making wide angle lens for ulf camera

[toguko]

I would like to make a wide angle aplanat (Rapid Rectilinear) lens that could cover 20"x60" negative size (image circle = 1800mm including the front movements). The lens has to be wide angle so that the vertical view could be normal (because of the panoramic ratio of the negative). According to my calculations, the best focal length would be 1000mm with the angle of view = 84°. I would like to ask the experts in optics on this forum that could advice me how to start. I would highly appreciate any help.

And this the prototype of the camera I am building:

[Mark Sawyer]

Just so you know, Wide Angle Rectilinears weren't Rapid Rectilinears. WAR's were usually f/16, while RR's were usually f/8. Both used achromatic doublets front and rear, but if you're using black and white film, you can probably get away with single elements front and rear.

[VPooler]

www.surplusshed.com has the materials needed

[Lachlan 717]

I'd really reconsider front movements, particularly tilt/swing. These necessitate a larger image circle than rear movements, and will be a considerable PITA when focusing.

[toguko]

Just so you know, Wide Angle Rectilinears weren't Rapid Rectilinears. WAR's were usually f/16, while RR's were usually f/8. Both used achromatic doublets front and rear, but if you're using black and white film, you can probably get away with single elements front and rear.

I will be using paper negatives hence Periskop lens would be too slow. It is my second choice though.

www.surplusshed.com has the materials needed

Perhaps they do have the materials but first I need to know which lenses I need.

I'd really reconsider front movements, particularly tilt/swing. These necessitate a larger image circle than rear movements, and will be a considerable PITA when focusing.

I will be using only rise and fall front movements.

[ruilourosa]

Hello

I have the same problem... i would love to have a rapid rectilinear made out of two achomats with around 1000mm but i have found some problems...

surplusshed has NOT any achromats of around 2000mm with a viable diameter (i would like at least 80mm or a bit more)

i have tried to find on other online optic stores but it´s hard... i didn´t find in any...

i turned myself to the low power (low diopters) achromat close up lenses and i have succeded, i made a +- 620mm out of two minolta achromat close ups, but 620mm it´s not a 1000 (i know i could make a 1000mm out of a +1 element alone, building a chevalier achromat, but i need more quality, at least a bit more, and also a bit more speed...), i would love to find two identical, coated 2000mm achromats with 80mmm (f:12) or ideally with 125 mm (f:8)

my 620 has a perfectly acceptable quality but it was not cheap to make... (around $100)

low quality achromats may be used but i have no knowledge of low power lenses (less than +1)

let me know if you know something

Cheers


Rui Lourosa

[Mark Sawyer]

I will be using paper negatives hence Periskop lens would be too slow. It is my second choice though.

A periscopic lens would be the same speed as an equivalent lens made with Achromats, you'd just lose the achromatic corrections. These would be unnoticeable in monochrome; Kodak once used achromatic meniscus lenses in its folding cameras, but switched to single lenses when they found there was no difference in the results.

[Amedeus]

Surplus Shed doesn't have a steady supply of large diameter (>125mm) lenses of any type. Once and a while you get lucky on a special to find out the focal length is rather short.

www.surplusshed.com has the materials needed

[Amedeus]

What is your budget ?

Why do you believe 1000mm with an angle of view of 84 degrees to be best ? Is this limited by bellows draw ? Wide angle lenses are harder to make ...

I would like to make a wide angle aplanat (Rapid Rectilinear) lens that could cover 20"x60" negative size (image circle = 1800mm including the front movements). The lens has to be wide angle so that the vertical view could be normal (because of the panoramic ratio of the negative). According to my calculations, the best focal length would be 1000mm with the angle of view = 84°. I would like to ask the experts in optics on this forum that could advice me how to start. I would highly appreciate any help.

And this the prototype of the camera I am building:

[alexn]

What lachlan said is my instant thought... walk around the camera, apply front tilt, walk around the camera, check ground glass, adjust focus slightly, walk back around the camera, adjust front tilt a little more, walk back, check.. throw arms in the air, walk back to the front of the camera, zero movements, stop down to f/295, shoot and deal with the diffraction as opposed to the frustration.. Rear movements would be a much better option for something of this scale I would have thought..