Metrogon-what means serial number? (DF SF XF KF RF)

[fbascona]

Hi,
What means SF, KF, DF and XF in the serial numbers of metrogon lenses (Bausch & Lomb the 1940´s 1950´s aerial camera)?.

Any patent, the cones?

Example-RF5640, SF322, XF2231 ...

A book or paper to find?

Thanks

[EdWorkman]

Have you googled? A coupla years ago there was a website about metrogon stuff. How about Google Patent Search? I'll see if I saved such in the pile of electrons in the bottom of my computer

[EdWorkman]

I no longer had a url, but a google turned this, and wiki- etc.
http://www.metrogon.20megsfree.com/

[fbascona]

I saw this URL and asked the webmanager. I read the patent 2031792, asked the USGS, wiki, google, surfing, Fairchild T-11 repair camera manual, Manual of Photogrammetry 1st Ed , JOSA,etc.
I've been looking for a few weeks but nothing

[Dan Fromm]

Here is a URL for B&L date codes: http://forum.mflenses.com/bausch-and...me-t20524.html

I think that the information in it is false. Use it at your own risk.

Use your Metrogons at your own risk too.

[fbascona]

Here is a URL for B&L date codes: http://forum.mflenses.com/bausch-and...me-t20524.html

I think that the information in it is false. Use it at your own risk.

Use your Metrogons at your own risk too.

Hi, I checked the schema code with 1035 lenses in a T-11 camera . From them I have a list with the calibration date (1951-1954). The data list is in agreement with the schema code.

Following, the first letter lens and their date calibration, extract from the list

SF242 2/26/51
KF252 12/17/51
XF258 10/18/52
DF 3762 2/19/54
RF145 8/15/54

1951, all lenses are SF and KF
1952, iden KF and XF
...
....

I think assambled process in the camera during 1 or 1.5 year, the calibrate date is the final process on camera manufacturer.

For the number I don´t checked it but perhaps it is the supose is correct. The user (kds315) don´t give any reference or source

Thanks