Lens length for enlarging 5x7 negs

[timbo10ca]

An enlarger I'm looking at for 5x7 comes with a 150 lens- is this long enough, or would I need to find a 210mm?

Thanks,
Tim

[Walter Calahan]

The ideal enlarger lens length is the measured diagonal of the film format.

The largest format I've ever printed is 4x5, and for it I have used both a 135 mm and a 150 mm lens. I only scanned 5x7 and 8x10 film, so probably I'd guess 180 mm for 5x7.

[Filmnut]

I've usually used a 210mm when printing from 5X7's, the 180mm I tried was a bit too tight for coverage at higher magnifications.
Keep in mind that size as or slight (X2) enlargements a shorter than standard lens will likely work fine.
If you need a 210, I might have an extra.
Keith

[Michael Graves]

I have both the 150 and 180 Rodagons. The 150 covers the negative okay, but when I print with that lens, every image needs corners burned. The 180 doesn't show that. But the 150 is marvelous for 4x5. With Rodenstock, I'd go with the 180 for 5x7. However, I started with a 180 Componon, and it didn't cover as well at all. It fell off worse than the 150 Rodagon. You would need something a bit longer if you go with Schneider.

[ic-racer]

An enlarger I'm looking at for 5x7 comes with a 150 lens- is this long enough, or would I need to find a 210mm?

Thanks,
Tim

I don't think either Schneider or Rodensock made a wide angle 150mm that would cover. You will probably need a new lens. As pointed out Rodenstock does make a 180 that covers, in addition to the 210.

[timbo10ca]

Thanks everybody- I believe the lens is a Rodagon 150. It's a Rodenstock for sure. Keith- I may take you up on that 210. I'll contact you.

Tim

[Turner Reich]

I use a 240 Rodagon lens for 5x7.

[Don Dudenbostel]

I've used a 240 G Claron and now use a 180 Componon S. Coverage with the Componon S is excellent. The particular enlarger might make a difference particularly if it's a condenser system. I print on a Drust 5x7 Laborator and have the proper condenser set which makes a big difference. Diffusion enlargers would not be as critical.

[Stephen Willard]

Be carefull when buying enlarger lenses. It is my belief that the enlarger lens is where most image degredation occurs in the process going from the orginal scene to the final print. Do not make compromises here. You want the best enlarger lens that you can afford.

All enlarger lenses are sharp in the middle including the cheap ones. What makes a good enlarger lens is edge sharpness. I had a 240mm Rodenstock that made very sharp prints from my 5x7 negatives until I started printing 16x40 and 20x50 panoramic images from my 4x10 negative. That is when I started to really noticed how unsharp the lens was at the edges. It was unacceptable.

I then odered over $4000 worth of enlarger lenses of various focal lengths and brands. I tested them all for edges sharpness. The lens that won was the EL-Nikkor 210mm lens. The difference between the Nikkor lens and the others was unbelievable. However, it was still soft at the edges, but much better then the rest of them. I returned the other lenses and kept the Nikkor 210mm lens.

Unfortunately, Nikkor does not make enlarger lenes any more and a buying used one means making arrangements for testing edge sharpness before final acceptance.

[CG]

Watch out when using a short lens for enlarging. You have a much greater likelihood of vignetting when the lens is short. By short I mean shorter than the normal for a given format. Normal being 50mm on 35mm, 80mm on 2 1/4 square, 150mm on 4x5, 210mm on 5x7, 300mm on 8x10 etc...

Shorter lenses "look back" into the enlarger at a wide angle as well as projecting a wider "beam" towards the paper. The wider view into the neg and light source demands the enlarger have a very large / wide light source to get coverage. The cone of light has to start very wide to accommodate a short lens.

Conservative practice is to use a normal or longer lens. Longer can make for more even illumination. I remember someone - AA perhaps? - writing about using a 480 on 8x10 with a horizontal enlarger.

C