Opteka 800mm f/8 Telephoto Mirror Lens for Nikon D40, D40x, D50, D60, D70, D70s, D80, D90, D100, D200, D300, D700, D3100, D5000, D7000, D3, & D30 Digital SLR Cameras

Despite my recent unfavourable comments to an earlier review I finally decided to purchase this lens, mostly because for an 800mm lens it is cheap, and unless I win the lottery I am never going to pay £7-8k for a Nikon telephoto lens.

When I attached the supplied T mount adaptor to the lens I found it to be loose allowing the whole lens to rotate, I found three fixing screws around the circumference which could be tightened down to stop this, fix the lens to your camera first so the lens is the right way up when you tighten these, the screws are not very obvious and appear to be hexagonal headed, I could not find an hex key to fit but eventually found a jewellers screwdriver that did the job, the screws were very tight, making me wonder if I was doing the right thing at first.

There were no instructions to tell me to do this and no tool supplied to give me a clue as to what needed doing.

The first thing I found when I tried it with my Nikon D80 was that the camera did not know the aperture of the lens, I had assumed that although the lens is fixed at F8, there would have been some feedback to the camera to allow the metering to work, but the only way I could get it to work was by setting the camera to manual and guessing the shutter speed.

The focusing is manual only, it is very coarse and difficult to get right, which could be a dissadvantage if you are trying to photograph a bird before it flies away.

I did not however consider it to be too heavy, it is lighter than my 50-500 Sigma plus 2 x converter which is the only other way I could get this sort of magnification, I had hoped that its more compact size might let me get away with a tripod, but no, you definately need a tripod.

Presumably because it probably has less glass to hold back the light than the 50-500 and 2 x converter the images appear brighter, and two images out of the twenty I have taken with it so far were not bad!

It is a lens that needs patience, practice and to be a good judge of exposure, something which I suspect most of us have lost a little of, mostly due to modern cameras doing everything for you.

Build quality seems surprisingly good, it is solid and metallic.

If you need a lens with that sort of magnification for professional reasons, then sorry you are going to have to spend a few thousand pounds, if you are a keen amateur like me who can afford to risk a couple of hundred on this, then go for it, you probably will not be dissapointed.

I would recommend that you save a bit more and buy a zoom lens with a range up to 500mm before you look at buying this, you will find it far more useful.

I bought this shot mainly for moon shots and the delivery was very fast, managed to get it the day before a full moon.

I must say this is a very badly designed lens, the 105mm front filter size means it is VERY wide and focusing isn't easy, hand held or on a tripod. With a light camera I was able to handhold at 1/125th pretty easily(and despite what people say about mirrors, I was using ISO200), being out of focus is a little more likely than camera shake from my experience, mainly because focusing with such a light camera and lens means it does shake a lot in the view finder. The barrel appears to be metal(cold to the touch, feels nice and solid when tapping it with your finger), the rear of the lens seems to be plastic but the screw in mount and the Nikon converter provided was all metal.

What I REALLY would love to have seen on this lens is a dedicated tripod mount. The lens(based on what I found on another sight) weighs 900g grams and it is very wide at 105mm, my camera weighs(again from what I can tell on another website) weighs just 600 grams without a lens, so having it mounted on a very sturdy tripod the weight of the lens alone changes the composition ever so slightly since you need to mount the camera to the tripod, compared to say a 1.1kg glass lens with a dedicated tripod mount which doesn't have such a problem despite being much heavier and much longer.

Optically it's very soft and has poor contrast. The bokeh is strange however all mirror lenses have this problem. Great for moon shots, not bad for bird shots but for anything else I would imagine it's too soft for anything other than printing to a post card. To give you some idea the cheaper 55-200mm "kit lens" from Nikon is much shaper and much MUCH better for contrast, this is not a fair comparison however, the two lenses are completely different and for different uses. From what I can tell, the only good mirror lenses for sharpness are the older and harder to find Russian 500mm lenses which are about 3 times more expensive.

So, why buy this lens? It's cheap, it's light compared to glass lenses, 1200mm focal length on crop and also works on full frame cameras. The lens is cheaper than the sharper 500mm mirrors but as I said these are hard to find used and they aren't in production any more. On a bright day expect to use 1/200th a second at 200 ISO, I wouldn't bother on darker days. Moon shots I found are best underexposed, so around 1/125th and 200 ISO.

PS, the lens focuses WAY past infinity which may or may not be ideal for some users.