Sinar X conversion to 12x20

[kevin_won]

I've been dreaming, sketching, planning and researching the exciting

possiblity of making a 12x20 converter back for my existing Sinar.

Those familiar w/ the Sinar design will know that the film plane of

the rear standard is detachable w/ a single screw from the actual

standard which contains all the 'business' parts. So, in theory it

would be 'easy' to replace this filmplane part with a (much) larger

one. I've read a few threads which are encouraging of the general

idea of modifying an existing monorail design. . . are there any good

reasons *not* to do that -- i.e. the weight is absolutely too much

for a sinar rear standard, that sort of thing.

 

<p>

 

My thought is to design and have built a 12x20 filmplane/groundglass

back which can be mounted on the rear standard of my existing camera.

Since I have a bit of autocad experience and very limited woodworking

skills, I've looked into the possiblity of having a .dwg (autocad)

file set up on a CNC machine. After talking to the only person I know

in the CNC/machining industry, it seems quite cost prohibitive to

build the thing in metal (he says the absolute minimum CNC (laser)

setup cost is $50,000) but that for my application that a better

material than aluminum is plastic which also has the additional

benefit of being much cheaper to machine.

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I spoke w/ a local plastic machine shop and they eyeballed my

preliminary specs at a rough $200.

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So my questions so far (and I have many I'm hoping members can help

me with) is if someone w/ cnc and or materials experince can judge if

this information I have is correct: that metal is too heavy and/or

too expensive, and that plastic is a decent enough material to use--

or that I should chuck both options and take a woodworking class or

two and do it with trusty old timber.

<p>

Also, on the bellows front, I got a quote from www.camerabellows.com

for a 12x20 for $400 usd. Ouch. Experience w/ camerabellows? price

comparisons?

 

<p>

Filmholders: I can't seem to locate s&s to get a price on a 12x20

FH. . . can anyone help there?

 

thanks

[armin_seeholzer]

Hi Kevin

 

For thad you would get the recomondation from Sinar to use there stronger back standard wich they also rec. for heavy and strong 8x10 use!

And thad one will not be cheap, sorry!

[david_flockhart1]

Ditto on the recommendation to use the 8x10 rear standard. I use a Sinar P and have

fitted an 8x20 as well as an 11x14 to the standards. It works very, very well. You'll

need to make up a riser for the front so that the lens board is centered on the ground

glass so you don't need to raise the standard up too high. Sinar made a base to

mount SLR tpe cameras on the standards which provides a stable platform to attach

to the back of the camera.<div></div>

[armin_seeholzer]

Hi Kevin

 

I forgot to say thad the X version is the only Sinar wich are built only to use as 4x5 thats why they are cheaper then the P2!

You can't change the format frame or you have to get a stronger standard!

Just looked it up on a Sinar reference brochure!

So you need a P or P2 or even better the strong P2 standard!

So on thad one you are not the lucky guy!

[james_driscoll2]

Armin, the Sinar X is built on the P2 4x5 standard bearer...there

is less engraving (scales) on it and the "frame" does come off,

but you need to use a screw driver, instead of your thumb. The X

also has different gears in the movements, which supposedly

require more effort than the P2.

 

The less engraving, is what actually drives the price down!!! But

engraving costs money....that is why Sinars (until recently) don't

have serial numbers. The $40 spent to engrave a serial number

at the factory...ends up being $500 by the time it gets to the

customer.

 

The above was straight from my old boss....who was a rep for

Sinar-Bron for 10 years.

 

The CNC machine idea....I have a custom made 5x7 to 4x5

reducing back for my Sinar. What makes it nice, is that it works

like the 8x10 to 4x5 back does....no refocusing because the 4x5

holder is in the same plane as the 5x7 holder. Sinar's 5x7

reducing back isn't, and requires you to refocus.

 

The guy I bought the back from, had a friend who was going to

"CNC" school/training or something, and made the back as a

"project". They got precise plans drawn up, by the father of the

guy who had it made-he was a mechanical engineer.

 

So maybe you can find a CNC machine student, and con him

into making it!!!

 

Th other idea, is check out www.glennview.com. His prices are

super high, but he has photos of his 11x14 and up sinar

conversion kits that he made out of wood. Inspiration maybe???

[armin_seeholzer]

Hi James

 

I just stated what Sinar writes in there brochure, and I'm sure it is not just the engravings it is the hole mechanics wich are cheaper thats why you use more power on the X standard.

And what your boss stated sounds a bit over the hill to me!

Half way down could be the trues!

[james_driscoll2]

Armin,

 

Camera companies do stuff like this all the time...What costs

money for a company is labor, not parts.

 

The story about the engraving is true, I was skeptical at first also

but after pressing my old boss a little, i got a lesson in how firms

that act as distributers mark up products and how little things

turn into big things.

 

How they (Sinar Bron) found out, was they were getting

complaints from Owners of $7000 Sinars about not having serial

numbers for insurance reasons. After contacting the factory...the

above answer is what they got. Engraving costs man hours, and

man hours in Switzerland are VERY high. So the factory said you

want serial numbers, the price of the camera will go up $500 (by

the time it reaches the purchaser).

 

Camera companies do stuff like this all the time....think of it this

way. Sinar already recouped their investment on the R&D for the

P2 (which came out in 1986) years ago. They already have the

machines, and the dies to make P2 components. Building a

"lesser" priced camera using most of the components of an

already existing design is cost effective. Of course things are

different. There is different gearing, and there is less

engraveing. Of the two, the less engraveing probaby saves the

most money. The gears are most likely sourced from another

company. The engraveing has to be done in house. The price

diff. is easy if you look at this way-

 

for argument sake lets say sinars engraving guy makes $50 an

hour. In 8 hours he can engrave 2 P2's, so the labor cost to

engrave a P2 is $200. So Sinar's cost is $200 labor and lets say

$40 for material and electricity etc. So it is $240. Sinar marks this

up 40% which turns the $240 into $336. This than gets sold to

the distributer who marks it up 40% which turns into $470.40.

The store than marks it up 30% which = $611.52.

 

If they can do 4 Sinar X's in the same amount of time $611.52

turns into $305.76. Of course, none of these prices are real, they

are just for arguementive sake. In real life, they are probably

much higher, because I didn't factor in the guy who has to fill in

the engraving with white paint, and the quaility control and such.

Hopefully you are starting to see how something as simple as

engraving can be quite complex!!!

[kevin_won]

Very interesting info. Thanks all. I particulary like the P 11x14 conversion picture.

<p>

 

What I'm planning on doing is going ahead with a plastic (or possible polycarbonate) version of my frame which I'm hearing will be sufficient for my application. If it's not, I'll burn $200 on a prototype which will be a good indication of what I'll be doing (or changes I need to make) in metal. I'll stick the plastic on the X rear and see how it does. From the looks of things, the 12x20 isn't going to be all *that* much heavier then the sinar 4x5 back in aluminum. . . I certainly puts more stress on the rear standard and if this project works out I will pick up a P rear on ebay as $$ allows (with the added benefit that I'll have my 4x5 set up back w/ having to monkey with unscrewing the frame from the standard every time I want to shoot microfilm ;-).

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When I get the autocad drawings done I'll post images. . .

[metairie_christophe1]

i have a sinar X and i'm building a 16*20 back ... see the picture, the back is made with carbon fiber , very strong dans light !! the sinar X is a very strong camera and there is no rigidity problem at all :-))

i'll send other pictures later

 

christophe - france .