from my understanding, Motion blur and Depth of field are not directly related (since the aperture size/focal length/f-stop and the shutter speed are not directly related to each other), but they are indirectly related through exposure. In order to keep exposure constant, f-stop and shutter speed must be inversely correlated (one increasing and the other decreasing, and so on). One example: The bigger the aperture size (the lower f-stop), the less exposure time we'd need for light to come into the sensor, thus shutter speed could be faster. In this case there will be less depth of field as f-stop is small, but as shutter speed is fast (1/125 in the first image), we'd get zero to none motion blur! In short, the trade-off between depth of field and motion blur comes from the fact that, we want to keep exposure constant (this is just my understanding, so please correct me if I'm wrong)
from my understanding, Motion blur and Depth of field are not directly related (since the aperture size/focal length/f-stop and the shutter speed are not directly related to each other), but they are indirectly related through exposure. In order to keep exposure constant, f-stop and shutter speed must be inversely correlated (one increasing and the other decreasing, and so on). One example: The bigger the aperture size (the lower f-stop), the less exposure time we'd need for light to come into the sensor, thus shutter speed could be faster. In this case there will be less depth of field as f-stop is small, but as shutter speed is fast (1/125 in the first image), we'd get zero to none motion blur! In short, the trade-off between depth of field and motion blur comes from the fact that, we want to keep exposure constant (this is just my understanding, so please correct me if I'm wrong)