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

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.

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).

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.

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.

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.

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

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.

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.

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;-)

....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? :)