[新手50D]

請各ching指教下..


本人用580exii + 50d的!
請問"高速同步" ,應在那個情況用?
睇說明書,佢話同影'人像'有關, 各ching可否詳細講解下?

唔該各ching!

[小小生]

你要用高速快門的時候就用囉

[tdt6446]

當你用快門1/250以上而又要用閃燈, 咁咪要高速同步

[fsyten]

其實我都唔係好明...
既然flash只支援至1/250s, 咁當快門快過1/250，flash又如何應付呢﹖
總之...唔明"高速同步"的原理唔功能

請問有冇高手可以解答呢﹖

[Obi-Wan]

when u shoot backlight photos under bright sunlight, the flash can be fired at faster than shutter speed 1/250, e.g. 1/1000 in order to keep the required aperture at a smaller value, e.g. f2.8.

See the following pages for details

http://photonotes.org/articles/eos-flash/

[biblekwan]

如果你背景係好光, 強光既時候, 你又想個景(藍天白雲)好清楚咁重現, 你就會SET 1/600 呀, 可能 1/1000既快門既時候, 可能你有個主體都好想影既(MODEL), 咁你就要用高速同步喇~
因為如果你藍天白雲緊, 你又要影個MODEL, 你用一般既閃, 係去到1/200左右, 咁你個人就入閃, 可以有正常既光, 不過你個影又會太光, 乜都白曬~
個時, 你就係閃燈要SET高速同步, 之後用個藍天白雲黎測光, 再對焦個主體, 咁閃燈就FEL左個主體先(MODEL), 咁再去影, 咁你個藍天白雲又會好清楚, 而個主體(MODEL)又會有足夠既光~
再睇下你想要出乜野既效果去SET +/-閃光.

以上唔知係唔係全對, 可能要D CHING解答祥細D同改正下~

[mike0210]

高速快門原理係:

一般快門係當前門簾完全開啟後後門簾先會關上, 係前門簾完全開啟時閃一下

但係當高速快門時(>1/250s) 後門簾係前門簾未開晒時開始關上, 如果只係閃一下, 只有前門簾與後門簾中間的'gap'能受光, 上下被前後門簾所遮蔽而變黑

所以閃燈會分幾次閃光, 替在不同時間的'gaps'補光

不過高速高頻既閃光人眼落同閃一次冇分別

[h0001244]

This is a very good question, I am not quite sure the answer as well.

But people said that 高速同步 would have few flashes at one single frame to compensate gap due to shutter not fully opened.
But I have doubt of uneven exposure on some parts as you can think of that some part might have double or triple flash exposure and some have only one flash exposure.