Cooke XVa and ULF?

[Ari]

A bit of a lull at work, so I'm indulging in some idle speculation.

I've been thinking of trying out 14x17 and doing some full-length (and closer) portraits with the format.
In searching for a lens that will cover the format, I almost pulled off a few deals for some 21"-25" process lenses that came close to covering 14x17 at infinity.

But then I thought that the Cooke might be able to cover at portrait distance. The only problem is I don't have any ULF camera, let alone a 14x17, on which I could try this.

Does anyone know, or have you tried to see, if the XVa will cover more than its intended 8x10 format? Maybe one of the longer FLs covers more than it's supposed to?

Thank you for indulging me.

[Carl J]

Hi Ari,

Might try this thread over on apug (if you haven't seen it already), even though the discussion is mainly around 11x14/12x20 it seems promising:

http://www.apug.org/forums/forum187/25912-triple-convertible-lens-11x14-12x20.html

Carl

[Ari]

Wow, Carl, thank you; that pretty much confirms what I thought about the XVa.
Quoting from that thread, in a nutshell:

Front and back - 311mm FL just covers 11x14 (can get about an inch of rise at f64)
Back only - 476mm FL - covers 12x20 with quite a bit to spare
Front only - 646mmFL - covers 12x20 with loads to spare

So if this is to be believed, shooting with the Cooke on 14x17 at portrait distance should not be a problem with either the 476mm or 646mm lens.
And it may be that the 646mm lens could cover 14x17 at infinity, or with just a slight darkening of the corners.

Thank you!

[Mark Sawyer]

It would cover 14x17 easily with single elements, although your maximum aperture would be similar to one of the process lenses you were considering.

[Ari]

It would cover 14x17 easily with single elements, although your maximum aperture would be similar to one of the process lenses you were considering.

Thanks, Mark.
The Cooke comes with a 3-position rotating aperture ring, constantly reminding you that f/16 is right around the corner should you want to try any ULF monkey business.
But the single elements are just as contrasty and sharp as the elements in normal configuration, so this is worth a shot, I think.

Thanks guys.

[William Whitaker]

Ari,

Sent you an email. Bellows factor ain't helpin' anything out here.

[Tony Lakin]

Hi Ari
Just conducted a quick test with my XVa, 312mm focused on infinity I can see the full aperture f32 on the screen at about 13 x 11 inches so I guess you would get full coverage without movements on 11 X 14 at portrait distances at f32 and maybe at wider apertures, I have run out of daylight but I will do some further tests tomorrow, I am sure you would get full coverage with the front and rear components used separately even at wide apertures.

[Ari]

Hi Will, thanks for the email, I'll reply presently.
You're absolutely right, the real problem won't be coverage, but bellows factor.
Despite the problems I'm sure to encounter, I was wondering about the Cooke's ability on ULF because, well, I have it; may as well start with what you already have.

Tony, thank you very much. I think the Cooke is turning out to be a real keeper, not just for its image quality, but for its versatility.
474mm at f11 is very doable, just the bellows factor would come into play at shorter distances.
Thanks again!

[William Whitaker]

Well, curiosity got the best of me and despite my better judgement I set up the 12x20 inside (talk about a pachyderm in the parlour!) so that I could have a view outside toward "infinity". The 19" cell of my Cooke XV (not XVa for the record) had no issue illuminating the corners at "infinity" (distant bare branches against snow). Closer than that and the front standard was approaching its own infinity of sorts - running off the rail with my lovely Cooke attached. The Folmer & Schwing only has about 22 1/2" of extension. Adequate for a banquet camera as it was designed, but regrettably lacking for re-purposing of the format as I'd like to do at times. As I'd predicted in my email, closest focus was just outside of 10 feet, so the backlit window blinds (which make such a nice focusing target) at 9 feet were never really in focus.

Time to get daring. I replaced the front cell of the Cooke for the 12" configuration and while it did not cover 12x20, it still was a remarkably broad circle and I think it might be worth further research for a couple of reasons. One is that you can and might want to have your sitter closer than 10 feet from the camera. That will buy you image circle as a trade-off for bellows factor. Two, the diagonal of a 14x17 is slightly less (by about 1 1/3 inches) than 12x20. Not much, but when you're splitting hairs, every bit counts. And third (OK, three reasons), I think that shooting a portrait, one is going to be less interested in the edges where fall-off occurs, particularly if you're careful about lighting and perhaps use a dark backdrop. So give the Cooke a good shake-down when you try the larger format. It may be a real player.

[Ari]

Thanks, Will.
I agree about the Cooke being a good option. If I can get my hands on a loaner 14x17 for a day, I'll give it a go with all three of the XVa's FLs.

Now, where to find a 14x17...

[angusparker]

Dear Ari:

From a recent blog post of mine here: http://www.angusparkerphoto.com/blog/2015/2/ulf-lens-recommendations-14x17

"Cheaper than the more modern process lenses list above, would be to use an old process lens from one of the former major lens makers. Allen Rumme's site has an extensive list of process lenses of which a bunch would work for 14x17 format. In particular look at the Ross Apo Process and Apochromat Xpres lenses from 21" to 48" and the Taylor Hobson Cooke Series IX Apochromatic, Cooke Series Vb Process, and Cooke Process lenses also from 21" to 48". I wouldn't consider mounting these lenses on a shutter but simply using them in a barrel stopped way down to get long exposure times you can manually execute."

Here is Allen's list: http://www.allenrumme.com/lensdb/Process.html

Basically it looks like any Ross or Cooke process lens over 21" has a fairly good chance of working for 14x17" especially at portrait distances. I haven't tried it myself though.

[Ari]

Hi Angus,
Thank you for that, a most interesting read.
I was looking at a TTH Cooke 21" Series IX, and I am also familiar with Allen Rumme's extensive list.
But perhaps I am overthinking this right now, as I do not have a camera, and investing more money before acquiring said camera would be chasing a ghost.
Re: the Cooke XVa, I think that, image quality-wise, there is no better lens available at any price, so I'd love to see what it can do on a larger canvas.

[angusparker]

Hi Angus,
Thank you for that, a most interesting read.
I was looking at a TTH Cooke 21" Series IX, and I am also familiar with Allen Rumme's extensive list.
But perhaps I am overthinking this right now, as I do not have a camera, and investing more money before acquiring said camera would be chasing a ghost.
Re: the Cooke XVa, I think that, image quality-wise, there is no better lens available at any price, so I'd love to see what it can do on a larger canvas.

The Ross lenses are coated while the Cooke ones are not - so I suspect that all things being equal the Ross might be a better choice.

[Tony Lakin]

Hi Ari
Just conducted a quick test with my XVa, 312mm focused on infinity I can see the full aperture f32 on the screen at about 13 x 11 inches so I guess you would get full coverage without movements on 11 X 14 at portrait distances at f32 and maybe at wider apertures, I have run out of daylight but I will do some further tests tomorrow, I am sure you would get full coverage with the front and rear components used separately even at wide apertures.

Hi Ari
Just to confirm, I have re checked the above result and can confirm that I can see the whole of aperture f32 at infinity in the corners of the 11 X 14 image area, focused on 10 feet the maximum aperture I can see the whole aperture is between f16 and f22.

[Ari]

The Ross lenses are coated while the Cooke ones are not - so I suspect that all things being equal the Ross might be a better choice.

Sorry for the confusion; I was referring to the new Cooke XVa. WRT older lenses, I would certainly agree with you.


Hi Ari
Just to confirm, I have re checked the above result and can confirm that I can see the whole of aperture f32 at infinity in the corners of the 11 X 14 image area, focused on 10 feet the maximum aperture I can see the whole aperture is between f16 and f22.

Tony, that's awesome; thank you.
I was smitten with the XVa before, now I'm twice as smitten.

[Ari]

I just wanted to update this thread; I have since spoken to Clive Russ, the US distributor for Cooke, and the man who sold me my Cooke.
Regarding using the Cooke on ULF, here is what he told me: "The Cooke will put light on 11x14, and even 14x17 but the image shows astigmatism beyond its specs. That may not matter if you are contact printing."
Mr Russ's evaluation is a little at odds with what the APUG poster found, so I'm eager to try this out and see for myself, before spending more money on another lens.

Over the summer I will take possession of a 14x17 camera; I've always wanted to try the format, now I'll have a chance.
I'll need to get a rudimentary darkroom going again, to make contact prints.

[karl french]

Illuminating the film area and producing a sharp image are two different things. I've been able get into the soft parts of the image circle by using lots of front rise on 8x10 with my Cooke XVa at 311mm. If it covered 14x17 well, this wouldn't be possible using an 8x10 Deardorff.

I'v only shot one sheet with the whole XVa on 10x12. Seemed to cover with a sharp image just fine without any significant movements.
I'm sure the individual components would be just fine on 10x12. 14x17 is a whole other story. Though at portrait distances you've got more image circle to work with.

[William Whitaker]

I'll need to get a rudimentary darkroom going again, to make contact prints.

Yesss!!!

Curious, too, what the actual effect of astigmatism is on a photographic image. I've tried reading the definition of astigmatism over and over again, but every time I get to tangential this and sagittal that, I fall asleep.

[Ari]

Yesss!!!

Curious, too, what the actual effect of astigmatism is on a photographic image. I've tried reading the definition of astigmatism over and over again, but every time I get to tangential this and sagittal that, I fall asleep.

I know, that stuff makes me sleepy, too.
I understood it to mean that there would be areas of softness next to/adjacent to, areas of sharpness, but that was after only a cursory read-through of online stuff.

[Ari]

Illuminating the film area and producing a sharp image are two different things. I've been able get into the soft parts of the image circle by using lots of front rise on 8x10 with my Cooke XVa at 311mm. If it covered 14x17 well, this wouldn't be possible using an 8x10 Deardorff.

I'v only shot one sheet with the whole XVa on 10x12. Seemed to cover with a sharp image just fine without any significant movements.
I'm sure the individual components would be just fine on 10x12. 14x17 is a whole other story. Though at portrait distances you've got more image circle to work with.

Yes, I was told that 11x14 would not be any kind of problem for all three FLs; the single lens elements will cover larger formats, though not without some kind of deterioration of image quality if going to 14x17 or larger, according to Clive.

[Sal Santamaura]

...Curious, too, what the actual effect of astigmatism is on a photographic image...As a lifelong myopic with astigmatism, that's something I've never had to be curious about. Removing my spectacles makes it "perfectly clear." :)

For the rest of you, here's an image that shows what the two types of astigmatism do to a field of points:


http://www.handprint.com/ASTRO/IMG/seidel3.gif

[William Whitaker]

For the rest of you, here's an image that shows what the two types of astigmatism do to a field of points:


http://www.handprint.com/ASTRO/IMG/seidel3.gif

The depiction of "sagittal" seems to resemble the "swirlies" that a lot of folks admire.

[Dan Fromm]

The classic astigmatism effect can be seen most easily when the subject is a grid. Years ago I bought a 1000/11 Celestron C-90 because at its close focusing distance (10 feet) it gave 1:4 magnification. It was just what I needed, I thought, to shoot a small elusive subject and I could afford it. When I took it to the field the subjects couldn't be found. My C-90 turned out to be a terrible lens. Anyway, I tried focusing it on a window screen. It could get the horizontal wires in focus or the vertical wires in focus, not both at the same time. That's astigmatism.