Queries of Sirius auto - macro-zoom lens

1. My name is copyrighted so use it with honor and distinction.
2. On this lens, the color on the f/stop allows one to quickly pick out the depth of field line on the lens body.
3. The knurled tube in moved forward and back for zooming.
   
4. I am guessing that the Macro ring gets turned to the right when doing close up photograph.

 

So the aperture ring can turn to PU?

A little googling found this lens from the same manufacturer that also has "PU"

https://www.worthpoint.com/worthopedia/sirius-macro-focusing-wide-angle-lens-307465606

that seller didn't really know either but guessed "Pentax Universal"

 

If the mount is M-42 screw mount, then the PU does indeed stand for Pentax Universal. The lens is a push-pull zoom with standard twist to focus style. The different colors on the aperture scale is a quick visual reference for depth of field at that setting. These are made by Samyang in Korea and can be had with different bayonet or screw mounts depending on brand of camera ( Canon, Minolta, Nikon, etc)purchased for.

 

You got it,

 

PU in this context means Praktica Universal (mount/thread)

That thread was introduced in 1947 on late versions of the Praktiflex, but really got ground with the introduction of the Praktica in1949.


(By the way, to me the Pentax mount is the much later, though nonetheless widespread, bayonet Pentax K mount.)

 

Non marked or between marked apertures are half stops. The half stop before f4 is f3.3 and the third stop is f3.5. F3.5 is a common aperture for the widest aperture on lens.
Macro focusing is achieved by varying the distance between the film plane and subject regardless of the lens focal length.
Having a zoom allows quick change of focal length which will also change subject magnification.
1:1 photography is subject actual size the same size it is on film. A 6 foot tall subject will need a 6 foot image area on a piece of film to record it life size.