Ross Xpress Great Britain lenses WO

[Miguel Coquis]

I am searching for info concerning Ross lenses and would like to know more about the fast Ross XPRESS lenses like the 8", 10", 12" f:2,75 samples.
Any body working with these or try them wide open ?
Thanks in advance for your help.

[Pete Watkins]

This might not be much help but according to a book on optics published in 1944 the f4 Wide-Angle Express lenses between 4 inches and 20 inches they had "6 glasses, 8 air glass surfaces", "the field covered in degrees" is 70.
To my shame I've had one for years and have never tried it.
Besr wishes,
Pete.

[Miguel Coquis]

Wich focal length is yours ?
Any pics of this lens ?
Thanks Pete

[Pete Watkins]

Miguel,
My lens is a 5 inch f4 - F11 and I've just noticed that it's an ex military lens with the reference 14A/843 engraved on it and A(crown)M engraved on it as well. The lens is numbered 143892. I can take a pics tomorrow if you still have any interesr after finding out that it's an ex Air Ministry lens. I had mounted it on a lensboard to fit my 5x7 B&J but as I have a 4x5 back I can't promise that it covers 5x7 until I look tomorrow, if you're interested.
Pete.

[Miguel Coquis]

thanks Pete, it is not the kind I am searching info for.

[cdholden]

Miguel,
There is currently a 20" on Ebay (US) right now. Maybe the seller can provide more info.

Chris

[Dan Fromm]

Per the VM:

"Xpres f2.75 This unknown lens is an oddity, just possibly a prototype or small batch special product, noted as a 3.5in lens in a black barrel mount but without an iris.It seems to use the 1+1+i+3 layout of the f2.9 Xpres and may be regarded as a narrow angle version of this, just possibly for some movie use."

Miguel, are you thinking of the f/2.9 Xpres, which is mentioned in an advertisement and a catalog posted on cameraeccentric.com?

[Miguel Coquis]

Per the VM:

"Xpres f2.75 This unknown lens is an oddity, just possibly a prototype or small batch special product, noted as a 3.5in lens in a black barrel mount but without an iris.It seems to use the 1+1+i+3 layout of the f2.9 Xpres and may be regarded as a narrow angle version of this, just possibly for some movie use."

Miguel, are you thinking of the f/2.9 Xpres, which is mentioned in an advertisement and a catalog posted on cameraeccentric.com?
No Dan, not the cameraeccentric.com one.

The Xpres seems to be Ross version of the Cooke Triplet, and f:2,75 might be an oddity, sharp all the way !!! (??) 3,5 kg clear/transparent glass.

[IanG]

Dan should be able to confirm better but my understanding is the Xpres is 5 elements two air space in the front cell and a cemented triplet in the rear. I assume that's the 1+1+ i + 3 he's referring to as well. The rear cell is a triplet itself.

So no it's not a Ross version of the Cooke triplet, rather a more complex derivation like the Zeiss Tessar which Ross had been making under licence. Ross wouldn't have replaced the Tessar by stepping backwards.

add: Ross literature states clearly it's a 5 element lens with the rear triplet

Ian

[Dan Fromm]

Ian, the original five element Xpres is one of a number of similar designs with the Tessar's rear cemented doublet replaced by a cemented triplet. These are supposed to have been cooked up to avoid infringing the original Tessar patent. More of a step sideways than backwards.

The OP gives the impression that he has in hand a large f/2.75 Xpres. The VM doubts that many f/2.75 Xpres (what is the plural? Xpreses?) were made. So I wonder why the OP mentioned three focal lengths.

I think that Pete and Chris are talking about other lenses entirely, could be mistaken.

Miguel, Xpres is a trade name, covers a number of designs. Just like Saphir.

[Miguel Coquis]

...So I wonder why the OP mentioned three focal lengths.
Dan, I thought there where few of them, like Dallmeyers and others.... It seems not.
Thanks

[Miguel Coquis]

...they are really nice !
they look like this....
and they go for $3500...

http://macoquis.caraldi.com/scaled/Ross%20XPRESS%2010%22/001.jpg
Ross XPESS 10"

[GPS]

Miguel,
My lens is a 5 inch f4 - F11 and I've just noticed that it's an ex military lens with the reference 14A/843 engraved on it and A(crown)M engraved on it as well. The lens is numbered 143892. I can take a pics tomorrow if you still have any interesr after finding out that it's an ex Air Ministry lens. I had mounted it on a lensboard to fit my 5x7 B&J but as I have a 4x5 back I can't promise that it covers 5x7 until I look tomorrow, if you're interested.
Pete.

Your lens is from the WWII Torpedo camera and it covers 5x7. The torpedo camera (panoramic) was taking pictures on 120 film, the picture was long 184 mm.

[Fotoguy20d]

Sorry to continue the hijacking of this thread (a little) but its timely. I have the common 5" f4 lens, with AM marking and a Ref No 14A/1101. Mine is a later serial - 171961. I removed the lenses from the barrel yesterday. The rear was easily disassembled and cleaned. The front, though, seems to have no provision for disassembly. Anyone ever take one of these apart? This one is showing 4 bright and one dim reflection for each glass grouping.

Thanks,
Dan

[Fotoguy20d]

Your lens is from the WWII Torpedo camera and it covers 5x7. The torpedo camera (panoramic) was taking pictures on 120 film, the picture was long 184 mm.

Per the VM:

It was an important lens for the air force, being used as a 5in for 5x5 and later as a 20in of very high quality and this may have decided the original choice of foci made. Some 8.25in f4 wide angles were used on the P39 Torpedo Training camera (D. Rendell, B.J.P. 08/02/1980, p124)

[Fotoguy20d]

Reading a little further on though:

"But the f4/5in lens for the MoD is apparently an f3.1 lens, as the front glass is some 28% oversize and actually bigger than a normal 6in. It covers an enormous field really well, most of 1/1plate in fact."

[GPS]

Per the VM:

It was an important lens for the air force, being used as a 5in for 5x5 and later as a 20in of very high quality and this may have decided the original choice of foci made. Some 8.25in f4 wide angles were used on the P39 Torpedo Training camera (D. Rendell, B.J.P. 08/02/1980, p124)

There you see one example showing you cannot take VM as a Gospel. The Torpedo camera never had 8.25in lens. It needed to be a wide angle lens in order to have the view of the torpedo path and the boat used for the exercise. Torpedo camera (I had 2 of them) had 5in f4 lenses for that reason.

[Dan Fromm]

Sorry to continue the hijacking of this thread (a little) but its timely. I have the common 5" f4 lens, with AM marking and a Ref No 14A/1101. Mine is a later serial - 171961. I removed the lenses from the barrel yesterday. The rear was easily disassembled and cleaned. The front, though, seems to have no provision for disassembly. Anyone ever take one of these apart? This one is showing 4 bright and one dim reflection for each glass grouping.

Thanks,
DanIf you look closely at the joint where the front cell meets the barrel, you'll find a set screw that locks the front cell and barrel. Unscrew it. Once it is out you'll be able to unscrew the front cell. But be warned, I did this and then couldn't get the screw back in.

[Fotoguy20d]

Dan,

I have the front cell out of the barrel (I was going to skip reinstalling all the setscrews anyway) but I can't figure out how to take apart the cell to get at the inner glass surfaces. I did not have that problem with the rear cell - that one was easily disassembled and cleaned.

Dan

[Fotoguy20d]

There you see one example showing you cannot take VM as a Gospel.

Interestingly, I found a questionable listing in the B&L section while I was looking up the Ross. Just below the 508mm f5.6 Tele (which I will need to confirm via reflection counting), I found this: "B&L E.F. Anastigmat f2.0 75mm This was a probably a Movie lens or an early oscilloscope recording lens. It was noted as a 6glass Gauss at No3,230,081 in uncoated form, ie pre-war. See below also."

My copy of this lens is not far off in serial number from their example. If it has 6 glass elements, the faint reflections are hiding well since I can't find them. Looks like 2 pairs of uncemented glass to me. Mine is marked Photomaton and, from my research, was used on photobooths of that name. There was a similar but not identical lens by Goerz of the same name, length, aperture and appearance (down to use of an Ilex General shutter) but different construction - perhaps that one has 6 elements.

Way off topic with that. Sorry. I return you now to the regularly scheduled thread...