Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!
I can relay my quite extensive experience with a aquantences 90mm f2 Cron (E55), the last version prior to the AA on both a perfectly calibrated M8.2 and M9. His lens would focus perfectly from min. distance to mid-range. At longer distances to infinity, his lens would quite evidently front focus. It didn't matter what apertures were selected. He had two very well qualified and techs on seperate occasions have a go at adjustment and although they somewhat improved upon the front focusing at long subject distances, it could never be fully fixed and simply remained as his only lens that exhibited this trait. I tested this particular lens pre and post adjustment. The lens was barely used from being brand new. No real difinitive explanation was given as to the cause of this front focusing, and it appeared both techs were stumped as to why...although they mentioned it wasn't the first time they encountered this in a lens.It is odd that it is not focusing accurately at longer object distances even when DoF is increasing. I would call Leica and ask them.
I think his problem is the other way around. Perfect at close distance and front focus at longer distances.It could be that the actual Focal Length of this particular lens is slightly too short. That is the only reason that I can think of to explain why a lens focuses at infinity but shows front-focus at close distances when used on a camera that is perfect with other lenses. I've had this problem on a couple of lenses. On the Summarit 5cm F1.5- Stopping down to F2.8 solves the problem with front-focusing at 1m, using at F1.5 the lens is perfect at infinity. Taking the optics out of the focus mount, the actual focal length scribed on the mount is 51.1mm. A second lens with the same issue: problem solved by moving the rear optics out slightly, which increases the acual focal length. "It just Works".
1950 KMZ J-3: first infocus images from a very early Jupiter.
Paul, the experience I relayed in my post above was with a Leica 90mm E55 pre alph. and not with a 75mm Lux, so I would think you have some way to go prior to panicking, especially if an attempt to adjust it hasn"t been attempted yet.Now I'm in a state of panic......
especially if this can't be corrected.......
I had a Noctilux (modern one) which did this - I sent it to Leica and it was fixed.Now I'm in a state of panic......
especially if this can't be corrected.......
Yes it can I now had my 75 Lux for 18months, and yes it is so important to have the calibration right. Originally it would focus within the cusp of DOF at MFD, and at mid distances it was way out, and yet infinity is was OK.My Lux 75 focuses fine at close distance, but front focuses when with distant subjects.
Can this be easily corrected?
Paul, do to panic. I routinely send any used lens I buy to Leica NJ. Often it is to 6 bit code the lens, but included in the $230 for 6 bit coding is the checkover that Leica does in recalibrating your lens.Now I'm in a state of panic......
especially if this can't be corrected.......