>>3193092I really wouldn't recommend any of them under 500mm. The benefits from 500mm just are not there for 300mm. I also don't recommend using the 2x Teleconverter that most of the cheap ones come with as they merely enhance defects, if you want to get "good looking" photos. If you merely need to capture something closer, go ahead and use it. Also, you really need to know that their focus is "soft", meaning "what the fuck, why can't I get this focus sharp as my other lenses!?" and difficult to get into focus in some instances, depending on how well you can see your camera's screen or viewfinder. You also should use a lens support, like the, "Manfrotto 293 Telephoto Lens Support," to help stabilize the lens. A beefy tripod that doesn't flex is also very nice, otherwise when you tighten the head the head will droop slightly changing your framing, though that is really only a problem if you don't have a lens support. Those balance the weight. You may also need to sandbag the legs, depending on circumstances. You can shoot freehand, but you really need to know what you are doing in respect to your camera's manual settings and your photo composition.
Basically, the learning curve is fairly steep with these mirror lenses. Once you "get it" then using it becomes much easier. I don't recommend these for someone with little patience, but any beginner with patience can learn.
