I have a home portrait camera that I bought with a Wollensak Betax No 5 shutter. Printed on the barrel is Cooke Lens, H>D> Taylors ...Series 5, 8 x 10, Eq focus 13.3 inches. On the other side of the barrel it says--Taylor, Taylor and Hobson ... 20 inches. I haven't been able to find any information about this lens. Does anyone have some information??
Mike

It is a Cooke triplet designed by H. D. Taylor and made under license by Taylor, Taylor & Hobson. The TTH Taylors were not related to H. D. H. D. was an employee of T. Cooke & sons, a microscope manufacture that didn't want to commercialize his invention.

TTH identified their lenses by Series numbers. Ser. V should be f/8 or f/10. They made replacement rear cells for the lenses that changed the focal length. Your lens' focal length should be 20 inches.

Thanks-- that s good information.

I finally got to check my lens and it only consists of the front element.
The stops appear to have been hand scribe. All triplets I have seen have three rows of numbers indicating the focal length depending on which element(s) where attached. What would be the focal length of the lens with just the front element? Also-- any idea where I might find a rear element?
Thanks, MM

No idea and no idea.

To find the focal length put the lens on your camera focus on an object 500 yards or more away set your infinity
Measure from about the center of the shutter to the film plane you now have your focal length lol give a millimeter or two