[scwong]

What is the relationship of ISO , 光圈, 快門???

e.g. 快門 = 1/60s, 光圈 f/8, ISO = 100
如果將 ISO change to 200.
- what is the new value for 光圈??? (快門 keep unchange) Is it f/16???
- what is the new value for 快門??? (光圈 keep unchange) Is it 1/120s???

thx

[Victorlolo]

iso多數影響快門咋嘩,所以光圈 keep unchange 快門便是1/120s

[embu31]

ISO 100 > ISO 200 gives you double the shutter speed or one aperture "stop" of light.

therefore if shutter speed remains at 1/60s, aperture value change from f/8 > f/11

aperture value, each is one "stop" gap:

1.4>2.0>2.8>4.0>5.6>8.0>11>16>22>32

if aperture remains at f/8, shutter speed changes from 1/60 to 1/125sec

shutter speed value, each is hafl of the former"

1sec >1/2s >1/4s>1/8s>1/15s>1/30s>1/60s>1.125s>1/250s>1/500s>1/1000s.

[mrskyhook]

the new F is F11, becoz one EV stop of Aperture is 1.4x, instead of 2x

[scwong]

Fist, thx for your help
- 系唔系,增加ISO(e.g. 100 to 200),就可以增加一級快門 or 收細一級光圈ar???
- 每支lens既光圈step好像不一定是一樣. (1.4>2.0>2.8>4.0>5.6>8.0>11>16>22>32)
e.g. EF 50mm f/1.8. (f1/.8 not include to the above list???)

[peterchan04]

what is the new value for 光圈??? (快門 keep unchange) Is it f/16???
---> f11

- what is the new value for 快門??? (光圈 keep unchange) Is it 1/120s???
---> 1/125s

[wewewawa]

"- 系唔系,增加ISO(e.g. 100 to 200),就可以增加一級快門 or 收細一級光圈ar???"

正確。

"- 每支lens既光圈step好像不一定是一樣."

因為有些鏡頭光圈係一級一級上﹐ 有些係半級上。 好似打麻雀有人打半辣上﹐ 有人等辣辣上一樣。

[scwong]

Thx so much!!!

What is the standard step (一級)??? Is it (1.4>2.0>2.8>4.0>5.6>8.0>11>16>22>32)???
有半級上既lens,系咪準d呢???

[beancurdbean]

一樣準, 因為可以用快門配合番

[scwong]

How about used in AV mode???

[beancurdbean]

唔關用乜mode事, 只要快門同樣有三份一或二份一級, 就算光圈得一級一級上, 都唔影響曝光?準誠

[scwong]

I use TV mode, fix the shutter speed, and then let the camera to find out the corrsponding aperture value.
Now, I have two lens. One is 一級一級上, but another once is 半級半級上.

e.g. If the correct value is (aperture value = f/1.8 and shutter speed = 1/125s)
If I used TV mode, and set the shutter speed to 1/125s. But my lens aperture step is (1>1.4>2>2.8>...)
The camera will find 1.4 or 2??? But the corrsponding aperture value should be f/1.8???

[beancurdbean]

你?, Tv mode 有機會唔準, sorry

[peterchan04]

呢個就係"專業機" 冋"普通機" 分別.
I guess u will just have to live with it and make the best out of your camera's given settings. Also, the differences between F1.8 and F2.0 are not that much.

[scwong]

thx for your comment~