| sent on September 01, 2012 (13:52)
Review: Acratech GP-s Ballhead
This is an excerpt from my review that is published on my website www.nature-images.eu under Reviews: Acratech GP-s Ballhead
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Acratech GP-s on Gitzo 1542T Traveler Series 1 tripod.
Performance
As far a I can judge for the time of writing this review - having tested the Acratech GP-s at home and used it once outdoors - it meets almost all my expectations that I had when I was ordering it.
The Acratech GP-s has a solid construction described above and works accordingly. The ball movements are smooth - though not so smooth as in Novoflex Classic Ball 5 whose ball is much larger - and allow precise positioning of the camera. I didn't expect the GP-s head to support 11.3 kg in tilted position because even the much larger and stronger Classic Ball 5 is capable for this. Acratech claims that their other product - Ultimate Ballhead - can withstand the impact of 13.6 kg (30 lb), and even shows photos of tests. However, the head is shown only under vertical pressure and horizontal tearing. There is no evidence of the same ability when the load is tilted, for instance, at 45 degrees which would better represent a real life use of it. I don't believe that such heads would have it. Anyway, it appears that my Acratech GP-s would barely support 5 kg in that position. I tried it with about 4 kg load, and had to tighten the ball lock very firmly to prevent my camera and lens from falling down immediately. I just can't imagine that the same can be done with over 11 kg.
The same applies for friction (or tension) control. In the user's manual we read the following: "Many photographers adjust the Ball Tension Knob tightly enough to keep their camera from flopping over when they le go of i, but loose enough to aloow them to position it for a shot." Yes, this is what friction control is for, and it works fine in Acratech GP-s only with a load up to 2.5-3kg. With heavier gear, the friction control is almost unusable. When I mounted an EOS 5D Mark II body (about 900g) and EF 300 mm F/2.8 L IS USM lens (about 2.5kg), i.e. total of about 3.5kg, the tension of the ball wasn't enough to support this load even for a moment: It was flapping over immediately. How about 11kg?
With the same load of about 3.5kg I also did a test of locking precision. Under heavy load many ball heads sag a little when the ball lock was tightened. This is a problem when a macro or super telephoto lens is used that need to be aimed precisely. My setup sagged for at least 2mm. However, it is difficult to say if it was the tripod or the head that was responsible for it. Certainly, such a lightweight tripod is not supposed to provide perfect support for heavy super telephoto lenses. In the same test with a 150 macro lens and the same camera, i.e. with the weight of less than 2kg, I didn't notice any changes of the camera position.
The Acratech GP-s fits almost perfectly between the legs of the Gitzo 1542T when it is folded (see the picture below), so that the total transport length doesn't exceed 43cm.
Gitzo 1542T with Acratech GP-s folded to minimum size for transportation. You see that the combined length of the tripod and head doesn't exceed 43cm this is currently the minimum that can be achieved for professional tripods.
Deficits and Drawbacks
Acratech recommends the quick release plate with screw fixation for use with large lenses. This was my reason to choose this version and not the one with leveler fixation. The plate with lever fixation has a very good scale that makes centering the camera and positioning focusing rails and nodal point adapters easier. Now, I am missing such a scale in my quick release plate. I assume that the scale was absent in the original version (with screw fixation) and the manufacturer added this obviously very useful feature later when the version with leveler was produced.
There is no friction limit control in Acratech GP/GP-s. Instead, the available knob adjusts friction gradually. The friction limit control that exists, for instance, in Novoflex Classic Ball or Markins Q-Ball, allows you to choose from several levels of friction. I like this more.
The friction control knob is too loose; even tightening it very firmly doesn't help with a 3-4kg load: The camera tilts over as soon as you have removed the hand that was holding it.
The ball lock wheel in Acratech GP, when it isn't firmly tightened, performs similarly to friction control: The camera isn't locked in position though their movements are not completely free. If the camera and lens combo is heavy, it will immediately tilt over if you loosen this screw just a little, and the friction control mechanism even tightened for full strength wouldn't prevent it. I wished a leveler instead of this wheel, like in Classic Ball and many other ball heads, that would lock or unlock the ball. In other ball heads, such as Arca Swiss Monoball, that have a wheel for locking, this wheel doesn't need to be tightened completely for the ball to be firmly locked. In Acratech GP you have to tighten it and to double check if your camera doesn't move after that. This is pretty annoying.
The head can support a 3.5-4 kg load in tilted position, and only if the ball lock knob is very firmly tightened. This is enough for most applications of outdoor photography but much less than 11.3kg promised by the manufacturer.
The ball of the Acratech GP is quite small. For the version GP-s that is intended for lightweight traveler tripods this is good because it reduces weight and size of the head. Since I have a GP-s for use with a Gitzo Traveler tripod, I am not complaining. However, for the version GP that is supposed to be used with larger tripods, it would certainly be a weakness because a ball with larger diameter would allow much smoother movements of the camera and its more precise positioning. Also friction control works better with large balls.
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Read the rest and see more pictures at Reviews: Acratech GP-s Ballhead |
| sent on September 14, 2012 (17:41)
Thanks for the review!
Looks good. Personally I've bought a Markins Q3. Excellent ballhead, I had to sell it and now I regret de decision! |
| sent on October 06, 2012 (15:49)
Christian, my main reason to choose the Acratech head was its panorama feature (i.e. possibility to use upside down). Otherwise, I would have preferred the Markins, too. |
| sent on October 06, 2017 (1:24)
What do you think Afterhours 5 years? |
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