mFT Adapter with Iris for Pentax Auto 110 Lenses (2010)
Pentax has taken so
long to give us an EVIL camera (despite all the suggestions...), and
since I realised how badly I wanted to try one out, I have presented
myself with a Panasonic GF1 body (without a lens, however, which wasn't in
the budget), but with an adapter, that allows the use of existing
lenses, even if that sometimes looks odd and out of place.
70-200 and 2x converter, 800mm perceived focal length:
But look, there are also those Pentax auto 110 lenses in the cabinet, and - by pure coincidence (?) - the 110 film format is just as big (small) as the GF1 sensor (within tenths of a millimeter, so if the image circle fits, how about a DIY adapter?
I did not find proper data regarding the GF1 register ("about 20mm") nor on that of the Pentax (no data anywhere) but when just holding a lens in front of the GF1 there was a sharp image - so there indeed is enough space for an adapter (about 7mm).
This seven millimeter space however also needs to accomodate an iris (auto 110 lenses do not have one, it sits in the body), and that turned out to be a little fiddly, because I certainly wanted to put the iris in the correct position, i.e. where Pentax put it.
Meanwhile, auto 110 to mFT adapters can be bought off ebay (no iris, however).
I did use:
- a hacksawed mFT to T2 adapter (EUR 17 off ebay, thank you China) (1)
- the iris from an old compur shutter (from a Dacora Dignette camera) (2)
bayonet flange from a Pentax auto 110 body (3, under the lens)
Filed to size and glued together:
Put on the camera:
How about the results? Given that the lenses are minuscule, designed for the small 110 film format ("digital" wasn't even a dream back then...) my hopes weren't high and it could be expected that the lenses do not live up to the GF1 sensor resolution.
This however isn't the case and I have to say I am positively surprised. The extreme edges are the weak points at least wide open, and to get the edges sharp, stopping down two or even three stops is recommended. The center resolution however is very good even wide open and does not improve much when stopped down. For a comparison, I also tested a Pentax s-m-c Takumar 1.4/50, whose center resolution wasn't better.
And to be honest, there are many lenses out there that show unsharp edges wide open (including some expensive ones, where this bothers me more) - and corner sharpness has almost no relevance in practical photography.