Hi. I have seen that the Summicron 35 mm First version (for M2) has these differences in the barrel with reference to the distances:

Feet 2'4 2'8 3 4 Meter 0.7 0.8 0.9 1.2

or

Feet 28" 32" 36" 3'4 Meter 0.7 0.8 0.9 1

Certainly there is a reason and, if it's possible, I would like to know it. Thanks Carlo

-- Carlo Caimi (cthomas87@hotmail.com), January 20, 2002

Answers

Carlo,

I have the lens you mention in front of me.

2'4" is the same as 28". 2'8" is the same as 34".

28" is roughly equivalent to 0.7 meters.

32" is about the same as 0.8 meters.

36" corresponds to 0.9 meters.

3'4" is 40 inches. One meter is 39.37 inches.

The meter calibrations don't always fall directly under the English ones because the correspondence is only approximate. Each marking is where it belongs to correspond to the actual focal distance, whether english or metric.

I hope this helps. It may be that I don't understand your question well enough.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 20, 2002.

Oops, a typo. I should say 2' 8" is the same as 32" not 34". I think you may be referring to different calibrations on different samples of this same lens. As I noted, they are just two different ways of referring to the same distances.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 20, 2002.

In the screwed up American and British Imperial measurement systems the following holds true. In a number like:

X'Y"



X refers to feet. one foot is 12 inches.



Y refers to inches.



Thus to convert to real measurements you need to multiply the number 
of inches by 2.54 (I think this is the number if i remember right 
from back in elementary school). So, 2'8 is actually supposed to be 
2'8" but is is shortened for writing on the lens. This means 2x12" + 
8" which gives you 32", etc.

I hope this helps. Now if only i could actually do something about getting the US and UK to change to a logical measurement system... didn't one of the recent mars missions have problems because somebody didn't convert from imperial to metric or something like that? I am pretty sure this did happen.

-- Matthew Geddert (geddert@yahoo.com), January 20, 2002.

fortunately the brits are now more and more changing to metric due to EU regulations. the beauty of the metric system is its clearity and simplicity. you can even calculate with your fingers (i have 10 of them, not 12)

my feet are 27cm long, so calculation is really hard for me.

-- stefan randlkofer (geesbert@yahoo.com), January 21, 2002.