Hi. I just unboxed my new (to me) Contax G 45. Something that stood out to me right away is that the front element assembly that extends when focusing has some wobble to it. My G 35 is very solid in this regard. Is this normal? Is there an easy way to fix it? If not, I can return the lens.
I can't say if the wobble you describe is normal or not, but I disassembled the G45 and its build is different than the typical legacy lens. To start, the aperture index doesn't line up until the lens is locked onto a camera or adapter.
If you were to unscrew the front name/ID ring you would see 4 screws. These 4 screws hold in place the lens and aperture assembly, which can be removed as one unit. The lens/aperture assembly is a quite small unit. So small that I tried to fit it into a Canon 50/1.8 rangefinder helical and LTM mount, but the mount broke and that is another story.
What the lens/aperture assembly is screwed to is a plastic internal cylinder that moves in and out according to the focusing screw sprocket action. The outside aluminum body positions the aperture ring and is more of a skin than anything. Between this exterior part and the plastic internal cylinder, is a large spring that is under tension preventing any slack or backlash. If this spring is missing or not doing its job, I can see where some wobble may exist, but I suspect the wobble is simply the slack in the plastic body that the spring removes. In other words, if untouched, the spring pushes the lens assembly to a parallel plane surface for proper absolute lens positioning.
I own another G45 today, which I tried now. Only now I realized that it wobbles only so slightly that I never really noticed it before. My G21 and G90 are absolutely solid.
Thanks for the feedback. I hope I'm not mischaracterizing the issue too much. It isn't a major wobble, but there is a little wobble. Interestingly, it seems to snap back in place when pushing on it a little, so I think the spring mentioned above is still doing most of its job. Anyone else have an opinion?
Douglas, I think you will be OK with it. You could look for signs of ill-dis-assembly like marred screw heads, but proof is in the testing.
It's a different kind of lens construction, having lightweight parts to be easily motor driven by battery power. I was always amazed that the G45, in particular, came thru with super sharpness, regardless of camera, in spite of the lightweight, spring loaded, focus mechanism.
More importantly, are you going to take to the adapter solution with backwards focusing? That was my dealbreaker.
JimBuchanan wrote:
Douglas, I think you will be OK with it. You could look for signs of ill-dis-assembly like marred screw heads, but proof is in the testing.
It's a different kind of lens construction, having lightweight parts to be easily motor driven by battery power. I was always amazed that the G45, in particular, came thru with super sharpness, regardless of camera, in spite of the lightweight, spring loaded, focus mechanism.
More importantly, are you going to take to the adapter solution with backwards focusing? That was my dealbreaker.
Thanks, I'll probably keep the lens. I actually don't mind that adapter all that much, but I may consider getting my 35, 45 and 90 converted to M mount at some point.
mine does that to. it always seemed to be correctly positioned if i'm not fooling with it and after i saw m-a-x's photo of the disassembly i figured the spring was what held it in position and the movement must be normal.
Yeah, I think I'll probably stick mostly with the C-Sonnar for the family, and wait to use this new Contax for when I go out in the world. I am curious to try out the 68mm equiv. focal length. Seems an interesting in-between.
Same here. My G 45 wobbles a bit when I jog it. My 28 and 90 also do, but, though it could be purely psychologycal, just a tad less so for the 28. No poblems with the IQ whatsoever.
