For the argument, all lenses on an Omega D2.
If the 135mm focal length is the normal standard for the 4x5 and the 150mm is the normal "long end" for the 4x5 format.. And with botch of them able to cover 16x20, and even i believe 24x20 enalrgements on the baseboard Is there any actual benefit to a particular focal length
Probably not.
Some may argue that a longer focal length may be better, because you use less of the far corners of the lens and more of the central sweet spot. This should be more noticeble at bigger enlargements, when the imagine circle of the lens becomes more critical. At the other hand, longer lenses will need more collum height and thus be more sensitive to vibrations. The shorter lenses will let you make bigger enlargements by a given collum height, without resorting to measures as wall projection or reversing the enlarger and making ground projections. Personally i am very happy with my 135mm Rodagon, tho i have to admit that i never did a direct comparison with a 150mm lens.
Schneider 150 has less light fall off than the 135 based on their literature. (red = 150; green = 135)
Also, because of the narrower angle of view, the 150 is less likely to show the edges of the mixing box. I have both 150 and 135 Componon-S on different enlargers and essentially treat them both the same--interchangeable.
so would i simply use the standard omega 2.75" enlarger cone for mounting the 150?Originally Posted by ic-racer
Schneider 150 has less light fall off than the 135 based on their literature. (red = 150; green = 135)
Also, because of the narrower angle of view, the 150 is less likely to show the edges of the mixing box. I have both 150 and 135 Componon-S on different enlargers and essentially treat them both the same--interchangeable.
I don't know about that 2,75" cone, but this is how I (had to-) deal with it as the right cones are very hard to find over here:
the 150mm
the 105mm
the 80mm
I've had great luck in using a 135mm Rodagon for 4x5 on three separate enlargers: a Beseler 45 MX, an Omega D2-V, and a Zone VI series 2. For the largest possible (30x40) print size from a vertical enlarger setup, I'll go with the 120mm Rodagon W.A. But this is with a Zone VI enlarger...whose light source is quite "oversized" for the 4x5 format.
The potential issue with using wider angle (shorter FL) enlarging lenses can occur if the light source area is "marginal" (under or close to under-sized) to begin with, as such a lens, when focussed, is relatively closer to the negative plane than would be a longer focal length lens, and the light rays nearer to the edges of the image will, therefore, need to travel in more oblique paths through a wider angled optic, which is fine so long as the outer dimensions of the light source are large enough to accommodate this.
While I've switched over to my Zone VI enlarger almost entirely for all negative sizes from medium format upwards (to 5x7), I'd never had any issues with the 135mm lens on my Beseler or Omega 4x5 enlargers...but would hesitate to use the 120mm W.A. on either of these 4x5 enlargers, for the reason stated above.
they're not. 150mm or 6" is the normal lens for 4x5, 135mm is a slight wide-angle.
Whenever practical, I prefer a longer than "normal" focal length rather than shorter. I have did own a 135 Rodagon for use on an old Chromega D2, and it did a decent job, but prefer the 180 Rodagon for 4x5 format - distinctly more even illumination than 135, or even 150. My 150 is an Apo Rodagon N instead, which I use more often for 6x9 film than 4x5, for the same reason - perfectly even illumination of field relative to film format. But I now have a nice and tall Durst 138 series enlarger instead of an Omega. But even when my Omega colorhead was still in good working order, I reversed the enlarger atop a 2-step cabinet for sake of more projection distance, allowing me to make 20X24 prints using the 180 Rodagon (with an extended lens cone).
I used a 150mm Componon for many years and switched to the 135mm El Nikkor for the new darkroom. On the Beseler MCRX the 150 will get the easel further forward on the baseboard and the 135, a larger image further back. Most of the big 3 lens makers corrected the 150s for closer working distances and the 135s for bigger enlargements. I don't have much literature from Fujinon.
The Schneider Componon-S 135 and 150 both perform better at 3X >6x>12x. The MTF curves are very similar except at the far edge of the 135.
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