Lens - 16 Mar 2016

DX - non full-frame
N - nano coated
FX - full-frame
AF-S - auto focus with silence wave motor
G - aperture adjusting on the body itself
ED - 超低色散
II - 2nd generation

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135 full-frame = 24mm x 36mm
diagonal from A to B = AB = 24(2) + 36(2) = ~ 50mm

non full-frame = 25mm x 18mm
diagonal from K to H = HK = 18(2) x 25(2) = ~35mm

factor:  50mm/35mm = 1.5

hence, 50mm used on FF, when switch to non-FF = 50mm x 1.5 = 75mm

meaning when used on a non-ff, a 50mm len has a much longer focal length of 75mm

when use a DX len on a ff body, a 135 film cannot be used fully then.

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FF ----->  < 35mm is wide angle lens
                 50mm i.e. the diagonal of the sensor itself is standard lens
                 > 80mm is tele-photo len

Non FF --------> 35mm - diagonal of the sensor itself


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Feature of wide angle
-  the centre of the object be exegerated; the two sides of the object dragged backward;
-  object at the back of frame look smaller.

Depth of field:
- range of sharpness

Wide angle feature:
-  the closer the object, the bigger the image

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When shooting semi-oblique object, must face the light

Shadow and light

Fish eye len - shoot closer - exeggerate the closest object

Black background ---> smaller f/x, the darker the background

Reflection ----> squad down to shoot

Mirror len (ball ball len) -----> out-of-focus object becomes "ball ball" or donnuts