rangefinder alignment pt. 2

[marke_gilbert]

Thanks for the responses to to my earlier post.

<P>I shot the noctilux at a variety if distances-- everything looks

ok.

<P> I also compared the noct. to 2 other lenses at distances from 1

meter to 25 feet-- they all agree perfectly-- It agreed with my 85 mm

nikkor-- which has the longest focus throw I used. I even went to the

tape measure from film plane to target. Everything agreed perfectly.

Or at least if it is off, the degree is so small that I cant detect

it with a .85 viewfinder, and it seems to be within the DOF at f1.

<P>

<P> But, the noct still doesnt quite line up at infinity-- as if it

would take turning the focus ring 1mm to align the images. The

misalignment shows itself slightly differently in the .85 v. the .72,

but that would be expected.

<P> Is it possible for it to be dead on from 1 meter on out, but off

at infinity? Or is it a question of the focus ring needing adjustment?

<P> For the record, I stand impressed at the precision-- we're

talking being able to compare these lenses to a fraction of an inch--

and it makes me glad I usually shoot below 28mm.

[jay_.]

Marke, you're talking about an old sample with a long and unknown history. Who knows what has been done to it and by whom? It is entirely possible for the cam to be off only at the very end (at infinity)due to manufacturing error, or someone's botched attempt at adjustment (a previous owner or an ignorant repairman could have decided to alter the infinity end of the lens cam instead of adjusting a misaligned rangefinder). It's really impossible to tell.

 

I suggest that you stop measuring and start shooting. Shoot wide open at targets at various distances. Since you know your rangefinder is properly aligned, if the subject is soft, the lens is off. If especially at close distances it's ok, then DOF will undoubtedly take care of a slight misalignment at infinity, if you don't want to return the lens or have it serviced.

 

And Leica does some mysterious things also. I checked multiple samples of the 280/2.8APO R lens and they all read f/3.4 as maximum in the R8, and everyone said it was just a glitch in the R8 coupling to the finder and they all got fine exposures with their lenses, yet it made no sense to me why one f/2.8 lens would act this way and the rest not. Plus, the meter read only 1/2 stop difference between f/2.8 on the lens and f/4, and this was true on the R7 as well. When I took a micrometer to the 3rd cam I discovered that it matched the f/3.4 cam on the 180 APO, not an f/2.8 cam. Samples which had been converted to ROM by Leica had the mount changed as well, and though it then read 2.8 in the finder, in fact the 2.8 position was then actually *past* the 2.8 detent on the lens and there was no movement of the aperture blades until the meter read 3.4. This is still a mystery which will never be settled because Leica isn't talking and most owners of this lens simply deny there's an issue. Since someone else mentioned they had a Noct that acted just like yours, it may be something Leica did to compensate for an unanticipated anomaly in the design. Test it on film, keep it if it's sharp.

[john_collier2]

I always expose film and, if it looks good, it is good.

[sal dimarco]

Marke, If the problem seems to bother you. Why don't you just send the lens in for adjustment?

[roger_michel]

i'm not sure why no one is answering your question. yes, it is possible for the cam to be misshapen in the lens, such that it is accurate at one distance but not another. cam pitch, etc. must be very precise. nikon and contax rf lenses are very similar, but have a dfferent pitch, creating the prob you describe (actually the opposite prob -- on at inf off at other distances). either get the sucker checked and repaired OR do your own GG test.

[_arne_hvaring]

Marke,

In my experience this is not unusual. I have encountered two Leica lenses with the same problem. The first was the latest 28mm Elmarit-R. When compared to my old Nikkor it was noticeably softer at infinity, but quite sharp at about 12-15 meter. If the focusing ring had turned about 1mm further infinity would have been sharp (and the distance scale a bit off). The next was my trusted old 35mm Summicron-M. I only discovered the misalignment when borrowing the new Asperical to compare. Same thing, didn't focus fully out to infinity. I sent the lens to Leica in Germany, they fixed it for a staggering $500.

Considering the prices Leica charges for these lenses, beeing able to focus them to infinity is hardly too much to ask.

Regards

Arne Hvaring