maandag 19 september 2011

using M42 lenses on your nikon: Glass vs non glass adapters

Glass vs. non-glass M42 adapters for Nikon

There are a lot of good lenses out there which are sometimes even cheaper than the old Nikkor lenses I normally use. They all have the Pentax screwmount, also known as the M42 mount. Unfortunately Nikon is the worst brand to use lenses on with another mount. Canon cameras, for example, can use an adapter without glass to obtain infinity focus. But because the difference in Nikon cameras between the sensor/film and the lens is longer than with most brands you can not obtain infinity focus without an optical element in your adapter.

However these adapters are not known for their optical quality, usually they go for 30 euros on Ebay, one can hardy expect any quality glass for that price.
In the summer I bought a Helios 58mm f/2 lens because of the “swirly bokeh” it produces when the background is full of these out of focus highlights. I thought that I would become frustrated with the lens if I could not use it until infinity so I ordered a relative expensive one and hoped that because of the price the quality would at least be a bit better.

Unfortunately it would produce extremely soft images, especially with the lens used wide open. After a bit of research I found out that the reflections between the adapter and the lens itself were most pronounced when there was a lot of light coming through the lens.
Stopped down the images look kind off alright, but it was certain that I would never get really sharp results from this combo.
I tried and I tried but I could not get a moderately sharp image wide open, when I shot a portrait, it would like one of these fashion photos were the editor went a bit too far with removing blemishes from the model’s face. And worst of all, somehow the adapter corrected for the swirly bokeh, the only reason I wanted this lens.

Luckily I ordered my adapter from a very friendly seller, and he accepted my complaints and let me return it. At the same time I ordered the non-glass adapter, so I could at least use my lens. The difference between your maximum focus distance and infinity differs per focal length, wide angle lenses suffer the worst from this, while some long telephoto lenses can focus up ‘till 10 meters. A 58mm gives you a maximum focus distance of something like 4 meters. You can make a headshot of your model, but that’s it. (and actually that’s the only way I wanted to use the lens, for portraits)
But because there’s not glass between the lens and the sensor/film the optical quality of the lens remains, and I have my swirly bokeh back.

So although the Nikon/M42 combo is not an ideal one, you can get some cool lenses for a relatively low price, even though (at least I would recommend using a non-glass adapter) you won’t have infinity focus.

Thanks for reading,