The stiffness of the PD tripod is roughly average for travel tripods and that is to say, it is very reasonable for what it is expected to do. Given the folded size of the PD tripod though, the results are astounding. The stiffness of tubes increases as the tube diameter cubed, so even small differences in tube size have a massive effect on the stiffness. Given the small folded size of the PD and the presence of 5 leg sections, making the bottom leg quite skinny, I had my doubts going in. While I knew what to expect given my experience testing for PD, the performance of this tripod significantly exceeded my initial expectations.
|Harmonic Mean Stiffness||518.45|
|Yaw Stiffness||349 +/- 1 Nm/rad|
|Pitch Stiffness||1007.8 +/- 2 Nm/rad|
|Yaw Damping||0.143 +/- 0.014 Js/rad|
|Pitch Damping||0.213 +/- 0.021 Js/rad|
The stiffness and damping data are the averages of 10 trials for each measurement. The reported error is the standard error, except in the case of the damping data. I have set the error in the damping at 10% as the standard error metric does not appropriately capture the error in fitting to the data. All of the reported specifications are measured, with the exception of the weight rating. The tripod is measured at full height, with the center column (if applicable) down.
The asymmetry in the tube shape causes the ratio in stiffness between the yaw and pitch stiffness to be lower than usual. Typically the leg angle causes the ratio to be around 1:4. Here though, the tube is wider than it is deep to create the space saving profile. Tubes naturally resist bending along their wider axis more so than their narrower one, and that is what we see here. The wider profile of the tube causes the yaw stiffness to be better than we would expect based solely on the cross sectional area of the tube and the pitch stiffness to be slightly worse. This is a good trade-off given that the yaw stiffness is usually the limiting factor in overall performance.
The damping is reasonable and in line with what we see in most travel tripods. I will note that the damping tested here is with the 3/8″ adapter. We do get a little bit of additional damping out of the head as can be seen on the next page. From the testing I did with PD though, I can say that you get a lot of additional damping (more than double the figures here) by using the included PD plate, which has a small rubber damping pad on the top. In most shooting scenarios you will be stiffness limited as opposed to damping, so this won’t matter much. But if you are using larger telephoto lenses with high moment of inertia, you may find that additional damping helpful.
Due to the space saving nature of the legs, the PD tripod by necessity has a fairly narrow center column. Naturally, there have therefore been concerns about the rigidity of the center column and I felt it was important to test this. The stiffness for the tripod as the center column is raised is shown below:
We lose 56% of the pitch stiffness and 40% of the yaw stiffness as the center column is raised to full height. This is in line for what we typically expect for the losses from a center column. The stability of the center column here is fine and well matched to the stiffness of the legs. We see less loss in yaw stiffness than typical because the center column is made from aluminum. While carbon fiber performs better in bending applications such as the legs, it does not do well when both bending and torsional stiffness is required and so aluminum is the preferred choice.
Recommended Gear Limit
The exact gear limit is highly dependent on the external conditions such as wind, and technique, such as the use of a cable release. Under perfectly still conditions using perfect technique, sharp images can be obtained using any tripod. Developing a consistent and broadly applicable set of guidelines for what kind of gear a given tripod can reasonably support is still a work in progress on this site.
On the Peak Design website they advertise the tripod as having “Pro-level stability”. I don’t know what this means except that we already have laid to rest any meaning of the term ‘pro’ in marketing literature. Sure, there will be people who use this tripod in a professional capacity. Should you? Depends on your application. The level of stability in this tripod is well quantified in the data above. If that suits your purposes, great. But please don’t base your purchase decision on a marketers interpretation of what professional means. I wish we could strike the term ‘Pro’ from the lexicon altogether, but that seems rather unlikely at present.
In my personal experience using the PD tripod, I was very comfortable using a camera the size of a full sized DSLR and 24-70 zoom in winds up to about 15 MPH (~24 kmh). Above that and I was getting some vibration affecting the images. Wider angle lenses should present no issue. Telephoto zooms such as a 70-200 should be stable in a 10 MPH breeze and longer telephotos will begin to struggle with long exposures in winds as low as 5 MPH. Fortunately, it is very rare to need to longer exposures with longer telephoto lenses and absolute stiffness isn’t required. The PD tripod will easily hold the weight of most common telephoto zooms. Once you get the large aperture telephotos though, you will want a bigger tripod. If you are hauling around a 500mm F/4 though, presumably you can also afford to carry a bulkier tripod than the PD.
Example Test Data
The following data is example raw data from the stiffness and damping measurements. The relevant information with regards to the tripod performance is entirely contained within the stiffness and damping figures presented above. The plots below are solely present so that the tested stiffness and damping figures are believed. Each plot and the corresponding Fourier frequency space plot correspond to one of the ten trials done on each axis to obtain the test results. For a more in depth discussion on the meaning of these graphs, see the methodology section and the “understanding the test results” page.
Very clean data.
Also very clean.
And here are the yaw and pitch oscillations with the head attached instead of the 3/8″ adapter:
Slight loss in stiffness as expected.
A little bit more loss in stiffness here than in the yaw direction, but still within the perfectly acceptable range. More discussion on the next page.