So don’t use the turret or get a custom Lapla made
So don’t use the turret or get a custom Lapla made
If I simply must use a lens that short for 8X10, its my 240/9 Apo Nikkor - a superb yet compact process lens which easily fits into a Durst turret ring if you have a 72mm adapter. Mine was made by Jim Galvin when he was still alive; but there are numerous other potential sources, including Glennview. If you need a wider f/5.6 maximum aperture, go with the Rodagon like like Bob advised.
Thank you, Drew.
Hello Neil, My photo use is only for potential clients, or students to refer when they have not yet, or are not able to be in my studio, relating to my figurative traditional sculpture work. I'm just getting back into large format photography after a number of decades - so my - with I guess some learned competence... yet. So perhaps the - I'm curious . . . to what kind of hands-on experience are you referring? is appropriate...
I did look into it some more like we discussed. Aristo Archive Lamps does offer a deluxe dual-tube (blue and green) VCL4500 model that is 8x8 inches and of shallow height, along with full controller and adapter options. You'd have to contact them about price and availability. If you prefer an LED equivalent, Heiland can make you something specific for your Omega for around $1500, depending on exchange rates at the time.
If projected image quality is a must, the APO process lenses ( APO artar, APO nikkor, APO ronar and similar) would be first choice. These APO process lenses are often best at f16 to f32 demanding significant light output from the projection light source. Much agreement with Drew on using a focal length no less than 240mm for 8x10 (240mm f9 APO artar is preferred for 5x7 _ 13x18cm projection printing). If projection light source output is a problem, the Rodagon, Componon S and similar f5.6 full aperture "enlarging" lens will typically be best at f11 to f16 reducing the demands on light source output.
On the Durst 138/184 use the three lens turret for smaller lenses as needed and will fit the lens ring with a taper. For big lenses, forgo the three lens turret and mount the lens on the large round lens board. These are held in place with a single tapered locking screw and two tapered stops in the rear making lens changes not that much more difficult than rolling the three lens turret. Direct mount allows using a recessed lens board for shorter than 100mm lenses which can be a problem projecting smaller roll films using the three lens turret (yes, recesses lens boards can and do fit the three lens turret, but completely negating any advantage of a rotating lens turret)
Given the requirement for high power light source output as the projection light source combined with the requirement for less than small distances precision, accuracy, repeatability, reliability these are a few facts and realities of why a GOOD floor standing enlarger is an absolute must and why table top enlargers for sheet film often produces frustrations and problems.
Bernice
Bernice, on my 184 with colorhead and 12X12 mirror box, I get fully even illumination and almost perfect edge to edge performance for 8x10 with the 240/9 Apo N. stopped down to f/16, in other words, one stop smaller than for a 305 or 360 Apo Nikkor - those can be used with total confidence at f/11. Note that's right where most conventional enlarging lenses come into their own too, right around f/11, so there is no loss in effective printing speed at all, but just less focus and composition brightness when wide open. But most of my light sources are so powerful that I often stop way further down when making b&w prints (no issue with the modest amounts of magnification involved when working with 8x10 format - diffraction loss won't even show in the print). Or else I resort to neutral density tricks. Rules would obviously change a little if the diffusion or mirror box itself were less efficient.
Ordinarily, I make black and white prints from 8x10 film on a cold light enlarger instead, and reserve my other 8x10 enlargers for color printing. My tallest one will easily accommodate a 360 focal length for making 30X40's from 8x10 film. I have all kinds of enlarging lenses on hand, and sometimes simply don't want the extreme sharpness or higher contrast of the apo versions.
Yes indeediee Drew,
On the Durst 138, typical printing aperture is f16 on the APO artar. This is using the Durst 138 condenser head with a set of 240 condensers in the drawer with a converted 300 watt halogen light source in the back of the 138 condenser head. Once the set up is properly adjusted, the illumination using a 240mm lens ( 9-1/2" APO artar for 5x7, 180mm APO nikkor for 4x5) is excellent with plenty of light output. The filter drawer places B&W paper contrast filters in the light path instead of the image path.
After using a number of cold light sources, prefer the look and printing capability of the Durst condenser head.
Bernice
My 138's are so tricked out I can't make the identical comparison. The previous condenser head is still on a storage loft. I sold all the mint condensers to the late usual suspect Durst dealer (he never did pay me). My 138 mirror boxes have a number of tweaks to match evenness of field to specific lenses and format sizes : lenticular array diffusers, ground plexi diffusers, even a tailored scrim in one instance. That's might be overkill for basic b&w printing, where simple burning in works. But when needing to generate precisely matched masks, separation negs, dupes, etc, particularly in color work, this degree of refinement is important; so I'm glad I factored all that in advance. The bigger 184 setup has such a surplus of area in its mirror box that I really didn't need to tweak it at all.
The dichroic reflector for the CLS1000 is, I believe the same as the one for the CLS1840/CLS2000. You may cause a fire if you use the lamp without the reflector, though, since the principle of the reflector is to let the heat go up and out, and only direct the visible light downward, maybe it will be OK if your fan works. Though the projected image may be dim or un-evenly illuminated.
Reflectors are out there, need some clever internet and ebay searching and WTB ads to bring them to the surface. Reflectors were once sold by "the late usual suspect Durst dealer" of which Drew writes. The reflectors were also re-manufactured in Russia.
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