Setting exposure by Ev - Tutorial article updated

[Doug Kerr]

I have just posted to my technical information site, the Pumpkin, a revised and updated edition of tutorial article, "Setting Camera Exposure in Terms of Ev", available here:

http://doug.kerr.home.att.net/pumpki....htm#SettingEv

The principal change is an expanded description of the early introduction of the "LV" system and the transition to the "Ev" system by Polaroid and Kodak. The Kodak material is largely based on information kindly provided by Al Olson of this forum.

[Helen Bach]

Doug,

Cameras using the Seikosha MXL shutters were available in '57, so that may, or may not, pre-date the Prontor SVS that you mention as being available in '58. The Aires 35-II-L, Konica III, Olympus LS/2C and Ricoh 500 (with "Triggermatic" rapid wind) all had the MXL. The MXL could be set to half LV settings.

Because of the non-arithmetic shutter speed series (eg 1/2, 1/5) the whole LV numbers did not all match to a standard aperture.

Best,
Helen

[Doug Kerr]

Hi, Helen,

Cameras using the Seikosha MXL shutters were available in '57, so that may, or may not, pre-date the Prontor SVS that you mention as being available in '58.

Thanks so much for this additional information. (I saw your further input in the other thread, too, but did not have the chance to respond.)

The Camerapedia entry for the Seikosha MX shutter says:

"The Seikosha-MXL is a variant equipped with the light value system, introduced in 1956 in #00 size only.", which matches well with your info.

From pictures of the shutter in the manual for the Richoh 500 camera (found on Butkus' site), it appears that the LV scale in fact corresponds to the later-standardized Ev scale.

Here's a link:

http://www.butkus.org/chinon/ricoh/r...xl/500_mxl.pdf

The clearest picture is Figure 18 on page 7 (PDF page count):



At least in the verison on the Ricoh, it seems that the MXL had permanent Ev coupling (that is, moving the shutter speed dial always changed the aperture).

Thanks again.

Best regards,

Doug