Bausch & Lomb Rapid Rectilinear; pictures, info please

[SXR_Mark]

This lens is a Rapid Rectilinear type made Bausch and Lomb. The focal length is not marked but is about 8.25 inches (210 mm). The maximum aperture is also not marked but is a small amount faster than f8. The lens is uncoated.

The lens is mounted in a (working) shutter with three settings, T. B and I. I know nothing about inter-lens shutters; how does one change the shutter speed in I setting?

If anyone can provide information (approximate age, type of camera to which it would have been fitted) on this particular lens I would be grateful.









The Rapid Rectilinear (RR) type is pretty ancient. According to Kingslake, it was introduced by Dallmeyer in 1866. It is the same as the Steinheil Aplanat introduced at the same time. Kingslake gives Steinheil credit for coming up with the design first. He also describes this type of lens as "fabulously successful" and "fairly expensive to manufacture".

The RR consists of two identical aplanat doublets placed equidistantly about the aperture stop and with concave surfaces facing each other. This symmetrical arrangement gives correction of distortion (hence the Rectilinear name) and also lateral CA and coma. For the time, the lenses were also fast (hence Rapid).

[SXR_Mark]

My initial results with this lens were really poor. The contrast was very low. But I lined the extension tubes which i was using to mount it on the camera with black, flocked paper and the lens is transformed.

The pictures below were all taken with my Oly OMD E-M5. This is unfair to a lens of this type as it is a very severe crop of the full image circle. Thus the recorded image has to be enlarged by a lot more than it would in its original setting. I see images that are a little soft. I expect prints made with a camera of the correct format would be more than sharp enough. What is amazing is the colour saturation and vibrancy. I am posting the pictures just as they came out of the camera (except the last one which was rather underexposed).

EDIT: I should point out they were all taken at f8

[iangreenhalgh1]

What you have there is most likely from an 1890's Kodak folder. That's a very early shutter so there are no speeds - Time, Bulb and Instantaneous are all you get.

Not surprised you need to do some work to sort out the contrast, the lens has a big image circle and all that unused light bouncing around reduces contrast, you get that (to a lesser degree) even with coated LF lenses. Light baffles are usually the solution, your flocking achieves the same result, well done.

If you want a RR to be really sharp, you need to close it to f16 or f22, which is how they were used on film. What role diffraction would play if you used it at those apertures on digital I don't know.

I like your results, the bokeh is typically smooth for a RR, these were very popular as portrait lenses used at large apertures, but also as landscape lenses when stopped down sufficiently.

[Mos6502]

Kodak took over Rochester Optical in 1903, so it's probably from around that era.

The "f stops" are probably given in the Uniform System which means that only 16 is equivalent to f16. 8 = f11, 32 = f22, 64 = f32, 128 = f45.

Diffraction has the same effect in any lens for a given aperture, so f16 gives the same diffraction on a 50mm lens as on a 400mm lens. F45 was acceptable on these old cameras because the negatives were so large that they could be contact printed - so in simple terms the diffraction caused by the tiny apertures was not magnified by enlarging for printing. Using the same stops on 35mm film would result in noticeable diffraction effects when the image was blown up for printing.

So your best bet for sharpness is probably using 16, stopping further down diffraction will probably offset any increase in sharpness.

Here is the sort of camera it was very likely mounted on originally:


(1906) Kodak Nº1 Premo Film by Ull màgic, on Flickr

[SXR_Mark]

Thanks guys for the information. i hadn't realised this lens is over 100 years old.

@Mos6502.

Yes, you are correct to say the aperture scale is Uniform System. Thanks for correcting me on this. Going from "8" to "16" halves the shutter speed i.e. one stop. So lens is f11 max aperture. This explains why is was getting such low shutter speeds, even on a sunny day. It also explains why going from "wide open" to "8" made no difference to the shutter speed (less than 1/3 stop).

I tested the lens at f11 and f16 and saw only a slight improvement in sharpness on stopping down. I agree with you, going below f16 will result in diffraction limiting the resolution.

Thanks also for digging up the Premo 1 picture. The shutter looks to be the same as mine. The lens looks similar too. Interestingly, the label under the lens is slightly different. The "8" is between the "p" and t" in "optical" on the lens pictured, but is between "optical" and "co" on mine. Anyway, the picture gives me a lead to do more research into my lens, so thanks for that.

Mark

[Farside]

"T" - "Time" which means you press it and let go, the shutter remains open, time with a stopwatch and press the lever to shut it again. Recall, that back in those days there were some awfully slow emulsions still in use.
"B" - "Bulb" use with an air bulb and rubber hose attached to the piston as an early form of remote release. It really works, too. Squeeze the bulb (or press the lever) to open the shutter and it remains open until you let the bulb relax or release the lever.
"I" - "Instantaneous" that's when you get shutter speeds, but in this one you only get the one by the look of it - probably 1/50th of a second.