[hellenkit]

http://www.dcfever.com/photosharing/view.php?id=998684

點解用了 2.8光圈都可有咁深既景深 ?

[h0001244]

當focus 於無限遠就，F2.8都變得好深景深
當focus 於0.3m就 F8都係淺景深

[hellenkit]

謝謝! 那麼是不是要用 Manual focus ，代替了 AF ?

[look_yau]

>>那麼是不是要用 Manual focus ，代替了 AF ?

no need

[hellenkit]

但見到佢個 focus係 : 焦距 : 15.0mm (相對於 35mm: 49mm) , 呢個係咪就係無限遠 ?


EXIF 作品拍攝資料
檔案大少 : 118878 bytes
日期時間 : 2011:01:04 00:11:01
相機品牌 : Canon
相機型號 : Canon EOS 7D
拍攝日期 : 2010:12:27 18:00:11
解像度 : 630 x 420
閃光燈 : No
焦距 : 15.0mm (相對於 35mm: 49mm)
CCD width : 11.11mm
曝光時間: 0.050 s (1/20)
光圈 : f/2.8
ISO 值 : 400
白平衡 : Auto
測光模式: pattern
曝光模式 : 光圈先決 (semi-auto)

[davidkan]

影響景深的, 除了光園, 還有焦距, 物距

[hellenkit]

請恕小妹愚昧．因為在晚上影用 2.8，背景好易散，如果要用 2.8　影到呢D相，　http://www.dcfever.com/photosharing/view.php?id=998684　，　應怎樣設定 ?

[ACanonGuy]

"焦距 : 15.0mm (相對於 35mm: 49mm)" is the 焦距 of the lens itself. In this case it is a 15mm lens (either 15mm prime or zoom at 15mm). There is another EXIF parameter calls "Focus dist." to show the focus distance. Here is an EXIF example of Infinite would look like.

焦距 : 50.0mm (相對於 35mm: 242mm)
曝光時間: 0.013 s (1/80)
光圈 : f/1.8
Focus dist. : Infinite
ISO 值 : 3200

In your sample picture Focus dist. was not shown. My guess is it would be something like Infinite. Using your sample picture as example, if you use Auto Focus, you may want set your focus to something far away from you such as the buildings in the left hand side of the picture. That should give you Focus dist of infinite depending on the lens that you use. If you focus on one of the tree on the right hand side of the picture, you will get not much 景深.

Hope this makes sense.

[bye2]

有 iphone 的話可以考慮一下這個：

http://itunes.apple.com/us/app/photobuddy/id290785551?mt=8

或者

http://www.dofmaster.com/