Beseler 810 MXT enlargergreenspun.com : LUSENET : Large format photography : One Thread
Greetings to all,
A recent discussion has raised the question of enlarging 8x10 negs, and it seems to me that the Beseler 810 conversion kit for the 45MXT is an attractive option. But I have a couple of fundamental questions that I think deserve a thread of their own.
Earlier discussions made the point that the use of the 240mm enlarging lens recommended by Beseler resulted in falloff from center to corners of a stop or more. As I understand the optics of the situation, use of a longer lens would help with this problem, but a greater lens to paper distance would be required. So, let's say I'm using a 300mm lens, enlarging an 8x10 neg to 20x24". What vertical clearance is required? To 30x40"? (And while we're at it, if someone could give me the formula for calculating the distance for a given focal length, that would be appreciated if you just remember that I'm about 35 years removed form high school math and need to go slowly).
Will the Beseler conversion kit coldlight produce enough light for prints as big as my examples?
Any other comments from users of the Beseler MXT 810 conversion kit not already covered in the archives would be appreciated.
All the best, Nick.
-- Nick Jones (email@example.com), December 11, 2001
Nick: A couple comments which sort of halfway answer some of your issues. (Well, nobody else has responded...) I have the Beseler conversion kit on the 45V-XL enlarger, and it works very well. At least with that set up I have used the Beseler branded (Rodenstock) enlarging lens (240 mm) without light fall off issues. I have also found that the enormous Nikkor 210 lens will cover an 8X10 and be sharp out to the corners. When you use it, you don't have to crank the upper stage up so far. (The only problem I have had with the V- XL is that the top stage droops toward the front when cranked up all the way with the big head on it. This is easily solved with a little prop on the front and a level at the beginning of the printing session. You shouldn't have to do this with a piece of equipment this expense, of course, but it has always been like this and I never bothered to figure out exactly why.) After I converted the tube in the head to the Aristo V54 tube, I found printing times acceptable in the print ranges you are talking about.
-- Kevin Crisp (KRCrisp@aol.com), December 11, 2001.
The 240mm lens sold by Beseler is an Apo Geragon process lens it really does not compare in performance to the 5.6 Rodagon 240mm which fully covers 8x10" and is rated for 2 to 8X magnification.
This lens has a 72mm mounting thread as opposed to the 50mm thread on the Apo Geragon. Also the process lenses work optimally at f22 if they are shorter then 600mm which is an uncomfortable aperture for printing.
The Rodagon hits optimal aperture much sooner and is considerably brighter for focusing as well as having the illuminated aperture scale.
-- Bob Salomon (firstname.lastname@example.org), December 11, 2001.
I've been looking for a good used 8X10 enlarger. Have you looked at the Zone 6 model?
-- tim kimbler (email@example.com), December 19, 2001.