Rodenstock Rogonar-S or Nikon EL-Nikkor, which is better?

[hadeer]

A few weeks ago I was given a set of darkroom equipment, including a Kaiser VPM 6005 enlarger with 2 objectives, a Rodenstock Rogonar-S 1:4,5 75 mm and a Rodenstock Rogonar-S 1:2,8 50 mm. Untill now I was using a Meopta Opemus 6 Meograde enlarger with the EL-Nikkors 1:4 75 mm and 1:2,8 50 mm. I am switching from the Meopta (interested, anyone?) to the Kaiser enlarger but wonder whether I should stick with the Nikkors (they fit). I checked the Rogonars with a densitometer and saw that they have less vignetting than the Nikkors, but find it difficult to see any difference in sharpness and contrast as that is much more difficult to measure. I would appreciate it if anyone who has experience with these lenses would give an opinion on this matter. I mainly enlarge 4.5x6 negatives in my darkroom.

[Fred Aspen]

Just a quick answer: The Rogonars are 4 el. designs as is the Nikkor 75mm. The Nikon 2.8/50 is a six element design. I own all of these and I would be hard pressed to distinguish between them at enlargements of 8x10 or less. You will see the difference at 16x20 and the 2.8/50 will be superior when using 35mm film and the 50mm enlarging lenses.

The 6x6 lenses will perform well up to 11x14 and perhaps even 16x20 when using 6x6 film. These 75mm lenses will only cover up to 6x6.

[Ian Grant]

The Rogonar lenses are similar to Schneider Componars in being 4 element Tessar type lenses as is the f4 50mm El-Nikkor, Your 50mm f2.8 El Nikkor is 6 element and a better lens.

The 75mm f4 Nikkor will be similar to the 75mm f4.5 Rogonar-S as both are 4 elements better used stopped down, you'll need to see which you prefer.

Ian

[hadeer]

Thanks Ian, Fred. On the basis of this information I think I will keep the Nikkor 50mm and the 75mm Rogonar-S, as that one has less vignetting than the 75mm Nikkor. Before making a definite choice I will do some more testing however.
Hans

[mdarnton]

The place where the 4-element lenses will burn you is sharpness in the corners. You'll be fine in the center, and as you move out from there, the grain will gradually turn first to mush, then blur, unless you stop down a bit farther than you really should, which will bring in the corners better but start wrecking the middle. The optimum balance will probably be around f11.

I would run tests with both of the longer lenses, at various stops, before I decided which long one to give up; of the 50s, the Nikkor is almost certainly the keeper, unless there's something wrong with it.

[ic-racer]

The place where the 4-element lenses will burn you is sharpness in the corners.

I agree with that and would also point out the place where 4-element lenses will be OK is when making small prints like 4x5". In that case you are only using the center of the image circle and the edges should be OK.

[Dali]

I agree with that and would also point out the place where 4-element lenses will be OK is when making small prints like 4x5". In that case you are only using the center of the image circle and the edges should be OK.

??? Please elaborate. I would be interested to read the rationale.

[mdarnton]

The image circle is more like a cone behind the lens--different size, depending on the distance from the lens. The farther you move the lens from the film, to focus closer, the larger the cone is at the film, and you are only picking out the middle of it, the best part, with the film. The crummy edges are off the edges of what's needed for the image. Not that it matters, because at small magnifications you don't see the problems, anyway.

That's how some legendary early macro lenses could come from the simple Tessar forumla.

[ic-racer]

. Not that it matters, because at small magnifications you don't see the problems, anyway.

Actually, it does matter. I present prints with other folks that show contact printed 4x5in and 6x6cm negatives. They are handed around and viewed at close distance. My 4x6 enlargements need to be top quality and have razor sharp grain to stand up next to the contact prints. I can say that 4 element lenses will provide excellent small prints, even upon close scrutiny of the corners.

Another way to put it, is that a Tessar design (4 element) process lens makes fantastic 1.4X enlargements of 8x10. This would be an 11x14" print. You don't need a magnifying glass to see the corners are sharp. And, likewise that lens is not going to be so good at the corners doing a mural 4feet across.