[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