Accessories – Reversing Ring
The reversing rings, together with the extension tubes and the close-up lens, is the perfect solution for those who want to enjoy macro photography without having to spend a fortune to buy the specific objectives.
After seeing the details tubes and lenses, eventually we begin to reverse rings which, as you can guess from the name, allows mounting on the contrary a lens on the camera body. A lens mounted on the contrary works a contrary optical court (wide angle) will produce an exaggerated magnification, a tele or zoom will produce a result a little ‘more decent.
It is mostly of metal rings, threaded on one side (for screwing the lens, like a filter) and the other, the bayonet coupling of the machine body (eye then both the machine model that the diameter of ‘aim to reverse).
The main problem is that, for the rings on the market, it lacks the electronics (of course, being the contacts to the outside) you lose any type of automation and control, including the one on the diaphragm http://smilesmultimedia.com. For the latter, essential, the easiest solution is to predetermine the opening. With the aim properly mounted, it should set the aperture you wish to use, press the view button deep and holding the lens release. In this way the diaphragm is locked at the opening chosen.
By contrast, in addition to brightness, there are also counted by a reduction of the sharpness (again due to the magnification factor). As with all enlargers (the tubes or the lenses), also in this case there is the problem of the increase of the sensitivity to the moved, so as to need almost always use the tripod.
We come to quality in fact there are major problems to the objective mounted right, although the risks associated with this practice are not negligible because we are exposing the internal optics outdoors (gentler) and the elettronica.Per this reason many photographers buy old fixed focal length lenses from sacrifice.
Normally most of photographers does not go beyond the teleconverter 1.4X low price, light loss after all acceptable and a multiplication factor that can transform, for example, a 105mm to a 147mm. Obviously preferable to mount a teleconverter on fixed perspective the brilliance of the original will in fact be greater than a zoom lens, to the benefit of the final shot.
Last note autofocus eye. With f 8 may start going into crisis because of the already low light introduced by the multiplier. These objects often forced to use the diaphragm fully open.