Need help identifying lens mount

[truls]

Came in a package - could not find info about this lens. The lens looks as it never has been used. Here is text on front of lens: SEARS WIDE-ANGLE 1:2.8 f=35mm 10045 LENS MADE IN JAPAN

[Stephen]

I would venture to say that a back part of the lens is missing..... or an attempt to fit it to C mount, ( Cine 16mm ), has been made at some point.

The back, if it has a T mount, would be bigger diameter, what there look as if the elements are far forward, therefore it might have been partially altered to fit a digital camera, but the rear element sticks out to far for that.

The other possibility is that it was altered to mount on an enlarger, 35mm and 28mm were used for Half frame and Minox.

Place the lens by hand in front of a reflex body, and see what the missing gap is at infinity, that will reveal how much has been altered.

It is not a Leica thread, that would be a thick adaptor to make up the distance from the T mount area to the Leica mount, about 35mm or so, can't remember the exact distance.

Sears did not make specialist lenses, they were just a US photo retailer and stuck to popular makes and fits.

Stephen.

[Stephen]

Also, more importantly, where is the aperture ring?, I think the lens is an adaptor to go on another section of lens etc in a cine camera body, with the aperture control inside the body.
The same sort of thing was done on some 35mm compacts etc., but I have never seen this small thread in any.

Stephen.

[philbirch]

From a Sears TLS 126 camera also Ricoh 126C Flex info below:

The lens was interchangeable but the aperture was inside the camera body. They used this small screw thread. Read on...

[Stephen]

Well spotted !!!!! it had to be a camera with the aperture inside...
Stephen

[truls]

Thank you gentlemen for qualified answers!

I have looked up the cameras, but this lens looks way bigger than it should. Here more pictures of the lens.


Relative huge lens


Relative huge lens


According to distance where infinity focus are, it could be mounted on camera with adapter like Ricoh 126 or Sears. I found more on this site: Ricoh 126 flex

So, I could actually get a camera for the lens, and load some 126 cassettes...?

[philbirch]

you can get a body and standard lens for not much, easily less than $30 inc post. The lenses are fairly rare so fetch a good price when sold.

I have no idea of the flange focal distance of this lens, it would definitely work on a mirrorless with a home made adapter, but I'm not sure about anything else because of the protruding lens. and of course with no aperture. Similar to the Pentax 110 lenses. but bigger.

[SidW]

Going back to Truls's first post, the lens is marked 35mm and wide angle. That means nothing smaller than full frame 35mm, to retain the wide angle effect. But it could still work on roll film, especially 12 or 16 on 127. That would also explain the larger size of the lens, and the size of the missing flange.

[truls]

But what would be the effective focal length using a 35mm lens an 126-film? Hmm.. 126-film is 24x24, or ist it? Wikipepdia says it is 28x28, but reduced due to masking when printing. Diagonal of 24x24 is 34mm. So, most likely a normal lens. Or?

[Stephen]

The "huge" size is the design being a full Retrofocus wide angle lens, the centre point moved forwards to allow for the shutter or aperture in the body. They started in France in the early 1950's and became the accepted way to design a lens for reflexes in the end.

The lens as it stands could fit a Digital camera via an adaptor, a cheap set of extension tubes could provide the back lens flange and the tubes the body, sawn to length.

But there is a flaw, a very, very, deep one, no Diaphragm at all, so only full open operation......

And I would add that the lens performance may be poor, 126 standards were generally low expectation of performance. Also the edge performance may be poor for a 35mm frame. It's coverage would fit micro 4/3 frame and act as 70mm crop. (less on a Canon).

So it would be convertible out of curiousity, but very impractical in reality.

Stephen.

[Stephen]

Sears clearly treated the 55mm as the Standard view, 35mm wide and 100mm telephoto, disregarding the smaller frame, for marketing the camera, rather than pure technical reasons to match the frame.

Don't forget a certain focal length always produces the same image size on the negative, it is only the cropping that alters, a 50mm always delivers exactly a 50mm type image and perspective, be it on a Minox, 110, 35mm, or on a roll film size. It is just the masking that turns it into a telephoto on smaller formats.

Stephen.

[Stephen]

The drawing shows the difference between a Biogon true wide angle, and the same focal length in a Retrofocus design, both give the same image size, but the glass is shifted forwards in the retrofocus design, the favourite for reflexes. The down side for the manufacturer is the big increase in the diameter of the front element, which increased costs.

Stephen.

[truls]

OK, if I understand correct, retrofocus lens: Producer of lens add front element to make it a wide angle, then it becomes large lens. One could assume that zoom lenses are retrofocus.

[philbirch]

Telephoto is the opposite of retrofocus more or less, ie making the lens physically shorter than the focal length. We are more familiar with the word telephoto than retrofocus.

A 28-200 such as I have would definitely be a retrofocus design, but an 80-200 wouldnt necessarily be.

I think there are no hard and fast rules for lensmakers but I suspect that a long focus lens would have better image quality then a telephoto and a short focus lens would be better then a retrofocus wide. simply due to the number of elements needed. All things being equal.

[Stephen]

Jul 19, 2014 1:29:06 GMT -5 truls said:

OK, if I understand correct, retrofocus lens: Producer of lens add front element to make it a wide angle, then it becomes large lens. One could assume that zoom lenses are retrofocus.

Yes, most zooms are basically a variable retrofocus, which means a reversed telephoto.

It was the reflex camera mirror than drove designers to use the design, to shift all the glass forward, but in the 1950's Zeiss and other makers who liked Compur and leaf shutters, realised the lens allowed interchangeable lens of wide angle on a leaf shutter, impossible before the French lens maker, Pierre Angenieux came up with the design in the late 1940's.

He was just interested in it at first for 35mm Cine cameras like Technicolor, who used the space behind the lens to have a huge gold filtered prism block to split the light to three colours. This block effectively stopped deep wide angles to be fitted to Cinema cameras to use in colour films.

Pre-war films like The Adventures of Robin Hood with Errol Flynn, full Technicolor, were shot without any wide angle shots at all, to get a wide view you had to step back! This led to a distinct look in early colour films, that only changed by the time of films like The Ten Commandments and Ben-Hur, that used wide angle lenses, (and wider screens).

Hollywood was demanding colour wide screen in the early 1950's, and desperately needed wide angle lenses and zooms for three strip Technicolor, and his design worked perfectly. The most famous wide screen wide angle retrofocus lens was the TODD-AO bug eye, with a massive 10 inch front element.

The problem with the Technicolor cameras not taking wide angle lenses led to the quicker adoption of Eastman Colour stock film, which could be used in a normal Mitchell camera that could take normal type lenses.

Zeiss were the first maker of retrofocus lenses outside France, with TTH in the UK, Zeiss realising it would work on Exakta, and the Italian Rectaflex. Within a year most makes turned to the designs.

As Technicolor three strip went out of use in Hollywood, the demand for retrofocus faded, but remains to this day in reflex still cameras. Movie cameras with TTL viewing still need retrofocus lenses though.

Digital cameras do not, in theory, need a retrofocus design, plenty of space behind the lens, but mirrors remain in some, and zooms are retrofocus anyway.

Stephen.