When I got my X-E1 I decided to get a mount adapter so I could try out some old film lenses to open up some more creative possibilities. After a bit of research it seemed like m42 screw mount lenses would be ideal. They’re cheap and plentiful as the mount was popular across a wide range of cameras for several decades. I mentioned to my Dad I was interested in getting some m42 lenses and it turned out he had some near mint condition Pentax Takumar’s from his college days. So I took possession of a 50mm f1.4 SMC Takumar and 135mm f3.5 Super Takumar. These old lenses were made at just the right sort of time to have damn good optics and have basic lens coatings which help minimise flare and improve contrast.
Both lenses have nice bokeh, the 50mm in particular. The 135mm can show some quite pronounced bokeh fringing wide open so is best used stopped down slightly, at least if being used for a colour shot. It’s impressive how sharp they both are considering their age and the demands placed on them by a 16 megapixel APS-C sensor.
I find focusing the lenses fairly straight forward using the magnified view to check for critical focus. The X-E1’s 2.0 firmware which added focus peaking definitely makes things easier still. Shooting moving subjects is undoubtedly a challenge so you need to carefully consider your composition and pre-focus as much as possible. The 135mm’s focus ring requires a considerable amount of turning to go through its range which has the advantage of making focus very accurate, but the downside that it can be frustratingly slow if you’re in a hurry.
There are lots of great m42 lenses out there that are easy to adapt to use on mirrorless cameras (and less easily on Canon and Nikon DSLRs). If you stick to names like Pentax and Zeiss you won’t go far wrong. Of course there are plenty of super cheap lenses from obscure branded Russian, Japanese and German companies and some may be fantastic, but it will be a lot more hit and miss. The older a lens is the more likely it will have performance issues on today’s cameras, so if you want a lens not just to use as a toy or special effect purchase, go for a later model with coated glass. Also beware of dust and fungus – never buy old lenses from sellers who don’t show you the innards or at least guarantee the glass is clear. A few dust spots won’t hurt and are inevitable, but fungus and other nasties will degrade the optical quality. Also make sure aperture rings are functional as they can seize up after decades of inactivity. On auto m42 lenses you may need to adjust the auto/manual switch before the aperture will close so beware of that.