Technika IV: lens center off the GG center?

[sparq]

Hello,

I have a naive question. I've recently purchased a SA 8/65; and when toying with various lens boards, I've realized that the center of a lens mounted on an original Technika board is not aligned with the center of the GG. This also applies to my other technika lens boards; they all are similarly drilled off-center (Wista, SK Grimes, chinese no-name). When the camera back is in the landscape position and the front standard is inside the camera on the internal rail, the lens's axial axis crosses the GG plane ~4mm above the GG center (See Fig-1). My naive question is: is this normal, or is there something wrong with my camera (seems unlikely to me), or are all my lens boards (including the original Linhof ones) drilled incorrectly? It seems strange to me that the Technika IV design would force users to use unwanted (even if small) rise/shift with wide angles. Am I a fool? Where's the error in my thinking / measurements? :confused:

http://farm1.static.flickr.com/193/511821407_00c25e613d_o.jpg
Fig-1: Flatbed scan of my Tech IV w/ Symmar 210 inside the camera

[Wimpler]

Don't know the lensboards, or camera, but have you tried rotating the lensboard? I know some lensboards need to have the lens hole off center, so rotating would influence the position.

[Bill_1856]

Famous German Engineering, perpetuated in the progression from earlier models because no von vould admit dot they might have made ein mistake. (Perhaps there's no German equivilant to the English word "mistake?")

[Emmanuel BIGLER]

It looks like you have taken this picture with a flatbed scanner. Am-i Right ?
If this is so, I'm cautious about parallax errors : you have noncontrol of the optical axis of the scanner lens.

-----------------------
digression, off-topic
The scanner is in principel not designed to take pictures of 3-D objects.
However you can actually take pictures of 3-D objects ;-)
http://farm1.static.flickr.com/232/503516677_703ff3ecf2_b.jpg

--------------

Back to the Linhof. The camera looks folded ? Right ?
So you should unfold the camera and set it up for normal action.
En even if you have 1 or 2 mm off-centre, where is the problem ?
Don't people use field and view cameras to get shift & tilts ;-);-)

[sparq]

Thank you for your answers, mates!


Don't know the lensboards, or camera, but have you tried rotating the lensboard? I know some lensboards need to have the lens hole off center, so rotating would influence the position.

I am sure the lens board is installed correctly.


Famous German Engineering, perpetuated in the progression from earlier models because no von vould admit dot they might have made ein mistake. (Perhaps there's no German equivilant to the English word "mistake?")

Well, I certainly have not intended to start a flame war here. ;)


It looks like you have taken this picture with a flatbed scanner. Am-i Right ?
If this is so, I'm cautious about parallax errors : you have noncontrol of the optical axis of the scanner lens.

Back to the Linhof. The camera looks folded ? Right ?
So you should unfold the camera and set it up for normal action.
En even if you have 1 or 2 mm off-centre, where is the problem ?
Don't people use field and view cameras to get shift & tilts ;-);-)

The picture from the scanner is just a demonstrator of my point, I can clearly see and measure the offset without a scan. Yes, the camera is folded, the front standard is inside - but that's the way to use super wides. Also, all rails (regardless if inside or outside) are in the same plane. 1-2mm would be fine, but 4-5mm that you cannot compensate for are more than expected.

Is this another use case for the Linhof wide angle focusing device? What if it not only lets you focus inside the camera, but also drops the axial axis of the lens a bit to compensate for this offset? That would make some sense but I do not own one so I cannot really tell.

[Michael Nagl]

Famous German Engineering, perpetuated in the progression from earlier models because no von vould admit dot they might have made ein mistake. (Perhaps there's no German equivilant to the English word "mistake?")

It´s Fehler
You made two when you tried to write equivalent.

[Bob Salomon]

The 90mm lens is supposed to be mounted on a recessed board. Presuming your lens is in a 0 sized shutter it belongs in the old 001015 board if it is in a Compur shutter and in a 001016 board if it is in a Copal shutter.

While these lens board numbers are still current the lens boards are different today.

Do you know if your lens is in the correct lens board?

[Oren Grad]

I just checked my Master Technika with one of the lenses I have mounted for it, a 90. It's on a flat, Nikon-labeled Technika clone board, but the drilling is offset downward as with original Technika boards.

With the front standard sitting on the rail inside the box and the bellows fully compressed as you have it, and examined through the open back, my 90 appears to be centered properly.

[sparq]

The 90mm lens is supposed to be mounted on a recessed board. Presuming your lens is in a 0 sized shutter it belongs in the old 001015 board if it is in a Compur shutter and in a 001016 board if it is in a Copal shutter.

While these lens board numbers are still current the lens boards are different today.

Do you know if your lens is in the correct lens board?

Bob,

Thank you for your response. The truth is, I do not know which edition of the lens boards I have. I have a modern flat original linhof lensboard plus a few non-linhof ones. They all have the hole centers positioned similarly, there are no variations between them. I also have an older recessed original Linhof board, but its hole is positioned a few mm closer to the board center (i.e. the opposite direction from what I need).

Is there any technical documentation describing various types of Technika boards? Do older Techs (IV, V) require different boards than modern models?

[Bob Salomon]

Bob,

Is there any technical documentation describing various types of Technika boards? Do older Techs (IV, V) require different boards than modern models?

No.

No.

The 90 belongs on a recessed board so that it is fully on the focusing tracks and so that rear extension is not needed for focusing.

[Kirk Keyes]

The real question is what's up with the black metal knobs on the back of your camera??

My Technika lenboards are off-center as well - both Linhof and non-Linhof varieties and the Linhof recessed ones too.

Bob- are you saying that there is a difference between Tech IV recessed boards and later recessed boards?

[sparq]

The real question is what's up with the black metal knobs on the back of your camera??


The knobs are plastic caps of film canisters. I used them as spacers between the camera and the scanner glass.

[Bob Salomon]

Bob- are you saying that there is a difference between Tech IV recessed boards and later recessed boards?

Yes. The current board allows you to set the aperture on a scale mounted on the front of the lens board. It allows you to open or close the press focus lever with a knob on the front of the lens board. It has a new cable release quick socket assembly without wires.

It no longer is a recessed board with an assembly inside it that pushes the lens back out to the proper distance. The lens is now mounted directly to the board itself.

There are now 3 recessed boards;
12mm recessed "Comfort" board 001015 described above for the 72 to 150mm lenses.
6mm recessed board 001047 for the 80 L and 120 XL Schneider lenses
21mm recessed board 001035 for the TK 45 with the 35mm Apo Grandagon

Additionally these boards have different lens ranges on different cameras. So a Technika 2000 and the new Technika 3000 use the 001015 with a 35mm but that lens on a TK 23 needs the 001047 and on a TK 45 that lens needs the 001035.

So yes the boards have changed from the time of the IV but the IV boards fit the current model cameras and the current boards fit the IV.

Complicated enough?

[sparq]

So yes the boards have changed from the time of the IV but the IV boards fit the current model cameras and the current boards fit the IV.

Complicated enough?

If I understand your explanation, the newer versions are more practical to use than the older ones; that seems to be the major difference. The position of the lens hole was not changing between the versions; that's why you can use all versions on all types of cameras.

I use a 90mm lens with a recessed board. My major concern is the use of a 65mm lens that has quite limited coverage. My little mystery remains unsolved.

[Brian Ellis]

I've owned about 10 different lenses all mounted on Linhof Technika boards of various vintages. On every single board the hole has been off-center so there's nothing unusual about that. My understanding is that the hole is cut off-center because of the way the front standard is constructed on the Technika cameras. Offsetting the center hole is supposed to actually center the lens on the film.

FWIW I used a 90mm Super Angulon for years on a flat board and it worked fine. You can keep the board on the focusing track by sliding the top rail back so that it mates with the small rail inside the rear housing. This may not be the approved Linhof way as Bob says and he knows much more about Linhof gear than I do but it did work fine for me. Recessed boards are a PITA and the only time I've used one was with an 80mm SS XL lens.

[sparq]

I've owned about 10 different lenses all mounted on Linhof Technika boards of various vintages. On every single board the hole has been off-center so there's nothing unusual about that. My understanding is that the hole is cut off-center because of the way the front standard is constructed on the Technika cameras. Offsetting the center hole is supposed to actually center the lens on the film.

I guess I was not clear enough in my initial post. My problem is that my off-center boards are not off-center enough. Look at the picture; the lens is too close to the board center, it should be ~ 5mm lower (even more off-center).

[Bob Salomon]

" My major concern is the use of a 65mm lens that has quite limited coverage. My little mystery remains unsolved."

The 65mm lens requires the accessory Wide Angle Focusing Device and a special 23 Technika lensboard. Unfortunately these accessories are no longer made so you are forced to look for used ones for the IV and later. Currently Linhof mounts the lenses shorter then 72mm on special helicoid focusing mounts rather then the universal Wide Angle Focusing Device that used to be used.

[Gary Beasley]

I guess I was not clear enough in my initial post. My problem is that my off-center boards are not off-center enough. Look at the picture; the lens is too close to the board center, it should be ~ 5mm lower (even more off-center).

Obvious solution to this is to buy a blank lensboard and have a machinist cut a hole precisely where you want it. Most board manufacturers sell the blanks to be cut to the proper hole size for your lens. SK Grimes may be the place to start your quest.

[sparq]

Obvious solution to this is to buy a blank lensboard and have a machinist cut a hole precisely where you want it. Most board manufacturers sell the blanks to be cut to the proper hole size for your lens. SK Grimes may be the place to start your quest.

That would not work i.e. for recessed boards. I don't believe other Technika IV owners needed to have custom drilled lens boards in order to have lenses properly aligned with film. Maybe the answer is: "hey, linhof engineers did not care about 5mm of misalignment because its effect is negligible for lenses on flat boards, and for wide angles the focusing device aligns the lens better with the film - so do not worry about it". I guess I have to live with that answer; even if it does not seem quite right to me.

[Bill_1856]

Here are photos from a Technika iii which clearly show the lens centered, so apparently it was a compromise in adapting the new front standard to the iv.

http://cgi.ebay.com/LINHOF-TECHNIKA-lll-CAMERA-TESSAR-150mm-F1-4-5_W0QQitemZ180120431849QQihZ008QQcategoryZ107927QQssPageNameZWDVWQQrdZ1QQcmdZViewItem