on 5 May 2011
I use a Canon EOS 450D and have a sturdy tripod. The 500mm lens, itself, is well manufactured, precise and light-weight. It comes with a small "kit", with useful items such as an air brush, which is a small bonus. The lens-camera adapter is very well machined and a precise and easy fit to both the lens and the camera body. The lens focusing ring is very smooth, sensitive and easy to operate. At 500mm, the lens is usable; it requires some "tweaking" of camera settings and lots of trial and error, but it is usable and even the manual focusing is not a massive problem. There is, unfortunately, a huge "BUT": the 2 x teleconverter, (which is also manufactured to a very high quality) quite frankly, is a waste of money. Since the lens is fixed at f8, with the teleconverter, this increases (or is it decreases?) to f16, which means a much smaller aperture and therefore considerably less light entering the camera. In cases of very bright light, 3 "filters" are provided, which screw in to the rear of the lens. These, too, are very well made and fit precisely and comprise a clear filter for normal use and two darker ones, for situations with considerably increased light (these replace being able to reduce the aperture even further). I'm not altogether sure how useful these will be, bearing in mind the already very small aperture.
It is relatively (and I use the term advisedly) easy to focus the lens manually, using either the viewfinder or the camera screen, although good eyesight and considerable patience are a significant bonus. However, taking a clear picture is still incredibly difficult. I do accept that, since the lens is all manual and very powerful, a lot of trial and error is inevitable and, to some degree, this is part of the "enjoyment" of photography, but it can still be extremely frustrating. When focussing, it is essential to take into account "camera shake" and, when taking pictures, mirror lockup (if your camera has this) can help to reduce this. Don't get over confused about depth of field; with this lens, because of the small aperture, the background will be blurred and the area in focus will be quite small. You won't be able to take photographs of far-off galaxies, distant landscapes or even celebreties in compromising situations! Close-ups of still items, perhaps even the occasional sparrow-hawk, are possibilities, although not from a considerable distance.
So far, I have only been able to produce very grainy, blurred and low-contrast images (and I have taken several hundred). I have used the lens in bright daylight conditions, with a tripod, but have still been unable to produce anything that is usable. It is virtually useless in low light and certainly no good for moving subjects, or any "spontaneous" photography; hand-held is just not going to work. A sturdy tripod, along with remote shutter release and other "steadying" features are absolutely essential. Considerable patience and many trials are also high on the priority list. Because the aperture is fixed, it is a matter of adjusting shutter speed/ISO rating and ensuring the camera is held as steadfastly as possible.
My unprofessional opinion, after trying the lens and reading many reviews, is that it is a high-quality build, light but sturdy and certainly has a "novelty" factor (it looks pretty impressive), but with the 2 x teleconverter, it is nigh on impossible to get good results. There are numerous views and reviews to be found, but these can confuse the issue. If you are an expert/professional photographer, I don't think you'd buy this type of lens. As an amateur, on a tight budget, being able to see and understand the facts is essential. I suspect most reviews relate to the 500mm lens only, rather than its usage with the 2 x teleconvertor. Even with the quality build and the "workable" 500mm lens, the usefulness of this lens is going to be limited. Please be guided by my experience: certainly, research this for yourself, but I'm sorry to say that I truly regret having bought this lens!