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Question: Is the panning smooth?
Document: After 2 months of continuous use - I can say this is really well built and user friendly head. I used several lens [24mm, f/1.4  to 300mm, F2.8 VR] on D800 for long exposures. This ball head is solid yet smooth for panning.
The knob itself has a fair amount of friction to it, and it's smooth and precise to turn. When released, the panning of the base is well damped and smooth, surprisingly so. I work with a fluid video head, and while It's not on that level, you certainly won't experience any "stuttering" if you do indeed use it for real-time panning. It is however damped enough that it will limit the speed of your panning.
I was there myself. I was so settled on one brand for a time I knew I'd be back. I love being wrong sometimes. Other than that - the knob placement is perfect. With the lock knob facing you in the starting position, and the plate turned so that the spirit levels are "up" when the camera is rotated to the 90 position the panning base lock is on your right.
The lower base is has scalloped edges as do many heads to facilitate gripping and removal. They are nicely done and the care in machining is evident. There is a notch in the base with an arrow markings for reference when panning. The numbers appear to be laser etched and are extremely clear and legible.The odd styling of the slightly curved body differentiates the Sirui from every other head on the market.
Pretty simple, but not always. The Sirui has a single tension/friction knob for (1) to lock the base position or allow rotation/panning. For the ball itself (2) it has a combined friction and locking knob. This is accomplished by a small friction screw set within the larger locking knob. Many other brands have a separate friction knob, and there's advantages/disadvantages to both layouts.
Could be slightly lower profile- QR quick lever not available- Panning QR base also not an option- Logo appears screened on, not etched or a plaque- Packaging & presentation could be betterBottom line:I believe there are ball heads out there that are more attractive. There are ball heads out there with better specs. There are ball heads out there with more features. There are ball heads out there that are functionally identical - or even superior.
Very smooth with very good reviews comparing this to much more expensive heads. I like the arca swiss plate too.
This might be one of my few complaints about the K-40X, I would prefer the numbers run sequentially all the way up to 360 (345 in number) so I can tell where I am anywhere on the line. While I don't usually use it this way I can certainly see a time for this need. If panning precision is paramount, then look elsewhere.The window is just wide enough to read one of the other numbers so you can tell which way you're going.
Yes, some are better. Some don't even have one! I have to go back and think that the panning base might be a cost cutting corner - but really it's more a design choice. Maybe they cut corners on using less paint?After setting the friction of the lock knob where you want it, moving the camera around is joyous. It's completely linear and you can apply an awful lot of friction to it and it can still move very smoothly, with perfect damping into position.
There are better designed systems out there, and you can pay for it. I don't believe however there are many that are of better materials or build. This is absolutely nothing that I would feel needs replacing - but would suggest Sirui offers a quick clamp system and panning head in the future. The panning QR head is useful for incremental rotation adjustments once you've angled your ball head and locked it.Ball Section:As I've mentioned, the ball is a massive 54mm hunk of aluminum.
Answer: I have had several ball heads and this is absolutely this best value. The panning is smooth but it is not a video head that is designed to pan.