Enlarging Lens for Copy Work. How? (mechanical aspect)

[jose angel]

I wake up this morning thinking about the same question than Peter L. Brown do i n the next post. (Excuse me Peter for this), but I'm only interested in the mech anical aspect. I hope this helps to others.

I have an apo-rodagon 150mm, and need to do copy work in the 1:2 to 1:4 range. R odenstock offer this enlarging lenses as one of the best to do this work, I read this also in other threads, but,

How can I do it? Which shutter could I use with this lens, in my Canham DLC? Which adapter ring/others (if so) do I need?

I'll be grateful with your help...

[Pete Andrews]

Macro or copy work usually involves fairly long exposures with tungsten light, or the use of flash. Neither of these requires a shutter. You can cap the lens with a piece of black card and pull it away for the duration of the exposure, or switch the copy lights on and off to regulate the exposure time. Open flash doesn't need a shutter either, as long as you turn off any modelling lamps, and dim the studio lighting so that it doesn't register.

Most enlarging lenses up to 150mm are fitted with the standard 39mm x 25tpi 'Leica' thread mount these days. You should be able to get a ready-made flange in that size fairly easily, and screw it to a spare lensboard.If it's only a short run of copying that you have to do, you can improvise with black tape, blu-tak or plasticene to hold the lens into a board.I thought half the challenge of being a jobbing photographer was to think of quick and easy ways to codge something behind the scenes, in order to make the subject look a million dollars.

[Bob Salomon]

There are several things to consider. Enlarging lenses are optimized to enlarge. That means that to work best for macro they should be reversed mounted. Rodenstock makes a reverse mounting ring for their 39mm thread enlarging lenses for just this purpose. But the 150 Rodagon has a 50mm thread and a reverse ring is not made. Nor is this as easy a size to fit into a shutter as the 39mm thread. Enlarging lenses are designed to work conveniently in near or totsl darkness. That is why they have an illuminated aperture mecanism to make them easy to read in the dark. But when used for copy/macro photography the port that lights up the aperture scale will also allow light (red and green filtered) to enter the aperture ring and hit the film. That is unless you mask off the port in the rear of the lens that lets the light in to illuminate the aperture ring.

[Wayne_6692]

Bob - Light entering the port for the aperture illumination will not hit the film when the lens is reversed.

[Bob Salomon]

Wayne,

Light entering through the aperture ring in daylight comes out the port on the back of the lens. That is why devices toi focus enlarging lenses on cameras, like the Rodenstock Modular Focusing Mount has a lens adapter that blocks the port on the rear when using an enlarging lens.

After all. If the light from the enlarger lamp can light up the aperture ring in the dark it has to enter the lens somewhere. That somewhere is what has to be blocked.

On the other hand a duplicating lens like the Apo Rodagon D does not have an illuminated aperture as it is not designed for enlarging. So the adapter to mount it on the focusing system has a different opening that would not block the illumination port on the enlarging lenses. Even though both are Leica thread.

[David A. Goldfarb]

Having tried reversing an EL Nikkor for macro use, I can verify that light coming through the aperture illumination port does register on film. The problem is easily solved with a little black tape.

Also, be extra careful to shade the exposed rear element from extraneous light with any reversed lens, since they can be prone to flare.

[Andres Suurkuusk]

I use 80/4 Apo-Rodagon N on Sinar F2, no shutter, lens is mounted normaly (not reverse) on custom-built plate. In dark studio, I pull out dark slide from film holder, wait about 1-2 sec to cut the possible vibration, manualy trigger my strobes. That's all. 50x60 Epson 9000 prints from 4x5 chromes look ok to me. Sample http://www.hot.ee/andress/leht_.jpg

[Bob Salomon]

But have you tried a comparison with the lens reversed?

"chromes look ok to me"

There is a reason why the lens manufacturers recommend reversing the lens. And it is not to sell a 1 up inexpensive reverse ring.

[Wayne_6692]

I'm mystified as to how the light can get into the image forming path when the port is at the front of the lens (remember it's been reversed) and the illuminated ring is outside of the lens/bellows enclosure. Are you saying that the light, instead of being piped outside of the optical path, is passed within the path of the imaging rays? Why would they do that?

[Wayne_6692]

Just got home, checked my Nikkors (why do I waste my time) - if you guys are getting light coming out of the front of the lens from any path other than the optical path you have a serious problem. I'm o.k., you're...