Completing The Set: The 70mm f2.8 Lens For The Pentax Auto 110 Super SLR Camera

Completing The Set: The 70mm f2.8 Lens For The Pentax Auto 110 Super SLR Camera

I'm a big fan of the Pentax Auto 110 Super, the dinky little 110-format SLR camera. Which is odd really, because I don't actually have one. It's the lens system for this camera that I really like, and the reason for this is because 110 film is almost exactly the same size as the micro four-thirds sensor and if you have an adapter you can use Pentax 110 lenses with micro four-thirds mirrorless cameras. Which is really cool.

Over the past year or so I've collected all of the Pentax Auto 110 lenses; the 18mm, the positively tiny 24mm, the 50mm, and the 20–40mm zoom lens. But one lens that has always evaded me is the 70mm telephoto lens. Until now. Of course, I came across it during a random search of the Kamerastore website. It was in the 'Not Passed' category,  with 'flaws that will affect typical use.' In this case, the lens, 'has dust in the central elements, as well as in the rear. These will lessen image quality. The lens also does not focus to infinity.'

The dust wasn't too much of an obstacle, but what gave me pause was that bit about the lens not focusing to infinity. And then I wondered ... . What if someone had tried to clean the lens and somehow, while reassembling it, had put one of the elements in backwards. Not only would this stop the lens focusing to infinity, I thought, but it might also give a really nice Deakinizer effect. 

If you're not familiar with the Deakinizer, it was a lens invented by cinematographer Roger Deakins that creates an image with a clear centre to the frame and blurred edges. A cheap way to make a Deakinizer is to hold a wide-angle converter reversed in front of a camera lens, and another way is to take an old lens and reverse one of the elements. This is often done to old Helios lenses, and can give a wonderful swirly bokeh effect. So with that in mind, I took the plunge and ordered the Pentax 70mm f2.8 lens.

The Pentax Auto lenses have no aperture adjustment and are fixed wide open at f2,8. Originally the Pentax Auto body contained an adjustable aperture. Consequently, have learned that in bright sunlight I may need to use a neutral density filter to cut down the light reaching the sensor. For reference, the filter size of each lens is 30.5mm (18mm wide-angle lens), 25.5mm (24mm f/2.8 standard lens), 37.5mm (50mm telephoto lens), 49mm (20–40mm zoom lens  and 70mm telephoto lens).

On its arrival, the 70mm f2.8 Pentax-110 lens was in lovely condition. As described there were a couple of big lumps of dust under or near the rear element, but otherwise it was fine. I fitted it into the adapter in the Olympus Pen E-PL2. With 'close' subjects the focusing was spot on, but as soon as I focused the lens to infinity, on the camera the image wouldn't focus at all. Mind you, it was a dull day and the LCD screen wasn't that easy to view when trying to focus properly. 

One thing that was apparent was a large vignette in the top right corner of the image, and in the bottom left it appeared to me that the lens wasn't focusing properly. That said, when I took the camera to the front of the house and viewed across the road, the buildings and trees in the middle distance were spot-on for focusing.

In conclusion, I reckon that at some stage a previous owner had tried to clean the lens and somehow had not reassembled it properly. That said, for my use, where I enjoy uneven focus across the image, this will be a fun lens to try out. I've a lot of projects on the go at the moment, but I'm certainly looking forward to using this lens again. And now I have a wide range of mirrorless prime lenses, which is awesome. 

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