Questions On Old Petzval With RECTANGULAR-Shaped Aperture Waterhouse Stops

[Steven Tribe]

Steven, regarding your comment that the Waterhouse slot was added later, there is a large-aperture zinc or ferrous washer-stop mounted inside next to the slot as a light shield: it looks very well fitted. FWIW.

I did this with a large barrel I made to accept 2 orphan Dallmeyer 3B lens cells. I have also seen it with WHS adaptions which are much less well carried out than yours. The earlier the conversion was was done - the more professional the result. Later conversions often manage with a single inserted zink plate, rather than two.

Even before your last insert, I was thinking about this set being the source of income for a street/"intermittant studio" photographer or even as a mug-shoot camera for an institution.

[IanG]

Echoing Steven's comments it looks like it wasn't a professional conversion by someone who'd done them before. If it was mine I'd make a new set of round stops, I make mine from aluminum as it's easy to work with.

Ian.

[leighmarrin]

Steven, yes, as this camera/lens combo came with a bag magazine holding 18 sheets, perhaps it was used for mug shots or by an itinerant street photographer.

Garrett, I saw a photo of a Carl Dietzler petzval, and the external rear cell ring looks very similar to mine, although the rest of the lens does not. So perhaps they shared small parts from the same Germanic parts jobber.

Ian, I plan on making a new Waterhouse round stop of the same internal diameter as the small rectangular stop, and see how they compare in side-by-side photos.

My math is a little feeble: what size ROUND hole would have the same internal area as a 10mm x14mm rectangle?

Thanks. --Leigh.

PS: a shout-out "thanks" to John/jnaian who PMed me CLA instructions for the Graflex shutter.

[Jac@stafford.net]

what size ROUND hole would have the same internal area as a 10mm x14mm rectangle?

~ 6.7mm diameter

[Taija71A]

... what size ROUND hole would have the same internal area as a 10mm x14mm rectangle?

~ 6.7mm diameter

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Jac, just so there is no confusion...
You of course meant to say... ≈6.7mm Radius or ≈13.4mm Diameter.
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Best regards,

-Tim.
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[Jac@stafford.net]

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Jac, just so there is no confusion...
You of course meant to say... ≈6.7mm Radius or ≈13.4mm Diameter.
--
Best regards,

-Tim.
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Radius! Yes. Gads I hate it when I mess up like that.
Typing faster than I can think.

radius = sqrt((side1 x side2)/pi)

Leigh, you can type this into Google's search box to solve for diameter

2* (sqrt((side1 * side2)/pi))
specifically
2* (sqrt((10 * 14)/pi))

Thank you, Tim.

[Taija71A]

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No problem Jac.

I too, have made that exact same mistake. *We are so 'anxious' to get the answer...
That we forget that the Equation is for 'Radius' and not Diameter.
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[Jac@stafford.net]

To make it simpler, 13.4mm is close enough to 1/2" that you can drill it with a common, inexpensive hole saw.

[leighmarrin]

Tim and Jac, thanks for the info. Jac, I've got a round 1/2" chasis punch, so it should be an easy job.