This is the first in a series of posts looking to answer the question “Given a set of tripod legs, what is the optimal ball head to pair with those legs?” The previous post on the combined stiffness of a complete leg + head setup gave us the tools to begin to answer this question. Our metric going forward will be to optimize the total stiffness / weight of the legs + head. Our ultimate goal will be a heuristic for choosing a ball head such as “Choose a ball head with stiffness of at least three times that of the legs.” It remains to be seen if such a simple guideline will be possible.

The only thing we are going to do in this first post is look at the general trends of stiffness vs weight of ball heads. This will become important later on. For now though we are just exploring the limits of what kind of performance we can expect on a weight adjusted basis. Diving right in, here is the yaw and pitch stiffness of every ball head I have tested against its weight:

The farther up and to the left (stiffer and lighter respectively), the better the performance. Immediately obvious is that the pitch stiffness of most heads is worse than the yaw stiffness. I’m not exactly sure why this is, but I suspect that it has to do with the stem between the ball and the quick release clamp. There is significant asymmetry here in the way that the stem bends under load. Yaw motions are torsional, while pitch deflections are of a beam deflection type. Tripods tend to be the opposite, with the pitch motions being stiffer than yaw.

The other apparent feature is that there is a strong linear relationship between the weight and the stiffness. There is no reason this should necessarily be the case, but this could be a useful feature to take advantage of in our future analysis. I have drawn two lines on the plot, roughly through the best performing heads. In yaw, the best performers seem to have stiffness around 15,000 Nm/rad per kg, and in pitch, that stiffness is around 8,000 Nm/rad per kg.

Note that a head that performs well in yaw stiffness, also tends to perform well in pitch stiffness and vice versa. So it doesn’t appear that there is a trade off between the two. There are three heads that stand out as particularly high performers. These are the RRS BH-25 on the light end, the Sirui K-30X in the middle, and the Feisol CB-70D on the high end. We will continue to see these heads pop up throughout this series of posts.

A plot of the mean stiffness vs weight tells a similar story as above:

Again we see those three outstanding heads well above the general trend. I have also plotted the three pan-tilt type heads that I have tested in green. The performance is very poor compared to every ball head. There are very good reasons to use pan-tilt heads, but optimizing your stiffness/weight isn’t one of them. That is why I am only including ball heads in this exploration.

Finally, while we are here, we can also plot the stiffness vs. the diameter of the ball as opposed to weight:

This is the harmonic mean of the pitch and yaw stiffness’. We can see again, to no surprise, that there is a strong relationship between the stiffness and the size of the ball. Bigger is better. We see fewer high performing outliers as before as all the top performing heads lie along a fairly consistent line. This indicates that they key to outstanding performance from a stiffness/weight perspective is packing a big ball into a compact and lightweight package. The RRS BH-25 is the epitome of this philosophy. The head has no tension control or separate panning lock, reducing the overall weight.

We have seen that for the best ball heads, the stiffness of the head is roughly proportional to its weight. Weight isn’t what gives the head stiffness, as we have seen plenty of heavy and not stiff heads, but there seems to be a practical upper limit to the achievable stiffness. This trend is going to be a useful reference point going forward for both calculating and making sense of the optimization results.

Of course, with tripods typically

being less stiff than ballheads,

ballhead stiffness isn’t such a huge

concern relative to smoothness of

operation and ergonomics…

The p0 tests badly probably because

of the relatively long and skinny

post connecting the ball to the base,

but it’s smooth as butter and the

tension/lock ring is so good;

conversely I had the BH-25 and found

it grabby when attempting fine

adjustments and awkward to use

because of its size.

In the next posts I am going to try to show just how much difference the stiffness of the head makes. I contend for that stiffer tripods, the stiffness of the head is quite important. But yes, stiffness alone is far from the only important factor. The ergonomics on the BH-25 are pretty terrible. I usually use larger heads simply because it is easier to operate the controls.

Now I want to know how the stiffness

relates to the post geometry. The

post geometry probably sets an upper

limit on stiffness that should be

easy to calculate (assuming a solid

post), but it would be neat to see

how close different ballheads come to

that limit.

As I mentioned, the p0 has a tall and

skinny post, but the Arca-Swiss p1

has a super short and stubby post due

to omitting the drop slot. So I

suspect it’s significantly stiffer.

I recall reading about a super stiff

ballhead someone favored that didn’t

really have a post at all; instead of

a post and a platform, it just had a

big wide cone with the narrow end

attached to the ball and the mounting

stud on the base of the cone. I have

no idea what it’s called, though, so

I don’t have any more information on

it…

I think that you are spot on. I don’t know yet, but I suspect that the post geometry is in fact the limiting factor on stiffness of the head. All three of the high performing heads have short thick posts, and weak ones such as the Gitzos have long skinny ones. It should be easy to calculate, just have to break out a mechanical engineering textbook. I forgot about the P1, that will be an interesting head to test someday. If you think of that cone head, please send it along, I would be curious about it!

I found it, it’s called the Burzynski

ball head.

The Burzynski head looks really interesting. Unfortunately it doesn’t seem like they are available anywhere.

Yeah, and I doubt anyone who owns one

will ever sell it…

The Novoflex MagicBall also has an

extremely minimal stem.

Lensrentals has it available so that

might be interesting to test…

I have had my eye on some of the equipment of over at Lensrentals to test. Will get around to it at some point.