Does the sun really burn Leica curtains?

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snaggs

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2. Sunset photos with the sun filling 1/3 of the frame, preferably with the ubiquitous New England lighthouse in silhouette? How fast can you say, "Hole in the shutter?"


Glad I read through Essay number 3... Is this true? What precautions do I have to take to overcome this?

Daniel.
 
Yes, it certainly does.

I recall a recent thread in which an RFF member did a test (using a former Soviet camera that already needed a curtain replacement) and the damage happened in seconds.

The good news from his experiment was that since the shutter curtains are a few mm in front of the film plane, there's actually LESS damage potential when the lens is focused at infinity. It's when the lens is focused closer (thus moving the infinity point forward) that the curtains are more likely to burn.

So I'd say that if you set the focus to infinity, then took only a few moments to line up your shot (or kept the lens capped until you were ready to shoot) you'd be pretty safe.

But if this advice turns out to be hooey and you pinhole your curtain anyway, I am NOT responsible! (Hey, what do I know? I'm a Canon and Bessa guy; these all have metal shutters that are less burn-prone!)
 
A friend of mine left his M6 with a 35 Summicron on the passenger seat of his car while driving. I'm not sure what time of day it was or how long he was driving for but the sun must have been coming through the windshield and shone directly on that lens at such an angle he burned a hole in his shutter.

Now, I had a theory but never tested it... if the shutter was cocked (thus having the white reflective shutter dot in place) would it have deflected more light and kept the shutter safe rather than having the shutter uncocked with just a black, therefore more light ABSORBANT surface?

I don't know if my friend's shutter was cocked or not. Didn't ask him.

So lesson to be learned, keep your M out of direct sunlight. Even on the shelf.
 
jlw said:
Yes, it certainly does.

I recall a recent thread in which an RFF member did a test (using a former Soviet camera that already needed a curtain replacement) and the damage happened in seconds.

The good news from his experiment was that since the shutter curtains are a few mm in front of the film plane, there's actually LESS damage potential when the lens is focused at infinity. It's when the lens is focused closer (thus moving the infinity point forward) that the curtains are more likely to burn.

So I'd say that if you set the focus to infinity, then took only a few moments to line up your shot (or kept the lens capped until you were ready to shoot) you'd be pretty safe.

But if this advice turns out to be hooey and you pinhole your curtain anyway, I am NOT responsible! (Hey, what do I know? I'm a Canon and Bessa guy; these all have metal shutters that are less burn-prone!)
Click to expand...


hey, maybe THAT'S why lenses had infinity locks back then!?

now that i have 2 canon bottom feeders with cloth curtains i guess i'll have to be vigilent.

joe
 
Yes, stopping the lens way down to f16 or 22 would reduce the amount of light entering the camera and possibly striking the curtain. Less light = less light energy for burning. Only M6 bodies (with built-in meters) would have a white dot on the tensioned curtain. But nothing beats a lens cap.
 
saxshooter said:
A friend of mine left his M6 with a 35 Summicron on the passenger seat of his car while driving. I'm not sure what time of day it was or how long he was driving for but the sun must have been coming through the windshield and shone directly on that lens at such an angle he burned a hole in his shutter.

Now, I had a theory but never tested it... if the shutter was cocked (thus having the white reflective shutter dot in place) would it have deflected more light and kept the shutter safe rather than having the shutter uncocked with just a black, therefore more light ABSORBANT surface?

I don't know if my friend's shutter was cocked or not. Didn't ask him.

So lesson to be learned, keep your M out of direct sunlight. Even on the shelf.
Click to expand...

Why didn't he just put the lens cap on? :confused:
 
If you don't have a lens cap, keeping the lens focussed at close focus and the lens stopped down will minimize the chance of burning a hole in the curtain. The close focus will spread the light from the sun, minimizing a hot spot (the sun is at infinity and focusing the lens at infinity will concentrate the light, similar to what kids do with a magnifing glass in order to light paper or fry bugs).
 
kabkos said:
the sun is at infinity and focusing the lens at infinity will concentrate the light...
Click to expand...

Yes, but the shutter curtains are about 3mm in front of the film plane. That corresponds to the amount of focusing extension required to focus a 50mm lens at 1 meter.

So, focusing the lens for a 1-meter distance on the film would actually correspond to setting it for infinitity focus on the shutter curtains, concentrating the sun's rays more and making it more likely that they'd burn.
 
So would doing a shot like this...

medium.jpg


be impossible with my Leica? (thats my wife btw)

Daniel.
 
Hello, hello, it was me who intentionally burned my deceased-Zorki 6 curtains.
The first result of the testing was the few mm difference between focus plane to the shutter. That is about the same difference in focussing infinity vs. close focus.
In other words: maximum concentrated solar energy on the shutter occurs at close focus.
Second aspect: f-stop. I tried the test with a Canon 1,2 which was shocking. Instant burns. Trusting on a white part of the shutter is no option unless you aim only that part into the sun!
From about f4 and smaller the effect of solar destruction changes quite rapidly from within seconds to about 10 seconds: Stopping down helps! 90mm at f4 (my largest) was not really destructive, not within seconds.

Main thing is to imagine the spreading of solar intensity on the shutter. If the sun is aimed at a shutter with a 50mm lens, it projects a circle of about 3mm diameter.
If the sun projects a larger circle, the average energy per square mm is less, thus the burning force is less.

I HAVE NOT TESTED THIS LAST OPTION OTHER THAT THE ABOVE MENTIONED 90MM TEST!

I will ofcourse accept no claims nor will I give warranties!

! would not hesitate to make a sunset photo projecting a large sun. Realise and understand the danger so you can act appropiately: Keep the solar projection as short as possible. YMMV!!

A sunset will also be stopped down, that would not harm?!

cheers, Rob.
 
kabkos said:
If you don't have a lens cap, keeping the lens focussed at close focus and the lens stopped down will minimize the chance of burning a hole in the curtain. The close focus will spread the light from the sun, minimizing a hot spot (the sun is at infinity and focusing the lens at infinity will concentrate the light, similar to what kids do with a magnifing glass in order to light paper or fry bugs).
Click to expand...
Heh, I'm still confused why a guy would be driving around with a three thousand dollar camera and lens and no lens cap.. ;)
 
It is false that this problem occurs only with RF camera's. In SLR's the energy of the sun
is projected upwards and concentrated on the focussing screen, which,this being plastic, causes it to sag, making for permanent misfocus.
I have, over the last 50 years, not heard of anybody getting into problems by including the sun in his photo. This is hardly surprising. It, as was mentioned in this thread, takes several seconds to burn through the curtain. That means a considerable time longer than it takes to cause a painful burn in your eye looking straight into the sun through the viewfinder.
 
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jaapv said:
It, as was mentioned in this thread, takes several seconds to burn through the curtain. That means a considerable time longer than it takes to cause a painful burn in your eye looking straight into the sun through the viewfinder.
Click to expand...

Jaap, that is not exactly correct. I burned instantly through the shutter curtain with f1,2 50mm. Even 50mm f2 burns almost instantly, within a second.
I guess a 90mm f2 also burns instantly, I don't have one to try.

General rule: avoid wide open larger than f4. From f2 up even 'brushing' the sun incidentally may burn. Avoid carrying a camera with a large aperture wide open. Better safe than sorry.
 
I agree totally with better safe than sorry. A camera should not be carried without a lenscap (more more reasons than this obviously), not pointed at the sun for any length of time and not put on a tripod pointing at the sun etc. But taking a photo is entirely possible. You would have to be extremely unlucky to damage it by doing that. I would be more worried about damaging my retina by looking at the sun through the viewfinder. That is not as easily replaced as a shutter curtain!
I wore sunglasses for this shot:
(btw not flare, but parhelia)
 
Reflections on ice-crystals in the upper atmosphere, the same as a ring around the moon. If you look carefully, you'll see a vague ring around the sun as well.
Called Sundogs in the USA.
 
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When I'm carrying the Leica without a lenscap (I prefer it because the time taking the cap off can mean a missed shot) I invert the strap rings (I use the OEM Leica straps) and then the camera hangs lens-down.

If I were to take time composing a shot against the sun, I'd just leave the lenscap on until I was ready to take the shot. Unlike an SLR you can compose with an M Leica with the cap on.
 
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