[bikram]

Ching, under what circumstances do we use TTL or TTL BL ? When use TTL, photos tends to be brighter (sometimes over), when use TTL BL , photos tends to be darker.. Thanks for sharing

[bikram]

no response????

[王迦南]

BL是Back Light時用，透過鏡頭內置的CPU與閃燈溝通，較準確地計算出背光時所需的閃光量。

[bikram]

Thanks Ching, if under sunshine day and the subject is not facing the sunshine, so what setting is better TTL or TTL BL. I have asked NIkon CS, they said it would be better to use TTL since the amount of flash from the flash calculated from the subject only. Is it correct?

[王迦南]

在一般情況下，用TTL可以了；若用了TTL BL，則因設計時相機的快門/光圈值的設定會變得較為寬容，照片質素可能適得其反。


在背光或前景/背景光差很大時，又欲照片得出較為均衡的曝光，則可用TTL BL模式。但TTL BL模式須配合D或G系列CPU鏡頭，且最好搭配P模式才能完全發揮，因為基於設計原則是：閃燈管前景，光圈快門管背景。

原則上TTL BL運作中時測光系統會評估出背景亮度，閃燈預閃評估出主體亮度，然後操作閃燈出力與機身曝光去盡可能的讓兩者亮度相近。


若有錯誤，歡迎賜正。詞不達意，則請見諒。

[bikram]

王迦南 Ching, Thanks for your comment. It is very usable for me...

[bikram]

If used in indoor, so which one is better to use TTL or TTL BL??