[pp_cheungss]

我想問下什麼叫cop factor

有人在forum 話Canon 係1.6

For example,

EF-S 17-85mm....

is 17 x 1.6 = 27.2mm

是什麼meaning?

[Xplore]

Bingo

[h0001244]

To make it clear....
1Ds x1
1D x1.3
5D x1
50D x1.6
500D x1.6
1000D x1.6

x1 is full frame (FF) on 135 system. The size of CMOS sensor is 36mm x 24mm
Due to high production cost of making FF, Canon made 1.3x , 1.6x products
where 1.6x size is 22mm x 15mm...... much smaller than FF... therefore lower cost
as 22mm x 15mm looks like zoom in 36mm x 24mm
therefore 17mm for 1.6x crop is equivalent to 27.2mm in FF


simpler speaking
ultra wide --> wide
wide --> normal
normal --> little tele
tele --> long tele
long tele --> super tele