[evoplane]

各位CHING,

當我用200MM影相時(我部係1.6CROP....=320MM (35MM FORMAT))......
用鴨記無線引閃飛燈....即係燈用M MODE...快門用1/200...因為我個BODY既X-SYNC只有1/200......
即係話我用比安全快門慢既快門黎影.....
我影人都唔會帶腳.....太重.....
好多時都手震左......

我想問....咁係唔係只可以用70MM-120MM (因為120MM1.6 = ~190MM)去影或者用番個腳架呢?

我想知有無高手有計???

另外,我經常一個人去影外景人像=無人幫手打板打燈........我用2米高燈架+透射傘+580EX.....外拍時經常比風吹番
用左相機袋"窄"住都係咁....可能因為大部份架生都拎晒出黎......名位CHING有無咩心得分享下呀???


多謝CHING...

[ks chung]

我不是高手, 但玩緊同你一樣的嘢! 我認為條數不是這樣計, 用200mm就是1/200s. 但你是否用支小白70-200無IS去影. 我個人覺得是技鏡長和重的問題, 用支定焦會好DD. 相對輕D. 不過好像你所說, 我用085和135時, 成功率又會大好多!
我都用傘, 上個用就跌壞了支燈. 大風時就不能用傘喇! 只好用番支燈的直射, 不過要在燈前拉出它的廣散片會好D.

[lokism3]

The guy who "design" the safety shutter speed is for full frame film (no matter the format), that means we may apply to 135 full frame digital as reference. You're using APS-C size with 1.6x crop factor digital, so the shutter speed should faster than 1/200; on the other words, the size of the image plate is smaller, so the speed should be faster. I'm not good at physics, so I can't tell exactlly the new speed; maybe lets assume from the lens side that is 200 x 1.6 = 320mm = 1/320. Always remember that the safety shutter speed is for reference only, and the original equation comes with ISO, & height to the horizontal too. It is designed to map shooting.

Back to your question, the x-sync speed is set to be 1/200 max., so you have 3 choice:
1. change to a lens with shorter focal distance or zoom to under 125mm;
2. review your holder camera method; and
3. use any thing on -site to support your arms.

Using tripod, is a very different style to what you are doing; learn it later. But normally, tripod in portrait works prefect with wide shot, and let the photographer to focus on communication with the model.

How to fix your umbella? it is the question of where are you shooting? consider on shooting place is not only because of framing, please also take the environmental factors too; you know where to put the flash strobe, so the place you shot should have sometime to let you support the light stand. Your bag is good, but sometimes you should bring along with graffer tape too.

[vital]

evoplane ching 請問你現場光及閃燈各佔幾多%

[evoplane]

多謝

ks chung
lokism3

兩位CHING既回覆, 小弟又學到野啦, 多謝晒

vital兄
小弟一般係大太陽下影.....閃燈只係用作補光....以現場光為主

[vk@photo]

我都有係室外用燈，週不時見倒其他人用D輕身燈架比風吹番!
冇計，我一定帶腳架!(拉車仔)......再係底部吊D重野落去，穩好多。

飛燈都手震，曰頭定夜晚?

[h0001244]

如果全黑加閃，你可以唔駛理什麼安全快門，因為閃只佔1/10000秒，唔會震的
唯一見震係現場continuous光，如你所講，<<係大太陽下影.....閃燈只係用作補光>>，咁你就要顧安全快門了，你可以試上 1/250s的，其實1/250 sync 唔準的情況都少
你用200mm唔係唔得，要睇你點hold鏡了，盡量將左手食指放上鏡前端，有助穩定鏡身的，機要盡貼面部呀！

[evoplane]

vk@photo兄: 係日頭呀...


再多謝其他CHING比意見

[hktsoi]

安全快門只和鏡頭實質mm值有關, 不用理會crop factor, 200mm就是200mm, 用於APS, 135, 120, 甚至是4x5相機都只是200mm鏡頭, 安全快門速度都是1/200s

不過安全快門速度只是一個參考值, 讓你知道要小心手震, 有人用50mm鏡頭1/500s拍攝一樣手震

戶外拍攝, 直打光是可以的, 光質也不硬, 因為有現場光補光, 令陰影不會很明顯

[lokism3]

"安全快門只和鏡頭實質mm值有關, 不用理會crop factor"
Mr. hktsoi, I'm afraid that it is not all true.

You should agree that the shutter speed is not related to film format, right?
And, I stated that the "theory" is designed for full frame, have you seen that?

In which full frame means the resultant image size. If there is a crop factor implied to any format, the resultant focal length should be affected too. And the "cropped" image is not the resultant image size, that's why many guys asked with the same question!

It is basic physics that image size, focal length, & object distance are related. If the image is cropped, therefore the focal length should be muiltpiled with relatively the same factor. Therefore, a 200mm lens "looks like" a 300mm lens; the confusion circle was not changed because it is in fact a 200mm lens, there is nothing changing on the depth of field charateristics. So I used the work "looks like", and I am not the first guy to explain like this.

The safety shutter speed should be counted base on the resultant focal length; as all we know the reference value of a 200 is 1/200 and a 300 is 1/300, they are very different. One extreme example for you guys to think, please assume that we are using 4/3 system. a 50mm would "look like" a 100mm in the system, what would be your choice in safety shutter speed reference? most of the guy should take 1/100s. right? the image that we see through the lens is 100mm and not 50mm in a result.

So, it is the same in digital photograpy on 120 & 4 x 5 format, we need to calculate the crop factor when it is not full frame.

[tam_dominic]

"安全快門只和鏡頭實質mm值有關, 不用理會crop factor"
Mr. hktsoi, I'm afraid that it is wrong.

It is not my humble opinion but a common sense :-)

[hktsoi]

呵呵, 這個問題我已經說過很多次, 也在攝影世界雜誌上做過測試, 証明安全快門和焦距有關, 不是同crop factor 有關.

這對於你們來說是比較難理解, 因為你們很少會接觸120, 4x5這些片幅.

Full frame全片幅是數碼才出現的名詞, 其實, 只是135和APS片幅的分別, 以前, 一直都有這樣的分別

就以50mm的鏡頭為例, 用於135和APS相機

照你們的說法, 50mm鏡頭用於135機上, 穴安全快門是1/50s

但是50mm鏡用於APS機上, 因為APS比135細, 有Crop Factor x 1.5, 所以50mm鏡會繳成長鏡, 因為拍攝視角會是135的80mm鏡, 所以安全快門就是1/80s , 而不是1/50s

我們用相同的說法用於135 和120機上, 因為很好前輩很喜歡將哈蘇鏡頭用於135機上

在120機, 80mm是標準鏡錢, 但是在135機, 80mm就是長鏡了, 如果以現在Full frame的說法, 80mm用於135上是拍攝視角等於120的150mm, 即是135是120的2x crop factor

那80mm的鏡頭在135機的安全快門是否要1/150s, 而不是1/80s呢

當然不是, 80mm鏡頭用於120上, 和80mm用於135上, 安全快門都是1/80s

Lokism3, 50mm在4/3的安全快門仍是1/50, 而不是1/100s

我在攝影世界發表過一個文章, 用了架長炮王, 甚麼35-450mm的prosumer機來拍攝,
那相機寫拍攝角度等同於135系列的35-450mm, 如果在這機的所謂450mm拍攝, 最低安全快門是1/450s, 我自問手持拍攝都很定的, 但是用135機手持真正的500mm鏡頭, 也要1/500s才可以不手震, 如果使用1/60s, 一定會手震

但是我用那於prosumer機的所謂450mm來拍攝, 只用1/60s已經很定, 沒有手震, 因為那相機的鏡頭實質焦距只有56mm, 用1/60s已經足夠

不信的, 自己找來試一下, 不要靠自己想像或是什麼common sense

[evoplane]

hktsoi兄,

比你咁講, 我有D亂呀.......因為實在有太多文章和雜誌所講既同你有出入...
好多謝你意見...

希望有多D CHING 比下意見啦...

[hktsoi]

是啊, 因為現在太多雜誌的寫文章的人攝影水平跟本沒有到家, 經常誤導.

[tam_dominic]

在攝影裏面,是永遠學習. 大師也在學習,尤其要向青年人學習。
(Dinshaw Balsara 1938-1988)