Burning a hole in your shutter curtain
Because Leica M rangefinder cameras lack a mirror between the lens and shutter, is it possible to burn a hole into the cloth shutter curtain if you carry your camera around without a lens-cap?
Within limits, you betcha!
This "hole stuff" is just another web-myth
Think again. A Leica M4-P I bought a few years ago had a tell-tale "hole patch" on its front shutter curtain. Likewise see these online discussion forum posts:
So stop shaking your head. It happens, it's real, get over it :?)
Here Comes The Sun
1. Cardboard simulations
What is required to burn a hole?
After doing a few experiments, it turns out a lens will only focus the sun into an intense enough spot if:
- The lens aperture is at ƒ2.8 or wider ( ƒ2, ƒ1.4 etc.)
- You hold the lens and camera absolutely still for @ 5 seconds
(BTW, I didn't actually burn any shutter-blinds during my experiments, but rather some black cardboard.)
Which means the above criteria will only be met if you leave your lens wide open and camera lying on its back at noon.
So if you think about it, burning a hole in your shutter is moderately unlikely. During sunny days your lens will be at ƒ4 or ƒ8 or ƒ16 - hardly at ƒ2. Secondly, if the camera is hanging around your neck or off your shoulder, then it is constantly jiggling about and there won't be enough time to form a hole-burning spot.
Nevertheless if leave your camera on its back in the sun for any length of time, then you can pretty much guarantee a hole. If you leave it out long enough, then instead of a hole you will get a nice little arc tracing the sun's path.
The solution? Stop down and use a bloody lenscap!
2. In-camera tests
In April 2006, Rob Spoon sent me the following note about hole-burning tests he did with his Zorki:
I performed a real life test with a deceased Zorki (of course) with a black cloth shutter. Depending the lens and the aperture a cloth shutter can burn instantly.
Myth 1: stopping down works sufficiently. Only true if you stop down at least to f8, depending on focal length. Myth partially true.
Myth 2: focus off infinity. Very much untrue. The shutter is about 2 or 3mm in front of the film plane. If a 50mm lens is focussed at 1m distance the point of focus is perfectly on the shutter cloth.
Myth 3: burning only occurs after holding the camera very still for at least 5 seconds. Do you feel lucky? Only true when stopped down and focused at infinity.
All this is also depending on which lens used. With a wideangle the projected sun is very small, maybe too small to burn quickly. Last year I did not yet have a suitable wideangle to try. A 50mm and especially a 90mm can be very lethal.
So be very, very careful. I was shocked when I performed the test. A black cloth shutter seems to burn more quickly than a piece of black cardboard.
The cloth-shutter using community should take good note of this. I am planning to extend the test with a few wide-angles to see what effect that has shortly. I will let you know. I will do some setup-pics as well.
Hole repair options
A hole isn't the end of the world. You have a number of options to get your shutter repaired:
Small cloth patch
The most common approach is to have a technician glue a small cloth patch over it. Works fine, but it's asking for trouble if you tend to hammer your camera with a motordrive.
DIY hole repair
Alternatively if it is only a very small hole, then the following tip by George Lottermoser may be worth a try:
[To patch the hole in a Leica cloth shutter,…] A teeny tiny bit of the liquid black rubber compound they sell for tool handles at the hardware store, judiciously applied with a que tip or tooth pick, to each side of the shutter; did it for me. Still going strong after 3 years.In Feb 2002, "Anon Terry" added:
BTW don't be squeamish about such a "low-tech" repair. The shutter on my M6 has had an 8 year old's finger poked into it, and two Shoe Goo repairs [to plug sun-burnt holes], since I bought it 4 years ago. No servicing, and works great to this day (and I still refuse to use lens caps).
The secret to a successful Shoe Goo repair is to spread it thinly and evenly, using the flat end of the toothpick to gently smooth it into the shutter fabric surrounding the hole on the front and back, and leaving the camera with bottom plate off to dry overnight before firing the shutter again.
Along with tool-handle compound and "Shoe Goo", you can also use Kodak Black Liquid Opaque or Liquid Electrical Tape. All of these are basically black rubber liquids which set to give a light-proof, flexible rubber film. Just make sure you don't get carried away and use too much, or else get impatient and fire the shutter before the liquid has properly dried.
Something you should also keep in mind is that if you do a crude or sloppy job, then even if the repair works, you can kiss goodbye to at least $300 off the camera's resale value.
Completely replace the shutter curtains
The most expensive solution, but it is also the surest and most long-lasting. Obviously you won't have to replace the entire shutter mechanism, just the front and rear cloth curtains. This is a "no-brainer" for any competent technician and won't cost as much as you think.
Why not use a metal shutter?
An unintended advantage Nikon found when developing their titanium shutter for the F and F2 cameras, was that it was also very difficult to burn a pin hole into. (See the Nikon website for a remark about this.)
Which raises the question, why don't Leica do the same?
The main reason is because a cloth shutter, burning aside, is incredibly robust and yet cheap and easy to manufacture, repair or replace. Furthermore a cloth shutter - any cloth shutter - is vastly quieter than a metal-foil or blade alternative.