Equivalent exposure rating. Advice needed.

Paulbee (e2 Member)

8

6 Dec 2006 - 4:18 PM

• Options
  • Report Error / Abuse

0

Is the old ASA rating the same value as ISO, or do I need to multiply the ASA rating by a correction factor?
I have recently had reason to doubt the exposure readings given on my Canon 300d,(badly over exposed), so I decided to dig out my old, and little used, WestonMaster III to give a comparison. As I hav'nt used it for about fifteen years it jolted the memory a bit to see the speed rating given as "Weston Rating". I think I remember that we treated this the same as ASA at the time, but what equivalent to ISO is ASA ? Any info on this would be a help,
scanned the forum topics but couldnt find anything.
Thanks, Paul.

Paulbee (e2 Member)

8

6 Dec 2006 - 5:27 PM

• Options
  • Report Error / Abuse

0

Thanks for that, now I know its the same.
Paul.

PS I don't use a winder these days, the new camera has battery.

c_evans99

9

6 Dec 2006 - 6:39 PM

• Options
  • Report Error / Abuse

0

Weston Ratings didn't always strictly match the ASA scale of the day and the company used to issue pamphlets of Weston Ratings periodically. I think they switched to ASA around the time the Master IV came out.

Ceri

Paulbee (e2 Member)

8

7 Dec 2006 - 2:22 PM

• Options
  • Report Error / Abuse

0

Thank you everyone for your input, Your info Barry takes some time to absorb. I will have to download it and read it again.
I suppose ISO has simplified the situation which existed where films were rated in both ASA (American Standard Association) and DIN (Deutsche Industrie Nummer) at the same time.
Regards everyone, Paul.