Enough bellows on 7x17 FS for 19" lens?

[Robert McClure]

Since I'm still getting my feet wet here, I would apreciate some information on the following questions. Thanks!

How much finageling will I have to do in order to have extension enough to infinity focus a 19" lens on a camera (F&S 7x17) that seems to max out on bellows at around 17." Before I buy the lens I'd like to know how someone else solved the specific dilemma. I mean without building a rear bed extension, or modifying the front standard.

Looking to me now like I can buy an inch at the rear by removing the stop. Another inch from front base tilt/rear tilt combination. What about building a recessed lensboard and reversing it?
I understand that about 1.2 times the FL is indicated. This puts me to nearly 23." Or am I missing something?

BTW, anyone ever make any front standard modifications to one of these cameras for the reasons I indicate above? I really doubt the need for anything longer than a 19" lens.

Many Thanks!

[Robert McClure]

I had another thought. I am in the process of ordering a new (primary) bellows for the camera. If a short bed extension is going to be the answer, maybe now is the time to build a longer bellows in anticipation of having the extension?? Any thoughts on this? Thanks!

[sanking]

Without some sort extension you certainly will not be able to focus a 19" lens at infinity on a camera that has a bellows with a maximum draw of 17".

Some people I know have built front extensions in the form of a box to allow the use of longer lenses. This would be very easy to make.

[Robert McClure]

Sandy,

Thanks for the input. Perhaps I was unclear. I was asking for someone who has been able, with simple manipulations/girations of the existing camera, to get 20" or 21" out of that specific camera. I am already getting a couple extra inches by playing with the standards and removing the back stop. Are you very familiar with that camera?

(No, I am not expecting to defy the Laws of Physics! Ha, ha! Wish I could!).

But yes, thanks. If what you are talking about is a, sort of, reversed recessed lensboard - that may be the best way!

Thanks!

[Donald Hutton]

Robert

An 'extension board' is definitely the simplest option - I'm not sure you're going to be able to get enough for what you want to do though. You could make a 3-4 inch extension board, but remember that if you hang a heavy lens on it (the 19inch you're looking at could be a very chunky lens) you end up with a lot of stress on the front standard caused by the weight of the lens "forcing" tilt in the front standard (the fulcrum is going to be a long way forward from the standard). I would think that to get much use out of the lens, even for landscapes, you're going to want at least about 21 inches. You'd probably get a reliable 2.5 with an extension board and if you can eek an extra few elsewhere, you could be home and dry. If you're dead set on a lot of bellows extension, I think a different camera may be the simplest option...

[Donald Hutton]

Sorry, I meant "center of gravity", not fulcrum (!!!)....

[Steve Sherman]

Robert,

I have done exactly what you are trying to do with the exact camera and lens combo you are questioning.

It's simple. The rear stop, a half moon brass stop attached to the bed and prevents the rear standard from retracting too far. I removed this stop and now carry a spacer with the high and low tracking grooves cut into the sides of the spacer, this allows the feet of the track to slide backwards. This 2" spacer now has the half moon brass spacer attached to it. The geared tracks allow the camera to be backed up nearly two inches and that is all you need for the 19" lens. I carry the 2" spacer in my camera backpack and whenever I want to use the 19" lens I simply take it out and attach it to the rear of the camera with two brass screws, which measure 2 1/2", less than a minute to install.

Naturally, whenever I use other lens on the camera I am careful not to move the rear standard at all, it remains locked in place for safety.

I have shot the 19" in both horizontal and vertical orientations without consequence.

Good luck

[Terence McDonagh]

Another option, with some fairly simple woodworking skills, is to make an extension to the back. Basically a box that fits between the back standard and the back itself. I know this is easy on koronas, but am not sure about F&S's. If the back is removable it should be fairly straightforward. As the back standard is usually sturdier than the front, the extra weight shoould be a little less of a problem.

I've seen one for a Deardorff on some other site, but can't remember which.

[Robert McClure]

Thank you very much to all!

Steve Sherman:

Yes, I can see that if I remove the rear brass stop I gain about two inches by racking the standard back to just where the pinion gears begin to disengage from the track.

Questions:

(1) Are you attaching your your 2" spacer with stop for safety's sake? What would be the harm of leaving the back at the maximum extreme (where the gears are just about disengaged from the track) and then focusing with the front standard? I mean, skipping the spacer altogether. Do you mean to use the spacer and stop for both safety and stability/rigidity? To help maintain your focus during jostling of back during insertion of holder? Versus no spacer and just letting the brass guides hang out from the end of the base?

(2) You mention shooting in vertical orientation. Do you use an "L" bracket arrangement?

Many thanks!

[Steve Sherman]

The spacer is for safety sake, it is so easy to install and to make for that matter. I will try to get a digital picture of how I modified the bottom of the camera. Really only amounts to a second tripod mounting point, I have a Gitzo tripod which has two mounting points on the head that I have. Works like a charm.

[Robert McClure]

Thanks, Steve. I apprecaite any help I can get!

[Steve Sherman]

Robert,

Can you e mail me your e mail address to send the picutres. Don't believe you can attach a file to this site.

steve@steve-sherman.com Thanks, Steve

[Robert McClure]

Many thanks to all for your kind input!