With B&H selling the Tokina 300mm mirror lens for only $200 and an upcoming trip to Panama and Costa Rica, I ordered one to play with. Frankly, I wasn't expecting much, as the reviews say the lens is a little soft and it is not very contrasty. But at maybe 3/4 the size of my 14-140mm and so cheap, I decided it might be worth a try for the wildlife shooting. My expectations were that the experiment wouldn't work out very well and I would probably be selling the Tokina after I returned home. OK, now back home. Here's what I learned. First, the GX7 and the Tokina are a marriage made in heaven as far as handling and focusing goes. The lens has the electrical contacts, so the body knows what lens is attached and knows when I touch the focus ring. The focus peaking works like a dream. 600mm (equivalent) lenses have never been easy to focus even in film SLR days. Typically the split prism in the center of the Nikon screens would black out and focusing was done on the surrounding ground glass. It wasn't easy then and it isn't easy now, but having said that I think the GX7 peaking makes the focusing at least as good as it would have been with my various Nikon Fs. Like any long lens, depth of field is an issue even at a distance. With conventional glass, I could usually count on the lens stopping down and bailing me out a little bit on both focus accuracy and depth of field. Not so with a mirror of course. To eliminate camera motion effects, I wanted fast shutter speeds. Thus, I shot at higher ISOs than I would have with shorter lenses. As high as 3200, which I have felt is my threshold of pain with the GX7. Conclusions: I'll probably keep the lens. The lens got me images I could not have gotten otherwise. They are not technically as nice as I would like, but they are much better than no image at all. A good one will stand printing to 8x10" and would probably impress non-photographers at even greater enlargements. I never saw the extreme flare and very low contrast that reviewers have reported. I always shot with the included lens hood, though, and may not have shot anything near-directly towards the sun. I do have a photo, shot almost straight up, of a 3-toed sloth hanging in a tree silhouetted against a bright blue sky, and the contrast is just fine. The lens demands patience and care. Inexact focus is punished, and the task is made more difficult when hand-holding vs shooting off a monopod (which I did sometimes) or a tripod. Just finding the subject can be a challenge. It's like trying to look for things through a soda straw. My trying to locate animals or birds in a sea of green jungle was not always successful and I missed some shots as a result. I didn't really have a sense that the IBIS was doing anything for me. Maybe it was, but I have many shots showing camera motion at shutter speeds under 1/500th. Overdoing the ISO, which I did, gives a significant reduction in image quality. If I had one thing to do differently on the trip, it would be to shoot at lower ISOs than the 3200 I was often using. I think setting shutter priority at 1/640th and letting the auto-ISO set the exposure might be a workable strategy for most shooting. It's not a replacement for the 100-300mm, which I have owned and shot in Africa. In addition to having autofocus and the ability to stop down, the zoom makes it much easier to find my subject. Start wide, then go long after the subject is located. But the 100-300 is significantly larger and more expensive. So here is a sample: This is the view from our deck in Costa Rica, shot with 35mm equivalent focal length. There is an iguana in the tree, indicated by the small red circle. He's a meter long, maybe a little more. Here's the iguana, full frame. 1/2000th and 800 ISO. Actually it's two iguanas. I was shooting the male in the foreground when the female in the background appeared, crawling along her branch. Note that even at a distance, the depth of field is shallow enough that the female is much less sharp than the male. You can also see the odd bokeh effects of the mirror. And here's a 100% crop of the male. What to conclude from all this? I'll leave that to the reader. For me, I think the lens is a keeper mostly because of its low cost and small size. I can get shots that I couldn't otherwise get and I think my technique will improve with practice. I'll use lower ISOs and use the monopod more. For a serious wildlife trip, like back to Africa, I'll pick up a 100-300mm and leave this one at home or sell it.