50mm Elmar hiding a stop?

[Sjixxxy]

Just got a 50mm collapsable 2.8 Elmar today as an everyday lens that I allows me to keep my camera in my coat pocket when I'm not in shooting mode. Anyways, I'm playing with it, and I noticed I can get the aperture ring to go a decent distance past the f/16 tick. To make sure I'm not partaking in bad science here, I'm running this past you guys who have been at this a lot longer then I have. I put the lens on my scanner and scanned it at 2400 dpi and aperture at the f/16 tick, and where it stops when I go past it. Opened up these files in photoshop and used the measure tool to see how wide the openings are.

f/16 tick = 3.1mm
Past the f/16 Ttick = 2.1 mm

50/3.1 = 16.
50/2.1 = 23.

Looks like the lens may be hiding a stop. Is there a reason why I wouldn't want to mark my own DOF scales for f/22 on this lens and use it in this position? Is my procedure completly obtuse? If I use it this stopped down, will it defract to the point where its softer then mud through a frosted window?

Maybe a short test roll is in order.

[Shac]

I'm not sure it indicates a problem (going past f 16) I have a few Lieca lenses where the aperture ring can move (without force) past the last marked f stop. They are all in excellent condition. Age does not seem to be a factor (lens age that is (:>)

[nikonhswebmaster]

This lens may need service, or someone took it apart and set the grub screws wrong. That is a lot of slop? Anyone else have one of these, I only have a Canon.

[Pitxu]

I've noticed this sort of thing on lenses that don't have click stops. It can sometimes work in the opposite direction too making you think the lens is faster than it is.
It's maybe just sloppy marking on the lens scale (ie FSU quality control).

[Bryce]

If you've got a camera that will mount the lens and has a ttl meter you should be able to find out quickly by pointing at a surface of known and unchanging brightness and comparing readings.

[oscroft]

I put the lens on my scanner and scanned it at 2400 dpi and aperture at the f/16 tick, and where it stops when I go past it. Opened up these files in photoshop and used the measure tool to see how wide the openings are.
You will have scanned it through (I think) 2 lens elements, so surely you won't be measuring the actual diameter at the diaphragm but the diameter of an image of it magnified by the lens elements?

(I've just checked my Elmar f/2.8 and it doesn't move past f/16)

[OldNick]

My Elmar 50mm f/3.5 will stop down one stop past the last one marked. I don't really see it as a problem. It is marked to f/18, but could easily go to f/22.

Jim N.

[Rico]

My Elmar 50/2.8 can stop down past f/16 to a noticeable extent. Works fine.

[richard_l]

Is yours the new model? The aperture scale on my 5cm/3.5 Elmar LTM is marked to f/22, but the aperture can be set about one stop beyond that mark. However, the aperture ring on my 50mm/2.8 Elmar-M (newest version) won't budge past the f/16 mark. I don't have the previous version of the 50mm/2.8 Elmar for comparison.

Richard

[Rob-F]

Late model black-scale Elmars do stop down to f/22. I have one of those. My guess is that the earlier ones stop down the same amount mechanically, but no marking or click-stop was provided. With the later examples, they finally got around to providing the click-stop.

Sheer conjecture, but it seems plausible. Agree or disagree?

[Rico]

Richard,

Mine is a dual-scale classic from the early 60s. Aperture range is f/2.8-16 with that uneven spacing.
http://patternassociates.com/rico/leica/misc/elmar50.jpg

[richard_l]

Richard,

Mine is a dual-scale classic from the early 60s. Aperture range is f/2.8-16 with that uneven spacing.....Rico,

It's probably designed to stop down further than f/16, but the way the aperture ring is constructed, it would be inconvenient for them to engrave another number on the ring. For consistency, they also marked the DoF scale only to 16. I doubt that many people use f/22 anyhow. (I use f/22 occasionally on my 35mm Summaron to get that enormous DoF using hyperfocus.)

Richard