Enlarging lens for copy work. How? (mechanical aspect)

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I wake up this morning thinking about the same question than Peter L. Brown do in the next post. (Excuse me Peter for this), but I'm only interested in the mechanical 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. Rodenstock 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...

-- jose angel (acquatek@teleline.es), February 07, 2002

Answers

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.

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 07, 2002.


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.

-- Bob Salomon (bob@hpmarketingcorp.com), February 07, 2002.

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

-- Wayne DeWitt (wdewitt@snip.net), February 07, 2002.

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.

-- Bob Salomon (bob@hpmarketingcorp.com), February 07, 2002.


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.

-- David Goldfarb (dgoldfarb@barnard.edu), February 07, 2002.



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

-- Andres (andres@suurkuusk.com), February 07, 2002.

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.

-- Bob Salomon (bob@hpmarketingcorp.com), February 07, 2002.


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 DeWitt (wdewitt@snip.net), February 07, 2002.

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...

-- Wayne DeWitt (wdewitt@snip.net), February 07, 2002.

One nice thing about some of the Componon S lenses is that one can remove the elements from the barrel and mount them directly into a Copal shutter. For example, the 150mm mounts directly into a Copal "0" shutter, and I believe that the elements from a 100mm mount into a Copal "00" shutter.

I haven't tried the latter, but I've tried the former and got great results. I photographed some paintings and was surprised at the sharpness of the results when viewing the transparency with a 4x aspheric loupe.

-- neil poulsen (neil.fg@att.net), February 08, 2002.



For magnification bigger than 1:1, one should reverce the lens.

Rule of optics is simple: smaller object goes in front of 'rear element' of the lens, bigger object in front of 'front element'.

Enlarging or any "normal" lens design assumes that smaller object (film) goes behind the 'rear element' of the lens and bigger object (ph.paper etc.) goes in front. It works for =ANY= magnification, e.g. if one doing macro grater than 1:1 (film size is bigger than the object) lens performs better in reverse position.

-- Andres (andres@suurkuusk.com), February 08, 2002.


When you reverse the lens the port that lets light in to illuminate the aperture now points to the subject. Any light entering through the aperture scale (frequently filtered to light up red and green in the dark) now comes out that port on the back of the lens (that is now facing forward if you reversed the lens) and may fall on the subject unless the port is taped over.

If you did not reverse the lens the port would face the film and the light entering the aperture scale would then reach the film.

When using enlarging lenses for shooting the port should be taped or (if used all the time) painted over.

If Nikon lenses do not have an illumintated aperture scale then this is a moot point.

-- Bob Salomon (bob@hpmarketingcorp.com), February 08, 2002.


Bob once again you turn around a wrong answer and pretend you never said it. And if you can get light to shine through the aperture scale and out the port onto the subject, well more power to you. I always thought that you should illuminate the subject and not the lens, guess you learn something new every day.

-- Wayne DeWitt (wdewitt@snip.net), February 08, 2002.

Nikon lenses do have an illuminated aperture scale. It may depend on where you put the lights, and maybe not all lenses have the same design in this respect, but when I've tried reversing a Nikon enlarging lens on a medium format camera without covering the port, I got some kind of stray light in the middle of the frame. I didn't notice it in the finder under modeling lights, but the flash was bright enough to register this stray light on film. I was comparing several lenses for this project, and the EL-Nikkor was the only one with an illumination port, and the only one with this problem. It's a simple problem to avoid.

-- David Goldfarb (dgoldfarb@barnard.edu), February 08, 2002.

All your comments have been so valuable to me. Im really grateful to all of you.

-- jose angel (acquatek@teleline.es), February 09, 2002.


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