[冰之淚}}]

大家好! 本人用CANON G2 的,因為岩岩學影相&未摸熟部相機,所以唔係好
識SETTING..,例如當我影人像時候,想做景深效果,但無論我常試用光圈F.5.6
或F2.0 , 人物距離約兩米,人像雖然清楚但係..背景唔濛... ,要有D乜野技巧呢?
係咪要加鏡呢?希望大家能夠教教我啦! ^_^v

[samlau]

The depth of field difference between f2.0 and f5.6 is not that drastic. If the camera is fully open at f2.0 and you still feel the depth of field is too much, the only way to do it on that camera is to zoom it to its fullest (105mm or more?) then step back and reframe your picture. With a 105mm or more focal length at f2.0, the background should be nicely blurred.

[占]

我都係用G2, 同樣有影深唔夠淺既問題
我都試過zoom到盡用最大光圈, 有d d 改善, 不過都係唔明顯
唔知係咪DC focal length 太長既問題定G2本身問題

我同時又試用SLR, 光圈4.5都已經好明顯

我都想知點先可以明顯減少G2/DC既影深

[hkhei]

係因為dc o既focal length太短..所以景深深
focal length短係因為一般dc o既ccd細

[samlau]

I agree with hkhei. Here is a demonstration to let us understand more:

http://www.ctlow.ca/Photo/FocalLength.html

[samlau]

Let me elaborate more:

Depth of field is "inversely" propportional to focal length. So a 200mm lens has much shallower depth of field than a 50mm lens.

Take the Canon G2 for example - Yes, it said wide at 34mm, tele at 102mm. BUT, the lens is actually a 7-21mm lens only! The 34-102 is 35mm (film camera) equivalent focal length.

7-21 mm has a lot of depth of field. This is the advantage, but also limitaion to D cameras (except D SLR models). With such deep deep depth of field, most picture will come out sharp and clear, travel pictures, sceneries, group shots, etc. On the other hand, such small cameras are not meant to take good portraits.

[Velsper]

>> On the other hand, such small cameras are not meant to take good portraits.

That means, compact DCs (eg. G2) can't take good portraits???
and do you mean that portraits must have 淺景深?

[samlau]

Velsper raised a good question. It's me that confused you. Let me put it this way, DC can usually take sharp pictures, sceneries, group shots, etc. It will take portraits with vibrant color, sharp resolution, etc.

BUT, if you want to take the "usually flattering" kind of portrait, say in focus people with good bokeh, DC cameras have their limitations. I made my point in the last thread mainly in response to HKhei and Jim's point.

* Bokeh is a technical term that one may not find in dictionary. It means "the quality of the out of focus area in a picture".

[占]

samlau's sentence "the lens is actually a 7-21mm lens only" has already cleared my doubt.
Thank you~~

but y a DC lens is much shorter than 35mm camera?

[hkhei]

因為ccd o既size細過135菲林

[samlau]

Jim/ I am not 100% sure, but ...

Because the CCD in a digital camera is much smaller than a 35mm negative (film camera)? It sounds very logical, doesn't it?

[samlau]

HKhei/ your email address is not posted. I need your advice on the S602 with external flash. Can we talk here or you want to email me at:

samlau@flash.net?

Thanks!

[Velsper]

samlau 兄,
呵~~很好(齊整)的解釋^__^

占兄:
dc的焦距比135相機短是因為它的底片(ccd)細得多...
所以相比下用較短焦距也可以做到相同的"等效焦距"

ps 用135機做標準只是因為它是最常用的罷了.

[hkhei]

可以send PM給我~或者o係呢度問我^^

[samlau]

Thanks HKhei, I just sent you a PM :)