2 ACCEPTED SOLUTIONS
Hi and welcome to the forum:
Your issue is one that often dogs wildlife photographers, particularly shooting birds. The challenge is getting close enough to get a good proportion of the animal to fill the frame and this is achieved by several methods.
The Fisher: so named because the photographer occupies a spot, likely camouflaged in a hide or clothed in DPMs, they wait for subjects to come to a previously identified spot within range of their gear and shoot away. Usually those subjects will be attracted to some food source or in a nesting location - note feeding animals to bait them is not a good idea it may well associate humans with food and that's not good if it's a large animal like a moose or a bear. This can bring the the subjects much closer and often birds will not be moving dramatically and against a very bright sky. One must take great care not to disturb or upset the bird or other animals. In such cases one can use devices like tripods or monopods to steady the camera, but it does require a lot of patience.
The Hunter: In this technique the photographer is mobile, roaming around and seeking their subjects actively. The challenges here are not getting close enough to the subject without spooking them, or causing them distress or to become aggressive if surprised or disturbed. Often there is not time to mount a tripod (and they can be clumsy to carry in vegetation, causing noise), so at best one might have a monopod, but often this involves hand-held photography.
This is where technique becomes critical. To get the best from a long lens, holding it correctly is critical, and a lot of folks hold modern cameras like cell phones at arms' length - for wildlife you need to have as stable a platform as possible, so the following image shows the correct posture.
The impact of focal length on shutter speed. To further reduce the possibility of camera shake, conventional wisdom suggests that the shutter speed should be 1/focal length (x2 for crop sensor bodies like your R7). This would suggest that at 400mm focal length, you would hope to be shooting at 1/(400 x2)sec shutter speed. The R7 has both In Body Image Stabilization (IBIS) that works with the lens Optical Image Stabilization of your RF 100-400 to help with hand-hold shooting so likely 1/400sec should be ok, given your arm injury.
Next, let's consider the camera and optics.
The R7 is currently the most capable of the crop-sensor bodies offered by Canon, but it has its challenges. Like most R-series bodies released since the 20221, it has animal eye tracking that, when activated, will find and lock onto the eye or at least head of an animal if there is enough contrast to show it. So, for best results you need to spend some time in the focusing system getting those setting configured - that's where the manual comes in or the video I shall link to at the bottom.
When shooting at high frame rates in electronic shutter mode one can get 30 fps, but the focusing system can struggle with this, resulting in intermittent focused / defocused images. Canon have recommended using a slower shutter speed around 11-15 fps, using first curtain electronic shutter to allow the focusing system more time to react. This may already be set up but you should check that too.
Lighting conditions and the impact on focus and exposure: If the subject is a bird in the sky, it may be fairly easy to lock on and track it, but there is a good chance the bird will be a lot darker than the background of the sky. 
By default, the camera will use evaluative metering that rather averages out the exposure across most of the frame, but that would leave your bird in silhouette if left to that setting. That is where you need to consider exposure compensation to boost exposure over what the camera's exposure system thinks is correct, or use a much more precise metering area to be able to tell the camera what specific point you want it to consider. As a wildlife photographer I use spot metering and lock the metering on something with a mid reflectance before focusing and composing - but there are many other techniques. For birds or animals in forest, bush or other shaded areas that may contain areas of high contrast being able to select that is the mid-reflectance level can be very valuable too.
The RF100-400 lens is a capable unit, but may still be on the short size for distant and small subjects - like birds in flight. When those subjects appear small in the image both focus it is possible to crop somewhat, but there are limits.
Focusing:
The critical element is to get the animal's eye in sharp focus, or the closest if one is closer than the other. The default focusing uses a matrix of points that will normally fixate on the closes clear point of contrast, but this will often not be what you need to focus on - it could be locking onto a branch, leaf or the nose of an animal but not the eye. Here again, precision becomes desirable and I personally use spot focus along with eye tracking. 
I focus on the eye of the subject and once focus is achieved, with eye tracking it should hold that focus while you recompose and take the shot. Quite a few photographers (me included) use a technique called Back Button Focus (BBF), where the focusing function is removed from the shutter button and the AF-ON button on the top right rear of the camera is used to establish focus. If the camera is also set to Servo mode (focusing menu) then a tap of that button will lock the focus, whereas holding it down will track the subject's movement. This is explained in the following video from Canon:
This is further pursued by wildlife photographer Simon D'entremont:
Finally, if you want to get to know your camera controls better, try this tutorial:
There is a lot here to digest and others may offer other comments and preferences, and that's fine, but the videos are great for getting to know the features available. Modern cameras are capable, but they require careful study to use and specific configuration for particular activities like wildlife.
Hi and welcome to the forum:
Your issue is one that often dogs wildlife photographers, particularly shooting birds. The challenge is getting close enough to get a good proportion of the animal to fill the frame and this is achieved by several methods.
The Fisher: so named because the photographer occupies a spot, likely camouflaged in a hide or clothed in DPMs, they wait for subjects to come to a previously identified spot within range of their gear and shoot away. Usually those subjects will be attracted to some food source or in a nesting location - note feeding animals to bait them is not a good idea it may well associate humans with food and that's not good if it's a large animal like a moose or a bear. This can bring the the subjects much closer and often birds will not be moving dramatically and against a very bright sky. One must take great care not to disturb or upset the bird or other animals. In such cases one can use devices like tripods or monopods to steady the camera, but it does require a lot of patience.
The Hunter: In this technique the photographer is mobile, roaming around and seeking their subjects actively. The challenges here are not getting close enough to the subject without spooking them, or causing them distress or to become aggressive if surprised or disturbed. Often there is not time to mount a tripod (and they can be clumsy to carry in vegetation, causing noise), so at best one might have a monopod, but often this involves hand-held photography.
This is where technique becomes critical. To get the best from a long lens, holding it correctly is critical, and a lot of folks hold modern cameras like cell phones at arms' length - for wildlife you need to have as stable a platform as possible, so the following image shows the correct posture.
The impact of focal length on shutter speed. To further reduce the possibility of camera shake, conventional wisdom suggests that the shutter speed should be 1/focal length (x2 for crop sensor bodies like your R7). This would suggest that at 400mm focal length, you would hope to be shooting at 1/(400 x2)sec shutter speed. The R7 has both In Body Image Stabilization (IBIS) that works with the lens Optical Image Stabilization of your RF 100-400 to help with hand-hold shooting so likely 1/400sec should be ok, given your arm injury.
Next, let's consider the camera and optics.
The R7 is currently the most capable of the crop-sensor bodies offered by Canon, but it has its challenges. Like most R-series bodies released since the 20221, it has animal eye tracking that, when activated, will find and lock onto the eye or at least head of an animal if there is enough contrast to show it. So, for best results you need to spend some time in the focusing system getting those setting configured - that's where the manual comes in or the video I shall link to at the bottom.
When shooting at high frame rates in electronic shutter mode one can get 30 fps, but the focusing system can struggle with this, resulting in intermittent focused / defocused images. Canon have recommended using a slower shutter speed around 11-15 fps, using first curtain electronic shutter to allow the focusing system more time to react. This may already be set up but you should check that too.
Lighting conditions and the impact on focus and exposure: If the subject is a bird in the sky, it may be fairly easy to lock on and track it, but there is a good chance the bird will be a lot darker than the background of the sky.
By default, the camera will use evaluative metering that rather averages out the exposure across most of the frame, but that would leave your bird in silhouette if left to that setting. That is where you need to consider exposure compensation to boost exposure over what the camera's exposure system thinks is correct, or use a much more precise metering area to be able to tell the camera what specific point you want it to consider. As a wildlife photographer I use spot metering and lock the metering on something with a mid reflectance before focusing and composing - but there are many other techniques. For birds or animals in forest, bush or other shaded areas that may contain areas of high contrast being able to select that is the mid-reflectance level can be very valuable too.
The RF100-400 lens is a capable unit, but may still be on the short size for distant and small subjects - like birds in flight. When those subjects appear small in the image both focus it is possible to crop somewhat, but there are limits.
Focusing:
The critical element is to get the animal's eye in sharp focus, or the closest if one is closer than the other. The default focusing uses a matrix of points that will normally fixate on the closes clear point of contrast, but this will often not be what you need to focus on - it could be locking onto a branch, leaf or the nose of an animal but not the eye. Here again, precision becomes desirable and I personally use spot focus along with eye tracking.
I focus on the eye of the subject and once focus is achieved, with eye tracking it should hold that focus while you recompose and take the shot. Quite a few photographers (me included) use a technique called Back Button Focus (BBF), where the focusing function is removed from the shutter button and the AF-ON button on the top right rear of the camera is used to establish focus. If the camera is also set to Servo mode (focusing menu) then a tap of that button will lock the focus, whereas holding it down will track the subject's movement. This is explained in the following video from Canon:
This is further pursued by wildlife photographer Simon D'entremont:
Finally, if you want to get to know your camera controls better, try this tutorial:
There is a lot here to digest and others may offer other comments and preferences, and that's fine, but the videos are great for getting to know the features available. Modern cameras are capable, but they require careful study to use and specific configuration for particular activities like wildlife.
