Wideangle closeup with 18-200VR and K-1 extension tube

Started Jul 18, 2011 | Discussions thread
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Wideangle closeup with 18-200VR and K-1 extension tube
Jul 18, 2011

After you got your first DSLR with a kit or superzoom lens, have you ever wandered what happened to that wide-angle macro mode you had on your old P&S? You surely didn't love the short working distance and you likely preferred the subject isolation that comes with longer macro lenses. But now and then one likes the "deep focus" impression that comes with wideangle due to low relative blur of the background (although there is no more DoF technically).

Well, it so occurs that this is achievable with a short FL, 18mm on various DX zooms is just fine, and a very short extension tube, like the thinnest Nikon K-1 ring (5.8mm). Anything thicker likely won't work because the working distance gets too short; with the K-1 it is about 3 cm (these lenses may be also reversed but then you get into super-macro rather than close-up range).

Unfortunately the old K-1 is fully manual, with no aperture coupling etc. It fits current cameras fine, but it is very tight with electric contacts of AF lenses, so one should preferably shave off some metal if not sticking with pre-AF lenses. Regarding possible further modding for more convenient operation: there really isn't any room for adding electric connection as with Kenko auto tubes; one may be able to add a Dandelion chip for metering but there is very little space for mounting its support; one would have to extend the aperture lever of the lens to regain auto-aperture by the body but I'm not sure how this'd be done reversibly.

Some first-time samples... "Deepest" focus with the aperture almost closed, so bright light is required to get useful shutter time at base ISO. One should pay more attention to dust on the front element than I did And dust on your sensor may happen to be the only really sharp thing in your image at this aperture - so don't peep for sharpness cause there is none! You don't really need a sharp lens for deep-focus; resistance to flare and small physical size seem to be more field-relevant. Compared to a typical P&S: P&S requires less light for base ISO so is more handholdable; but modern Nikkors have much more DR at base ISO so fare better if playing with midday sunlight and pseudo-HDR (these are quick&dirty Picasa raw conversions).

If you want to reduce diffraction blur or get more light in, you need to stop down the aperture a bit by fixing the aperture lever with a piece of cardboard or rubber. But the deep-focus effect decreases. Samples at unspecified intermediate aperture...

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