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thighslapper

Infinity Calibration with Manual Lenses .....

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I'm possibly the least qualified to comment, I am not involved in Q/C, I merely fly the areo-stuff on a daily basis.

 

My comment stands though, and I agree with the OP, I don't think this is "Leica at it's best". jaapv has made the point that expansion etc must happen, and I agree with that, and always have, with the longer focal length lenses especially. But if one follows that logic, why does the same Leica lens when fitted to an ordinary M body, not show this effect? The only "variable" if you can call it that is the M-T adaptor. How many of us used to (or still do) slap a lens on, roll it to infinity, and shoot, knowing/assuming that focused at infinity means just that.

 

Now if that said adaptor was made anywhere other than Leica, and freely available on that auction site for a mere $15, then I'd agree, shoddy machining, you get what you pay for.

 

But this is Leica, made by Leica, for Leica. It should be right, and if there was any slight leeway to compensate for that expansion etc, it would/should be so slight it wouldn't be noticeable.

 

Gary

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Now if that said adaptor was made anywhere other than Leica, and freely available on that auction site for a mere $15, then I'd agree, shoddy machining, you get what you pay for.

You could get an expensive ‘Made in Germany’ Novoflex adapter and it will still focus past infinity. This is by design.

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The only "variable" if you can call it that is the M-T adaptor. How many of us used to (or still do) slap a lens on, roll it to infinity, and shoot, knowing/assuming that focused at infinity means just that.

 

It's not the only variable.

 

On an M the helicoid containing optical elements is mechanically connected to the rangefinder, so the problem is only seen with long-bodied lenses.

 

On the T you have no (mechanical) focusing connection...as well as three disparate mechanically-coupled metal units, each with their own tolerances. (stacking)

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Did somebody read the Instruction booklet of the Leica M adapter T? See A. Focusing/Note:

 

"The distances set on the lens are slightly shorter when using the adapter than when used directly on Leica M cameras. For example, sharp depiction of a distant object is achieved immediately before the mechanical infinity stop on the adjusting dial. This is for technical reasons and is not a fault."

 

So they had an intention!!!!!

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mmmmm..... I wonder what the technical reasons are ....... presumably to ensure that whatever dodgy lenses you use there is always enough lee-way to allow focussing at infinity .......

 

Anyway, I prefer to have it self-adjusted so that all my lenses work as I want them .....

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Sure it's not reasonable to expect any MF lens to focus at infinity when set to infinity … that's both optimistic and dogmatic. Any lens' actual infinity focus position will depend on the ambient temperature thus there is usually some tolerance built in so that the lens focuses past the infinity mark.

 

dunk

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I am using on a daily basis the 28PC Super-Angulon-R on both the M240 and the MM.

The maximum detail at infinity is achieved when the fixed white line coincides with the left side of the infinity symbol, that is, when the physical stop has not be reached.

Just my 2 cents...

Regards from Barcelona.

Manolo

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I have just bough a Leica T so still in the infancy regarding use. But I have a lot of Leica R lens (and a couple of Leica Ms) that I have been using with adapters (Panasonic m4/3 and Sony A7R). With tele lens and adapters they usually focus past infinity. You have to be very careful with focusing, and it is a bit frustrating, but in my experience this is how it works!. Anyway better to be past infinity (you still can focus sharply) that short of infinity (you cannot focus at infinity!).

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Does not there exist adapters, that can be adjusted by the user?

 

The leica-built LTM to M adapters are not spot on too?

Jan

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Problem with adapters is:

too short and lenses will focus past infinity, which might be annoying but is not a big problem

too long and lenses will not reach infinity at all, which is not just annoying but an actual problem

spot on and some lenses will either go beyond or not reach infinity because they were manufactured badly or because they are old

 

Bottom line: to be on the safe side for all possible scenarios you would make the adapter just a tiny bit shorter than required. What separates the quality adapters from the rubbish is the ability to shim it in order to reach mechanical perfection - if you absolutely wanted it. 

 

I understand that it seems to be en vogue to bash Leica these days, but let us not forget that they are telling people in the manual that the adapter is slightly shorter. This is the best solution for real life (i.e. people who actuallly take pictures with the product) 

 

BTW: none of my Novoflex adapters is spot on. I have measured them. 

BTW2: the LTM adapter is precisely 1mm - not hard to produce

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Interesting issue. Mine focuses beyond infinity also.

 

Another question however. Do you all think the distance scale on a M lens is accurate on the T with adapter? What about the focal range?

 

Since it the T sensor multiplies the focal length 1.5 I'm not sure if these scales are affected.

 

Thank you in advance for your comments.

 

Jim

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