[My-Ricky]

大家好!! 小第初到貴境, 係度同大家打聲招呼先 ^^


小弟想買支鏡(for D70)唔洗用腳架可於夜晚/暗環境下, 只用slow sync影人(例如4個人wide)加背境(例如係museum / 聖誕燈飾), 咁以下那一支較適合?

Nikon 50mm F1.4; F/1.8
Sigma 24mm F1.8

用24mm一定可以好易cover晒4-5個人加埋背境, 但亦由於相機同subject距離唔洗咁遠都cover到(再遠d人就好細了), 用F1.8時, 會否境深大淺而背境唔清? 係呢個情況下, 用50mm F1.4/1.8會否好d? 因相機同subject距離要遠好多(我大概計過要24mm只要8呎, 50mm就16呎) 先可以cover到, 咁境深應該可以深好多而較適合?

另外, 有冇地方可以跟據光圈值及相機同subject距離就show境深幾大?

Thanks各位!

[Philippe]

你可以去呢度計吓http://www.dpreview.com/learn/?/Glossary/Optical/Depth_of_Field_01.htm
用大光圈避免用腳架是不太實際的,背景會好散.你影四個人會好啲,因為可以行得遠啲.但離理想有一段距離

[My-Ricky]

多謝你!

我去左其他site都搵左好多有關資料, 以宜家科技(dslr iso/noise)睇黎用大光圈被免用腳架真係唔掂, 因個境深真係好淺, 我諗唯一方法係將來dslr可以大幅提升iso值, 例如去到5000或10000而又有好好o既noise level, 咁就唔洗大光圈都可以做到深景深啦 ^^

[小小生]

這個DC就有好處,因為DC景深深很多
我用A1 28mm ISO-200 f/4.0 快門1/10秒 開AS 就得

[rickywck]

Using large aperture to take night scene portriat can give you some special effect - all bright spots will be diffused into circle, which can give very nice picture. Below are some examples (not taken by by me) :

http://avbuzz.com/new_home/w/200412/model/nlm2004128/Sarika/0998.jpg
http://avbuzz.com/new_home/w/200412/model/nlm2004128/Sarika/09.jpg
http://avbuzz.com/new_home/w/200412/model/nlm2004128/Sarika/gh.jpg

For focal length, wide angle is more suitable, I would suggest 24-35mm range. For aperture, F1.8 is just marginally enough, it is better to have F1.4 - based on my experience, I still need to use ISO800 with f1.4 to get 1/60 shutter speed.

Please note that you still need flash to bring the subject clear enough.

AS/VR/IS can be useful as mentioned. However, you can't obtain the effect I said earlier unless you use SLR and large aperture.

[My-Ricky]

我都知效果幾得意, 但如果全部都係咁就死得, 即係去旅行唔洗照人像夜境了(d境變晒一個個圈) >.<

Nikon支28mm f1.4d要成萬銀, 太貴了!! 如果買, 我諗買Sigma支24mm f1.8或者20mm 1.8都夠了, 如果用埋iso400, 相信提供1/30s快門是冇問題的, 而係20/24mm, 1/30s己是基本安全快門了, 相信唔洗1/60s的~~

[Philippe]

我覺得與其諗大光圈,不如向防震埋手,以下的相也是手持(影得求其請唔好插).景深係冇DC咁長但係DC就算加咗防手震都唔容易影得咁光.
http://dcfever.com/photosharing/enlargephoto.php?photoID=216389
我係用17mm焦距的,Nikon有支24-105vr我諗其實可以考慮,雖然光圈唔太大,不過要影埋景其實大光圈唔係咁重要

[B and H]

如果要影人(例如4個人wide)加背境(例如係museum / 聖誕燈飾而唔用腳架, 我覺得枝AFS24-120mmVR更適合.

因為如果您用大光圈, 基本上背景會很模糊, 因景深很淺. 如您只想強調主體, 背景只做”親”托, 那又不同.

但看您形容, 您是想人要sharp, 但景都要看到, 與旅遊照差不多. 是不是??

[My-Ricky]

冇錯呀, 與旅遊照差不多, 要前後境都清

支24-120mm vr得f3.5, 如果用iso400 24mm係暗d環境時, 我諗得1/10或者更低快門速度, 請問係呢個快門速度用左vr鏡, 會唔會手震? 我平時最叻都要1/15-1/20快門速度先唔震....

Thanks

[Philippe]

嘩,我諗你係一個手好定的人.咁應該絶對冇問題.
支鏡聲稱可以降低三級安全快門,照計可以用盡可以去到1/5秒都唔會手震.
我算係比較手震的人.我用17mm照計可以去到1/3秒.我試過真係得,不過係要好心無雜念先得.當兩級用就好好多,1/6秒多數OK,1/8秒就差不多百分百.
所以通常我會用快門先決set死1/8秒,用iso 800,等相機去用最細光圈.好多時都唔駛用到f2.8.所以我認為f3.5夠用.

[B and H]

My-Ricky,

支24-120mm vr得f3.5@24mm, 無錯, 但如果開啟vr, 看您"我平時最叻都要1/15-1/20快門速度先唔震....", -----> 低三級, 可以去到1/4s-1/5s, 在晚上可以影好多嘅嘢.

我真係試過在晚上影人加夜景唔用腳架都OK.

如果您要前後境都清, 大光圈末必適合您.

但枝24-120mm vr成像就無大光圈鏡"禁"sharp.

[My-Ricky]

多謝你地~~

但我記得支24-120mmVR好似要大概係80-120mm時佢先會啓動放震功能, 係24-50mm時係冇用的, 可否confirm呢點?

[raymondlovecat]

" .... VR operation offers the equivalent of using a shutter speed 3 stops faster at 120mm ...."

See: http://www.nikonusa.com/template.php?cat=1&grp=5&productNr=2145

[My-Ricky]

我就係見過類似spec先問以上問題....

咁即係話係24mm時, 不能開啓vr..... 亦即係個vr function對我没用了...

[raymondlovecat]

At first I had the same understanding ...

But after reading this specification, my interpretation is the VR function work throughout the entire zoom range (with the strongest effect up to 3 stops faster at 120 mm).