Enlarge lens 150 vs 135

[Two23]

I tried a 135mm for 4x5 on a Beseler 45MX and got the frame corners cut off. A 150mm worked perfectly. Keep in mind I'm a beginner though.


Kent in SD

[monochromeFan]

The lens isnt bad, its not a light up window version. But hey, its still got 14 aperture blades.

[Mal Paso]

The lens isnt bad, its not a light up window version. But hey, its still got 14 aperture blades.

That's better than the Componon S with 5 blades and a Star aperture. Nikon has 12. I think I had the 150mm El Nikkor not the Componon, the barrel is very familiar.

[Mark J]

Well, you're not looking for bokeh on an enlarging lens.

There must be some reason Schneider did this, and I'm not sure why. it's not a cheap diaphragm either, it's dual-layer.

[maltfalc]

Well, you're not looking for bokeh on an enlarging lens.

There must be some reason Schneider did this, and I'm not sure why. it's not a cheap diaphragm either, it's dual-layer.

something to do with breaking up the diffraction rings that form around fine details at small apertures.

[ic-racer]

That's better than the Componon S with 5 blades and a Star aperture. Nikon has 12. I think I had the 150mm El Nikkor not the Componon, the barrel is very familiar.

How or why?

[Mark J]

something to do with breaking up the diffraction rings that form around fine details at small apertures.

It will do that, but the pattern will be modified, with some 10-fold symmetry, and a little more energy in the rings. However the effect on MTF ( ie. for most continuous subjects) is likely to be very small, probably only in the 1 to 2% level ( having looked into to things like this before ). So it still doesn't make much sense to me. However it's a fine lens (/series).

[Doremus Scudder]

I own both. An older El-Nikkor 150mm and a rather newer 135mm. Both deliver superb results. I use the 150 mostly, but switch without hesitation to the 135mm when I need to make a substantial crop from a negative and want a 16x20 print. Keeps the enlarger head height more manageable.

Best,

Doremus

[Drew Wiley]

Some of these enlarging lenses probably utilized apertures already developed for sake of graphics lens application where different aperture styles were significant. I've encountered specific reasons for each in the relevant older literature, but don't want to hunt that down again. Even adjustable square apertures existed and had a real purpose.

Typically, enlarging doesn't involve small apertures; and graphics usage often standardizes at f/22. But enlarging lenses are basically direct cousins of graphics process lenses, based on formulas adaptable for other applications as well. Lens designs get repurposed as needed. For example, Componons sold as enlarging lenses got repurposed as close-range tabletop studio lenses when equipped with shutters.

[Mark J]

I'm wondering if it's that a more 'pointed' aperture shape makes the transition between being in focus and slightly out of focus more obvious - ie. it snaps into focus a little more clearly ?

ps. I just received a late model Schneider 100 from the US today, I hope to compare this to my El-Nikkor N 105.