Advise on how to pick good lens

[leica1215]

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I have been reading many who need lens calibration to camera body to get precise focus.

 

Can someone advise on how to pick the precise lens when purchase? I'm not a technical person.

 

When turn lens focus ring to infinity should it be perfectly on focus ? Vice versa when turn it on shortest range let's say 0.7m should it not pass over the 0.7 mark on the lens at the same time perfectly in focus?

 

Tips appreciated

 

 

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[spydrxx]

I use a variety of measures. First, acquaint myself with what are the described characteristics of the lens by bona fide serious users, and on what camera. Next what is the condition of the lens elements themselves, are there signs of separation, fungus, moisture, cleaning marks. Next I look at the exterior physical condition...are there marks, dents, scuffs, dings which might indicate damage to calibration of the lens. Is the focusing mechanism smooth throughout its range, and what is the condition of the diaphragm and its blades...do they move freely and are they free of oil. Issues such as you mention may be indicative of a variety of causes. I would typically check the lens focusing on a body...with a film body, I'd open the back door and place a fine ground glass on the film rails and examine the images with a loupe at various distances; I'd put the camera and lens on a homemade focus tester, use the rangefinder to focus at several known distances and examine the image for front/back focus issues and do the same at infinity. This might sound like a severe case of OCD and that I'm a perfectionist....that is not the case....I have acquired many lenses over the years which have minor issues which don't affect the picture....I just want to know what it is I'm looking at acquiring and how to price it.

[Michael Geschlecht]

Hello Leica1215,

 

Spydrxx's suggestions are a good starting point. Especially if you do the focusing measurement parts on a solid tripod with a sturdy tripod head.

 

You might try focusing at 1 meter, 3 meters, 10 meters & the (actual) Moon.

 

Best Regards,

 

Michael

[IWC Doppel]

I have an M9-P and an MM, both have been calibrated at some point since I bought them. A number of my lenses have been serviced and calibrated. If I ever have a problem that I notice in real use I investigate and look to resolve if needed. I've long since given up fretting about focus shift absolute precision and tests that are interesting but rarely cause issues in use.

 

Sounds to me as though you are worried about buying a lens with focus problems, don't be just check for focus shift if you must from reviews, I can measure it but it has rarely caused me an issue and I've had over 20 different Leica lenses about two really benefitted from adjustment

[jaapv]

I have been reading many who need lens calibration to camera body to get precise focus.

 

Can someone advise on how to pick the precise lens when purchase? I'm not a technical person.

 

When turn lens focus ring to infinity should it be perfectly on focus ? Vice versa when turn it on shortest range let's say 0.7m should it not pass over the 0.7 mark on the lens at the same time perfectly in focus?

 

Tips appreciated

 

 

Sent from my iPhone using Tapatalk

Just buy from a reputed dealer. Then start using it. If it turns out you have a problem, your dealer will see you right.