Pentax 110 – 18mm, 24mm, 50mm, and 70mm f/2.8 on MFT
Back in 1978 Pentax released an SLR Auto 110 film camera that used f/2.8 interchangeable lenses. Conveniently these lenses cover the same image circle as MFT lenses. Thankfully, someone already realized this and cooked up a Pentax 110 to MFT adapter that allows mounting these miniature sized lenses on my Olympus E-P1. How do these little gems perform?
Lacking any sort of diaphragm in the lens, all Pentax 110 lenses are f/2.8 so the camera can meter correctly. The camera does have a diaphragm built in that can step down to a fixed size and is immediately behind the lens, but this is of no use on an MFT camera that doesn’t have the appropriate diaphragm.
The original 3 lens kit was the 18, 24, and 50mm f/2.8, that were followed later by an 18mm pan focus, 20-40mm, and 70mm f/2.8 lens. The 18mm pan focus is a fixed focus lens that is set for hyper-focal distance. The lenses are all extremely compact, the standard 24mm f/2.8 weighs in at only 0.4 oz, the 18mm f/2.8 weights 1 oz, and the 50mm is the heavy weight of the bunch at 1.8 oz. The 70mm I will weigh once I get it.
The 18mm has a minimum focusing distance of 0.25m or 1 ft, the 24mm is 0.35m or 1.2 ft, and the 50mm is at 0.9m or 3 ft. These focus distances are fairly long for lenses of their class, but probably help maintain the smaller size. Filter rings rotate while focusing as well.
All the Auto 110 lenses use the same coating that the K mount Takumar lenses used, and are not the well known SMC coating. These lenses will be less resistant to flare and have lower contrast (boost in post processing). Hoods are also hard to find in the filter thread diameters, so be aware of the light when shooting.
The lens barrels are mostly plastic construction with only the mount being metal. They do use-multi element lens designs that are respectable for an inexpensive camera kit. The 18mm is 6 groups in 6 elements, the 24 is 5/6, the 50mm is 5/5 and the 70mm is 5/6.
So as cute as these lenses are, how do they perform?