The true size of ZM lenses is? (Size does matter!)

[visiondr]

I was wondering what's up with the size measurements supplied by Zeiss for their lenses. According to the Zeiss info, the 28 Biogon ZM is 51mm long. That would make it BIGGER than the 28/1.9 Aspherical Ultron from Voigtlander at 47 mm!

According to Steven Gandy's site, the Voigtlander measurements are based on the length of lens protruding from the camera. Is Zeiss measuring from other than the infinity focus from camera body to distal end of the lens? Am I missing something here?

If Zeiss has some different form of measuring lens length, what are the actual lengths of the 28mm Biogon and the 25mm Biogon?

After all, no matter what they tell you, size does matter! 😉

Ron

 

[peter_n]

I'm a bit hazy on the Zeiss stuff but the Zeiss measurements include the M-bayonet mounting plate I think.

 

[back alley]

i don't remember...huck finn posted this info before, someplace.

 

[visiondr]

Joe,

You're right, Huck Finn did post just such a question. However, it wasn't a very satisfying answer. I think this is an important question especially for rangefinder users. It would be cool if users of Zeiss ZM lenses here at RFF could get out their collective rulers and measure the distance from the mounted lens from the camera body to the distal end of the lens (while focused at infinity).

Ron

 

[back alley]

i can do that tonight for my 3 lenses.

distal?

joe

 

[back alley]

distal - situated away from the point of attachment or origin or a central point

 

[Huck Finn]

Peter is correct. Zeiss measures the length of the lens including the bayonet while Leica & Cosina measure the length that the lens protrudes from the camera body. No need to get out the rulers. The lengths of the ZM lenses using the same system as Leica & Cosina are already published on the Zeiss section of the Cosina website:

www.cosina.co.jp/z.html

You don't have to be able to read Japanese. Just click on the lens you want from the list on the side. Then scan down the list of information about the lens (in Japanese) until you find a number followed by "g". That is the wieght (g = grams). The number on the next line is the length. The number on the line above the wieght is the filter size.

So, if you follow this procedure for the ZM 28/2.8 bogon, for example, you'll find the following:

filter size = 46mm
weight = 220 grams
length = 37.7 mm

 

[visiondr]

distal - situated away from the point of attachment or origin or a central point

Yup, that's right; i.e. the front end of the lens. Sorry, it's a term used in anatomical descriptions (back to my days in the anatomy lab in college). The opposite term being "proximal".

Thanks Joe. Anyone else have a lens they could measure to all to the ersatz database?

Ron

 

[visiondr]

It looks like Huck Finn has a fine solution to the issue.

Thanks.

 

[Huck Finn]

You're welcome, Ron. I'm glad it was helpful.

Huck