Why is the hole on lens boards just below center?

[Eric Rose]

GreyWolf and I were pondering this last night. Why is it that on field cameras in particular the lens board is very often drilled with the mounting hole just lower than center. Then when you bring the front lens standard up to the center marks it seems to center the lens with the rear standard.

I've been making my lensboards with the hole in the middle. Have I been committing some grave error?

 

[Donald Miller]

Eric, Thanks for bringing up this observation. I have been doing the same thing (centering the hole). I don't have an answer other then to think that maybe one uses front rise more often then fall, at least that is my experience.

 

[lee]

I think you are correct with this observation. I also don't think you are committing a grave largeformat error.

lee\c

 

[Eric Rose]

Hey I just had a brain wave! Oh that hurt. Anyway the former post about increasing rise gave me an idea. You could actually extend rise or fall by just turning the lens over. So if you need to increase rise you would position the lens so the hole was above center.

Darn now I have to make all new lensboards! Lucky I make them out of very thin plywood used for modelling. That and some flat black spray paint and I'm off to the races.

 

[Prime]

I've read that drilling the hole off-center is actually fairly common. Probably a lot cheaper than buying a new Linhof.

Of course, you could drill the hole off-center, buy the Linhof anyway, then give that new camera to your best friend as a birthday present. Ah, well...just an idea.

Your best friend,

Prime

 

[Robert]

Wait they're supposed to be centred?-))) Not just for rise and fall. You can put the hole anyplace that helps.

 

[Ole]

Linhof lensboard holes are supposed to be off-center. I believe it has something do with the construction of the Technicas, although I could well be wrong.

All Linhof (Technika) original boards I have seen have been off center - both Tech III and IV boards, for 6x9, 4x5" and 5x7".

 

[Poco]

Linhof techs have rise, but no fall. By drilling the boards off-center, the zeroed position gives a bit of fall the camera otherwise wouldn't be capable of.

 

[Joe Lipka]

Well, then I guess you might be able to only rotate the lensboard 90 degrees and get a little extra shift. 8)

 

[Ole]

I used to think it was due to the lack of fall too, but found out I was wrong. There IS a very slight fall possible; and when the lensboard is centered on the mark, the lens is centered on the film.

Since the lensboards are ony almost square, they only fit in one position.

 

[xeric-sw]

Regarding offsetting the hole in the lens board, you should read Kerry Thalman's review of the Toho. The lensboard is round, and there is a special eccentric lensboard with the hole off-center. The lens can be positioned differently by rotating the lensboard, thus helping to move coverage one way or the other.

See http://www.thalmann.com/largeformat/toho.htm

 

[David A. Goldfarb]

It's only on Linhof Technikas and cameras that use their lensboards that the board is off center in the neutral position. I think it's just a function of how they have been constructed, historically or perhaps to make more room for the lensboard clamp on top or for the wire-frame finder that sits on the front standard on the older Technikas.

My pre-war Linhof Tech II actually does have significant front fall (but not as much as it has front rise), but not front forward tilt. If you want front fall on a newer Technika, I guess you would drop the bed, tilt the lensboard back to level, and then adjust up from there or turn the camera upside down and rotate the back.

 

[fhovie]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Prime @ Mar 16 2003, 12:39 PM)</td></tr><tr><td id='QUOTE'> I've read that drilling the hole off-center is actually fairly common. Probably a lot cheaper than buying a new Linhof.

Of course, you could drill the hole off-center, buy the Linhof anyway, then give that new camera to your best friend as a birthday present. Ah, well...just an idea.

Your best friend,

Prime </td></tr></table><span class='postcolor'>
Now I am really laughing! I really did do this - except it was an old Burke & James give away for a light weight Tachihara purchase. - Of course the Crown Graphix and the Speed Graphix had only rise - Good, I guess for buildings, but not good for landscapes. The Super Graphic had both rise and fall. I still have thoughts of getting a Super Graphix - nice camera - My medium format gear seems to make it a mute point and the only thing I would use it for is 4x5 hand held and I am not sold completely on that - hand held medium format is bad enough.