Gimbal tripod heads make using big super telephoto lenses very easy. With a level tripod under them (and the lens collar tightened at precisely 0° or 90° rotations), gimbal heads allow a neutrally-balanced camera to be easily panned and tilted up or down with the camera always remaining level. All of the gimbal heads I've used provide an adequate range of motion for most of the subjects typically encountered, but occasionally, there is a need to shoot at a strong upward angle. For me, those occasions seem to frequently have the word "eclipse" associated with them and fresh on my mind is the Jan 2019 lunar eclipse.
When shooting at a strong upward angle with a gimbal head, the bottom of the camera will typically impact the tripod apex and that impact will solidly prevent any further upward angle to be achieved. Most of us photographers will not let gear get in the way of a good image and there are some work-arounds for this one.
Remove the Battery Grip
When the bottom of a camera impacting the tripod is the problem, a battery grip compounds the problem. Remove the grip to gain some extra degrees of upward rotation. If battery life is going to be a problem, periodically swap out the drained battery with a fresh one.
Before reading any further, I need to raise a very important point: using any of the strategies discussed below will destabilize your tripod and the entire setup tipping over will be a real concern. Use extreme caution if implementing any of these ideas and be ready to catch your rig if tipping happens.
Highly recommended is the use a very strong tripod (the UniqBall IQuick3Pod 40.4 for example). Extending one or more of the tripod legs longer while using the next-higher leg locks can provide a larger, more-stable footprint. The orientation of tripod legs relative to the camera's weight can make a difference in stabilization. Also wise is to strap/stake the tripod down, add weights to the tripod feet and/or to use counterweights. Pressing long, spiked tripod feet deep into the ground can also aid tripod stabilization.
Tripod Leg Orientation
Orienting the tripod legs so that the camera is centered between two of them usually provides the camera the most range of vertical motion. If the subject will be moving horizontally (solar and lunar eclipses check this box), the tripod may need to be repositioned to keep the camera centered.
Lens Plate Position in Clamp
Observe your setup and determine if adjusting the lens plate or tripod foot dovetail's location within the gimbal head's clamp will provide additional clearance. Remember that longer lens plates offer a greater range of adjustment.
Raise the Gimbal Head Cradle
When using a gimbal head with a height-adjustable cradle, such as some of the excellent Wimberley Gimbal Heads, typical is to place the center height of the lens at the axis of the tilt pivot. This position provides ideal balance and handling. However, raising the cradle higher will raise the camera higher above the tripod apex, providing more clearance and allowing a greater degree of camera tilt. The cradle is raised only partially in the above image, but this height provided enough angle to photograph a high-overhead sun (important: solar filter in use). This tactic also moves the center of gravity of the camera and lens combination when the lens is not positioned level. Tilting up will then make this setup back-heavy.
Use a Tripod with a Narrower Apex
Tripods designed for big camera and lens combinations often have big, broad apexes. While a large apex is great for strength and rigidity, it can impact cameras at lower angles than narrow apexes. If a strong-enough tripod with a narrower apex can be used, a few degrees of upward angle may be gained. Note that the tripod legs can also be the first-impacted. The top of the legs being positioned tighter together can be helpful in this regard.
Tilt the tripod Apex
If the tripod and head combination will not provide enough upward angle, it might be time to tilt the tripod, or more accurately, tilt the tripod apex to move it out of the camera's way. This may be as simple as extending a leg or two by a short amount or it can be more involved such as using far-rear-extended legs positioned in the next-up angle lock (reaching back like the wheelie bars on a dragster) with the front leg angled more sharply toward the ground and raised higher.
Tilting the apex of course eliminates the level base that is ideal for gimbal head use. One solution is to use the camera's tripod collar to level the camera each time it is repositioned. Much better is to use a leveling base or a tripod that has a leveling base built in.
Use great caution with the tilted-apex strategy as the tripod can become strongly unbalanced.
Reverse the Vertical Arm
If the gimbal head uses a vertical arm design similar to that of the Really Right Stuff PG-02 Pano-Gimbal Head and FG-02 Fluid-Gimbal Head, reversing the vertical arm places the camera to the side of the apex, clearing potentially great amounts of space. The image above shows a pro-sized DSLR (Canon EOS-1D X Mark II) and a non-gripped Nikon D850 is shown in this article's lead image.
Both of these rigs are shown with the reversed vertical arm as close to the center of the head as possible. Moving this arm toward the other end of the horizontal panning base would permit even more rotation, potentially 360°.
Assuredly, this technique is going outside of the manufacturer's intended use for this gear and tipping of the tripod is a serious risk. Consider positioning a longer-extended leg locked into the next-up angle lock under the camera and lens' center of balance. Also note that the right hand (or a reaching-over left hand) will be needed to access the gimbal head's now-right-side-located tilt angle lock.
Use a Video Head
Some video heads are able to direct a tripod-collar-mounted lens straight up, and the heads with a counterbalance avoid the lens flops risk.
Use a Ball Head
With the tripod foot raising the camera up and a drop notch likely available for use, a very high upward angle can often be achieved when using most ball heads. The downside to this option is that using a big, heavy lens over a ball head is not ideal and such a lens tipping over can cause an entire tripod to crash to the ground. Finding the sun and moon in a 1200mm angle of view while using a ball head is very challenging and keeping that setup level increases the challenge. But, it can work. A strong ball head is needed if the lens is substantial in size.
Mount the Camera Directly to the Head
I hesitate to offer this suggestion due to the awkwardness and risk involved, but most tripod heads are capable of angling a mounted camera straight up. A large, heavy lens supported by a camera's tripod mount will make engineers cringe and the setup is difficult to manage with a high risk of toppling over. However, this option can orient a camera and large lens straight upward. As always, you are at your own risk.
I don't shoot at strong upward angles with my big lenses very often, but when I do, I quickly remember that camera or lens contact with the tripod quickly becomes an issue when using a gimbal head. While perhaps none of the above strategies may be the perfect solution, hopefully a combination of them can get your upward shooting angle job done.