Enlarging lenses: APO or not?

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.

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

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

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

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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.

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Thanks to all.

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Diego Rigatti (Milan, Italy)

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.

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But then, with today's technology, if you're making large color prints

you're better off going digital.

<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. >

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

comparison.

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This becomes trivia rather than factual.

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Now for some facts.

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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.

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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.

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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

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.

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

Just so we can all be sure Dick.

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You are printing from a good negative in a glass carrier with

aproperly aligned enlarger?

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

performance?

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

onto paper.

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And that is why some can not see the difference.

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:

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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.

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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.

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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.

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4. Based on my tests and experience, for critical color work, my

choice is the APO Rodagon.

>>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.

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And were you in a glass carrier?

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.

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Keep posting.

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enjoy yourselves,

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Fred

>> 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.

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

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There was a 300mm Apo Rodagon Process lens.

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Secondly the Apo Rodagons are optimized for up to 15x magnification

and you are far past that.

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Thir the proper lens for murals from Rodenstock would be the 300 or

360mm Rodagon G.

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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

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.

</I>Let's hope this turns off the italics.

<p>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.

<p>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.

<p>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.

<p>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

Hi all

I just looked at the MTFs on the APO and non APO Rodagon. At f 11 the Rodagon is in many parts better then the APO with f 8.

But Bod states thad you need a class carrier to get all out of your lens. Ties is only the half trus. With a double side glas carier you need thies anti newton class and with thad you will loose some resolution. The best compromise is to use class only on the downside and not a anti newton and then you get all out of your lens!

In my case I work without class but with the Rodagon 150mm on f 11 till I get a carrier without class on the top! And then I`m happy to get sharper prints then with APO and double class!!HaHA

" you need thies anti newton class and with thad you will loose some

resolution. The best compromise is to use class only on the downside and not

a anti newton and then you get all out of your lens!"

Not sure what you mean. newton rings are caused by the base side of the film

contacting glass. The base side is on the side away from the lens. Therefore

the AN pattern is not in contact with the emulsion and is not degrading

resolution. Plain glass is in contact with the emulsion.

Hi Bob

I talked to the sharpness Guru in germany mister Detlef Ludwig about a year ago on the phone! You find his company under :http://www.gigabitfilm.de/html

He developed the Gigabitfilm and he found out if you work with the sharpest films like Gigabit or Techpan you are loosing resolution if you take the film between to glasses and the one on the top is a AN glass. So he recomands only one glass ( of course not a AN) at the bottom so the 4x5 neg can not hanging down in the middle! And he recomands not to stop down to much also! He tested all out to get the sharpest enlargements out of hes Gigabitfilm!

Ask him why he is always very helpfull and he has a big knowledge also about optics etc. For me it make sence!