Quote:
Originally Posted by wlaidlaw
Harold and Peter,
I think the point that a lot of us are trying to make is that the current rangefinder, sadly, has proved to be inadequate for longer lenses, even for the 1.3 sensor. It is very easy to prove this for say a 75/f1.4. According to my DOF calculator, the DOF for the M8 at 7.5 meters is 10cm at f1.4. Focus the lens at an object 7.5 meters away. Now move the camera back 10 cm. Can you see any change in the image convergence - I bet 90+ out of 100 people cannot. The rangefinder will be even more lacking, as and when the next generation sensor comes along, when it is quite likely the pixels may be even more tightly packed than the current one.
Now Leica could try and improve the tolerances on the RF, extend the RF base line and make their lenses more accurately. However, I suspect there are not huge improvements to be had. That is why many of us are thinking about ways we could keep a manual RF system but have some way that this can work better for the longer/large aperture lenses. The RF is perfectly fine for 35mm f1.4 and in reasonable light for 50 f1.4 (but I want to use the 50 at f1.4 in poor light). Many of us older guys struggle with much beyond that.
You only have to look at the many threads with RF issues and lens back-focus to realise there is a fundamental problem, unless we are prepared to limit ourselves to the shorter lenses - maybe we are. I know I am not using my longer lenses very much at all now, almost to the extent where I may sell my 135/f4 and 90/2.8 and stick to the 75/2.5 as my longest lens.
Wilson
|
Wilson, with the greatest respect to the points you've outlined above, is it not more a problem with the .58 viewfinder as opposed to say a .85 viewfinder when using focal lengths of 75 to 135mm?.
With regard to tolerances of the Rangefinder, I would seriously question the accuracy of the calibration of the RF leaving the factory, from day one I was always concerned about the difficulty in viewing a perfectly converged image in the VF, I always felt something was not quite aligned exactly. On a service visit to Solms I asked for this to be checked and the camera was returned with such an obvious miss alignment that I resorted to adjusting the vertical convergence myself.
All I can say is since this DIY tweak was done and adjusting the cam roller myself I no longer have any issues with focus from 28mm through to 90mm even at f:/2. I have analysed the way the front to back depth of focus falls with the 90 which tended to be 2/3 front and 1/3 back if I focused from near to far and 1/3 front 2/3 back if I focused from far to near. So now when I use this lens I always focus beyond the subject and then bring the focus back to the subject with perfect results.
However I have experienced front/back focus with lenses new out of the box, these were purchases made in the last 12 months and upon return to Solms the issues were resolved. Purchases of older 2nd hand lenses pre M8 launch always seemed to focus correctly. You can draw your own conclusion on that, It would suggest to me the issue is/was recent. Perhaps a slip in manufacturing lens tolerances highlighted by the digital sensor.
I don't really know how much of the problems can be equated to user error, I'd like to think not much but I only have my own experience to draw upon. I've noticed myself struggling with my eyesight over the past few years, finally requiring glasses. When I started to use the M8 I got a diopter and the 1.25x magnifier. I discovered after a long time I had better results when using my eyeglasses than using the correct diopter. I tend not to even use the 1.25x now, I seem to be able to focus without it. But it has been a long hard road analysing mistakes and trying to re-learn methods long forgotten in reliance of AF systems. I have nothing against AF except for the weight and bulk they bring to a system. They worked very well on my Canon system and very quick to use accurately. But in the end I moved away from Canon, it's bulk, weight and automation somehow clouded the basic joy of photography for me.
I'm not suggesting Leica has a perfect system that can't be improved upon, everything can be made better. But I would like to hold on to the simplistic essence of the M system or at least be able to retain use of the manual lenses and not be bamboozled later in life with buttons, switches and menus.
