Red 'R' on my Focus Scale - 50 Summicron Rigid

[MT0227]

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HI there....my 50mm Summicron Rigid seems to have the same red 'R' in the focus scale as I've seen on some 50mm Duel Range Summicrons and older screw mount Rigids.  My serial# starts with 147 and is an M mount, can someone explain the significance?

~Marc

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Edited July 10, 2019 by MT0227

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[spydrxx]

If I recall correctly It is thefocus  mark offset for shooting with infrared film or an infrared filter..

[adan]

It is, of course, an infrared-focus index.

If you're asking about the historical anomaly of it being on a Rigid rather than a DR, then:

1) Probably best to move this to the Historica Forum, but

2) Leitz was rather variable in the exact markings on lenses in the 50s. A little image-scrounging shows me Summarits with and without IR markings (and sometimes a red "R+dot" and sometimes a black "R+o") and DRs with and without the marking, and Collapsibles with and without the marking. Some had feet and meters, some had only one or the other. Some DRs had magnification scales (e.g. 8:1) and some didn't.

It's not a DR part that accidentally got onto a regular rigid lens - they are very different machinings.

And its always possible someone with a need simply sent the lens back to Wetzlar requesting that the engraving be added.

Or it could just be the tech responsible for engravings had a bad bratwurst for lunch that day.

Edited July 10, 2019 by adan

[MT0227]

Thank you both. 

[steamboat]

More lens trivia? My Noctilux has "00" on focus ring to the right of where it says "feet m". My memory is that Leitz use to mark some lenses with the exact focal length on the focus ring altho I was thinking it was only one number. For instance if it said "2" the actual focal length was 52mm. An "8" meant 48mm. My old Summicron doesn't seem to have that on the lens, but I just noticed the "00" on the old Noctilux f1.0.

[Michael Geschlecht]

Hello John,

Marking the focal length to the 1/10th of a millimeter (Without using the decimal point.) began around 1960. Dependent on lens.

It was always a 2 digit number so your "00" is really a 50.0mm lens.

Just as a "63"  on a 135mm lens would be would be a lens with an actual focal length of 136.3mm.

Best Regards,

Michael

[steamboat]

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23 hours ago, Michael Geschlecht said:

Hello John,

Marking the focal length to the 1/10th of a millimeter (Without using the decimal point.) began around 1960. Dependent on lens.

It was always a 2 digit number so your "00" is really a 50.0mm lens.

Just as a "63"  on a 135mm lens would be would be a lens with an actual focal length of 136.3mm.

Best Regards,

Michael

Thanks, Michael - that clears that up. 'Appreciated!

[Michael Geschlecht]

Hello Again John,

The 2 digit number is not always next to the "M" over or under the "feet" engraving. Sometimes it is further down on the focusing barrel away from the "feet" & the "M" engraving. The 2 digit number is engraved at a right angle to the other numbers on the barrel.

Best Regards,

Michael.

[luigi bertolotti]

Tricky detail, indeed…  btw both my rigid and my DR (1.98x and 1.76x) have NOT the R marking.. how is the front lettering of yours one ? Italic or Capital ?

Edited July 11, 2019 by luigi bertolotti

[Michael Geschlecht]

Hello Luigi,

I think that there is a lot of variation in terms of whether there is an "R" marking at all. And, also: At or between which "F" Stop that "R" mark ends up being placed varies.

I don't have a 50mm, F2, Summicron. Not even 1 with a "*" on it with a different name. Not even 1 that has a "2" on the depth of field scale along with knurled valleys with smooth peaks for your hand to hold on the grip on the focusing barrel. None.

Interestingly, the engraving of the last 2 digits of the focal length measured in 1/10th's of a millimeter without the decimal place, which began with lenses with 1959 manufacturing dates, did not start to become common until they were used on lenses with 1960 manufacturing dates. And some of these later lenses do not have the last 2 digits in 1/10ths without the decimal place.

And some lenses never have these numbers engraved on them. I think 1 example of this might be the 50mm, F2, Dual Range Summicron.

And lenses less than 50mm in length do not seem to have these numbers engraved on them either.

Best Regards,

Michael

Edited July 11, 2019 by Michael Geschlecht

[steamboat]

On 7/11/2019 at 6:02 PM, Michael Geschlecht said:

Hello Luigi,

I think that there is a lot of variation in terms of whether there is an "R" marking at all. And, also: At or between which "F" Stop that "R" mark ends up being placed varies.

I don't have a 50mm, F2, Summicron. Not even 1 with a "*" on it with a different name. Not even 1 that has a "2" on the depth of field scale along with knurled valleys with smooth peaks for your hand to hold on the grip on the focusing barrel. None.

Interestingly, the engraving of the last 2 digits of the focal length measured in 1/10th's of a millimeter without the decimal place, which began with lenses with 1959 manufacturing dates, did not start to become common until they were used on lenses with 1960 manufacturing dates. And some of these later lenses do not have the last 2 digits in 1/10ths without the decimal place.

And some lenses never have these numbers engraved on them. I think 1 example of this might be the 50mm, F2, Dual Range Summicron.

And lenses less than 50mm in length do not seem to have these numbers engraved on them either.

Best Regards,

Michael

I looked at my 50mm Summicron (type 3 1969-79) and I spotted the numbers next to the "m" and below the "feet' clear as day. So it says "19". So my 50mm is actually a 51.9mm lens. Yeah it always seemed a little long. 🙂