Ross Info?

[KentC]

Hi! I have a newly acquired Folmer & Schwing that came with a Ross Rapid Symmetrical #41658. I'm trying to find any info about this lens (aperture, focal length, characteristics, history) before I start testing with in in the next few weeks (hopefully). Any info much appreciated

[Dan Fromm]

Hmm. You want us to give a lot of information but have given practically none.

The VM, as usual slight muddled says:

Rapid Symmetrical Lenses for Portrait Views, Interiors, Copying. These were possibly the most useful in
existence. They were supplied in 4.5in for stereo 4x3in; and in 6.0, 7.5, 8.5, 11, 13, 16, 20, 24, 30in, where
7.5in was suggested for 5x4in. Larger sizes to special order.

and

Rapid Symmetrical This is said to have been introduced in 1874.
It was made in: f8.0 4.5-6.0-16.0-30in (Foci may vary with time.)
One list gives 3.0, 4.5, 6.0 for 5x4in, 7.5, 8.5, 9.0, 10.5,11,12, 13, 14 for 10x8in, 16, 18, 20, 24, 30, 34in.
Rather more foci were in 1889 than later. The layout is shown as RR, Ros012, Ros013. It was suggested to
use 6 or 7in for 5x4in. This may be the standard product but is not very common most being rather small
lenses in 1.5in fine threads for 1/4 and 1/2 plate. An example No42,44x for 10x8 is probably from the redesign
type below. The lens flange here is 24TPI but 65mm (2.6in) dia. which seems an anomalous choice.
This may have been redesigned in 1890 approx. as then it was again listed as 'new' and this may be a sign of
the use of Jena glass beginning. At that time the foci listed were :
3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10, 12, 15, 18, 21in.
Examples: a f8/6in No59,67x was noted on a Lizars 5x4, and a 9in No7 size No23,79x was on a wet/dry plate
from the 1867-1874 period..
Stops were No0, f8; No1,f11.3; No2, f16; No3, f22.6; No4, f32; No5, f45.2; No6, f64.

The one solid thing is that the lens is probably a Rapid Rectilinear type.

[KentC]

Hi Dan- thanks for your response and sorry if I didn't give enough info- what else would be helpful? I guess I had hoped one of you would have been instantly familiar with this. I'm new here obviously. Thanks again!

Hmm. You want us to give a lot of information but have given practically none.

The VM, as usual slight muddled says:

Rapid Symmetrical Lenses for Portrait Views, Interiors, Copying. These were possibly the most useful in
existence. They were supplied in 4.5in for stereo 4x3in; and in 6.0, 7.5, 8.5, 11, 13, 16, 20, 24, 30in, where
7.5in was suggested for 5x4in. Larger sizes to special order.

and

Rapid Symmetrical This is said to have been introduced in 1874.
It was made in: f8.0 4.5-6.0-16.0-30in (Foci may vary with time.)
One list gives 3.0, 4.5, 6.0 for 5x4in, 7.5, 8.5, 9.0, 10.5,11,12, 13, 14 for 10x8in, 16, 18, 20, 24, 30, 34in.
Rather more foci were in 1889 than later. The layout is shown as RR, Ros012, Ros013. It was suggested to
use 6 or 7in for 5x4in. This may be the standard product but is not very common most being rather small
lenses in 1.5in fine threads for 1/4 and 1/2 plate. An example No42,44x for 10x8 is probably from the redesign
type below. The lens flange here is 24TPI but 65mm (2.6in) dia. which seems an anomalous choice.
This may have been redesigned in 1890 approx. as then it was again listed as 'new' and this may be a sign of
the use of Jena glass beginning. At that time the foci listed were :
3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10, 12, 15, 18, 21in.
Examples: a f8/6in No59,67x was noted on a Lizars 5x4, and a 9in No7 size No23,79x was on a wet/dry plate
from the 1867-1874 period..
Stops were No0, f8; No1,f11.3; No2, f16; No3, f22.6; No4, f32; No5, f45.2; No6, f64.

The one solid thing is that the lens is probably a Rapid Rectilinear type.

[Dan Fromm]

Well, knowing the barrel diameter and the lens' focal length would be useful. If the focal length isn't marked anywhere on the lens, you can guestimate it by pointing the lens at a window so that it forms a more-or-less in focus image on the wall opposite the window. Then measure the distance from the wall to the middle of the barrel (half way between front and rear). Won't be highly accurate or precise, but will give you an idea of what you have. The right definition of relative aperture (the f/ number) is the focal length divided by the diameter of the lens' entrance pupil. Focal length/barrel diameter is a crude approximation that will get you in the ball park.

[Ron (Netherlands)]

the lens reads 10x8

[KentC]

Not sure I completely understand the focal length determining method but will do some homework. The lens is 2" in both diameter and length. This being my first LF camera and lens I wasn't certain what the 10x8 was referring to. I did some research on serial numbers and placed it somewhere ~1890, though I'm not certain.

http://www.earlyphotography.co.uk/site/SRL_lenses.html

[Steven Tribe]

I have this exact lens - which was made over about a 20 year period at the end of the 19th C. Some people preferred it to the Dallmeyer rapid rectilinear (patent).
The 10x8 means “covers at least 8x10 imperial inches”. Giving coverage instead of effective focal length was a period fad!
The UK rapid rectilinear lenses were, unfortunately for to-day’s photographers, came when photography was in its huge expansion. This meant that the assembly mechanism was adapted to speedy and simple procedures. The front and rear lens are mechanically sealed in their cells in a lathe. Not a good solution when the inevitable need of replacing the balsam in these two lens appears.

Focal length is 14” according to my quick check. I have the equivalent data for its Dallmeyer competitor, below.

[Tin Can]

Is it possible Ross never considered the lenses would be used for so many years?

buy the next big thing?

I have this exact lens - which was made over about a 20 year period at the end of the 19th C. Some people preferred it to the Dallmeyer rapid rectilinear (patent).
The 10x8 means “covers at least 8x10 imperial inches”. Giving coverage instead of effective focal length was a period fad!
The UK rapid rectilinear lenses were, unfortunately for to-day’s photographers, came when photography was in its huge expansion. This meant that the assembly mechanism was adapted to speedy and simple procedures. The front and rear lens are mechanically sealed in their cells in a lathe. Not a good solution when the inevitable need of replacing the balsam in these two lens appears.

Focal length is 14” according to my quick check. I have the equivalent data for its Dallmeyer competitor, below.

[Steven Tribe]

Is it possible Ross never considered the lenses would be used for so many years?

buy the next big thing?

This is the correct answer!

[KentC]

Thank you Steven! Very helpful!