R.O.J.A Vorm Emil Bausch Rathenow lens

[geoffrey_chen]

Hi I was asked about a large format collectible lens, but I don't know the answer. I believe someone from this forum can help us out. It's a R.O.J.A Vorm Emil Bausch Rathenow Rapid Aplanat #2 Series D F8 brass barrel lens. The lens is about 50 mm tall, front diameter about 40 mm and rear 35 mm. F stops labelled as 8, 12, 16, 20,...., 360. Does anyone know about its construction (elements in groups), coverage, focal length, and sharpness? Thanks in advance.

[dave_willison]

I don't have an exact answer but I'll take an educated guess and wait

for someone to correct it!

 

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I believe the lens is a german lens manufactured by Rathenower

Optische Institute (ROJA) under the direction of Emil Busch. According

to Kingslake, aplanat is an old term for a lens corrected for

spherical abberation. The aplanat was originally designed by Steinheil

and is similar in design to Dallmeyer's Rapid Rectilinear. The lens

has four elements cemented in two groups with an aperture in the

middle. The lens is symmetrical with the front and rear elements being

identical. The term rapid apparently comes from the fact that the lens

has a maximum aperture of f8, which was faster than earlier

distortionless lenses. According to Kingslake, the RR lens was

introduced about 1866 and "fitted to all the better cameras for nearly

sixty years."

 

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I don't know which Rapid Aplanat you are describing or its focal

length. Wooden's Large Format Reference Manual lists three rapid

aplanats: 7 3/4" (5x7), 10" (8x10), and 13 1/2" (8x10). All three

rapid aplanats are listed as f8. Wooden's book also lists four series

D aplanats: 150mm/f6.5 (4x5), 165mm/f6.5 (4x5), 170mm/f7 (4x5) and

200mm/f7 (5x7). I would put the lens on a camera, focus at infinity,

and measure the approximate focal length by the distance from the film

plane to the lensboard.

 

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I hope this helps.

 

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....................

[geoffrey_chen]

Thanks, Dave! The lens was sent to me by UPS ground, and I'll test

it next week.

[steve_hostetter]

I just bought a 13" Busch Rapid Aplanat mounted on a Thorton Pickard roll shutter and am very happy with it....! I had it mounted on an 8x10 Sinar and could find the edge of the image... It's been listed on other sites as covering 7x17" ...I wish I could post a photo taken from this lens ,,, very sharp and detailed images with a unique color..

 

Steve