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Diego Rigatti
29-Jun-1999, 04:51
I am going to buy a 150 mm. enlarging lens, mainly for B&W printing. I will choose between Rodenstock Rodagon, the normal one and the APO version.

On the better performance of the APO I read and heard opposite opinions. The M TF graphs show that the non APO has more regular performance (the lines are stri ght), with also a better resolution for the 40 l/mm line (the one supposed to gi ve a microcontrast index).

Does anybody make real direct comparaison between these APO and non APO lenses?

Which one is the best? From what enlarging ratio on?

I am not talking about a better reolution under a 6X loupe over a 20"x24" print, but a visible (even if slight) difference of this print hang on the wall.

Thanks to all.

Diego Rigatti (Milan, Italy)

Darron Spohn
30-Jun-1999, 11:40
Although I haven't made a direct side-by-side comparison, I have used many lenses over the years. My conclusion? The APO lenses are worth the extra money only if you're making 16x20 or larger color prints. Even then, the differences are extremely subtle if you stop down to a middle aperture as you should. The slight difference will be visible only at close viewing distances, and only if your enlarger is aligned properly.

But then, with today's technology, if you're making large color prints you're better off going digital.

Bob Salomon
30-Jun-1999, 19:20
<Although I haven't made a direct side-by-side comparison, I have used many lenses over the years. My conclusion? The APO lenses are worth the extra money only if you're making 16x20 or larger color prints. Even then, the differences are extremely subtle if you stop down to a middle aperture as you should. The slight difference will be visible only at close viewing distances, and only if your enlarger is aligned properly. >

In other words you have formed a conclusion by not making a direct comparison.

This becomes trivia rather than factual.

Now for some facts.

Apo enlarging lenses, at least the Apo Rodagon N series from Rodenstock perform as well for black and white as for color. The advantages of the Apo are better contrast and resolution, larger range of magnification, larger range of working apertures, the elimination of color fringing which makes fine lines reproduce thinner than with a non apo.

If you want to actually form an opinion you should take an excellent negative with fine sharp detail over the entire negative area. Put it in a glass carrier in a properly aligned enlarger and make prints with apo and non apo lenses at sizes within the optimization range of the lenses.

You will find that the Apo will be sharper from edge to edge, has better contrast, has more choices of optimal apertures, hits optimal aperture at least 1 stop sooner and the differences are as important and visible for B&W as

Richard Fish
30-Jun-1999, 21:54
I have great respect for Bob, and his information is always useful. However, I have never [o.k. so I do wear glasses!] been able to actually SEE the difference between APO and non-APO enlarging lens results. I admit that I've only been a working photographer for 40 years, so there probably are folks with lots more experience. I have friends who do custom printing for museums and who SWEAR APO's are better. It's just that I can't see it; maybe you can.

pat j. krentz
1-Jul-1999, 04:33
I agree with Dick, if you cannot see the difference with your eyes, what difference does it make it it is detected by a machine? Save your money for paper and film, some of the highest selling prints in the world have been made with regular lenses, before APO was ever dreamed of. Pat

Bob Salomon
1-Jul-1999, 06:38
Just so we can all be sure Dick.

You are printing from a good negative in a glass carrier with aproperly aligned enlarger?

Or did you eliminate one or more of these requirements to optimal performance?

If so you will never see what any lens is truly capable of putting onto paper.

And that is why some can not see the difference.

steve_530
1-Jul-1999, 11:13
I own APO Rodagon lenses, Schneider Componon lenses, and El Nikkor lenses and have done direct comparisons between the lenses with the same transparency printed on Ilfochrome material. I have also compared the three lenses on black and white material with the same negative and my results show the following:

1. On black and white material you cannot see the difference in sharpness when the lenses are used at the same f/stop. All tests were done at f/8.

2. The APO lens is flatter field and can be run wide open successfully while the Componon and Nikon lens have to be stopped down at least 1/2 stop from wide open to get sharpness in the center and at the corners. Enlarger alignment and lens alignment were checked when each lens was mounted prior to making the print.

3. The APO lens is FAR better for color work. The matched prints have better contrast, and a GREAT deal more detail separation in red areas. When comparing three matched prints, the red areas show more shades of red with the APO lens.

4. Based on my tests and experience, for critical color work, my choice is the APO Rodagon.

Bob Salomon
1-Jul-1999, 19:27
>>I own APO Rodagon lenses, Schneider Componon lenses, and El Nikkor lenses and have done direct comparisons between the lenses with the same transparency printed on Ilfochrome material. I have also compared the three lenses on black and white material with the same negative and my results show the following: 1. On black and white material you cannot see the difference in sharpness when the lenses are used at the same f/stop. All tests were done at f/8. 2. The APO lens is flatter field and can be run wide open successfully while the Componon and Nikon lens have to be stopped down at least 1/2 stop from wide open to get sharpness in the center and at the corners. Enlarger alignment and lens alignment were checked when each lens was mounted prior to making the print.

And were you in a glass carrier?

fred deaton
1-Jul-1999, 21:38
I have been printing commercially for bout 25 years and have used all of the lenses available at one time or another. I find this topic extremely interesting because I am not convinced that optically we can see the difference in the Rodagon, the APO Rodagon, the Schneider, or the Nikkor in smaller prints. I am accustomed to printing REALLY large and for a long time considered anything 30 inches by 40 inches to be small. The last large prints I did (12 feet x 20 feet) were done on a Durst 2501 horizontal enlarger (naturally in glass) with APO Rodagon 300mm and it was razor sharp edge to edge, but I'm not convinced that in sizes smaller than 30" by 40" any of us can see the difference. Anyway, this is interesting and I hope the thread continues for a while--Are any of you large format people getting into digital. That is all I am doing now.

Keep posting.

enjoy yourselves,

Fred

Bob Salomon
2-Jul-1999, 06:39
>> I have been printing commercially for bout 25 years and have used all of the lenses available at one time or another. I find this topic extremely interesting because I am not convinced that optically we can see the difference in the Rodagon, the APO Rodagon, the Schneider, or the Nikkor in smaller prints. I am accustomed to printing REALLY large and for a long time considered anything 30 inches by 40 inches to be small. The last large prints I did (12 feet x 20 feet) were done on a Durst 2501 horizontal enlarger (naturally in glass) with APO Rodagon 300mm and it was razor sharp edge to edge, but I'm not convinced that in sizes smaller than 30" by 40" any of us can see the difference. Anyway, this is interesting and I hope the thread continues for a while--Are any of you large format people getting into digital. That is all I am doing now.

First there simply is no Apo Rodagon 300mm enlarging lens.

There was a 300mm Apo Rodagon Process lens.

Secondly the Apo Rodagons are optimized for up to 15x magnification and you are far past that.

Thir the proper lens for murals from Rodenstock would be the 300 or 360mm Rodagon G.

Now why not try the lens designed for speciffically what you are doing and then see what the difference is. We have talked to innummerable custom labs who print on very long vertical or on rail mounted horizontal Durst 810 enlargers who do murals and they csn see a difference. So can th

Peter Olsson
2-Jul-1999, 06:42
The effect of a non-apo lens with color-fringing is easy to see even for small enlargments. For instance, when I make enlargements from 6x6 as small as 20x20 cm (8x8 inch.) and the image includes branches against a clear sky, the non-apo lens gives very noticable color- fringing. Actually, even the non-critical cannot find this acceptable. If an APO-lens delivers what Bob says in this respect, it would be the ONLY alternative for someone who can afford it.

Darron Spohn
2-Jul-1999, 11:21
</I>Let's hope this turns off the italics.

Fred, yes, some of us large format types are getting into digital. I just bought a new PowerMac G3/450, installed 512MB RAM, got a color calibrator, and plan to scan some slides and black-and-white negatives on a Tango drum scanner soon. One of my friends does this for a living, and the prints he produces out of a LightJet 5000 printer are amazing.

We can discuss APO versus non-APO all day (and I'll defer to Bob's expertise on the merits of the lenses) but very few people can afford a darkroom good enough to match the quality digital has attained. I know this is going to generate a lot of heat from people who haven't tried digital, and some people are going to argue that the digital output is only as good as the person perparing the image in PhotoShop. That is true. But printing large color images (especially from slides) is extremely difficult. Digital ensures consistent results, and eliminates variables such as enlarger alignment.

Maybe we should start a different thread on this topic, as I have had several offline discussions around this in the last few months. I'm eager to learn from people who are practicing digital printing, and willing to share what knowledge I have as my skills grow.

The most difficult part of going digital is learning PhotoShop, or GIMP if you're a UNIX type. The key is getting a color calibrator and setting up your ICC or ColorSynch profiles so your monitor matches your prints. The good news is you can get an excellent color calibrator for $400 these day