Rodenstock Rodagon f/4, 80mm lens

[Ka]

Hello All,

I recently purchased a perfectly lovely Rodenstock Rodagon f/4, 80mm enlarger lens. It appears spotless, clear, perfect in every way. I use it with my Saunders Dichroic 670 enlarger and 120 film.

Is there a reason why everything I print on it appears a little SOFT? I am experiencing the same soft results on Agfa Classic, Agfa Premium, and Forte V.

I have used it on other similar enlargers with the same result.

(I am in the process of acquiring a Schneider Componon S 80mm for comparison.)

I am quite interested to hear your thoughts.

Thanks.... ka

 

[glbeas]

Are you sure of it being spotless? A fungus inside the lens will not be apparent unless you hold it up to a bright light just off axis so the light is not centered but just behind the rim of the barrel. Anything on the elements will stand out.
Other defects might include lens elements in the wrong place from an inept tinkerer.
Another thing to remember is a dichro enlarger is a diffusion type and does not give the snappy appearance of a condensor enlarger. This is not good or bad, just has to be compensated for with the proper selection of paper or negative contrast.

 

[Ka]

Thanks Gary,

I'm getting it now to inspect as per your directions.

You're right, condensors are snappier, but I have used a Nikkor 75mm lens on the same dichro enlarger with Sharp results. So, perhaps my perfect lens isn't quite perfect after all.

 

[Thilo Schmid]

K.L.,
the Rodagon 4/80 is usually tack sharp. However, your lens may may require some trimming for optimum performance. Have you unscrewed the front and/or back element and perhaps lost or left one of those thin trimming rings?

 

[Ka]

Thilo,

Yes, it does have a little thin ring. I didn't know what it was. I thought it was supposed to be used to attach to the lens board. For what am I supposed to use the thing ring?

Meanwhile, my two Schneider Componon-S lenses (and 80mm and a 50mm) arrived today. So I'll keep the 80 I like best and sell the extra.

 

[Ed Sukach]

Yes, it does have a little thin ring. I didn't know what it was. I thought it was supposed to be used to attach to the lens board. For what am I supposed to use the thing ring?

If this is truly THIN - less than, say, 1mm, it is probably necessary for the proper location of the front element. My Rodenstock lenses, both of them, have been used with filters, and occasionally, in removing the screw-in filter, the front element will unscrew. There is, in both - and usually - a very thin shim between the front element and the rest of the lens - essential for the performance of the lens.

I would suggest two possible courses of action - first, unscrew the front element - **GENTLY** - if it doesn't disassemble easily - by hand - FORGET IT!! and go to the second suggestion. Clean (again **GENTLY**) the screw threads, element seats, *shim* and interior - and re-assemble.

OR - second - contact Rodenstock - Most of their lenses come with a lifetime guarantee - in any event, they are fully capable of repair and reconditioning.

I have two Rodenstocks and a Schneider - all are, IMHO, superb!!

 

[David R Munson]

FWIW, looking through a lens towards a window or something won't usually show you the presence or lack of fungus in a lens. Hold the lens upright and shine a flashlight through it from the bottom. If there's fungus, it'll stand right out. Brighter the flashlight the better.

 

[Ka]

Thanks all. I'll have a closere look.

 

[philosomatographer]

I know this is ages out of date, but there is no way a little bit of fungus, or even a scratched element, will contribute to softness. At best (worst) these things, in massive amounts, will cause contrast to drop a bit.

I actually started using a Rodagon 80mm f.4 two days ago, and mine is a very beat-up example - scratched, bit of fungus, the works - but it's still the best lens I've used thus far for enlarging 35mm negatives. I much prefer the extra working distance, and don't do huge prints.

It is visibly superior (resolution, shadow/highlight rendering a.k.a. contrast) to the El-Nikkor 50mm I was using. Soft images must point to focus error, or enlarger head mis-alignment, or (if you didn;t test with nother enlarger lens) a soft negative to begin with.

 

[Sirius Glass]

That is my experience, too.

Steve