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View Full Version : Seneca Improved View Lensboard Design/Installation?



Scott --
2-Jun-2010, 07:30
Hi, all -

I'm rehabbing a Seneca Improved View 8x10 right now, and have just refinished the front standard:

http://i531.photobucket.com/albums/dd359/smpsweeps/IMG_0400.jpg

Now, I have a Seneca Competitor 5x7, and installing the lensboard is a matter of turning two little stops, placing the board in the standard, then twisting the stops to lock the board in place. The Imporved View, though, has no twisting stops, and no sliding bar. So, even though I'm sure this is painfully obvious to most, I'm at a loss as to how the board is designed to go in.

Anyone have one of these that can enlighten me? This camera had a little metal bar installed by a previous owner to act as a twisting lock. I removed that ugly thing in reworking the standard...

Thanks,
Scott

David Karp
2-Jun-2010, 09:26
This is how the board on my WP Improved Seneca works:

The opening for the lensboard is smaller than the height of the board. Slide the board up into the slot in the top of the opening. Make sure the bottom of the board can now slide down into the bottom slot. Once this is done, the board is "trapped" by the slots.

Scott --
2-Jun-2010, 09:30
Ok, David, that makes sense. Can you tell me if there's a lip around the inside edge of the board, or is it a single thickness?

Thanks,
Scott

David Karp
2-Jun-2010, 10:32
There is a lip.

Scott --
2-Jun-2010, 10:47
Thanks, David. For future reference, I made a flat board of 1/8" stock - the board is just shy of 4-3/4" wide by 4-5/8" high. Looks like a 3/16" or 1/4" rabbet around the edge will allow it to slide in and out. Total thickness around 1/4" to 5/16" will work.

David Karp
2-Jun-2010, 11:10
Later, I will dig out my Seneca lensboard and will give you the measurements.

Kirk Keyes
2-Jun-2010, 12:34
Someone modified my Improved Seneca for two little twisting stops. I guess they did not trust the factory system.

Scott --
2-Jun-2010, 12:55
I think the factory setup is a good one, but if my quick-and-dirty lensboard is any indication, the tolerances on dimensions for this style are way tighter than with other modes. Gotta be right, gotta be square. Any slop, and it'll fall out. Good thing I'm making the lensboards... :rolleyes:

cdholden
2-Jun-2010, 19:26
My Seneca 6B (5x7) is not designed for easily changeable lensboards. My front standard looks like a similar design as yours, but smaller. The lens that it came with is the only one I've used with it. Swapping the lensboard would involve a screwdriver and some patience to remove 4 screws of either the top or bottom retainer.

Scott --
3-Jun-2010, 06:51
My Seneca 6B (5x7) is not designed for easily changeable lensboards. My front standard looks like a similar design as yours, but smaller. The lens that it came with is the only one I've used with it. Swapping the lensboard would involve a screwdriver and some patience to remove 4 screws of either the top or bottom retainer.

Chris, it sounds like someone replaced the board with one too large to slide in and out, again thinking it'd be more secure. You could trim the top of that board to size it correctly, or get some new ones made... ;)

David Karp
3-Jun-2010, 09:39
Scott,

Your board for the 8x10 is larger than the one for my WP camera.

At any rate, here are the measurements.

Height: From front - 158mm; From rear - 99mm
Width: 150mm (uniform from front and rear)
Thickness: 5mm (except at the top and bottom lips. At the lips, the board is maybe a bit under 2mm thick)

cdholden
3-Jun-2010, 18:35
Scott,
Mine doesn't look like it was designed to be easily replaceable. If it was, there would be some sliding mechanism or some other means besides removing screws. The board looks to be a good fit, so I don't think it's bad aftermarket hack. I can offer up a photo this weekend if you need more detail.

Chris, it sounds like someone replaced the board with one too large to slide in and out, again thinking it'd be more secure. You could trim the top of that board to size it correctly, or get some new ones made... ;)

Scott --
3-Jun-2010, 18:44
That's the same setup I have, Chris. Top and bottom retainers are screwed in place, no mechanism for sliding or twisting anything to lock the board. The trick (now as David has made it more apparent to me) is that the board tilts in under the top retainer, slides up enough to allow clearance over the bottom retainer, then slides down. The sizing is such that it's held in place by a few millimeters on the top.

I'll see if I can make a vid for youtube tomorrow to better demonstrate what I mean.

Scott

Scott --
4-Jun-2010, 14:33
Here 'go - a video of the quick-and-dirty lensboard being installed (http://www.youtube.com/watch?v=gC28YYw_Wks)...

Uncle Jim
4-Jun-2010, 15:03
Scott,

Quite a number of Japanese and Indian cameras have this same feature. There is also a very stiff spring in my 8.5 x 15 at the top to retain the lens board under pressure.

uncle jim

David Karp
4-Jun-2010, 18:27
Always remember to make sure that the board is seated properly. In other words, that the bottom of the board is well seated in the lower slot.

Scott --
6-Jun-2010, 10:56
Will do, David. FWIW, I'm moving along quite nicely on the four poplar lensboards I'm making for this camera (http://scottperryphoto.wordpress.com/2010/06/06/lensboards-joinery-and-glue-up-seneca-improved-view-8x10/). Next step - sizing the boards and milling the rabbets.

Curt
6-Jun-2010, 19:12
I have a Seneca 8x10 and a 5x7 and the boards are made to very exacting specifications. The board is put in top under the metal strip and then it slides down slightly to seat under the bottom metal strip while still captured by the top metal strip. It's not much so the board has to be made very close to the original design. If you have one you can use it for measurements, if not then start with the metal strips off and make a board that fits the rectangle, I'd didn't say square, then put the metal strips back on the camera and try the board, it won't fit but that's OK. Sand or micro remove a bit of material from the top or bottom of the board until it fits. Be careful a little too much and it's not going to work. It seems time consuming but really it's not that hard. You might want to sand the board on the edge by placing a sheet of sand paper on a flat surface and moving the board across to sand down to size.

Good luck,
Curt

David Karp
6-Jun-2010, 21:54
Wow! Those are going to be a lot nicer than the plywood versions I glued together for mine. Very cool.

Scott --
7-Jun-2010, 07:00
FWIW, and drifting away from the original post, here's the skinny on the boards: The edges do not have a consistent rebate along the edges. The top and bottom of the board ebd up with a lip about 3/16" thick, while the sides have a lip about 1/8" thick:

http://i531.photobucket.com/albums/dd359/smpsweeps/IMG_0439.jpg

Easy enough to do if you sneak up on it, make a lot of test cuts in scrap, and have a horizontal router table. ;)

It's a neat, if strange, design. The boards slide in and fit like a glove. Here it is, finished and with the Wray Process Lustrar installed:
http://i531.photobucket.com/albums/dd359/smpsweeps/IMG_0440.jpg