Andrew Ross (1798–1859) founded his company in 1830, from 1840 he began producing camera lenses signed "A. Ross".

During Andrew Ross's lifetime, the company was one of the foremost lens manufacturers in the UK and beyond.  His company was definitely there from the start of photography much like Voigtlander in Austria and Lerebours in France.

I've always dreamt about owning a lens from the first decade of photography and when I came across this lens recently, I rescued this one to extend similar TLC like I've done with the Cooke RV from my previous blog posting.

It was clear the aperture was missing from this landscape lens and all associated parts such as washer stops with it.  The lens did come with the original flange and the original lens cap.  Even the fabric used as a seal on the cap looks from the time.

It was not uncommon for landscape lenses to be uncorked during the Pictorial days for portrait taking or maybe the aperture was simply lost.  There are clear marks on the inside of the barrel where the aperture would have been.

Below are a few images of different Ross landscape lenses to give an idea of what a complete landscape lens might look like in the early days of photography.

The landscape lens above, not mine, bears serial 2802.  The aperture is clearly visible with the cap and a smaller aperture cap is visible at the right in this image.  This is a landscape design without sliding focusing ability.  So either this was for a sliding box camera or there were bellows involved.

A different sliding barrel design with serial #8688 from clearly a much later period shows a washer stop design front.  This image below is incidentally from the same seller I acquired the #1520 from.

Based on the marks inside the barrel of #1520, I believe that design looked similar than in the image above from serial #8688.

For Another Ross landscape lens, #2926, a serial number relatively close to the #1520, see below.  This image shows the lens assembled backward in the sliding sleeve (no rack and pinion in none of these pictured Ross landscape lenses.)  I picked this 20", f:20 lens up few months back as my first early landscape lens.  

By now this lens has been flipped in the sleeve for proper configuration.  There's one stop installed in the rear of the inner tube to make for what I believe is the native f:20 aperture.  The cap with additional washer stop inserts is no longer there.  I might replace this with an adjustable iris in the near future to enhance functionality.  Lens diameter for the #2926 is just over 4", this is one massive landscape lens !

As for optical performance of serial #1520, the focal length of the #1520 is measured at 13" or roughly 330mm.  The diameter of the achromat in the rear is about 72mm.

Again I decided against a permanent restoration of aperture.  Difficult as there's no data of what the exact design would have looked like and I don't want to confuse the next owner with a historical paradox.

As I've done with the Cooke RV, I opted to add a removable modern iris to the lens so I can use this gem as landscape and soft portrait lens.

Found a Rodenstock iris in the spare parts bin that looked it would fit over the barrel after some machining to enlarge the inside and create a flush stop against the barrel.  This iris was formerly used with a Rodenstock Heligon lens as an aftermarket aperture control addition.  Provision to lock the iris box was through three M2 set screws which I replaced with nylon-tipped set screws to not mar the beautiful patinated finish of the late 1840's brass.

I removed all Rodenstock iris references while I had the iris assembly on the lathe.

The end result of the unmounted lens can be seen below.  No, the original cap  will no longer fit over the new iris but this is only a small inconvenience.  The assembly can be restored to "as bought" by loosening the three set screws, removing the iris and popping the lens cap back on.

Best of both worlds, make a lens from the early days of photography usable again without affecting the as-found condition.

This lens is ready to be mounted on a SInar lens board for use on my SInar P2 8x10 camera.

WIth the iris the aperture runs from f:4.8 fully open to f:26 at the smallest opening, roughly 5 stops.  Coverage may be slightly impaired compared to the original design since the aperture sits about 1.5" farther out of the achromat but testing will need to evaluate this

To be continued !

Dating a lens with a low serial number is always iffy but i believe it is safe to say that this lens originates somewhere between 1846-1848.  It is commonly assumed that serial #3,000 for Ross was reached around 1850.  I'm not an A. Ross history expert and any further insight from scholars would be appreciated.

Cheers !