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View Full Version : Mah lens is too big... mah lens, is TOO BIG! 610mm nikon tries to mate with Sinar



snuck
28-Jul-2008, 17:57
Ok, anybody remember Don Hertzfeld?

Ok, I have this issue. I have just recieved a truly amazing lens, a 610mm Nikon multicoated from John Schneider. But now I'm trying to think about how to mount it. I use a Sinar Norma, and the lens is huge at 4.5" insertion diameter. The flange itself fills the standard Sinar lensboard at 5.5". Have any of you dealt with this lens and machining out lensboards? Is there anybody in the Toronto area adept at chopping some really huge round holes in aluminium?

Cheers

john wilton
28-Jul-2008, 20:38
Why not just let skgrimes.com do it? Rhode island not too far from Toronto.

If an OEM lensboard won't mount on the camera with flange attached, they will drill and thread a hole in your lensboard in short order. They can also supply a thicker lensboard if necessary (probably not.)

snuck
28-Jul-2008, 20:48
Wish I could, but I am trying to economize by screwing it up myself.

:D

BradS
28-Jul-2008, 21:54
Any competent machinist could accomplish this in not much time. I have a guy at work who would probably do it on his lunch break for a small token of appreciation (a case of good beer).

John Powers
29-Jul-2008, 04:09
Any competent machinist could accomplish this in not much time.


…and a few incompetent retired software salesmen. If you have a portable power drill you can do this with little expense. Go to a large hardware store (Lowes or Home Depot in the States) and buy a 2 inch drum sander accessory that chucks into your power drill. Also buy a package of three 2” sander refills. You will need an artist’s compass or dividers, not a navigational compass.

Start with a lens board that already has a Copal 3 hole. Scribe the correct size hole to use as a target. Make sure the scribed hole is equidistant from all edges. Lock lensboard in a vise using a rag on either side to protect the finish. Start grinding away. Frequently check to see the hole is growing in a perfectly round shape using the dividers at different positions on the board. Total investment, less your time, is $10-$15 in tools you may be able to borrow. Wear safety glasses to protect your eyes from flying aluminum chips and dust.

Got to get on with my retired incompetence. The dogs need a hike.

John

snuck
29-Jul-2008, 05:55
…and a few incompetent retired software salesmen. If you have a portable power drill you can do this with little expense. Go to a large hardware store (Lowes or Home Depot in the States) and buy a 2 inch drum sander accessory that chucks into your power drill. Also buy a package of three 2” sander refills. You will need an artist’s compass or dividers, not a navigational compass.

Start with a lens board that already has a Copal 3 hole. Scribe the correct size hole to use as a target. Make sure the scribed hole is equidistant from all edges. Lock lensboard in a vise using a rag on either side to protect the finish. Start grinding away. Frequently check to see the hole is growing in a perfectly round shape using the dividers at different positions on the board. Total investment, less your time, is $10-$15 in tools you may be able to borrow. Wear safety glasses to protect your eyes from flying aluminum chips and dust.

Got to get on with my retired incompetence. The dogs need a hike.

John

Not bad at all. Although if any of you have stumbled across a sinar board with an irregularly large hole, even if it doesn't match, I'd be game for taking it off your hands.

John Powers
29-Jul-2008, 06:38
Not bad at all. Although if any of you have stumbled across a sinar board with an irregularly large hole, even if it doesn't match, I'd be game for taking it off your hands.

Thanks,

The Labs liked the hike as well.

A carpenter friend showed me how to do this after another friend did a board with a power hacksaw. That was not a tight fit. The carpenter had a $150 drum sander with five different size drums, but he said the big hardware stores had the drums for power drills. It worked for me to mount Ilex #4 and #5 shutters increasing the hole size from Copal #3.

John

eddie
29-Jul-2008, 06:45
buy a big hole saw close to the size you need. put the board on a block of wood. add two wood screws per side to hold it in place, so it does not spin. drill hole!

i do this with all my boards. works fine.

eddie

Pete Roody
29-Jul-2008, 07:26
You will have to clip the flange so the board can mount to camera. You may also have to add a spacer to allow for mounting or if you plan to use a Sinar shutter behind the lens.

Alan Davenport
29-Jul-2008, 09:19
An alternative to the simple hole saw, is a flycutter. I use flycutters for all of my lensboard holes up to 1/8" aluminum boards. Believe it or not, Harbor Freight sells a nice flycutter that has a cutter on both ends of the bar; more difficult to adjust but well-balanced and cuts fast. Of course you MUST use a drill press. Run the thing as slowly as possible, feed the cutter slowly and keep your hands clear.

W K Longcor
29-Jul-2008, 09:29
Alan: Do you, by any chance, have the cat.# for the Harbor Freight cutter? When I check the internet listing, the only fly cutter they list has a maximum cut of 1 3/4".

jetcode
29-Jul-2008, 09:44
Ok, anybody remember Don Hertzfeld?

Ok, I have this issue. I have just recieved a truly amazing lens, a 610mm Nikon multicoated from John Schneider. But now I'm trying to think about how to mount it. I use a Sinar Norma, and the lens is huge at 4.5" insertion diameter. The flange itself fills the standard Sinar lensboard at 5.5". Have any of you dealt with this lens and machining out lensboards? Is there anybody in the Toronto area adept at chopping some really huge round holes in aluminium?

Cheers

I always found a metal shop to expand lens boards. There are lots of them around. The smaller shops will take walk in piece work.

snuck
29-Jul-2008, 10:30
I think what I may do is cut a giant square hole in a Sinar lens board with a hacksaw and trim down the pre-existant lensboard. Then bolt the two together. That way there won't be too much circular hole cutting. Thank you all for your ideas.

Pete Roody
29-Jul-2008, 10:40
I think what I may do is cut a giant square hole in a Sinar lens board with a hacksaw and trim down the pre-existant lensboard. Then bolt the two together. That way there won't be too much circular hole cutting. Thank you all for your ideas.

Don't waste money on hole saw bits if don't have one. The square hole in the lensboard is fine. You can drill small holes at the corners that will allow you to start the saw. Use a spacer block between the lens and board. Make it out of mdf or plywood. You can rough cut a round hole in the spacer alot easier than in the metal board. You can attach the lensboard to the spacer with wood screws. Same for the flange to spacer.

snuck
7-Aug-2008, 09:19
Ok, well I did finally mount it, and I had a request as to how I did it. The answer is that it isn't pretty and you could probably do a better job. That said... I simply did this

The order of fitting is the lens, sits on the original lensboard/holding board, which is then bolted to a Sinar board.
1) Using a small hacksaw and cutting oil, I chopped an enormous hole into a spare junky Sinar board I had lying around. Sinar boards are made out of good aluminum in most cases, so they take the punishment. If you take a look at the bottom fo the lens board, the distance I had from the INTERIOR CORNER of the BACK SURFACE to the EDGE OF THE NEW SQUARE HOLE is 9mm, on all sides.
2) I used a trusty flat file to file away excess aluminum and clean up the holes. You'll find that using a hacksaw is a major PITA, is messy and leaves jagged edges. If you have a jig or scroll saw I would highly recommend using that instead.
3) I trimmed the resin lensboard to 5.25" (13.3cm) to a size just smaller the sinar board. This is important because of the way that sinar cameras hang onto their boards. If your lens doesn't come with a preexisting board like mine did, make one out of plywood and use the Nikkor's mounting flange to attach the lens to the plywood.
4) Finally I drilled 4 holes at the corners of the resin board (I was pretty imprecise too -ugh), drilled 4 holes in the Sinar board that it was to sit on top of. Bolted the assembly together, and walla. Pics to follow.

Issues:
- For those of you using Sinar Shutters, you will probably need 1/4" thick holding board to ensure clearance. I sure hope that the Sinar Shutter has a 2.5" diameter hole in it, because that's how large the back element of this thing is.
-The front end looks intimidating, because the lens assembly sticks over the sinar board a little. But the rear element is manageably small and sticks through the Sinar board, with little fuss.

snuck
8-Aug-2008, 12:04
Ok here are some images of this thing.

The first image is of the front. As you can see the lens mounting flange clearly overlaps the Sinar lens board. Good thing that the screws for the mounting flange fit well within. The resin board that the lens is attached to, is cut just smaller than the sinar board, because the Sinar needs a little real estate at the top and the bottom of the lens board, so the camera can hang on to the lens and board assembly securely. If the lens were not pushed away from the Sinar board, by the resin board, the aluminum bit at the bottom and the aluminum sliding lock would have nothing to grab on to.

As you can see the lens mounts on its original resin board via black hex screws, which in turn is mounted by the silver screws onto the Sinar board.

In the second image, you can see this gory thing from the back. showing that the little hex screws that attach the APO-Nikkor to the resin board. here you can also see the nuts that attach the resin board to the Sinar Board. I am eventually going to spraypaint the back of this with matte black and use a dremel cutting disc to take out the excess screw length.

Finally finished. Here it is mounted on my camera. Notice that in order to focus this monster, you really need both extension rails, small and larger on the base rail in order to get enough. You'll also need two bellows, as one won't be enough, and a standard to hold them up. Don't use the Norma Bellows I'm using. I was just doing that out of desperation-I suspect it vignettes. Anybody want to give me their spare square profile Sinar bellows?

I love my Norma, I really do, because the front standard is so stiff, it holds this lens up without complaint even in wind. Although since the lens is housed in aluminum rather than brass, it is much lighter than it looks.

Instead I found out that the weak point in this assembly was unfortunately, the inherent flex of my tripod and ball head. When I use the cap as a shutter, I get shake from the tripod Now I need to get another tripod somehow (big sigh).

CG
8-Aug-2008, 15:44
That "thing" is huge.

C

snuck
8-Aug-2008, 16:57
Which is exactly why the Norma is a nice camera. It holds the damn thing up, with no mess, and no fuss.

Lighter than it looks however. Now I need to find a ~95mm protective filter for it.