Waterhouse stops?

[matthew_hoag]

I have a 480mm Nikon Process lens with a slot and sliding lever to cover this slot. Can anyone tell me what and why this is for and why the numbers (which see to corrispond to degrees)?

 

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Thanks in advance to all those who reply and those who don't but who have contributed to this wonderful forum and increased my knowledge of LF photography immensely.

 

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Matthew

[per_volquartz1]

I own the same lens.

 

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The lever has no use for regular photography but had a function for

making color separations.

The Waterhouse f.stop plates (if you have them) are great for precise

exposure - again when making color separations. For all practical

purposes you do not need these to use your lens. Instead use the

standard diaphragm that stops down from f:9 to f:128.

If you do use the Waterhouse f stop plates you will get extremely fine

pinpoint specular highlights - perfectly round...

 

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This lens will cover 11X14 and is incredibly sharp - as you may have

noticed.

[merg_ross]

The stop plates are scored and can be punched out to form square

openings of different sizes.For photo-engraving they can then be

pushed into the slot and rotated for a range of 45 degrees in order

to place the square in different relative positions to the screen

lines.

[pete_andrews]

Nearly all process lenses have this facility for using shaped stop

inserts. It was never really meant for round stops.<br>As Merg says,

the plates had square, or sometimes diamond-shaped apertures punched

in them. This gave a more precise shape to the halftone dots that the

lens had to reproduce for process platemaking.<p>In colour separation

work, the screen orientation is rotated to a different angle for each

of the four CMYK plates. The stop was also rotated to line up with the

screen.<br>Sorry for reiterating much of what was said above, but I

didn't think that the purpose was properly explained in the previous

posts.

[wayne__]

What a coincidence. A 480mm f9 Apo-Nikkor just fell into my lap

today!(and only 25 dollars fell out). What a nice looking, but huge

chunk of glass. What size shutter do these need? It way looks too big

for my #4 Betax

[wayne__]

"It way looks too big for"

 

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Geez, am I a valley girl or something?

 

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You know what I mean...

[merg_ross]

Pete,

thanks for clarifying my jumbled post. Yours makes sense. Cheers,

Merg