nick.edwards1 Posted July 12, 2010 Share #1 Posted July 12, 2010 Advertisement (gone after registration) I am seeking an opinion. Yesterday loaded my MP with Tri X, mounted my 50 lux asph and went to take a few photos. After about 10 frames, camera slid off my shoulder - ended up with a small dent in the lens hood and the B + W yellow filter. My 50 lux asph seems to now have a very slight bit of backlash. I mounted the lens on my M8 - the back focus was as before, but I am coping with it and everything else apart from the slight backlash seems the same. What do other people do in these circumstances - carry on using the equipment accepting the rough & tumble of life or send it back to Leica? - in my case to have the backlash (& back-focus) sorted and maybe a new lens hood without the dent. Years ago something similar happened with my (built like a tank) Nikkormat and 105 2.5 - then I just carried on using it. However the Leica seems more delicate. Regards, Nick. Link to post Share on other sites More sharing options...
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andybarton Posted July 12, 2010 Share #2 Posted July 12, 2010 If the lens wasn't 100% right in the first place, if I were you, I'd use this opportunity to have it repaired so that it is good for both the MP and the M8 Link to post Share on other sites More sharing options...
jaapv Posted July 12, 2010 Share #3 Posted July 12, 2010 The 50 Summilux asph should not have backfocus on the M8, nor backlash. It may be the floating element mechanism is off. The tolerances there are in the order of 1/1000 nd of a mm....I would advise you to send it in. Link to post Share on other sites More sharing options...
wattsy Posted July 12, 2010 Share #4 Posted July 12, 2010 The 50 Summilux asph should not have backfocus on the M8 It shouldn't but many do (or did). As far as sending it back to Solms, I would factor in the possibility of being without the lens for a couple of months (or more). With the backfocus, dent and apparent backlash I'd say it is definitely worth getting Solms to repair it but it may be better to send it in at a time when you are going to miss it the least? This of course assumes that you can still use the lens (and workaround the current problems). Link to post Share on other sites More sharing options...
jaapv Posted July 12, 2010 Share #5 Posted July 12, 2010 Mine did from new, it got taken in by Leica CS when I passed by, now it doesn't Link to post Share on other sites More sharing options...
wattsy Posted July 12, 2010 Share #6 Posted July 12, 2010 Mine did from new, it got taken in by Leica CS when I passed by, now it doesn't As did mine (though I didn't notice until I got an M8;)). Leica sorted it out on the second attempt. Link to post Share on other sites More sharing options...
keithdunlop Posted July 12, 2010 Share #7 Posted July 12, 2010 Advertisement (gone after registration) What's "backlash"? Link to post Share on other sites More sharing options...
nick.edwards1 Posted July 12, 2010 Author Share #8 Posted July 12, 2010 Thanks Andy, Jaap & Ian for your replies, I will send it back for repair. I note that Leica are offering a fast or express repair service for a price. It is obviously a concern if my 50mm lens is away for months so I may take them up on the fast service. Keith - 'backlash' was a term I came across during the engineering stage of my apprenticeship (many years ago now) and was described to me as follows: - Imagine a threaded nut running on a screwed rod - if there was no clearance between the thread of the nut and the thread of the rod the nut would not be able to turn on the rod, so a clearance is necessary. Rotating the nut moves it along the thread, if the rotation is reversed to move the nut back, the clearance is taken up before the nut begins to move backwards - this is known as backlash. i.e. the play or slack. Best regards, Nick. Link to post Share on other sites More sharing options...
hoppyman Posted July 12, 2010 Share #9 Posted July 12, 2010 Backlash is not normal and certainly can affect critical focus accuracy. Since it has been dropped as well and you report back focus too, I certainly would send it to Solms. Link to post Share on other sites More sharing options...
aesop Posted July 12, 2010 Share #10 Posted July 12, 2010 The 50 Summilux asph should not have backfocus on the M8, nor backlash. It may be the floating element mechanism is off. The tolerances there are in the order of 1/1000 nd of a mm....I would advise you to send it in. ...now that is über-precise engineering, Jaap. Re: the robustness of the 50mm Summilux ASPH in the real world, are there any non-scientific anecdotes as to how much of a knock it can take before "optimum" image delivery starts to deteriorate? Have you recently bounced yours off the sidewalk but continued shooting with it, with no visible adverse effects to the images produced? Please share. I own one but it has seen very little action in 3 years - can't seem to abandon my venerable pre-asph. Incidentally, I can vouch for the robustness of the pre-asph. It is a real workhorse of a lens, with the added bonus of being able to absorb an appreciable level of abuse. Link to post Share on other sites More sharing options...
jaapv Posted July 12, 2010 Share #11 Posted July 12, 2010 I would translate it into inches for an Englishman, but I'm too lazy... Link to post Share on other sites More sharing options...
aesop Posted July 12, 2010 Share #12 Posted July 12, 2010 I would translate it into inches for an Englishman, but I'm too lazy... ...and I would have to ask you to translate it back from inches, Jaap, for I am no Englishman. Link to post Share on other sites More sharing options...
hoppyman Posted July 13, 2010 Share #13 Posted July 13, 2010 Jaap I think that you put too many zeroes for mechanical tolerances. Lens element surface would be a different sum though. 0.001 mm would be 0.00003937 of an inch plus change About one/ twenty five thousandth of an inch. Even the Leica folks probably don't have a CNC machine that good! Link to post Share on other sites More sharing options...
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