Burning holes in your shutter - 2 questions
Old 09-08-2019   #1
nickthetasmaniac
Registered User
 
nickthetasmaniac is offline
Join Date: Jul 2011
Posts: 1,206
Burning holes in your shutter - 2 questions

G'day everyone, I was taking a walk and pondering the meaning of cloth focal-plane shutters (as you do), and two rather oddball questions popped into my head...

- Would leaving your lens at it's MFD (rather than infinity) significantly lower the chances of burning a hole in your shutter curtains?

My thinking - The sun is essentially at infinity, so by leaving my lens focused at infinity (which I usually do), I'm bringing the sun into focus on the shutter. This is basically how I started fires with a magnifying glass as a kid... Would leaving the lens at MFD project the sun as a big diffused 'bokeh ball'?

- Is it possible for the shutter curtain to actually ignite inside the camera? Ie. flames and the like...

Thanks
__________________
Ricoh GRII | Pentax SV, SP-F, MX & LX | Leica M2 | Olympus Pen F + 35RD | Minolta Autocord | Hasselblad 500cm + SWC/m

Instagram @other_strange_creatures
  Reply With Quote

Old 09-08-2019   #2
peterm1
Registered User
 
peterm1's Avatar
 
peterm1 is offline
Join Date: May 2006
Posts: 5,636
I do believe I have heard it recommended to focus at MFD. I have not tried it though.

I have never heard of ignition inside the camera however. Though logically there has to be some degree of burning if a hole is being burned, I would expect this to be suppressed by the relative lack of O2 inside a small enclosed box. And in support of this I have certainly never seen or heard of more than a pinhole or a bit larger being the result.

PS I have effected a repair to such a hole by using a small amount of black "liquid electrical tape" (available widely in hardware stores and auto parts stores). I have also seen such a curtain repaired by gluing a small patch of spare curtain material over the hole. This was done by a technician however.
  Reply With Quote

Old 09-08-2019   #3
Huss
Registered User
 
Huss is offline
Join Date: Sep 2014
Location: Venice, CA
Posts: 7,826
Once when I was bored... I conducted an experiment with my M3. I held the shutter open at B, and put a piece of paper where the shutter would be. At infinity and with the lens wide open (a 50mm lens), it would burn through the paper in a few seconds. Stopped down it took forever..
I did not try mft because I wanted to burn a hole.
  Reply With Quote

Old 09-08-2019   #4
K14
Registered User
 
K14's Avatar
 
K14 is offline
Join Date: Oct 2008
Location: Washington State
Posts: 278
I've always kept mine covered whenever possible. The guys on Dual Survival would have had fire much quicker carrying a Leica.
  Reply With Quote

Old 09-08-2019   #5
Doug
Moderator
 
Doug's Avatar
 
Doug is offline
Join Date: Sep 2003
Location: Pacific NW, USA
Posts: 13,093
Useful experiment, Huss!

Long ago I worked at a camera shop in Rapid City. The show windows faced west. We would put spacers under the lenses of display cameras to tilt them up so window shoppers could see them better. I recall two occasions when I took out a used camera for familiarization and found the shutters had multiple holes. One was a barnack Leica and the other a Nikon S2. We made sure after that to display them with the lenses set at MFD...
__________________
Doug’s Gallery
RFF on Facebook
  Reply With Quote

Old 09-08-2019   #6
Freakscene
Deregistered user
 
Freakscene's Avatar
 
Freakscene is offline
Join Date: Aug 2006
Location: In exile
Posts: 1,638
1. It sure slows it down. I just repeated Huss’ experiment (thanks for the materials and methods!) in my back yard with an MP, a 50/1 Noctilux and regular office paper. At infinity and f1 we had smoke and a hole very quickly. At mfd and f1 it was very slow. Stopped down to f16 I got bored waiting for something to happen.

2. My guess from this experiment is you could definitely get some smoke. A fire? Maybe, but as an Aussie kid who also spent their youth igniting things with a magnifying glass you’d remember that it is hard to do unless you have a few layers of fuel. With only one layer all you get is a rapidly appearing hole and the energy is no longer being transferred. My guess is the nce you have a hole things cool down rather rapidly.

Marty
  Reply With Quote

Old 09-09-2019   #7
retinax
Registered User
 
retinax is online now
Join Date: Aug 2015
Posts: 940
The shutter is a bit in front of the focal plane, i.e. depending on the focal lens, the sun should be focused on the shutter curtain when the focus for the film plane is at intermediate or near distance.
  Reply With Quote

Old 09-09-2019   #8
wolves3012
Registered User
 
wolves3012's Avatar
 
wolves3012 is offline
Join Date: Sep 2006
Location: Wolverhampton, UK
Age: 62
Posts: 2,817
I did a similar experiment some years ago - there's a thread on here somewhere. I used some leftover pieces of shutter cloth to see if I could burn holes with a camera lens. I can't remember the figures but it was amost instant at f/2, pretty fast at f/4-f/5.6 and by the time I got to f/16 it might be scorched if you had the time to wait and could hold it on the same spot.

By the way, the shutter itself is just in front of the film plane, so at infinity the image on the shutter is slightly OOF anyway (not sure it's enough for safety though) so worst-case is probably to set the lens at a bit closer than infinity? [EDIT: Retinax beat me to it]
__________________
Zorki: 1e (x2), 2C, 3M, 4, 4K, 5, 6
FED: NKVD, 1g, 2e
Kiev 4, 4A
Leica IIIC
Yashica Minister III
Zenith C, Zenit C, Zenit E
Minolta XG-M, XD-5
Nikon P50
Panasonic Lumix G2, 14-42 Kit lens + 45-150mm

"The way to see by faith is to shut the eye of reason." - Benjamin Franklin
  Reply With Quote

Old 09-09-2019   #9
David Hughes
David Hughes
 
David Hughes's Avatar
 
David Hughes is offline
Join Date: Dec 2007
Posts: 7,510
I have often wondered if it would work with the camera placed on a flat surface, so the blind would be vertical and the lens axis horizontal. Would the sun be too high in the sky to be within the FoV?


Regards, David
  Reply With Quote

Old 09-09-2019   #10
Huss
Registered User
 
Huss is offline
Join Date: Sep 2014
Location: Venice, CA
Posts: 7,826
Quote:
Originally Posted by retinax View Post
The shutter is a bit in front of the focal plane, i.e. depending on the focal lens, the sun should be focused on the shutter curtain when the focus for the film plane is at intermediate or near distance.

You're forgetting about DOF at infinity. It doesn't matter which is why shutters get burnt.
  Reply With Quote

Old 09-09-2019   #11
Huss
Registered User
 
Huss is offline
Join Date: Sep 2014
Location: Venice, CA
Posts: 7,826
Another thing.. this will damage any shutter in an RF kamera. Not just Leicas. A metal shutter blade would get scorched/warped etc. It is just that with a cloth shutter it happens much quicker.
  Reply With Quote

Old 09-27-2019   #12
Goodtimes
Registered User
 
Goodtimes's Avatar
 
Goodtimes is offline
Join Date: Aug 2019
Posts: 5
Smile

Leica M262 Combat ready by Joan, on Flickr

To prevent any such problem on any of my cameras this is how I carry them around.
The small leather bag is actually a jewlery pouch. It is attached to the body strap and can be pulled from the lens and shade in a half second, still hanging on the camera. It also protects from shocks, dust and sprayed water and cannot be lost like an original lens cap could be.
  Reply With Quote

Old 09-27-2019   #13
Ko.Fe.
Kostya Fedot
 
Ko.Fe.'s Avatar
 
Ko.Fe. is offline
Join Date: Jul 2013
Location: MiltON.ONtario
Posts: 7,499
Your layers of protection have serious flaw. The pillow from jewel box is missing on the top plate. You need one with your current strap.
It is most garbage strap I ever have. I have to remove German engineered attachment pieces and replace them with normal quality, made in China rings.
The reason, sooner or later somehow one of those Leica crafted attachments will disconnect and camera will fall of.
It did twice. I decided not to wait for third time.
  Reply With Quote

Old 09-27-2019   #14
Ambro51
Registered User
 
Ambro51's Avatar
 
Ambro51 is offline
Join Date: Jan 2016
Posts: 170
“KamraKondom”. :-). If you wanna talk “heat”, try my 6” F8 Refractor pointed at the Sun. It would melt the camera!
  Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 06:42.


vBulletin skin developed by: eXtremepixels
Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.

All content on this site is Copyright Protected and owned by its respective owner. You may link to content on this site but you may not reproduce any of it in whole or part without written consent from its owner.