[herbertau]

請問点先知支鏡有無走焦,同埋咩叫走焦呢?

[snoopybee]

走焦 ... 近兩三年先至有的名詞.

我理解係, 你想 focus 某一點, 但部相機 focus 左去第二度. 此情形會被 "形容" 為走焦. 點解唔係話 out focus, 要用 "走" 來形容, 就係因為隨著機身進步, 有 51點, 而機主 "不懂得" 去調較一個適合自己的攝影模式, 繼而每次半按 shutter 時, 發覺 "部機對唔到焦", "時前時後" 等等, 所以稱之為走焦.

要對正下藥, 你只要將部機調較去單點對焦, AF-S, 包唔會有所謂 "走焦" 出現.

現今大部份人都話 "走焦" 係 "廠做得唔好", 但事實係, "人用得唔好".
(去到尾, 睇完 manual, 活學活用就唔會有事)

[herbertau]

Thanks very much.C-Hing

[pky]

Thanks a lot for the explanation of the term. I also mistook the term meant not focusing properly. However, if one should stick with single-point focusing, why did so many people concern about the number of focusing point in a camera (it seemed to be a big deal when people were comparing cameras). Personally, I prefer single-point focusing as I found multi-point focusing is very confusing and random. The camera seems to have a mind of its own. I would like to know how should one effectively use multi-point focusing. Would you care to provide some pointers?

[snoopybee]

Bro-pky, I would like to emphasize this term particularly because if there were focusing problems, we would call it 對唔到焦, 對錯焦 ...etc., then it would require calibration or even repair at the SC. However by reading numerous threads over this 走焦 topic, I realized people were typically referring this as the effect of "not being able to focus on the subject where the user wanted".

Referring to your Q about those 51-matrix focusing system, most c-hings won't use it neither. If you have been picking up the essence from the advertisements, these systems best work under the situation where you cannot predict the next move of the subject and where the subject is moving at a fast speed i.e. car racing (that's why they always use this in their ads). Manufacturers want to build a "smarter" processing unit which can "predict" the next focusing point under extreme conditions to give a better impression to consumers. In reality, the most common focusing modes people use would be spot or dynamic (in fact, if one read the manual carefully and by understanding the meaning throughly, manufacturers didn't suggest to use 3D focusing mode with "normal" shots).

Last but not least, I would not let manufacturers affect my purchasing decision. Even they emphasize 51-point matrix ...etc on their products, I would focus on my "needs" to pick my gears. It is typical marketing strategies that manufacturers emphasize their "strengths" and make consumers loose track of their needs. ^_^

[pky]

snoopybee:

Thanks for the info. I stopped doing serious photo taking about 20 years ago. It was not until the last couple years did I pick up a dSLR and has been using it just like the old film SLRs. Recently, I got a GF1 and got a bit confused when trying out all the bells and whistles.

[look_yau]

誤清楚就誤好亂噏...

Google 下仲好D:
http://blog.dcview.com/article.php?a=VGpSMQ1rBDo%253D

[snoopybee]

你 quote blog 上的一些所謂 "數據" 就當係 "真理"?

現今有一班人喜歡搞一大堆 "數據" 出來支持某種 "理論".
另外又有另一班人喜歡見到網上睇落比較 scientific 就當真.
而小弟正係一副食古不化的老骨頭, 比較喜歡親身實踐以及向 "實際" 方面去睇事情.

唔係話佢講係錯, 個理論係正確, 不過有冇諗過你用部機, 中間個點 focus 老遠的東西時, 就連你隻眼都未必可以在 viewfinder 中對得準, 當中還有反光問題另到不能對焦等等, 點解部機要識得知道你想 focus 去邊點? 點解做人往往要吹毛求疵?

個 blog 講緊基本 trigonometry, 要搬出來講實在多餘. 要套系統遠距離不能有 +/- 1cm 的偏差? 首先你地知唔知道就算連美國最精密的導彈系統, 係容許有差異? (即係由空中掉粒炸彈落去, 可以有一百幾十米差異. 我唔係吹水, 我以前接觸過有關項目)

唔太離題了, 我要指出的係, 若然部機或支鏡對唔到焦, 要去整. 但係若然係講緊這幾年先出的所謂 "走焦" 問題, 新一派的師弟門, 睇熟本 manual, 最緊要係識得融匯貫通. 唔好下下少少事就拆天. 事實係, 點解所有師兄師叔師公用 DSLR 都唔會有 "走焦", 偏偏叫救命的, 話影唔到相的, 要係你地. 反思下啦.

[snoopybee]

讓我補充一下. 我要並不是要指出這些理論的對錯, 如我所講, 這些理論是正確的. 但在實際環境及應用, 作為用家應該有適當的態度罷了.

[look_yau]

同意, 要清楚了解你自己用的工具.

但係如果只係自動對焦選錯點就誤係走焦羅...
如果你買支 Sigma 走焦就用邊點都係走焦, 如果誤係便洗 cal 鏡

[look_yau]

或者噤講: 如果只係自動對焦選錯點 - 人問題

[snoopybee]

Yup.