Queries of Sirius auto - macro-zoom lens

tonyowen · Dec 6, 2018

Got a Sirius 28-200mm ‘auto macro zoom’ – but do not have, nor cannot find, any user instructions.

The attached image shows the aperture ring to which I have queries:-

1] what does PU mean

2] why is f16 yellow, f11 & f8 green and f22, f5.6 & f4 white??

3] how is this lens used?????

Regards

Tony

Sirius Glass · Dec 6, 2018

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

tonyowen · Dec 6, 2018

[QUOTE="Sirius Glass, post: 2136300, member: 18240"My name is copyrighted so use it with honor and distinction.[/QUOTE]

agreed and no doubt, but what about the PU mark?
also, unless the adaptor ring is misaligned there are unmarked aperture click stops between the
regards PU and the (f)4 mark.
regards

abruzzi · Dec 6, 2018

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"

tonyowen · Dec 6, 2018

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

Thank you, given the thread mount that makes sense.
I googled PU many times but didn't find anything!!
Thanks again
regards

Rick A · Dec 6, 2018

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.

tonyowen · Dec 6, 2018

Rick A said:
If the mount is M-42 screw mount, then the PU does indeed stand for Pentax Universal. .

Thank you, a supplementary question :-
The lens has a 'macro ratio' from 1:4 to 1:7 - but rotating the focus ring does not improve focus when in the macro mode - [macro ring rotated fully clockwise].
What seems to work is to rotate the focus ring [clockwise] to 'the minimum' setting and then use the zoom to focus!!
Is this how it works or am I missing something?
regards

Rick A · Dec 6, 2018

tonyowen said:
Thank you, a supplementary question :-
The lens has a 'macro ratio' from 1:4 to 1:7 - but rotating the focus ring does not improve focus when in the macro mode - [macro ring rotated fully clockwise].
What seems to work is to rotate the focus ring [clockwise] to 'the minimum' setting and then use the zoom to focus!!
Is this how it works or am I missing something?
regards

You got it,

AgX · Dec 6, 2018

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.)

shutterfinger · Dec 6, 2018

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.

Queries of Sirius auto - macro-zoom lens

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