Meandering discussion about the utility of aerial lenses

[Asher Kelman]

Asher
Don't get too carried away by dpi/lpm yet.
Explore the idea of a 4x6 ft print and see what happens at 10 inches.
Better yet, get a closeup look at a billboard.
You can't see the 4x6 picture at 10 inches nor can you see the picture on the billboard at 10 feet- all you can see is dots, and so what if you can see 20 or 40?

Hi Ed,

Thanks for your input. I know all about the dots. Also some pictures seen small are not very impressive. However the same image with no more detail on a large wall becomes impressive and magnetic because the size of presentation can change the experience.

In this case, I'm not concerned with the overall composition and gestures which are indeed appreciated for 10 -20 feet or more from the photograph. That is for the magnetic draw. I'm also interested in there being new detailed imagery when one is at 16-20 inches too!

The rest of your post is magnificent!

Form is translatable from those dots only if you have enough to show variation of gray or color. Ya gotta GET BACK to see the picture.
I like sharp and strive for it and hate it when I fail, but I have learned a coupla things
A looong time ago we took a pinhole photo of the inside of a "3 dimensional space modulator" in architect school and presented it as a 2D print with the 3D model. The idea was to used curves surfaces to define positive and negative spaces. The instructor pointed out what we had discovered. The pinhole pic was small in order to get inside the model. On the board the print was large. Viewed at 10-20 inches the print shoed NO depth or form, but viewed properly from 4 feet it popped, and difraction effects were not significant. When the instuctor backed up he agreed.
The second i learned from a mistake- I was using a rangefinder and after i had exposed the neg I found I had knocked the f stop setting and wasn't going to get the overall sharpness I thought I wanted. But the print, which appeared to be sharp, was slightly soft beyond the main subject and I got depth- a duuuuuh moment and a better image.
There's a 4x6 foot print in the Camera store in San Luis Obispo [ well I haven't been downtown in years, it WAS there.] One can't get close without going behind the counter. i know the neg was made on 116 film in 1937 by an amateur. From the public side the picture pops. An 8x10 from that neg looks very mediocre in one's hands.
IF you are a spy and want to make and 8x10 neg and blow up a .2x.2 inch section to , well say 8x10, ignore all of the above.

[Asher Kelman]

Asher, Seriously, I recommend this book. It got me on the right path. I veered off the path later, but the knowledge base is indeed intact.

Image Clarity by John B. Williams. Published in 1990. As Dan says, there are many bricks in your building besides the lens.

Jim,

Yes, that's a good book but does not end up as a practical guide for choice of lenses I seek. In fact, the lenses I'd like may be just the best modern lenses in modern shutters, albeit expensive. I want to have great detail with one shot, eschewing the stitching I already do well but with great time waste!

I have a good concept of the limits of human vision, both the physiology and psycho-physiology of how images can be perceived and interpreted. I know about the physics of optics enough to understand everything the author puts forward. I have an appreciation of the changes in user experience in seeing images at both different sizes, on various backgrounds, circumstances and viewing distance. All these are subjects that I use in my work.

Here, however, in my quest for older high quality lenses, I am still learning the types of available lenses and wishing to not to have to buy brand new costly digitar types designed to meet the challenges of an 80 MP back!

That having been said, outside of my fascination with soft focus portraits of things and people, I want to explore the following.

Images where the composition and motifs work at the viewing distance of 20 feet and then when one approaches to 18 inches or so, there's surprising and fascinating extra detail and activity, all over, just like in a Peter Bruegel the elder picture, but 3 times the size.

Asher

[GPS]

...

However, for aerial, surveying, mapping lenses and the like, on a LF camera, I'd like to just take advantage of resolution made for these applications and use that for detail rich scenes and magnifications greater than I can get by single shots with my current lenses.
...

You won't get that. For the simple reasons, mentioned already by Sevo, that the lens itself is not delivering the "advantage of resolution" you want to have. The lens must be paired to a rigid body (forget manually installed lens standards) and a vacuum back. Aerial cameras, conceived to get the most of details under a high magnification have their constructional logic, something you like to ignore.

[toolbox]

toolbox, one would think that it should cover 8x10. But the USAF data sheets say that it is for 5"x5", also that it isn't very sharp wide open.

12"/5 Aerostigmats have been discussed a bit over the years. I don't recall strong favorable comments, doubt that this means much.

By all means try it out and tell us how it does for you.

Also, would you please count reflections and tell us whether it is a tessar type. If a tessar type, there should be four strong and no weak reflections from the front cell, two strong and one weak from the rear cell. The weak reflection may be hard to see. I ask because I recall discussions, with no clear conclusion reached, about whether the 12"/5 Aerostigmat is a tessar type.

I've seen a couple 9x9" recon/mapping cameras it was also supposed to be used on, so I'm pretty confident it'll cover 8x10. Guess we'll find out for sure though . And being a little soft wide open isn't a deal killer...not everything needs to be pin sharp . I tried to check the reflections this morning...the front looked like it had 3 strong, the rear two strong (they all looked pretty strong to me, but maybe I just don't know what I'm looking at). I couldn't see any weak reflections, but I didn't have a lot of time to mess with it, so I could be wrong. I'll take a closer look tonight, and see what I can see...

[EdWorkman]

Okay Asher, I understand, I think, that you want a BIG print of say, San Francisco Bay Area and be able to walk up close and identify people walking on Market Street.
I see how that works from space from my favorite TV crime shows, but I can't think of a horizontal theme. Something akin to shooting the North Rim from the South Rim and being able to walk up close to the giant print and be able to pick out the mountain sheep on the cliffs? i can dig that.
GO for it and let us know if it sucks, or you need a filmholder that does.
regards and success
Ed

[Asher Kelman]

Okay Asher, I understand, I think, that you want a BIG print of say, San Francisco Bay Area and be able to walk up close and identify people walking on Market Street.
I see how that works from space from my favorite TV crime shows, but I can't think of a horizontal theme. Something akin to shooting the North Rim from the South Rim and being able to walk up close to the giant print and be able to pick out the mountain sheep on the cliffs? i can dig that.
GO for it and let us know if it sucks, or you need a filmholder that does.
regards and success
Ed

Hi Ed,

I've been doing this with stitching many separate digital shots of 60-100 people and then assembling them in a large background shot of a school courtyard with magnificent architecture, that also a pano assembly. However, it takes 40 hours of work to perfect the background and then one has to put in the people and match the perspective, which itself is dependent on the projections used in making super-wide panos.

I now realized that assembling people and shooting with one lens can reach the quality I seek without going crazy with math and blending, matching color temps and so forth.

So I decided to leverage my investment in LF, (done for my "Galliitis" love of soft portrait), to enable me to do massive compositions in one or two shots. Actually a vacuum back would not be any problem at all! What I realize now is that illumination and rendering across the field should be uniform as possible. I can correct illumination perfectly in Photoshop or Capture One if need be. Softness in the periphery, however, cannot be repaired without deconvolution software and added complexity. So that's why I thought that lenses designed for mapping and the like would have all these technical aspects aced.

Until now, my lenses where chosen on the basis of having softness and some vignetting. Here, I have to start from the beginning. That's my interest in stellar lenses.

Of course, my existing lenses, stopped down, might give the contrast at high resolution to allow 10-16 foot high prints that one could walk right up to and admire the hairs on a moustache or the finesse of silk on a young woman's body or else the plumage of a humming bird hovering over a flower.

Working backwards from 10-16 ft and imagining observing the many objects from just 10-18", what lens can do this?

I assume that one needs ~ 4 lp/mm for the impression of perfect sharpness. So we can set the magnification to 20x for 8x10 for a nominal 12 ft high print. That would seem to ask for 80 lp optics! However, Schneider optics might be in the range of 20-40 lp/mm. Maybe 40lp/mm in a uniform image circle would be just fine!

That's why I asked about aerial lenses! So many own them, but besides the Aero Ektar, one does not often see work done with them! Are they mostly owned as trophy paperweights?

Asher

[Struan Gray]

Asher, your application sounds perfect for a scanning or rotating panoramic camera. You get cylindrical perspective for free, and the lens only needs to cover the short dimension of the image, which boosts your chances of ultimate sharpness.

If you must use an aerial model, there were prism-scan cameras with Biogons inside which imaged onto MF film. Otherwise your best bet in analogue would be to join the Circut brigade.

But. Were it me, I would look seriously at the use of a scanning back in panoramic mode. Jim Collum has shown some great examples here in the forum.

[EdWorkman]

Sounds as if you need a very large DOF
If that's a problem Mr. Scheimflug can't solve could stitching solve it as Dan suggested?
More specifially, a shot for the folks plus a shot for the architecture- two different and more limited DOF planes. I'm still trying to think of the solution as one of planes, in the above planes assembled to approximate 3D

[John Schneider]

...If you must use an aerial model, there were prism-scan cameras with Biogons inside which imaged onto MF film...

KA-56 and later KA-71 (as memory serves me). I've got one in the garage, but it seems too much effort and too little apparent benefit to mod'ing it for land use off a terrestrial power supply.

[Asher Kelman]

Asher, your application sounds perfect for a scanning or rotating panoramic camera. You get cylindrical perspective for free, and the lens only needs to cover the short dimension of the image, which boosts your chances of ultimate sharpness.

If you must use an aerial model, there were prism-scan cameras with Biogons inside which imaged onto MF film. Otherwise your best bet in analogue would be to join the Circut brigade.

But. Were it me, I would look seriously at the use of a scanning back in panoramic mode. Jim Collum has shown some great examples here in the forum.

Struan,

I'm a great fan of Jim's work both his beach scenes with the scanning back and his mixed media Platinum prints color pigment prints, which are also spectacular.

The scanning back gives the resolution and contrast needed but anything moving will be lengthened or shortened. Imagine many people at once then might be difficult. However, one could have retakes and blend the best of each. So it's very practical.

Thanks for the suggestion!

Asher