Acratech and Hasselblad 203FE Arca-Swiss Adapter Problem
There's an incompatibility between the Hasselblad 203FE Arca-Swiss plate (sold by a number of vendors including ClearSight) and the newly redesigned "pin" quick release clamp on the Acratech Ultimate Ballhead. This is the 203FE AS plate on my 203FE, it replaces the Hasselblad quickrelease tripod plate on the bottom. To the left and right are side rails which reduce the amount of space available for a QR clamp to slide in.
When Acratech redesigned their AS clamp, they increased the thickness of the clamp walls considerably. This made the clamp more solid, but it reduced the side clearance to the point where it no longer fits easily onto the 203FE AS plate.
The idea of having a pin embedded in the clamp is brilliant because it prevents one of the problems in the AS mount, namely that the camera can easily fall off the mount if the knob isn't tightened properly. Acratech designed the new clamp so that you would loosen it all the way and slide the camera in diagnally from the side (instead of sliding it in from the front or back). But you can see here that the Hassie side rails prevent this from happening.
The right hand side clamp wall curves outward and is only about 2 mm too thick to slide easily in.
If you try to slide the camera in from the rear, it goes in - barely - until it hits the pin stop. But the clamp wall is rubbing against the side rail, which is not a good thing for either one. In this case, reducing the side of the clamp by 1mm would solve the problem of excess rubbing.
Really Right Stuff Clamp
In comparison, this is the Really Right Stuff clamp. As you can see, the side walls of the clamp are considerably thinner. This means that it easily slides in from the front/rear or diagonally from the left or right without problems.
The outer walls of the RRS clamp are straight/paralel with the inside clamp, which also works to reduce problems.
Specs and Solving the Problem
I'm working with Acratech to solve this problem. They've been very responsive so far and I have no doubt that it'll be quickly fixed. Reducing the maximum thickness of the clamp walls by about 1 mm would solve it for sliding it in from the front; by 2mm would solve it for sliding it in diagonally from the side.
Here are some measurements.
Hassie 203FE AS Plate
38mm wide
Hassie 203FE Side Rails
61mm left to right
Acratech QR Mount Closed
60mm wide
Acratech QR Mount Opened
64mm wide
Acratech Side Wall Thickness
13mm
knob side
12mm
RRS QR Mount Closed
53mm wide
RRS QR Mount Opened
57mm wide
RRS Side Wall Thickness
11mm
knob side
9mm
Ballhead Name
Ultimate Ballhead
Monoball B1
BH-55
PH-163 / PH-273QL
Manufacturer
Acratech
Arca Swiss
Really Right Stuff
Velbon
Place of Manufacture
USA
Italy
USA
Japan
Date of Manufacture
Design
Unique 45° open ballhead design.
Fully trapped elliptical ballhead with traditional single notch design
Fully trapped spherical ballhead with dual notch design
Fully trapped spherical ballhead with dual notch design
Controls
Primary ballhead friction control.
Secondary drag friction control (normally locked)
Pan head friction control
Primary ballhead friction control.
Secondary friction limiter.
Pan head friction control
Primary ballhead friction control.
Pan head friction control
Weight Limit
10kg
40kg
23kg
? / 5kg
Height
104mm
114mm
94mm
109 / 114mm
Ball Diameter
54mm elliptical
55mm
Weight
450g
770g
840g
400g / 455g
Retail price
$280
$400
$455
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