Dealing with falloff on beseler 810

[Jrewt]

It's been awhile since I posted in here, but I've been lurking I promise!

So I've had a Beseler 810 MXT for a long time now, but just recently got funds to start actually using the thing. I've got an older schneider 240mm enlarging lens which is silver. The light falloff from center to corner is amazingly bad! I don't know anything about enlarging since I have been a contact printer since I started shooting at 16.. So, I did a lot of searching, but could only find people complaining about the falloff and no real fixes/work arounds. I would eventually like to be able to enlarge to 20x24, but I've got roughly 200 sheets of 16x20 to play with- and I don't want to WASTE paper burning in edges and screwin' it up half the time.. I know many of you have experience with this enlarger, so I am begging you for possible solutions or workarounds.. I don't know anything about enlarging lenses, but I suspect that maybe a 300mm lens would allow me to enlarge to 16x20 without so much falloff. There is a eskofot- ultragon 305mm on KEH that seems reasonably priced, anyone know anything about these?

Sorry about the ramble!

Cheers

[Brian Ellis]

I've never used an 8x10 enlarger but with 4x5 135mm is the usual minimum and 150mm is better (IMHO). So I would assume that all other things being equal, 8x10 would require 270 at a minimum and 300mm better.

[resummerfield]

......I suspect that maybe a 300mm lens would allow me to enlarge to 16x20 without so much falloff.......I think you're right. I've enlarged 8x10 with El Nikkor 240mm and 300mm lenses, and the 300mm has less falloff in the corners. I'm not familiar with an eskofot-ultragon 305mm--is it a process lens, and what is its angle of coverage compared to a true enlarging lens like the El Nikkor line?

[ic-racer]

Is this a 'table-top' enlarger? If so, perhaps someone can chime in as to if you can actually do a 16x20 with a 300mm lens on the 810MTX. There is a reason other 8x10 enlargers are such monsters. I checked mine and with a 300mm lens, making a 16x20 enlargement requires roughly 17" of bellows extension and I measured 50" from the negative plane to the paper plane.

[Jrewt]

arg, yes it is a tabletop, which is why I bought it... I see no reason to keep it around if I can't enlarge to 16x20 with a 300mm lens :( Kind of a bummer, but I can't really afford all that big paper anyways! I might be able to wall mount it when I move in November.. If anyone is using a 300mm with it, I would love to hear your experiences.

Cheers

[Turner Reich]

There is a eskofot- ultragon 305mm on KEH

KEH, NO, don't get it.

Get a 300mm enlarging lens from someone or eBay, but not KEH they rate by cosmetics and not condition.

[ic-racer]

arg, yes it is a tabletop, which is why I bought it... I see no reason to keep it around if I can't enlarge to 16x20 with a 300mm lens :( Kind of a bummer, but I can't really afford all that big paper anyways! I might be able to wall mount it when I move in November.. If anyone is using a 300mm with it, I would love to hear your experiences.

Cheers

I'm no expert on that enlarger and it is a 'compromise enlarger.' However, many people have good results with that setup in table-top mode. I think the key to success with that 810 MXT setup is to get a 240mm lens with a larger image circle than that one you have now. If you are really concerned about the light fallof, the Rodagon 240mm has been mentioned by Bob Salomon in this thread as having minimal falloff: http://photo.net/large-format-photography-forum/003Dn1 However, it may be a challenge to mount that lens on the Beseler: http://photo.net/large-format-photography-forum/003zKe

BTW the 300mm Rodagon lens also has a 72mm mount, so fitting it to your enlarger may not be any easier than the Rodagon 240mm.

Also, realize there is no perfect world. You always are going to get some light falloff at the edges, especially with a wide angle enlarging lens. As a comparison, when I do a 16x20 from 35mm I'm using an expensive 45mm APO Schneider. It has a significant light falloff at the edges. You just have to realize these things and work around it (ie burn the edges :) ). If this was easy everyone would be a 'master printer.' :)

http://www.schneideroptics.com/pdfs/photo/datasheets/apo-componon/apo-componon_40_45_1.pdf

[Gary Beasley]

The ideal solution would be a center grad filter like used on ultra wides on an LF camera. If you felt crazy you might try using lith film in a holder under the lens (no neg!) with a short exposure and developed just enough in dektol to level out the illumination. This would need to be kept clean and unscratched to be worth using but if good notes were taken replacements would be easy to make.

[George Stewart]

When I did my 8x10 enlarging work (now digital), I started with a 240. Then I acquired a 300mm and noticed an immediate improvement in fall-off. I think the shorter focal lengths are for setups with minimal projection distance, meaning a short column or not enough ceiling height. There is nothing wrong with a 240mm lens if one realizes that corner work will be required. Before one purchases a 300mm lens, ensure that the lensboard will hold it, and that there is enough room to focus the enlarger at the print sizes that will be required.

[Sal Santamaura]

Two suggestions:
Shoot 6-1/2 x 8-1/2 negatives. Eliminate the falloff completely. :)
Have S.K. Grimes mount whatever lens you'd like on the enlarger.

http://www.skgrimes.com/thisweek/9-12-05/index.htm

[CG]

The geometry of enlarging with such a short lens is such that you will see the worst fall off with the lens at it's minimum extension and with big enlargements from the whole neg. If you were using an 11x14 or bigger enlarger, the light source would probably be big enough to accomodate a wide lens. Essentially your lens is looking through the negative from very close by, and at a wide angle of view, and is seeing the dark areas outside of the source of illumination.

Just to make things worse, wide lenses themselves are generally more to falloff. So the odds are you have taken on the most challanging set of obstacles.

The good news - and there is a little - is that when you do a smaller enlargement, you move the lens further from the negative, and have effectively narrowed the angle of view the lens is actually using. Lets say you do a same size image: you will be extending your 240mm lens to something like 480mm, and should find the falloff utterly gone.

Great enlargements are happiest with longish lenses, and smallish enlargements work quite well with shorter lenses.

C

[Jrewt]

Thanks for all the info guys, it will definitely help me out! It seems to me that the design of this thing is pretty flawed. Should be pretty fun and frustrating working with it heh, wish me luck..

Cheers, and thanks again.

[Dave Brown]

First, don't be afraid to buy from KEH. In my considerable experience dealing both with KEH and ebay, KEH is always your better bet. I've bought at least half a dozen items from KEH that were rated "BGN" and every one of them was better than anything I've ever gotten from ebay, including things rated by sellers as "ex++" or "LN". I'm sure others have had the occasional bad experience, but I'm also reasonably certain KEH will let you return an item that is mis-graded.

Second, the previously stated idea of making a mask from lith film is an excellent one; you should try it.

Finally, if you haven't already, you might try stopping your lens down further. While your lens may not be at its sharpest at say, f 32 vs. f 8, you're only talking about enlarging 2X (from 8x10 to 16x20), so a little loss of sharpness shouldn't be an issue.