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View Full Version : Arca-Swiss 4x5 Compact: Is Small amount of rail movement normal?



Leslie Gordon
23-Sep-2004, 09:59
After much research, I have decided to purchase an Arca-Swiss 4x5 F-Line Compact. I had the opportunity to try one out extensively at a used camera dealer, and came away very impressed.

There was one thing that bothered me: the Compact model has a collapsible monoral. On this particular camera, when it was placed on the extension bracket, there was a very, very small (much less than 1-degree -- we're talking about approx. 1 or 2mm total) lateral movement. In other words, the rail would "wiggle" ever so slightly on the bracket when I was testing the swing and shift movements. When locked down, everything else was extremely rigid, so this particular movement was stood out.

I don't want to get hung up on finding the ultimate in rigidity, but I was wondering if this sort of "give" was normal on a camera like this. Perhaps other owners of this camera could comment. Thanks.

Glenn Kroeger
23-Sep-2004, 10:14
Leslie:

Depends on the style of the extension bracket. Older ones clamped the rail from both sides, so the movement you describe wasn't physically possible. The new one uses a lever to draw the rail downward against the bottom of the bracket. So depending on how tight it is, there could be a little side to side wiggle. If this is what you are descibing, it is possible to increase the tension by adjusting the lever. The lever is held in place by a set screw (hex head if I recall).

Leslie Gordon
23-Sep-2004, 10:21
Glenn:

I guess the camera I was taking a look at had the newer style clamp. There was only one lever (on the left side, as you are facing the groundglass). I'm taking another look at the camera this weekend, and I'll experiment with adjusting the lever as you suggest. Thanks, L.

Scott Atkinson
23-Sep-2004, 10:31
Leslie: I have two Arca rail sets, both the lever type. Neither has the slightest bit of wiggle when clamped down, and the clamping action isn't strained at all. The clamps come matched to the particular rail; it's possible that yours was swapped out at some point.

Leslie Gordon
23-Sep-2004, 10:49
Scott:

Hmm.. that hadn't occurred to me. The clamp that was on the camera was this:

http://2point8.org/i/arca_clamp.jpg

(This picture is from the Arca brochure) I assume that's the normal, stock clamp that I should have, right?

The rear of the collapsible rail fit on the clamp in such a way that most of the rail overhanged the clamp (about 30% over the clamp, and the rest of the rail with no support underneath it). I assume this is normal -- somehow I thought that the rail was supposed to be centered on the clamp, but this might not be the case with the F-Line Compact model. Sorry if this thread is boring everyone to tears... it must be obvious to other Arca users.

tim atherton
23-Sep-2004, 11:01
You've fitted the clamp uincorrectly onto the rail byt he sounds of it.

The rail just slides onto the clamp and then you flip the lever on the side and it locks it - anywhere along the rail you want it to be - middle, one end, or the other.

The only thing is, that with the little locking knobble on the bottom of the rail (to hold it closed when folded), you can only slide it onto the clamp from one end. Don't make the mistake of trying to line up the "peg" in the clamp (that moves up and down to tighten when you move the lever) with the circular hole on the bottom side of the rail - that hole is only there to accomodate the locking knobble when you fold/close the rail.

I just checked mine - there is absolutley no movement when the rail clamp is locked. Just a very sligth wobble when it isn't lock

Leslie Gordon
23-Sep-2004, 11:08
You've fitted the clamp uincorrectly onto the rail byt he sounds of it.

The rail just slides onto the clamp and then you flip the lever on the side and it locks it - anywhere along the rail you want it to be - middle, one end, or the other.

A-HA! I bet that's it.

OK, this is what I get for being left unattended in a store with a camera. I will investigate this further this weekend. Thanks everyone for your help.

Glenn Kroeger
23-Sep-2004, 12:22
Leslie:

I had the new style clamp, and it was possible to wiggle the rail just a tad because the lever wasn't pulling the rail down tight enough. Now the wiggle wouldn't have bothered picture making because it took considerable force to slip... but I did manage to tighten the lever as follows:

1. tighten the lever all the way.

2. loosen the set screw in the lever, and move the lever back a bit and lock it in place with the set screw.

3. now the lever could move farther tightening the rail a bit more.

Hard to descibe, but easy to do. In short, it is easily adjusted.

Emmanuel BIGLER
24-Sep-2004, 11:57
Leslie. The rail you have is the modern type II rail. I think you probably need some fine adjustment as described by Glenn. I have a similar 30 cm rail fresh ex-factory and it works like a dream. But pay attention that the total up/down travel of the locking "screw" is less than 0.5 mm. Often people tighten Arca Swiss knobs and locks too strongly which is un-necessary. You should check your locking knobs on function carriers as well. Tightening should also be extremely progressive and smooth but with an absolute lock on the movement. This is the Arca Swiss feel.



The 8.5 cm bracket locking lever should operate in a very progressive and smooth action and the lever should not touch the rail when totally locked. An actual end-of-travel lever position shift by 10-20 degrees is related to an actual up/down travel shift in the range of 0.1 mm. So the previous owner, after extensive use, might have slightly un-set the mechanism, you might need a fine-tuning.



And you are definitely right to raise the question here. We are not speaking about, say, a 1890's wooden 'field' camera ;-) We are speaking about someting designed to be precise but where uncompromising smoothness and precision sometimes need a fine tuning;-)

Leslie Gordon
24-Sep-2004, 14:05
....and the lever should not touch the rail when totally locked.

That comment from Emmanuel was very helpful. Well, as you probably guessed, I bit the bullet and bought the camera this morning. The dealer echoed Glenn's instructions to me. It took a little trial and error but once I realized that the lever shouldn't be at the rail, it became clear to me how "off" the clamp had become. It was pretty far from the correct position.

Now... any tidbits for cleaning the camera or maintaining it that I should be aware of? :)

Emmanuel BIGLER
25-Sep-2004, 02:07
Leslie. I'll check the actual clearance left between the locking lever and the end-of-slot for my 8.5 cm connecting bracket which has just been calibrated at the factory.

In older "type I" brackets things were simpler, if the clamping strength was not adequate you just had to re-tighten a screw. Exactly like the quick clamping system for racing bicycle wheels, once the priviliege of the Tour-de-France ;-), now applied to all kinds of regular or moutain bikes ;-);-)



But this screw could unscrew easily, so in fact you had no guarantee that the mechanism was always properly set. Exacly like a bicycle wheel clamp. In a sense the more elaborate "type II" clamping mechanism is an improvement, but the new bracket is heavier and more complex. So we are speaking here about refinements, in fact.



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On a second-hand F-line camera, you should also pay attention to the zero click-stops of base tilts and swings.



One of the common problems encountered in good ol' wooden field cameras is that the zero click stops
for tilts or swings are too strong or not precise enough. Remember for the day you'll have to apply a small tilt angle either front or back that about 5-10 degrees is often sufficient to bring the plane of sharpness from vertical to ground/horizontal. So there is a trade-off between a strong force setting the zero click for tilts and the required smoothess to control a fine Scheimpflug tilt around 5-10 degrees.



This trade-off is achieved in Arca Swiss function carriers by a precise machining of rotating parts with no play, the right combination of steel, brass and light alloys to achieve the best trade-off between precision, friction, weight and and resistance to wear, with just a tiny bit of grease to keep things smooth. So the zero click stops for both tilts and swings should be at the same time very precise and very smooth to allow the 5 degree setting easily. This also applies to the optional Orbix tilting movement if you have one on your camera, a fresh Orbix is something incredible and could probably need to be cleaned some day in order to perform like new in the long range. If dust has accumulated in the tilt/swing mechanisms after years of extensive use, it might or might not require a careful cleaning and re-lubricating. I would certainly not even think I could attempt to perform those operations myself ;-);-)



This is more a question of comfort and smooth feeling. You'll not do any harm to the camera if you continue to use it as is. Good luck and enjoy good photo sessions with your monorail.

Emmanuel BIGLER
27-Sep-2004, 10:45
I checked how far the locking lever of my new 8.5cm extension bracket can go. The total travel of the lever is 90 degrees. From the 100% open position (front) it definitely locks the rail after sligthly more than half travel i.e. ~50 degrees. So with use I'm expecting it to travel more than 50 degrees some day but in no case it should reach 90 degrees.