Olympus DPS I Binoculars 8-16 x 40 - zoom - porro

The clarity of this product was nothing short of stunning. On 8x magnification the image was pin sharp and clear. When using 16x magnification some support is required for a steady image but this is not a negative comment. The focusing wheel is very responsive and easy to use. I would thoroughly recommend this product, especially for wildlife enthusiasts.

I was looking for a compromise between great optics (usually found with 50 mm lenses) and small size. For me, these offer the best of both worlds - small enough to take on a hike, but with a good clear image. Even with 16x zoom, it is possible to have a steady image. I use mine on 16x zoom most of the time, so I'd be happy not to have the zoom - maybe it will come in useful one day. My only complaint (and a very small one it is) is that the lens covers are not attached to the binoculars, so one has to be careful not to loose them. Highly recommended.

I've owned a pair of these for about 18 months and have used them thoroughly in that time. I'm a member of the RSPB, WWT and my local Wildlife Trust, and I regularly take these binoculars birdwatching. I bought them to get back into birdwatching after 20 years away from the hobby. They seemed good value for a brand I trusted and the zoom sounded like a great idea - 8x magnification for scanning around and then up to 16x for more detail was my theory. However, to be honest, I now wish I'd done a lot more research before making a purchase.

At the lower magnifications(8x to 10x) the image is bright and clear. There is also a good depth of field meaning minimal refocusing even when scanning across a lake or open field. However, the higher you go the more the performance drops off. At 16x magnification the image is noticeably darker and quite fuzzy. Also, at 16x the depth of field is extremely shallow which means it is difficult to attain perfect focus and you are constantly having to refocus if the point you wish to view changes slightly. You will also need VERY steady hands to use them at 16x - even with both elbows planted on a flat surface the image can be a bit shaky.

A minor bugbear is that when you zoom in or out on an object, it doesn't stay in focus and you need to refocus each time, so you might miss some action or lose track of a bird in the process. After a while though, you get used to how much you need to adjust focus and in which direction to minimise viewing disruption, but it will still take a couple of seconds to get sharp focus back.

At 8x the field of view is 5°, which is OK, but could be better. The field of view is basically the width of the image you see through the lenses. The greater the angle the more you can see without having to swing the binoculars left, right, up or down. 7° or more seems to be the benchmark for a reasonable pair of bins. At 16x the field of view drops to 3.4° as you'd expect with the higher magnification.

Close focus is fairly poor at 10m. Many bins will focus allow you to focus on objects as close as 2m.

These binoculars are "porro-prism" type binoculars. This refers to the configuration of lenses and prisms inside the casing that reflect the image to the eyepieces. It gives them the traditional binocular dog-leg shape. However most birders these days favour "roof-prism" type binoculars that have the objective lens in line with the eyepieces. Roof-prism bins are comparatively smaller and lighter than porro-prism equivalents. The benefit of porro-prism binoculars is that they are generally less expensve for similar optical performance.

I must say at this point I cannot fault Olympus' after sales service. The zoom mechanism on my binoculars broke recently, leaving them stuck at 16x zoom. Olympus replaced my binoculars with a brand new pair and had them back to me within 2 weeks.

So, to sum up, these binoculars are not bad at all at the lower zooms and are reasonably good value at around £50, but the zoom lever and 16x magnification in my opinion are a bit gimmicky and I rarely use the higher magnifications. In hindsight, I probably should have bought something like a pair 8x42 or 10x42, fixed zoom, roof-prism binoculars for birdwatching. And I DEFINITELY should have gone to a dealer and tested a range of different models.

Edit 31/07/12:
Just to add to my review above, I was recently caught out in a heavy rain shower while at RSPB Conwy. Unfortunately, my Olympus 8-16 x 40s proved not to be very watertight. One of the objective lenses fogged up on the inside as moisture had got into the barrel - even though I'd tried to keep the majority of the rain off the binoculars by holding them inside my jacket when not in use. This was not particularly surprising, I suppose, as they do not claim to be nitrogen filled and waterproof like more expensive pairs. And I guess the zoom mechanism makes them more vulnerable to moisture ingress. However, the fogging made them almost impossible to use. After a week in a large Klip Lock sandwich box packed with silica gel sachets and they are clear again, but I have since bought myself a new pair of RSPB branded binoculars. The Olympus binoculars have been relegated to a stand-by pair that I keep in the car.