04-28-2014, 06:56 AM
(This post was last modified: 04-28-2014, 07:00 AM by popo.)
Apart from the sun I don't think there are sources of light you would normally encounter which could burn a shutter. I have heard stories of people having damaged sensors from shooting at laser shows, but that type of damage is different and only affected the sensor.
During an exposure the sensor has to be powered and it will build up heat by itself. What you're shooting is probably minimal. The long exposure doesn't build up anywhere near enough heat to damage itself. I've done continuous sequences of exposures of up to 8 minutes each before with no problem.
There is one more thought to the sun theory: A lot of the sun's energy is infrared. Normal lenses aren't generally well corrected into IR and in those wavelengths may have a different focus point. It may be coincidence that the difference is the same as the sensor to shutter distance for some lenses.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
I don't think the focus has to be very precise. The light is being concentrated even if not focused exactly. I'm starting to wonder about the imprinted shapes near the burn marks on the shutter. Thinking something physical was going on, after all maybe. But I'm still not sure what.
When the sun decides to show it's face I going to do a few experiments using a lens of decent aperture and various pieces of sheet material, we all know from our youth that the larger the magnifying glass the hot the focused point of the sun becomes, I will try some aluminum (blackened) very thin sheet from a tin can or something to see in practice if it could burn a hole.
BTW Is the camera taking perfectly good images now, or does the hole produce a bright streak etc?
About the photos I can take being perfectly good...The answer is yes and no. Here is a photo where I think most people would say it was fine. It takes a close look to see anything wrong:
Here is an example of it at its very worst, before I even cleaned the sensor, though cleaning it would probably not have effected the large artifical comet flying through the sky:
By examining my photos I have determined (with the help of the input from here, and Flickr) what happened. As unlikely as it seems (the shutter is metal!) the hole WAS made when I tried to photograph the sun in order to create a flare. I WAS pretty stupid, as it turns out because I did have the camera on a tripod and I was using live view so as not to fry my eyes. I realize now what I did wrong. In between failed attemps, I think I must have used mirror lock up so that I could sight down the barrel of the lens from behind the camera in order to get the best alignment, but I did not what the sun in the viewer to be a distraction. So I locked up the mirror, thinking, if anything, the shutter would protect my eyes and the camera sensor. As it turns out it was the shutter that was more vulnerable than the sensor.
How could I have not noticed for two weeks? Look at the flower photo! Would you have noticed? Plus, I did notice that in the lower left contrast was not good. First I suspected the lens I was using, then I suspected that the sensor was smeared with something...Oil, or sweat, or something.
Let this be a lessen to you! (As if anyone else would need to hear this...) The sun in nothing to take lightly! The energy from it when focused even a little, can destroy. I probably am lucky I did not look through the viewer. At some level I knew I was playing with fire, but I wanted to get this effect.
Oddly enough, a little before or after, I did get the effect a little. It didn't even take the sun to do it. But I've sort of lost interest in the subject of creating unusual flares. Now, like everyone else, I will be avoiding them like the plague!
Well, we now know! an unfortunate sequence of events that lead to the damage of the shutter, and you did well to post that here, it was a puzzler.
I did a dumb thing two weeks ago, I put the kettle on the gas and went out to fiddle with something, forgot the kettle and twenty minutes later I went back in to find steam everywhere, windows steamed up etc. Three days ago whilst preparing some of my lenses I noticed that my Sigma EX 50-150 2.8 had two clumps of mould growing on the inside of the front element, I managed to undo the front retaining ring took out the element and cleaned it, luckily there was no sign of further fungus inside, a simple stupid thing that could have been a large repair bill, not counting the other dozen or so lenses which fortunately were untouched. Who would have thought that making a cup of tea could ruin your lenses!
As they say stuff happens!
BTW. You've some very nice images on your flickre site. Good luck!
Sometimes you have to get burned in order to learn I guess. Fungus in a lens due to poor storage conditions has been one of my lessons. Before it happens to you, you think of it one way. Afterward, you are much more careful! I am very prone to being absentminded. So much so that I question if I should really be pursuing a hobby where mistakes are so expensive!
I guess I'm going to have to find out about what the cost of replacing this shutter will be. You know, I will say that both of my Canon DSLR's have been very reliable. Still, my camera is four years old. It may be time to look at DSLR #3.
Thanks for you comments on my Flickr images! I have deferred a lot of learning of good techniques in favor of seeing more. I have also deferred buying many expensive lenses. That doesn't mean I don't see the value of technique, superior lenses, and other styles of photography, it's just that my curiosity to see to next photo makes it hard for me to slow down.
I just recently obtained a couple of lenses that may be game changers for me. Arrrrgh! And now this thing with the shutter! Knowing me I might keep shooting with the camera the way it is, until it bursts into flame.
Dear Arthur, not only your shutter, also the post-processing of your avatar imply that you shouldn't expose yourself to the sun too much
Very interesting topic though, a case for the cabinet of curiosities!
Cheer up though, any loss can be the long needed reason to make an upgrade in your equipment.
And who of those with a ring on their finger doesn't know the quote "you wanna buy a new lens AGAIN?????"
I may have to downgrade before I upgrade, however, at least I can start evaluating the alternatives! I can say there are some good options out there.