1 stop in light loss = what in % at DVinfo.net

John Harvey · March 8th, 2005, 11:05 PM

1 stop in light loss = what in % loss from original?

if measured light equaled 100% and you stoped down the iris by 1, what is the percentage loss?

thanks for the edu.

jh

Jack Smith · March 8th, 2005, 11:25 PM

50 %

John Harvey · March 9th, 2005, 12:41 AM

wow.
so one stop more would be half again? IE 25%of the original 100%

2 stops = 25%

jh

Aaron Koolen · March 9th, 2005, 01:13 AM

Yup.

Aaron

Kris Carrillo · March 9th, 2005, 07:36 PM

also, keep in mind that your camera may not stop down incrementally in full stops. both the PD150 and DVX100 can be adjusted in half-stop increments. the full stop scale is:

1 - 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22

hope this helps,

kris

John Harvey · March 9th, 2005, 10:11 PM

why the jumps from 8-11-16-22?

jh

Kyle Ringin · March 9th, 2005, 11:37 PM

The scale starts at 1 to get every second stop:
1, 2, 4, 8, 16
and 1.4 for every other:
1.4 ,2.8 ,5.6, 11.2(rounded to 11), 22

This gives double/half the light with each full stop.

Cheers.

John Harvey · March 10th, 2005, 01:12 AM

when I'm on a set I hear the DP's and thier "people" talking "two eight" alot, figuring they mean a 2.8 stop. is this some mean value they are looking for from setup to setup for continuity?

jh

Josh Bass · March 10th, 2005, 01:22 AM

See also this informative thread that I started:

http://www.dvinfo.net/conf/showthrea...hlight=numbers

One thing that's neat and helps you remember is that every OTHER stop is twice/half that of the one that is. . .um. . .two before it. . .er

What I mean is - 1, 1.4, 2, 2.8, etc.

2 is double 1, 2.8 is double 1.4, and it goes on like that.

halves and thirds, I don't know if there's an easy trick to them other than just rote memory.

John Harvey · March 10th, 2005, 01:38 AM

THE PERFECT THREAD!

Opps, sorry for shouting.

that was a good read indeed. now I understand, just don't ask me to explain it yet.

jh

Josh Bass · March 10th, 2005, 02:26 AM

My ignorance is your intellectual treasure.

Aaron Koolen · March 10th, 2005, 03:10 PM

As I said in that thread, it's just square root of 2 times an f stop is the value of the next one:

1 * 1.4 = 1.4

1.4 * 1.4 = 2

2 * 1.4 = 2.8

etc etc etc

(approx here of course)

Aaron

Kyle Ringin · March 10th, 2005, 03:12 PM

Sorry, I forgot to mention the doubling thing to get every second stop, which was kinda the point of my post...

March 8th, 2005, 11:05 PM	#1
John Harvey Regular Crew Join Date: Feb 2005 Location: los angeles, ca Posts: 76	1 stop in light loss = what in % 1 stop in light loss = what in % loss from original? if measured light equaled 100% and you stoped down the iris by 1, what is the percentage loss? thanks for the edu. jh

March 9th, 2005, 01:13 AM	#4
Aaron Koolen Trustee Join Date: Apr 2002 Location: Auckland, New Zealand Posts: 1,727	Yup. Aaron __________________ My Website Meat Free Media

March 10th, 2005, 01:22 AM	#9
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	See also this informative thread that I started: http://www.dvinfo.net/conf/showthrea...hlight=numbers One thing that's neat and helps you remember is that every OTHER stop is twice/half that of the one that is. . .um. . .two before it. . .er What I mean is - 1, 1.4, 2, 2.8, etc. 2 is double 1, 2.8 is double 1.4, and it goes on like that. halves and thirds, I don't know if there's an easy trick to them other than just rote memory. __________________ The Bass' camerawork The Bass on IMDB

March 10th, 2005, 02:26 AM	#11
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	My ignorance is your intellectual treasure. __________________ The Bass' camerawork The Bass on IMDB

March 10th, 2005, 03:10 PM	#12
Aaron Koolen Trustee Join Date: Apr 2002 Location: Auckland, New Zealand Posts: 1,727	As I said in that thread, it's just square root of 2 times an f stop is the value of the next one: 1 * 1.4 = 1.4 1.4 * 1.4 = 2 2 * 1.4 = 2.8 etc etc etc (approx here of course) Aaron __________________ My Website Meat Free Media

March 8th, 2005, 11:25 PM	#2
Jack Smith Major Player Join Date: Nov 2003 Location: ontario Posts: 445	50 %

March 9th, 2005, 12:41 AM	#3
John Harvey Regular Crew Join Date: Feb 2005 Location: los angeles, ca Posts: 76	wow. so one stop more would be half again? IE 25%of the original 100% 2 stops = 25% jh

March 9th, 2005, 07:36 PM	#5
Kris Carrillo Regular Crew Join Date: Jun 2002 Location: Los Angeles, CA Posts: 28	also, keep in mind that your camera may not stop down incrementally in full stops. both the PD150 and DVX100 can be adjusted in half-stop increments. the full stop scale is: 1 - 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22 hope this helps, kris

March 9th, 2005, 10:11 PM	#6
John Harvey Regular Crew Join Date: Feb 2005 Location: los angeles, ca Posts: 76	why the jumps from 8-11-16-22? jh

March 9th, 2005, 11:37 PM	#7
Kyle Ringin Major Player Join Date: Oct 2004 Location: Melbourne, Australia Posts: 241	The scale starts at 1 to get every second stop: 1, 2, 4, 8, 16 and 1.4 for every other: 1.4 ,2.8 ,5.6, 11.2(rounded to 11), 22 This gives double/half the light with each full stop. Cheers.

March 10th, 2005, 01:12 AM	#8
John Harvey Regular Crew Join Date: Feb 2005 Location: los angeles, ca Posts: 76	when I'm on a set I hear the DP's and thier "people" talking "two eight" alot, figuring they mean a 2.8 stop. is this some mean value they are looking for from setup to setup for continuity? jh

March 10th, 2005, 01:38 AM	#10
John Harvey Regular Crew Join Date: Feb 2005 Location: los angeles, ca Posts: 76	THE PERFECT THREAD! Opps, sorry for shouting. that was a good read indeed. now I understand, just don't ask me to explain it yet. jh

March 10th, 2005, 03:12 PM	#13
Kyle Ringin Major Player Join Date: Oct 2004 Location: Melbourne, Australia Posts: 241	Sorry, I forgot to mention the doubling thing to get every second stop, which was kinda the point of my post...