off-center lens

[Ootsk]

Hi all...new to LF photography. I have an Omega 45E. Just bought a petzval lens, and am awaiting a copal3 shutter to hopefully mate them up.
I plan to do collodion, but also film.
I have a new lensboard on the way, that I plan on drilling out for the copal 3.
I'm planning on doing mostly portraits.
As I understand it, the petzval has a "sweet spot" of roughly 30 degrees in the center, where things are sharp.
My question is, would it benefit me to slightly offset the lens-board hole to place that sweet spot closer to where the face of my subject would be?
I could rotate the front lensboard if I were doing portrait or landscape, when necessary.
Just curious...and thanks for any help.

[Louis Pacilla]

No. You do not need to off set the hole in the lens board. Just place it in the center.

[Jim Galli]

You're overthinking this perhaps. The Omega has tons of front standard movements. No need to fiddle with placement on the board. Also you DO Not have a 30 degree sweet spot. You have a 30 degree cone of light forming your image with perhaps 3 - 5 degree sweet spot. That's why you bought a petzval.

[StoneNYC]

Bringing up a semi-old thread.

My question is, what IS the purpose of an offset lens board? I've seen it a lot on eBay type sites and even here people selling offset boards, what's the purpose?

(I'm relatively new to LF, about 4 months now, so still learning) .

[Vaughn]

One possibility: Some cameras have more fall than rise, or the other way around (I forget) -- so offsetting the hole places the lens in the middle of the range of the rise/fall movements.

[StoneNYC]

One possibility: Some cameras have more fall than rise, or the other way around (I forget) -- so offsetting the hole places the lens in the middle of the range of the rise/fall movements.

Sound good enough, unless someone else has more info, I'll take this as the reason.

[Leigh]

My question is, what IS the purpose of an offset lens board?

The most commonly-encountered offset boards (in my experience) are for the Linhof Technika camera.

The Technika was apparently designed from the outset to accept recessed lensboards, so short FL lenses could be used.

Recessed boards require that the hole be offset from the centerline of the recess to accommodate controls on top of the shutter.

Once that lens axis location is defined for the camera, it determines the geometry of the front standard.
All lensboards for that camera must have that offset, even when it's not required by other factors.

- Leigh

[StoneNYC]

The most commonly-encountered offset boards (in my experience) are for the Linhof Technika camera.

The Technika was apparently designed from the outset to accept recessed lensboards, so short FL lenses could be used.

Recessed boards require that the hole be offset from the centerline of the recess to accommodate controls on top of the shutter.

Once that lens axis location is defined for the camera, it determines the geometry of the front standard.
All lensboards for that camera must have that offset, even when it's not required by other factors.

- Leigh

Weird, I have two linhof technica lensboards, one is recessed, (I own a toyo but have the adapter) and neither of them are off center... Hmmm however the recessed board has a special arm built in that extends the shutter release to outside the recessed area.

Still that makes more sense...

[Bob Salomon]

Bringing up a semi-old thread.

My question is, what IS the purpose of an offset lens board? I've seen it a lot on eBay type sites and even here people selling offset boards, what's the purpose?

(I'm relatively new to LF, about 4 months now, so still learning) .

In the case of Linhof Technika cameras it places the optical center of the lens on the optical center of the ground glass when all controls are at 0.

There are three cases of the 001119 Linhof Technika 45 board for 3 shutters that have a z after the last digit in the catalog number. That indicates that this board has a hole milled off the normal position for a Linhof hole so the rear barrel of the lens will fully clear the inside of the front standard and allow the lens board to properly lock in place on the camera. That special board is for the 210 Super Symmar XL Asph on a 45 Technika (not a TK), the 240mm Apo Sironar-S on a 45 Technika or any TK, the 300mm Apo Symmar-L on a 45 Technika and 45 TK and the 400mm Apo Tele Xenar Comp on a 45 Technika.