Archived posting to the Leica Users Group, 2006/06/11

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Subject: [Leica] Just back from India, question about burning hole in shutter
From: bdcolen at comcast.net (B. D. Colen)
Date: Sun Jun 11 16:51:07 2006

Damn! And here I always thought that closing the lens down focused the light
and burned a hole....Of course what you say about the light and heat is
totally logical...and Lord knows you can burn paper with a big ass
magnifying glass... ;-)


On 6/11/06 6:16 PM, "Walt Johnson" <walt@waltjohnson.com> wrote:

> Philippe
> 
> You burn holes in shutters at wide open apertures. so the smaller the
> aperture the small the risk..BTW f16 is much smaller aperture than
> f1.5...bigger number but smaller hole... ;-)
> 
> Walt
> 
> Philippe Orlent wrote:
> 
>> Weren't you saying then -contrary to me- that the smaller the lens
>> opening was, the higher the risk?
>> If not, then I misinterpreted you from the start.
>> 
>> 
>> Op 11-jun-06, om 17:56 heeft Walt Johnson het volgende geschreven:
>> 
>>> It seems simple....light=heat....less light=less heat....f16 is  less
>>> light (heat) than f1.5...Voila..Elementary my Dear Philippe :-P
>>> 
>>> Philippe Orlent wrote:
>>> 
>>>> Damn Walt, you got me thinking and testing.
>>>> Took a Summarit and burned within 1 sec a hole in a newspaper page
>>>> at  f 1.5.
>>>> The distance was about the one to focal plane.
>>>> Did it again at f 16. A smaller circle on the newspapern but no
>>>> burning even at 10 secs.
>>>> I also think I know why. Do you?
>>>> ;-)
>>>> 
>>>> 
>>>> Op 11-jun-06, om 14:56 heeft Walt Johnson het volgende geschreven:
>>>> 
>>>>> Vick
>>>>> 
>>>>> Simply take the lens off and outside to find the solution to  your
>>>>> question. Focus the sun on your arm  stopped down and wide  open
>>>>> and  prove to yourself which is more likely to burn the  shutter
>>>>> curtain.
>>>>> 
>>>>> Walt
>>>>> 
>>>>> Vick Ko wrote:
>>>>> 
>>>>>> I am just back from a very interesting trip to Bangalore (too
>>>>>> few  days, but
>>>>>> in a way, just enough days).  Interesting to see the thread on the
>>>>>> temples...hmm.
>>>>>> 
>>>>>> I was visiting my workteam, and a bit of sightseeing.  The
>>>>>> camera  on my trip
>>>>>> was a Leica CL.
>>>>>> 
>>>>>> One question, on one day, my workteam took me out to  play
>>>>>> cricket  and when
>>>>>> it was "team photo" time, one of the guys took our cameras
>>>>>> (there  were 2 of
>>>>>> us), stood back and took our photos.  My camera was at f16, and
>>>>>> I  noticed
>>>>>> that he put it face up on the ground.
>>>>>> I had thoughts of horror as I worried about the sun burning a
>>>>>> hole  into the
>>>>>> shutter.  I did notice that he wound the film on, so I think at
>>>>>> least there
>>>>>> was a chance of the sun, coming in at f16, hitting the meter.
>>>>>> 
>>>>>> So my LUG questions:
>>>>>> 
>>>>>> 1. can the sun at f16 burn a hole?  I'm not wanting to try the
>>>>>> experiment
>>>>>> 
>>>>>> 2.  can the sun at f16 hurt my CL meter?  It seems fine.  I
>>>>>> suspect the sun
>>>>>> is not at its focal point for the meter face
>>>>>> 
>>>>>> I did notice a discoloured patch that is off to the edge of the
>>>>>> shutter, 1/4
>>>>>> of the way to the edge.  It doesn't look like the sun "melted"
>>>>>> the  rubber
>>>>>> there, maybe it was there always.
>>>>>> 
>>>>>> Thanks in advance.
>>>>>> 
>>>>>> Regards,
>>>>>> 
>>>>>> Vick Ko
>>>>>> 
>>>>>> -------------------------------------------------------------------
>>>>>> -- ---
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
>>>>>> Leica Users Group.
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>>>>>> 
>>>>> 
>>>>> _______________________________________________
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>>>>> 
>>>> 
>>>> 
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>>>> 
>>> 
>>> 
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>> 
>> 
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>> 
> 
> 
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Replies: Reply from walt at waltjohnson.com (Walt Johnson) ([Leica] Just back from India, question about burning hole in shutter)
In reply to: Message from walt at waltjohnson.com (Walt Johnson) ([Leica] Just back from India, question about burning hole in shutter)