"Also... are any of you using PTX110 adapters on your Q? I know the 110 Pentax lenses are actually a good size for our sensors... even big enough for the Q7 sensor. I was thinking that Pentax 110 size lenses might be the best option for old glass on our small crop."
I've got PTX110 Adapters for the 18mm, 25mm, 50mm, and 70mm. They work great on my Q7 and Q-S1 but with some issues:
The PTX110 adapters need to be shimmed to achieve proper infinity focus. I simply remove the mount on the PTX110 adapter (three screws) put a layer of thin box-sealing tape over the opening, cut away any excess, and re-attach the mount.
The 110 lenses all benefit greatly from having a 'deep' lens hood—especially the 24mm which has gotten a bad rap on the lens reviews for flare. You might have to get creative on this (I used part of an old flashlight for one), it may be hard to find the right sizes except for the 70mm which accepts 49mm.
A good hardware store should have 1 and 1/4" rubber washers with a 3/8" hole which fits inside the 110PTX adapter giving an effective f-stop of 4.5, which seems to be optimal for the best balance of sharpness and diffraction with these lenses. Used at 2.8 they are a little "glowy" but quite usable.
The 110PTX adapter mount's 'tightness' in gripping the lens depends upon tension from two thin slots in the inner part of the mounting ring, which have to adjusted from time to time if you put the lens on and off a lot. Once it's set, it holds. The original Pentax mount on the 110 camera has a proper spring which did not need adjustment.
The 110 lenses do vary in performance, I've got a couple of each of the 18, 24, and 50 and found some variations in quality, one of the 18's was unusable.
The 50mm makes a great combo with the Q system: small, sharp and light. The others work well, the 70mm suffers a bit from fringing, but is very usable and gives an incredible 325mm equivalent FOV in a pocketable lens.. The 18mm works well, but not much of an advantage compared to the normal 02 zoom at 15mm. The 24mm with the diopter lens makes for a handy
little macro set-up.
The electronic shutter is automatically engaged when using the PTX adapter. It can produce distortions, much like any focal plane shutter at high speeds. I haven't found it to be a problem, but I don't do much action photography. Flash sync is only at 1/13th of second, however.
The real beauty of using these lenses is the fact that the Q allows you to dial in Shake Reduction (on start-up). Not many other cameras with adapters allow you to do that so easily.With a little practice it's easy to get sharp images with the 50mm (230mm effective FOV!) at 1/10th of a second
handheld.
The 110 lenses actually cover quite a bit more than the Q sensor and are optimized for center sharpness, therefore giving edge to edge sharpness and illumination, better than using these on a M4/3 camera and
much better than a D-mount lens.
A sample of what the 50mm (with f4.5 stop) can do:
_IMP2763_zpsy3bblms8.jpg Photo by dktrfz | Photobucket
Last edited by Professor Batty; 09-22-2015 at 06:20 AM.
Reason: typos