After losing the 12-24mm lens in the river, I needed a replacement. With the recession and the fact that I no longer feel tied to Pentax, I was reluctant to replace it just at the moment. I bought the 18-55 kit lens, which I am happy enough with. To compliment this, I also bought the Digital King DSW 0.7 wide adapter lens, to provide near 12mm coverage at a reasonable cost.
Here in the UK, the DSW retails at around £70, quite a wad really. My version came for £18 from Hong Kong via eBay. Despite being a fraction of the cost, the one I have looks identical to the £70 version, so I have no reason to believe it is anything but the real deal.
What you get
My version is designed to fit onto 52mm filter size lenses. It is a lot larger at the front though, and will take a screw in 77mm filter, although you are likely to get vignetting (darkening or black areas in the corners of the photo) at the wide setting.
Below you can see a comparison between the field of view with and without the adapter.
This is not an exhaustive test, it is really just observations of how it is in use. It is not a bad idea, and for a quick and dirty solution to give a wide view, a reasonably good solution. As you can see above, the difference when using it is not spectacular. I would have liked a 0.5x effect, but I suspect the problems below would be even more pronounced.
One thing you will notice is that it changes the focussing distance of the lens. This is because it is a single glass element with no correction lens (like the one that also acts as a ‘macro’ lens on other wide adapters. So, when it is on the lens, it focusses closer than the actual distance. The only real problem with this is that it does alter the real close focussing distance, you will not be able to get as close to things with the wide adapter as you can without. On my 18-55 it is actually pretty similar to the close focussing of the 12-24 I used to have, which was never that spectacular.
Image quality also takes a bit of a hit. Firstly, you will notice more vignetting (darkening of the corners) when you use this lens, even if you cannot see the edge in the corner of the photo. Not that bad, a setting of 65 or so will correct it in RawTherapee. Without the filter a setting of 24 will correct the vignetting of the kit lens. It is most noticeable when the lens aperture is widest, stopping down to f8 reduces it, and by f22 it is not noticeable.
Also, you need to careful of the corners of the adapter or any filters as they can be visible at the wide setting. You can place it on top of a filter, for example I have used it on top of my 52mm infrared or circular polarising filter. As it has a 77mm front thread, you can also use that size of filter on the front. Either way, you are likely to get the filter ring visible in the corners. Zooming in slightly or retouching the image will all sort this out though.
The other main problems with the image are the loss of detail at the edges. You can see the effect of the resolution at various apertures below. Again, you need a pretty small aperture of f16-f22 or so if you don’t want everything smeared. Note that the edge views here are from the middle, the top and bottom corners will be slightly worse.
You can also see that there is a bit of blue chromatic aberration (coloured halos on high contrast edges) on the edge of the image. It can be corrected and is not that bad in comparison to the blurring at the edges.
For less than £20, this is actually not that bad a buy. The cheapest super-wide zooms start at about £340, so you can see the benefit if you are tight on cash. That said, it is only available in 52mm and 58mm fittings, so it is only designed to be used with the kit lens. With small apertures and a bit of care, you should be able to get satisfactory results for holiday photos, but don’t expect to sell any to the stock agencies, the image quality is not up to scratch.