| Author |
Message |
    
Aford
Tinkerer
Username: Aford
Post Number: 85
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 03:14 pm: | 
|
I have a Ernst Leitz Wetzlar lens - Summar 50mm f2 made in 1937 that has these seven rather strange apertures.
12.5, 9, 6.3, 4.5, 3.2, 2.2, 2
Instead of the normal
22, 16, 11, 8, 5.6, 4, 2.8, 2
Does anybody know the reason for this?
Thanks - Alf |
Finnegan
Tinkerer
Username: Finnegan
Post Number: 51
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 05:25 pm: |
|
Sure, that is how apertures were listed back then. I'm surprised you didn't mention f18 also. Later on f stops were re-standardized to the way it is now. |
Aford
Tinkerer
Username: Aford
Post Number: 86
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 01, 2010 - 04:08 pm: |
|
Thanks Tom - the reason I didn't mention f18 because this lens apertures only go to f12.5
Now I need to get myself a 1930's exposure meter as my Weston IV is not much good! Perhaps I might find a Weston model 617 (1934) some where.
regards - Alf |
Ron_g
Tinkerer
Username: Ron_g
Post Number: 47
Registered: 07-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2010 - 02:30 am: |
|
I have a Weston model 650 in the original box with strap and it has a little leaflet in an envelope with reference to settings that were current as of 06/'47.It responds to light properly and could be considered as in new condition.Make me an offer if it is something that you could use.Ron G |
Aford
Tinkerer
Username: Aford
Post Number: 87
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2010 - 10:08 am: |
|
Ron
Thanks for your offer but I think I'll stick with sunny sixteen! - Alf |
Aford
Tinkerer
Username: Aford
Post Number: 88
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2010 - 10:13 am: |
|
Ooops! that should be sunny f12.5 - Alf  |
Inwo
Tinkerer
Username: Inwo
Post Number: 2
Registered: 01-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 28, 2011 - 09:51 pm: |
|
Wow this thing is good old, it is made in 1937, it should be considered an antique |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 41
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2011 - 10:58 am: |
|
Alf,
Those are 1/3 stops. The other thirds you are missing are 2.5, 3.5, 5, 7, and 10. Hope this helps when you do your conversion calculations.
PF |
M_currie
Tinkerer
Username: M_currie
Post Number: 249
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 11, 2011 - 08:40 pm: |
|
Remember too that the Leica that this lens was made to fit had some odd shutter speeds as well.
A Leica III went 1000-500-200-100-60-40-30-20-8-4-2-1
You can't just set this baby to a specified EV and maintain it by adjusting shutter and lens by corresponding clicks. |
