[TTHOBBY]

人地成日講EF鏡頭,其實EF係咩...??

[thestone11]

It is a mounting system....Another canon using on their crop cameras is called the EF-S

[叮噹仔]

係Canon EOS 鏡頭mounting既叫法,
分EF-S, 同EF 兩種,

只講流行既DSLR,
EF-S 只係適用於APSC (e.g. 1100D, 600D, 60D, 7D)
而EF鏡頭係適用於所有Canon DSLR機種, 包括APSC, APSH, 同FF.

[kickbutt]

Electronic Focus

[Minipod]

google 吓就有答案

EF stands for "Electro-Focus": automatic focusing on EF lenses is handled by a dedicated electric motor built into the lens.

[Curtismnw]

Electro Focusing

[Curtismnw]

And EOS stands for Electro Optical System.

[h0001244]

how about FD lens ?

[Curtismnw]

I think it should be Fast Dismounting.....

[h0001244]

sounds reasonable

[epao]

"I think it should be Fast Dismounting....."
Haha, good try Simonmnw Ching! My guess: FD = 快d

[pongyee]

>> I think it should be Fast Dismounting...

剛好相反：

... The advantage of this type of mount is that the contact surfaces between the body and lens do not rotate against each other when the lens is mounted. This prevents any abrasion, which could conceivably reduce the very precise lens-to-film distance. The disadvantages include SLOWER lens changes; later FD ('New FD') lenses mounted more like bayonet-mount lenses in that the photographer twisted the lens body to mount and unmount, even though the actual mount surfaces remained fixed.[3] Canon chose a bayonet-style mount for its new EOS system's EF lenses.

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

其實There is no known meaning for 'FD', and Canon has never disclosed what, if anything, it stands for.

[Curtismnw]

It was a one-tounch lens release botton on the lens barrel. So dismount the lens was very handy----- Oniy by one hand operation.