Need super bright LF lens for macro

[aopie]

I'm shooting extreme macro 4x5 tintype with a copy camera I've rigged up. It has 62" of bellows draw . I'm working on achieving the range of magnification up to 20x (is the goal, more would be fine).

I have shot a lot of 4x5 and 8x10 tintypes mostly on a horseman 8x10 and have a bunch of lenses but nothing that will let me get as much magnification as I want AND be bright enough to work easily in this configuration.

I just bought a Nikon Nikkor 75mm SW - without thinking through how bright it would be - it's physically small and so at my extension it's a bit dim.

Does anyone have a suggestion of a physically large lens that would work for my needs?

Lenses I have to work with and have tried:
Ilex Optical 6 1/2 - great up to 8x
Schneider-Kreuznach 360mm - up to 3.3x
Schneider-Kreuznach 135mm Enlarger Lens Backward 4.5x
Fujinon W 250 - 4.5x - nice for smaller magnifications as well
Front Element Ilex Oscillo Paragon 75mm - up to 16x with possibly serious chromatic aberration, not yet tested

Ones I own but have but haven't tried yet
Ilex Copy Paragon 9"
Ilex Calumet Series 2 215mm
Turner Reich Anastigmat series II 8x10
Ross London 10" XPress
Ross Rapid Symmetrical 9x7

Thanks you,
Alexandra

[Bob Salomon]

A good reversed enlarging lens. Like the 50 mm 2.8 Apo Rodagon.

[Dan Fromm]

The relationship between extension (lens’ rear node to film) and magnification is e = f*(m + 1) where e is extension, f is the lens’ focal length, * is the multiplication operator and m is magnification. This is true for all lenses, regardless of pupillary magnification. When the lens is focused at infinity, m = 0.

For a symmetrical lens, with entrance and exit pupils the same size, i.e., pupillary magnification = 1, effective f/ number is f/ set * (m + 1) and the exposure increase factor is (m + 1)^2. Read f/ as “f over.” ^ is the exponentiation operator. So with a lens whose aperture is set to, say, f/4 the effective aperture when magnification = 1 is f/8 and, equivalently, the exposure increase factor is 4.

For a lens with pupillary magnification <> 1 mounted front forward, effective f/ number is f/ number set * ((m/p) + 1 ) where p is the pupillary magnification. With the lens reversed, effective f/ number is f/ number set * (1/p)*(1 + pm).

All of these relationships are well-known. Emmanuel Bigler, professor of optics and microtechniques at École Nationale Supérieure de Mécanique et des Microtechniques de Besançon recently derived them from first principles just to check.

In plain English, Alexandra, you're toast. At 20:1, for a symmetrical lens (many, not all, lenses for LF are approximately symmetrical) effective aperture will be aperture set * (20 + 1). Fast macro lenses for high magnification (think MacroNikkor, Luminar, Photar, ...) are no faster than f/2.8. 21 * 2.8 = 58.8. Sorry, toast.

[Pere Casals]

Does anyone have a suggestion of a physically large lens that would work for my needs?

Hello Alexandra,

I've a suggestion that I think is to work fantastic for your needs, I think: if you want to go 20x your filed of view has to be small.

This an SLR camera lens: Nikon 50mm f/1.8 , use it reversed, of course.

If you invert the lens... what was normally the field size it will be the negative size, so it vill cover well 8x10", and what was the negative size (24x36mm) it will be your field.

After focusing you can close diafragm in order to increase DOF.

The f/1.4 version may be less suitable because it has some distorsion and it is a tinny bit less sharp than the cheap f/1.8. Also you can use Nikon enlarger lens, EL-Nikkor 50N, as Bob says, the f/2.8 is the right one.

Best Regards,
Pere

[Will Frostmill]

Some people have had luck with reversed 35mm lenses. Working distance is very poor - basically flange focal distance, so for Nikon, 46.5mm. T-mount is 55mm, and Mamiya RB/RZ67 lenses are right around 100mm.

The field of view is going to be 24mmx36mm, (except for the Mamiya) so I don't know if your subjects are going to fit. But the angle of view directed toward the tintype is going to be as wide as the native angle of view, so you don't need enormous lenses.

You can get really nice macro lenses in those mounts for cheap. The Micro Nikkor 55/3.5 has a great reputation, and I think there's a 90/2.5 in T-Mount. I would also try a straight Nikkor 50/1.4, or especially a Pentax SMC 50/1.4.

[aopie]

Dan,

Ha! Toast. I usually operate best struggling against the limits of possibility....got myself there as usual. My math skills are so limited that I use online calculators, experience and testing to figure things out. Thanks for the plain English summary!

My understanding is that lenses with a certain aperture should give the same amount of illumination in spite of size but I don't find this to be true - that or the principle I think I understand is totally wrong. Working with 8x10 and long bellows extension it has seemed to me that the physical size of the lens does make a difference. I was hoping that someone knew of a 75mm lens that is huge that I could look for.

Thanks

[aopie]

I have a few and have used them for other macro work but find them too small - not bright enough in this application.

[aopie]

Will,

I have never tried any small or medium format lenses for this. I have a bunch of those I can try. I worry about size and therefore smaller illumination. Also working distance can get to be a real pain.

[Pere Casals]

Some people have had luck with reversed 35mm lenses. Working distance is very poor - basically flange focal distance, so for Nikon, 46.5mm. T-mount is 55mm, and Mamiya RB/RZ67 lenses are right around 100mm.

Just I've tested with the Mamiya RB67 Sekkor 65mm f/4.5. It looks great, two stops less bright but better working distance, as you pointed.

[Dan Fromm]

Alexandra, magnification, slow emulsions and an apparent aversion to turning the lights up are what's toasting you.

A magic formula of some importance: Extension = focal length * (1 + magnification). Whence focal length = extension/(1 + magnification). You have 62" of bellows, you want to shoot at 20:1. The longest lens that will give you this has a focal length of 62/21 = 2.95" = 75 mm.

Will Frostmill made a good suggestion. A reversed 55/2.8 MicroNikkor AIS shot at f/4 will give superb results. At f/2.8, ok results that will be more than good enough for tintype. Will suggested a 55/3.5. We have one in the house but since I've never tested it I can't say much about how well it performs reversed at high magnifications. But I have tested our 55/2.8. Will is mistaken about image circle. It grows with magnification. Following Emmanuel Bigler's reasoning in http://www.largeformatphotography.in...-lens-coverage, at 20:1 a 55 mm macro lens for a 35 mm camera will cover 43 * 21 mm = 903 mm. That should be enough for you.

At 20:1 you'll need to use flash -- quite small flashes near the subject will do, so will hot lights at a greater distance -- or very long exposures. Focusing and composing may be a little difficult.

Do yourself a favor. You've asked a short apparently simple question that really needs a book length answer. Buy the book. Lester Lefkowitz' The Manual of Closeup Photography.