f/6.3, 9, 12.5, . ??. .

[bobkatz]

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Friends...

As far as you know, the Hektor 2.8cm has f/6.3, 9, 12.5, 18, 25. and the Xenon has f/1.5, 1.6, 2.2, 3.2, 4.5, 9. I am confused: this f stops are the double/half like the actual f stops? those f stops have a counterpart with actual f stops?..Thanks in advance.

Bob.

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[luigi bertolotti]

It used to be the old "European" scale, opposed to the well known "International" scale (1,4 2 etc...) that Leitz adopted after WWII (and , in fact, Hektors 28 were made after WW also with the new scale... they are rare and valued... ).

The old scale had the same "logic" as new : geometric progression with Square Root of 2 (1,414...) - so double any two stops - and its values have the same significance as modern ones: to say, 1,5 is almost open as 1,4, 12,5 is a little closer than 11 and so on.

The "modern" scale has a natural origin around 1 : I do not know on which base the values of the old scale took their origin... maybe always starting from 1 but with 1,414... rounded to 1,5 instead of 1,4... probably someone else can be of help in this historical detail.

[Fokalfissur]

Origin is the square root of 10 = 3,2

 

Thus the complete row is: 1,1 – 1,6 – 2,97 – 3,2 – 4,5 – 6,3 – 9 – 12,5 – 18 – 25 – 36 – 50 – 71 – 100. The German wikipedia artcle has some information: Blendenreihe (Optik) – Wikipedia

[luigi bertolotti]

Origin is the square root of 10 = 3,2

 

Thus the complete row is: 1,1 – 1,6 – 2,97 – 3,2 – 4,5 – 6,3 – 9 – 12,5 – 18 – 25 – 36 – 50 – 71 – 100. The German wikipedia artcle has some information: Blendenreihe (Optik) – Wikipedia

 

THANKS !!! I wondered of this origin... this forum is always great... so now I also understand why Zunow was so proud to have made a f1,1 lens...

[bobkatz]

Luigi and Fokalfissur....thanks a lot...So good information¡¡¡ Apppreciate your comments...

Best..

Bob.

[David Hughes]

Here's a link to an English article: F-number - encyclopedia article about F-number.

 

I think I ought to add my 2d worth as there were several sets of aperture scales used. F'instance the Universal Scale or US system and worse. An old Kodak folder with its instruction book will soon confuse anyone as the cameras had different scales according to the shutter used (some were bought in with the lenses).

 

Also THE lens in THE camera was, for many people the f/3·5 5cm Elmar and so its aperture scale ran from f/3·5 but matched the shutter speeds which were also odd by today's standards.

 

So the Elmar should have run f/3·5 theb f/6·3 then f/10 then f/18 in whole stops but the shutter didn't go in whole or double/halved steps. It was 1/20th then1/30th then 1/40 then 1/60 then 1/100 then 1/200th and lastly 1/500th.

 

All very confusing until it was decided to start from f/1 and halve for each stop (the international scale) but they kept a little confusion by having either a half stop version or a third stop version.

 

Exposure meters of the same vintage are very confusing too with special "Leica" versions of the Bewi, for example, with a special red scale in the 1930's.

 

I can easily put a picture of a Leica version of the Bewi on smugmug: if anyone's interested.

 

Regards, David

[luigi bertolotti]

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Yes, the confusion in the old exposure meters is terrible, and fascinating too... I have a pair of old selenium Gossens... one is postwar, all neat and simple with International apertures, std. scale 1 to 1/1000 and ASA/DIN setting; the prewar one is an almost incomprensible mess based on round "exposure values" plus two different aperture scales, to be matched with times on a correspondance table engraved on the meter's bakelite body... as for film sensitivity, no settings on the meter, and you have to follow a table written on a small cardboard sheet that is attached (folded) inside the meter carrying case (so that is "easy" to read it with the meter operating in your hand)... apart that the cell is no more active, I doubt I would have learned to use it ...

[bobkatz]

wowow.....an interesting stuff...

Bob...

[David Hughes]

Here's the Bewi meter pictures:

 

http://idrh.smugmug.com/photos/463275574_MtG53-L.jpg and

 

http://idrh.smugmug.com/photos/463272357_dwmyC-L-1.jpg

 

Roughly speaking the little German label says use the two red scales for the Leica which is in 1½ steps. It's a well designed meter, I just wish it worked but the cell is probably long dead or else the meter is knackered.

 

Regards, David

[UliWer]

I just acquired a nice 3,5/3,5cm Elmar which seems to be coated and has a serial no. of 67853xx, so it should be from 1948.

 

It still has the old European scale, which makes me wonder at which time Leitz generally started to use the "new" international scale.

 

It is said that the international scale was already applied for the 1.5/8.5 Summarex during wartime, so obviously both systems were used at the same time for some years. It would be interesting to find out about the last lenses and serial numbers with the old Euopean scale for f-stops.

 

Anybody knows a lens with a higher number than 67853xx and still with the European aperture scale?

[luigi bertolotti]

I have an all-chrome Elmar 9cm which is just a little older than Your Elmar 3,5cm : 676.686 (fine number... ) and it too has the European scale... my next number is of another Elmar 9 cm (with vulcanite ring) : 719.221 and new International scale, no surprise.

 

Lager displays an Elmar 3,5cm of your same batch (678.337) which too has the European scale : one can argue that all the items in that batch (to 679.000) are like that; interesting is that Lager displays also an Elmar 5cm 691.673 ... and it closes to f16, but there is another batch of Elmars 3,5cm (693.001 to 696.000) with later numbers : Lager says that Elmar 3,5cm "retained the continental scale" but both Van Hasbroek and Laney do declare that "the late" Elmars 3,5 (i.e., the above batch of 3000) have the International scale: personally, I never saw an Elmar 3,5 like that.

 

The transition between the two scales seems to have been not so straight, even considering the batches... for instance, Summitars around 657.xxx were "International" while, as I wrote before, Elmars 90 of the same age are "European" (but there is also some confusion about numbering in those years... see Puts)... in general, my impression is anyway that the Elmar 3,5 has been the last to abandon the old scale, if it even did...

[Pecole]

Here's the Bewi meter pictures:

 

http://idrh.smugmug.com/photos/463275574_MtG53-L.jpg and

 

http://idrh.smugmug.com/photos/463272357_dwmyC-L-1.jpg

 

Roughly speaking the little German label says use the two red scales for the Leica which is in 1½ steps. It's a well designed meter, I just wish it worked but the cell is probably long dead or else the meter is knackered.

 

Regards, David

 

And here is one more photo of an Electro-Bewi "Spezial für die Leica-Kamera".

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[UliWer]

I have an all-chrome Elmar 9cm which is just a little older than Your Elmar 3,5cm : 676.686 (fine number... ) and it too has the European scale... my next number is of another Elmar 9 cm (with vulcanite ring) : 719.221 and new International scale, no surprise.

 

Lager displays an Elmar 3,5cm of your same batch (678.337) which too has the European scale : one can argue that all the items in that batch (to 679.000) are like that; interesting is that Lager displays also an Elmar 5cm 691.673 ... and it closes to f16, but there is another batch of Elmars 3,5cm (693.001 to 696.000) with later numbers : Lager says that Elmar 3,5cm "retained the continental scale" but both Van Hasbroek and Laney do declare that "the late" Elmars 3,5 (i.e., the above batch of 3000) have the International scale: personally, I never saw an Elmar 3,5 like that.

 

The transition between the two scales seems to have been not so straight, even considering the batches... for instance, Summitars around 657.xxx were "International" while, as I wrote before, Elmars 90 of the same age are "European" (but there is also some confusion about numbering in those years... see Puts)... in general, my impression is anyway that the Elmar 3,5 has been the last to abandon the old scale, if it even did...

 

Thanks a lot for your detailed information!

 

In the "Kleines Fabrikationshandbuch - Leica-Objektive" (3rd. edit 2007) - which isn't always reliable, though not necessarily wrong - Hartmut Thiele lists the numbers 693.001-695000 as the last batch of the 3.5/3.5 cm Elmar and he adds that for the numbers 693.001 to 696.500 there is no information whether any and which lens were produced. The first batch of 1000 3.5/3.5 cm Summarons from 1949 should according to this list have the numbers 706.001 to 707.000.

[Michael Geschlecht]

Hello Everybody,

 

There is a small typo in Focalfissur's list of #s.

 

What is shown as: 2.97 should read: 2.2

 

The numbers he has shown are the numbers for f-stops we all use today made 1/3 stop smaller.

 

One is no more or less better a scale than the other to use.

 

Both have full stop increments.

 

Perhaps the currently favored system was simply easier to engrave or read.

 

Or perhaps it's relationship to 2 was easier to calculate than a relationship to 10 in the days before electronic calculators.

 

Speculation on my part. Who knows.

 

1.5 is a form of pushing the envelope. It is 1/6th of a stop faster than the 1.6 whole stop of it's time. It is that ammount slower than today's 1.4.

 

Just like 0.95 is 1/7th of a stop faster than 1.0.

 

BTW: 3.5 is 1/3d of a stop faster than f4 and 4.5 is 1/3d of a stop slower.

 

Best Regards,

 

Michael

[luigi bertolotti]

Thanks a lot for your detailed information!

 

In the "Kleines Fabrikationshandbuch - Leica-Objektive" (3rd. edit 2007) - which isn't always reliable, though not necessarily wrong - Hartmut Thiele lists the numbers 693.001-695000 as the last batch of the 3.5/3.5 cm Elmar and he adds that for the numbers 693.001 to 696.500 there is no information whether any and which lens were produced. The first batch of 1000 3.5/3.5 cm Summarons from 1949 should according to this list have the numbers 706.001 to 707.000.

 

Ah ! Thanks for the info (I haven't Thiele's book) ... this could explain why an "International scale" Elmar 3,5cm has never (afaik) be seen... and also the discordance between Lager and Laney+Van Hasbroek. Summarons, I think, were made all with the International scale (I have a 750.xxx item... closes to f 16)