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1/2" extra extension, but what about the rangefinder?

 
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RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Sat Aug 19, 2006 5:36 am    Post subject: Reply with quote

A post on another forum stuck in the back of my head and finally popped out tonight...

There was a mention of extending the reach of the bellows by using forward base tilt and rise. Of course my first thought was "why not on a Speed?"; mostly because I do need an extra 3/4" or so...

Tonight I tried it on my Super. Sure enough with forward tilt you can get an extra 1/2" extension out of the bellows. Unfortunately, it's not as simple with the Speed... The forward tilt is accomplished with the bed drop, then rear tilt to make up for it, then rise. This would be true for any axial tilt camera... Unfortunately, I don't think the 1/2" will be enough for me, but that will be checked later. It's all for mounting the 380mm tele without an adapter and still using the cammed RF...

Which now brings up some thoughts. On this Super, dropping the bed makes the RF move by 5 feet, roughly... Now if I'm doing the 380mm I may not have a problem? But what about a 90mm and using a dropped bed? The RF will still move so infinity moves (and can't be reached) but the lens doesn't. Doesn't this throw the RF off? Or is it just this Super? Don't have acces to my other Super at the moment...

And thinking about it now, the lens does actually move away from the film plane when the bed is dropped if it's sitting on the infinity stops... Hmmm, so the stops should be adjusted with the bed dropped... Uh-oh...

Okay, so I haven't put much thought or work into this, but I got bored and felt like "talking"... Besides, who among us can't use an extra 1/2" now and then?


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ImageMaker



Joined: 20 Jun 2006
Posts: 93
Location: North Carolina

PostPosted: Sat Aug 19, 2006 9:02 pm    Post subject: Reply with quote

To me, this looks like a situation where you'd pretty much have to focus on the ground glass. I wouldn't expect the RF to still bear any useful relation to the lens position with this kind of lash-up.

An alternate, much simpler setup (that would, however, have to be dismounted to close the camera) would be to simply make an extension lens board. Easiest way for a Super or Pacemaker would be to get an original type board cut for #3 shutter, make an extension box out of hobby plywood or Masonite, and epoxy it to the front of the original board. This should pretty readily accommodate up to #1 shutters; if you need to mount a #3, you could pretty easily open out the original hole enough to pass the retaining ring and spanner.

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Rick from OZ



Joined: 05 Jul 2006
Posts: 40
Location: near Melbourne, Australia

PostPosted: Sun Aug 20, 2006 3:44 am    Post subject: Reply with quote

Rich,

I hope you enjoyed the chat !

FWIW I think you answered part of your own question.

If you intend to use a lens with the bed dropped, then you need to place the infinity stop with the bed already dropped.

My concern is how much the 'triangle' effect of a dropped bed will have on the rangefinder. I'm assuming you are bringing the lens back to parallel using front rise and rear tilt.

If so, then effectively the rangefinder is measuring the hypotenuse of a triangle, rather than the actual extension length of the bellows and thus the lens.

This would be further complicated because the front standards are no longer vertical. But this may also, in effect, correct the measurement error ?

My suggestion: measure it !

I'm assuming you have a cammed speed graphic as well as the super ? Don't know this would be worthwhile with a side mounted kalart !

First, try the rangefinder on a flat bed and measure the distance to the axis of the lensboard, and check the rangefinder reading. A couple of different extensions & focus points would probably help, eg: infinity, 15 ft. 5 ft.

For simplicity, I would suggest using a lens that doesn't require all the rail length to use all the rangefinder focus from infinity to 5 feet for this test

Then:
* reset the rangefinder infinity stops for the same lens but with the bed dropped
* add front rise to bring the lens up to 'flat bed' height
* extend the axis of the lens to the same point(s) (measured on the flat bed) and
* check the rangefinder distance.

Given identical axis extension = identical focus for the same lens, then if the rangefinder reads the same distance, you should still be able to use the rangefinder, with appropriate infinity stops.

I'd like to know the outcome, but have to admit an extension board would be quicker to take shots with in the long run. Again, all you need to do is have the infinity stops set for the lens with extension board.

I believe some aluminium muffin baking trays are around the right size and thickness to attach to an existing graphic board and to take a standard diameter lens. Probably give you at least 50 to 75mm extension.

That's around 2 inches I think, and I'd take an extra 2 inches any day )

The bonus - they come in trays for six muffins so you can use one of the others in reverse to make a board for that superwide you always wanted but couldn't focus close enough (or so you can focus it using the front rails on the super !)

Hope it helps !
. Rick

[ This Message was edited by: Rick from OZ on 2006-08-19 20:49 ]
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RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Sun Aug 20, 2006 5:31 am    Post subject: Reply with quote

I wish I had the time to look seriously into this...

I may be wrong, but I think the Super can use a 90mm with the bed straight, which solves the problem there. But for a TRF Pacemaker which is supposed to have the bed dropped for a 90, the 'problem' is interesting. I wonder if the cams are designed to work with a dropped bed? Or does it really make any difference at all? Unfortunately, I'm not sure I have a 90 cam for my TRF Camera? More checking...

I have no problem making an extension board and that was my plan all along. No rush as how important is it really to use a 380mm with the RF? I harldy ever use the lens at all anyway. Just part of the hobby and I'm sure there will come a time where I "need" it. Probably the day before I put it all together

With a bit of luck, early next week I'll get the 380 and cam on the Super to see what happens. As I said, I don't think the 1/2" will make it as I remember needing at least 3/4" and planned on making a 1" extension. I'm still searching for the Graflex adapters for the 380 and 65 lenses. They have part numbers, prices and occasional mentionings but neve a picture... I would think if they made an extension or recessed lens board they would have called it that. They did list every lens board they made, so it must be something else?

To me, it will be just one of those neat things if the 380 can be used by simply dropping the bed. I do have a feeling it won't work though... And as far as having to focus on the GG, then there wouldn't be any need of an extension because you could just rack the rails out an inch. It's the cam & RF that counts.

And unfortunately, what counts more here at the moment is two little girls, two new rabbits, and the lack of rabbit hutches or available space in the shed. Little time for cameras....


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45PSS



Joined: 28 Sep 2001
Posts: 4081
Location: Mid Peninsula, Ca.

PostPosted: Sun Aug 20, 2006 5:41 am    Post subject: Reply with quote

Quote:
And unfortunately, what counts more here at the moment is two little girls, two new rabbits, and the lack of rabbit hutches or available space in the shed. Little time for cameras....

Time to break out the stew pot.



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RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Mon Aug 21, 2006 4:11 am    Post subject: Reply with quote

they've been warned many times and I think they take it seriously. So, they betetr take care of them, or I will


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Rick from OZ



Joined: 05 Jul 2006
Posts: 40
Location: near Melbourne, Australia

PostPosted: Mon Aug 21, 2006 11:46 am    Post subject: Reply with quote

Rich,

With a couple of little girls around surely there are some spare baking trays you could 'try out'

I have to admit I have a similar issue with my twin boys, space, time, and sport.

. Rick

[ This Message was edited by: Rick from OZ on 2006-08-27 05:12 ]
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RichS



Joined: 18 Oct 2001
Posts: 1468
Location: South of Rochester, NY

PostPosted: Tue Aug 22, 2006 5:13 am    Post subject: Reply with quote

Yep, plenty baking dishes of all sorts around. Fortunately, they're all mine and mostly stoneware

Somehow I doubt the stoneware would make a good lens board extension? Although a lot of other photogs out there do think we're living in the stone age
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