Hey all. I'm brand new and happy to be here. I look forward to all of your advice, as I know I'm exactly where I ought to be. Here's the situation: I am looking to get into professional equine photography. I've owned and worked with horses majority of my life, have taken a few photography courses, and already do commissions for graphic design -- so, I'm really excited to try and expand in order to combine several of these hobbies. This means I am in desperate need of a new device and lens suggestions for said device. I will be photographing very large, rapidly-moving subjects. Stills will be a given on occasion, but every client always wants a crystal-clear portrait of their galloping horse. I need a fast frame-per-second and shutter, quick buffering, something that doesn't weigh 1000lbs as I'll be hiking with it in-hand, and I would love a camera that preforms well in low-light. Beyond that, I'm hesitant to make any concrete decisions just yet. I was initially looking into the Nikon D4, but it looks fairly hard to get your hands on and appears to also be bank-breaking. This has lead me to exploring options like the D810 (Under $5000 with 24-120mm Lens Kit), Nikon D750, and Canon 5D Mark III. I'm finding it fairly difficult to compare them with the sort of close-up/action shots I want to do in mind. There are a few reviews out there, but mostly for birds -- so, I have no idea whether or not horses will produce a remotely-similar product. Do any of you guys have other suggestions entirely? Experiences? I'm open to hearing it all and am super grateful for whatever you can provide me with. Good device/lens combinations would be fantastic, as well. I don't have much experience in looking for lenses. Thank you so much!