[Obi-Wan]

The safety shutter speed rule (安全快門)

safety shutter speed = 1/{equivalent-35-mm-focal-length} second

Quote from
http://www.techniphoto.com/wiki/index.php?title=The_shutter_speed_rule

"The usual translation in the digital world for APS-C sensors is that you should take the crop factor into account (1.5). This means that a 200mm lens will give you a field of view equivalent to a 300mm on a 35mm camera and hence will need a shutter speed of 1/300 sec or faster. "

There is a mathematic proof for those who loves maths.

[reflexboy]

Copy and paste again? 

Someone really keen on making thing as complicated as possible! He might think it would be easier to intimidated others that way.


Do us a favour. If u know it  well. Just use his formula to calculate the result of using 135mm and remember to show your steps.

Let me tackle it with the simplest explanination.

If 1/focal length X crop factor stands strong. Then pixels should never be counted as a factor for safety shutter speed. We all know crop factor is about the sensor size. 

Interestingly, if number of pixels is counted at a factor of calculating the safety shutter speed. Then the  crop factor should never be counted. Coz number of pixels on a sensor will increase from generation to generation. Then it should be 1/focal length X (variable). Simple enough? This is easy to understand if those who love photography! And it's a paradox!

[Obi-Wan]

When I wrote someone who doesn't know
someone may naturally think that this stuff is copy-and-paste

if u believe in maths
u can go through it easily

also reflex仔 do u mind telling me that u insist reflex lens mirror is mafe of mercury?

每次我好心教好你，你都唔信。
你真係點都唔知你錯連reflex仔支mirror係Ag做都唔知！

[KALKAL]

哈哈~
真係開左TOPIC, 有中文就好了....

其實, 安全快門是否一條完整的公式?
如果只係一個概念, 冇建基係固定, 準碓既基礎上的話, 點計都冇意思的.

[698]

又嚟!!!

[tam_dominic]

In my humble opinion :

You are both right !

When the blur effect is measured on 1:1 display, reflexboy is right

When the blur effect is measured on fixed size print out eg 16 x 20 inches, obi-wan is right

Let us shoot happily and no war.

Happy shooting !

[reflexboy]

dominic, 影相應從攝影方向考慮先,定還係從放相角度考慮先? ff機影o既野唔通唔可以放得更大?(In your case大過16X20) o甘safety shutter speed又應該點計? 又要諗o的野出來攪大佢?(倒果為因)? 呢o的就叫偽知識同偽科學.

仲有,井底之蛙大屍所講o既係人地o既料, 而我講o既係我o既料. 呢樣野都要清楚.

歡迎井底之蛙大屍再上網揾o的人地料出來反駁! I NEVER SAID I WAS RIGHT! BUT U CAN'T PROVE ME WRONG. THEN MAY BE I WAS RIGHT!
sounds familiar o可?

[Obi-Wan]

小朋友係度亂吹反射鏡用水銀造是否偽科學？
我用中文講多一次
reflex lens 反射鏡用銀silver 做反射面
你EQ 低到錯都唔肯大方地認，有曾sir風格喎！

[ibausu]

安全快門這個問題其實有很多不同的說法。 好多人都會話 1/焦距 (35mm) ...但是根據紐約攝影學院，1/(2x焦距) 才是絕對安全快門速度。 當然最好就是用腳架啦！ :P

小弟的Blog:
http://lovelightstudio.blogspot.com/

[九龍人]

安全快門係幾多都好,一定要計埋crop factor.

[reflexboy]

唉........大屍！睇吓你自己啲post. 對自己幾咁絕望! 真可憐！

[Obi-Wan]

CPS/NPS member, u never answer my post

When u know u are wrong, u only play personal attack. (I don't mind personal attack on me, because it only shows the attacker no other evidences to support his view.)

This ends my play with u this round.

If u wanna play with me again
please
accept that what u said MERCURY is SILVER
OR
change to another name & play

**** I am not a CPS/NPS member, but I love to share photography knowledge with everyone ****

[reflexboy]

你有能耐，歡迎任何時間出席，在下全天候恭候你，不過請再花多多多啲時間上網攞多啲人地啲野出來！

叫咗你吾好攪啲technical野！其實講啲可有可無嘅topic咪幾好！

good night!

[reflexboy]

搬字過紙，不求什解，人云亦云，以耳為目，畫蛇添足，外强中乾，認屎認屁，自卑感強！

仲學人學雷台，不自量力！

[reflexboy]

呀.......大屍！吾記得提你多一樣野！在下都係一啲討論區嘅mod. 所以我知道mod可以做一啲特權。所以吾需要喺我面前表演！

仲記吾記得以前我層經叫過你sticky一啲thread？？？