com/citylights/show_case
.

 

[ajkessler]

so anybody know what the letters actually mean? i quickly checked the canon museum but didn't see it...

Electronic Focus? or are they just arbitrary letters...

 

[ARShutterbug]

http://en.wikipedia.org/wiki/Canon_FD_lens_mount

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http://www.pbase.com/arshutterbug/

 

[snowboard9]

amazing site

 

[Lemming51]

Canon's bayonet/breech lock mount lens system for their first commercial SLRs (CanonFlex) were "R" series for "Reflex".

The next generation of the mount was FL (still "reFLex"), introduced with the FX/FP/FT/TL line of SLRs. It incorporated "auto" aperture control that closed the aperture to the set value when the shutter was released then automatically returned to wide open. TTL stop-down metering, but still manual exposure.

FD was introduced with the F-1/FTb and added a mechanical pin that communicated the lens's maximum aperture to the camera, enabling open aperture TTL metering, as well as anticipating full auto exposure with the "A" aperture setting. Guess as to the meaning of FD is "reFlex auto Diaphram".

New FD simply removed the breech lock ring in favor simple twist on of the bayonet with locking pin.

EF is "Electronic F", F still meaning "reFlex". "Electro Focus" is a commonly used, but F is not for focus only since the system uses electronics for actuating the diaphram as well as communicating all lens data (max/min aperture, focus distance, etc.)

so anybody know what the letters actually mean? i quickly checked
the canon museum but didn't see it...

Electronic Focus? or are they just arbitrary letters...

 

[Mats Isaksson]

The ones without AF do not have the "EF" in the names. (M-PE, TS-E).

They are still listed under EF-lenses in the Canon homepage.

Mats

 

[HarryLally]

FD stands for Fully automatic Diaphragm. They were introduced with the FTb which I had in the 70's (?) and were the first Canon lenses to stop down automatically when you fired the shutter. The connection between tha camera and the lens was mechanical, via a small lever at the bottom of the mirror box which shifted a pin that stuck out the back of the lens. The previous Canon lenses, the FL series, had to be stopped down manually before firing. Then around 25 years ago(?) Canon introduced an electrical contact between the camera body and lens so that the body could control the lens electronically. They called this lens the Electrical F lens.

Michael