rod_sainty2

Scott, I deliberated over the same question when I put together a Pentax 67 kit (nearly 20 years ago!). As primarily a scenic photographer, I had usually found the 50mm lens in 35mm format to be somewhat tight, so I favoured the wider or 'looser' view offered by the 90mm lens. And the 90 fitted better with my 45mm, 165mm and 300mm. In addition, I reasoned that the 90mm lens was more compact in size, focused quite a bit closer, and, as the much newer design of the two, might be sharper. I bought mine new, and was certainly pleased with the results it gave me. However, as I came over time to do more portraits, at times I wished for the longer perspective of the 105mm. And the 105mm is no slouch in sharpness either; I recall the 1999 (I think) test by Popular Photography rated it as 'excellent' at most apertures and a pro told me that he considered his 105 to be very sharp indeed. Certainly, either lens will have better contrast than your 135 macro, plus they're much more compact and provide brighter viewing. Make sure you get a later production copy with the Pentax 67 designation and check it against a bright specular light source for hazing on the elements which seems to afflict many lenses, I think due to either humidity deposits or heat volatilising the helicoid grease. I sold most of my kit when I eventually switched to the Mamiya 7 system but bought a like-new 105 as a portrait lens for the body I kept, for a low price. It's a very nice lens and does offer slightly brighter viewing and the shallower depth of field.

<p>Hi Dan, hi Bob. I can see how the locating screw might be deemed to be unnecessary by manufacturers if the rear ring is regarded as sufficient, but, unless vibration makes it come out, in what way can it be a nuisance?<br /> <br /> Of course, the problem my technician found is that there is insufficient thread present at the rear to enable the ring to be tightened to stop the rotation. Hence, in this instance, the pin was needed. Can you suggest any alternative?</p> <p> </p>

<p>Paul, you were correct. The technician found that the locating pin was missing. Thank you for your advice.</p> <p>He didn't have a Schneider pin at hand to replace it, but found a substitute. He had a screw from a Canon lens that had a matching screw thread but a much larger diameter post head. He was able to reduce the diameter of the post head on his lathe. I think that's pretty impressive service in this day and age.</p> <p>He also commented that it seemed that the original locating pin was never present, as there appeared to be no way it could have escaped from inside the lens. Perhaps the alignment had previously been achieved only by the retaining ring at the rear.</p>

<p>Thank you, Bob, for your considered response. The feedback from the technician today was that he believes the nut was centered because it was not undone enough to not be centered. He also clarified that he is not proposing to move the shutter forward but, rather, to move the nut back in order to expose more thread. He assured me that the focus will not be disturbed.</p>

<p>My Schneider Super-Angulon 72mm XL lens is mounted on a Schneider helical focus mount and Cambo Wide DS mounting plate, for use on the Cambo Wide DS 4x5 camera. I've just returned from a month-long overseas trip shooting architecture in colour and B&W, which involved frequent changing between the centre filter and red filter. Sometimes, probably due to expansion in the heat, one or other of the filters became stuck and required additional force to remove. Although I attempted to protect the lens from the torque, the lens eventually became loose in the mount. The entire lens is able to be rotated freely within the helical focus mount and the Cambo mount plate. <br> Back home, a repair technician removed the rear lens group, exposing a blackened brass ring with spanner slots rearward of the diaphragm and shutter. He was surprised to find that tightening the ring did not fix the rotation of the lens, though it did impede it somewhat at first before loosening entirely again as the lens was rotated. He suspects that there is insufficient thread present for the ring to move forwards on to fully clamp the lens, and proposes (if I understood him correctly) to move the shutter assembly forward in order to provide additional thread at the rear. This sounds logical but I'm concerned it may upset the focus adjustment set by Cambo at the factory. <br> Has anyone experience with this problem and able to offer advice? <br> Thanks,<br> Rod</p>