Home · Register · Software · Software · Join Upload & Sell

Moderated by: Fred Miranda
Username  

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Canon Forum | Join Upload & Sell

  

Burning a sensor
  
 
bipock
Offline
• • • •
Upload & Sell: On
p.1 #1 · p.1 #1 · Burning a sensor


I took the attached picture yesterday after a fellow photographer asked me about the ability of the AD200 to overpower the sun. Settings were 1/200, f11, ISO 50, flash was 1/2 power for a reflector on it. Turned out pretty good, so I posted it to a FB page. Someone mentioned being careful about not burning my sensor.

I understand what is meant by "turn the sensor". However, I'm not certain I understand how one would do it/Under what conditions it could happen. I would have thought a long exposure puts you at risk, especially with the sun in it, but wouldn't have thought this one could cause risk.

Can anyone explain the phenomenon to me?







Oct 18, 2017 at 01:19 PM
Herb
Online
• • • •
Upload & Sell: On
p.1 #2 · p.1 #2 · Burning a sensor


I saw examples of burning the lens iris, sensor and areas around there from the eclipse if they werenít using an appropriate filter.


Oct 18, 2017 at 01:55 PM
bipock
Offline
• • • •
Upload & Sell: On
p.1 #3 · p.1 #3 · Burning a sensor


Herb wrote:
I saw examples of burning the lens iris, sensor and areas around there from the eclipse if they werenít using an appropriate filter.


I would guess that they were trying to fill the entire image area with the eclipse though, right? With the sun just a small portion of the picture, I wouldn't think that the risk is high in this situation.



Oct 18, 2017 at 02:12 PM
Photonadave
Offline
• • •
Upload & Sell: Off
p.1 #4 · p.1 #4 · Burning a sensor


Yes the sensor can be damaged by the sun however in your scenario, assuming you werenít using live view on your 5D Mark IV, due to the fast shutter speed & small aperture used itís not likely. The chance of damage is more likely to occur elsewhere in the mirror box, viewfinder, lens or even your eye if the camera is held somewhat still if even briefly. Remember that during focus & compos the lens aperture is normally wide open.

I think sun damage can occur with any lens. Iíve been lucky not sun damaging a camera so far, knock on wood.



Oct 18, 2017 at 02:21 PM
Bryston3bsst
Offline
• •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Burning a sensor


What you have done here won't pose a risk to the sensor.

To do that the sun would have to be aligned almost perpendicular to the sensor. At that point, with the lens, then acting as a magnifying glass, it's heat would be amplified to the point of beginning to melt things inside the camera and lens.

In the picture above, the sun is not at aligned to allow the suns rays a straight entry into the lens opening, therefore the glass won't concentrate the rays and in turn amplify the heat.

You can demonstrate this to yourself by taking a magnifying glass outside and burning a leaf, like when we were kids. Notice if you turn the glass so the beam is off of a straight axis to the sun, the leaf is much less likely to burn, as the rays are not concentrated enough.



Oct 18, 2017 at 02:27 PM
jcolwell
Offline
• • • • • • •
Upload & Sell: On
p.1 #6 · p.1 #6 · Burning a sensor


Bryston3bsst wrote:
What you have done here won't pose a risk to the sensor.

To do that the sun would have to be aligned almost perpendicular to the sensor...

... if you turn the glass so the beam is off of a straight axis to the sun, the leaf is much less likely to burn, as the rays are not concentrated enough.


I don't buy this line of reasoning.

All parts of the image receive the same magnification, whether on-centre or off-centre. When you turn the magnifying glass, the reduction in heat production is not because the sun is 'off center', it's because the point of sharp focus for the image coming from the magnifing glass has been moved off the leaf.



Oct 18, 2017 at 02:38 PM
Clicky94
Offline

Upload & Sell: Off
p.1 #7 · p.1 #7 · Burning a sensor


bipock wrote:
I would guess that they were trying to fill the entire image area with the eclipse though, right? With the sun just a small portion of the picture, I wouldn't think that the risk is high in this situation.


No, quite the reverse, a large image of the sun will spread the heat over a large area, a smaller image will concentrate the same total amount of heat on to a small part of the sensor making it more likely that damage will occur. The same process that happens if you use a magnifying glass to burn things using the sun.



Oct 18, 2017 at 02:40 PM
Bryston3bsst
Offline
• •
Upload & Sell: Off
p.1 #8 · p.1 #8 · Burning a sensor


jcolwell wrote:
I don't buy this line of reasoning.

All parts of the image receive the same magnification, whether on-centre or off-centre. When you turn the magnifying glass, the reduction in heat production is not because the sun is 'off center', it's because the point of sharp focus for the image coming from the magnifing glass has been moved off the leaf.


Buy it or not, that is how it works. You said it yourself, 'the point of sharp focus'. Exactly right, the point of sharp focus is the point of greatest concentration of the light. When the light is off axis that point is not as concentrated as the light is coming through the glass at more of an angle. Therefore, the sensor, or the leaf, doesn't see that point and won't burn.



Oct 18, 2017 at 08:37 PM
Photonadave
Offline
• • •
Upload & Sell: Off
p.1 #9 · p.1 #9 · Burning a sensor


Bryston3bsst wrote:
Buy it or not, that is how it works. You said it yourself, 'the point of sharp focus'. Exactly right, the point of sharp focus is the point of greatest concentration of the light. When the light is off axis that point is not as concentrated as the light is coming through the glass at more of an angle. Therefore, the sensor, or the leaf, doesn't see that point and won't burn.

Iíll buy-in, with a really big caveat, that a single element magnifying glass will tend to burn something a quicker on access rather than off access near the edge of its image circle. This does not apply to multi element highly corrected camera lenses! Not even close.

Hereís why, since the single element magnifying glass is not corrected for Spherical Aberration (Coma) and therefore cannot focus the sun off access to a clean image leaving it severely smeared effectively spreading the suns image over a larger area as compared to the on-access image. Itís so bad that the sunís round shape is rendered spread out in sort of an hourglass shape. A well corrected camera lens reduces the Spherical Aberration to the point that there is very little difference in size of the sunís image on the sensor. Fisheye lenses are a minor exception to the image size however is still way better than a magnifying glass.



Oct 18, 2017 at 09:38 PM
Photonadave
Offline
• • •
Upload & Sell: Off
p.1 #10 · p.1 #10 · Burning a sensor


Clicky94 wrote:
No, quite the reverse, a large image of the sun will spread the heat over a large area, a smaller image will concentrate the same total amount of heat on to a small part of the sensor making it more likely that damage will occur. The same process that happens if you use a magnifying glass to burn things using the sun.


No to your ďNoĒ!

The generalization that the large image of the sun produced by a telephoto lens will ďspread the heatĒ compared to a short focal length lens like the OPís 24mm lens (EXIF Data) will not ďconcentrate the same total amountĒ. This generalization implies that all parameters are the same except focal length.

Hereís why, since the exposure settings (ISO, shutter speed and aperture) for an image of the sun only, not compensating for the effect of the surrounding day or night sky , for any lens is the same within reasonable tolerances. This means that the energy/heat is the same per unit area for any lens used in this scenario.

With this in mind, for example, compare a 24mm f/2.8 lens to a 400mm f/2.8 lens where both will expose the sun the same, even wide open, for all practical purposes in this comparison. The sunís image from the 24mm lens will be .21mm diameter and the 400mm lens will be 3.48mm diameter (derived from ďFocal length/~115Ē for the size of sun/moon in focus from earth) on the sensor that works out to a surface area of .035 sq. mm for the 24mm lens and 9.51mm sq. mm for the 400mm lens, unless I have pie in my face. ;-) That works out to the 400mm lensís focused image of the sun dumping over 271x the total heat load greater than from the 24mm lens!

So I ask you, which lens is going to cause the most damage to itself or itís mounted camera in the least amount of time?


BTW, some trivia, with our sun being 92.96 Million Miles from Earth such that in order for the 24mm lens to produce the same size image of the sun as the 400mm lens here on earth your camera with 24mm lens mounted would need to be a few steps closer, like 87.83 Million Miles closer, to be at 5.58 million miles. Doing this will produce the same total heat load with the 24mm lens as the 400mm lens while using all the same settings (shutter speed & aperture).


Edited on Oct 19, 2017 at 12:31 AM · View previous versions



Oct 18, 2017 at 10:54 PM
 

Search in Used Dept. 



Roland W
Offline
• • • •
Upload & Sell: Off
p.1 #11 · p.1 #11 · Burning a sensor


Even though a long lens spreads the solar image over a larger area, it is getting much more energy in to the sensor or shutter, and thus a long lens is considered more dangerous. The heat per unit area is related to the f/stop of the lens, but the total heat hitting is related to the image area. That means up to 100's of times more total heat coming in with a long lens than a wide angle. The on axis vs. off axis makes no difference, because the lens is designed to provide sharp images of nearly uniform brightness all the way to the edges of the frame.

There are three things that can and do get burnt, the sensor if in live view or shooting video, the shutter if it is closed like when aiming or viewing through the lens, and the aperture blades that are close to where the total light from the lens concentrates before spreading back out to for an image. The current aperture of the lens matters, but usually it is wide open between shots. How well the lens is in focus makes a big difference, but usually the lens ends up in focus if it was last shot near infinity. The amount of time the energy is focused in one location matters a lot, and the worst case of that is an un attended lens that ends up pointed for a long time with the sun in the frame.

For wide shots, minimize the time that the sun is focused on the sensor or shutter. Minutes are likely fine, but avoid 10's of minutes. For long shots, you should likely only allow brief time with the sun in focus in one location on your sensor or shutter, like seconds. Then, for sure avoid any possibility that you leave a long lens un attended and pointed at the sun. There are specific reports of people seeing little clouds of smoke coming from their camera, which would lead to a really bad day, and an very expensive repair.

If you really need to image the sun with a long lens, go with a true solar filter, that is made for that use, and is also safe if you look through the lens. Your camera will then be perfectly safe, and your eyes will be perfectly safe, and you will still have plenty of light to give reasonably short exposures.

Note that when the sun is very low near the horizon, its light is going through a lot more atmosphere, and thus a lot more UV and IR are absorbed. That makes both eye safety and burnt cameras less likely, but there is no easy way to know ahead of time how much is absorbed. So you might get away with more, but should still just assume the worst, and continue with the same precautions.



Oct 18, 2017 at 11:40 PM
scalesusa
Offline
• • • •
Upload & Sell: Off
p.1 #12 · p.1 #12 · Burning a sensor


A short exposure is not a issue, using live view so that heat builds up can be a problem. During the eclipse, people, including me had their camera pointed at the sun for a hour, without a protective filter, that would cook things. The heat can potentially cook a lens aperture, mess up lubes and the cement that bonds elements, cook a camera shutter, blind someone looking thru the viewfinder, and , damage the sensor as well.

Short exposures just cause flare.



Oct 19, 2017 at 01:51 AM
fplstudio
Offline
• •
Upload & Sell: Off
p.1 #13 · p.1 #13 · Burning a sensor


If you stay away from live view in these circumstances I would not bother at all with such issue.


Oct 29, 2017 at 12:31 PM
shutterbug guy
Offline
• •
Upload & Sell: On
p.1 #14 · p.1 #14 · Burning a sensor


I shot the last eclipse successfully using the special filter, using live view, and watching it on my iPad via WiFi courtesy of CamRanger without any known ill effects or damage. When the total eclipse occured for the 2+ minutes I removed the filter and continued to watch on live view via my iPad again with no ill effects or damage noticed.

Earlier I've shot many shots of the sun without any protection and again without any known damage or ill effects. Of course to leave it on live view with a shot of the glaring sun would be highly risky if not stupid imho, even if for a short period of time.









Full Eclipse, Grand Island, Nebraska







Sandhill Crane Migration, Gibbon, Nebraska



Edited on Nov 08, 2017 at 11:13 AM · View previous versions



Oct 29, 2017 at 12:42 PM
Jefferson
Offline
• • • • •
Upload & Sell: Off
p.1 #15 · p.1 #15 · Burning a sensor


.. I'll play ..

What part would the angle of the rays from the sun play and the time of day .. rays being more perpendicular during summer and rays in early morning having to pass through much more atmosphere than they would later in the day (independent of season), .. the latter contributing to "better light" for morning and late afternoon photography .. ?

This should be more applicable the farther North or South of the Equator you travel ..


Jefferson



Oct 29, 2017 at 03:25 PM
AJSJones
Offline
• • • •
Upload & Sell: On
p.1 #16 · p.1 #16 · Burning a sensor


The diameter of the front element will control how much sunlight/heat is captured (total photons, visible and IR/heat) - the angle of the optical axis to the sun will modulate this. The size of the image on the sensor (in mm^2) will determine the energy flux that hits that area (in photons per mm^2). Then the exposure time at that flux determines the amount of damage. If the aperture is stopped down, then it will receive much of the heat energy collected by the elements before it and spare the sensor that amount.


Oct 29, 2017 at 03:31 PM
AmbientMike
Offline
• • • •
Upload & Sell: Off
p.1 #17 · p.1 #17 · Burning a sensor


I look at it like burning leaves with a magnifying glass. I'm not saying I don't do it, but I don't leave it pointed at the sun long. It takes a little time to burn the leaves. But not long!

I like to use the EVF on a m4/3 for sun photos. I'm never looking directly at the sun, afaik, just the EVF. Rather the evf/sensor ruined than eyes. Of course, I'd rather have neither ruined.

This was mentioned above, a longer lens should have a larger image of the sun, more spread out and less per unit area. But, if it's a 300/2.8, I think you'd still have a bright image, due to more of the suns rays focused, due to the bigger elements. I think it would be the same intensity as an f/2.8 wider lens, but bigger. So overall, more powerful



Nov 01, 2017 at 04:12 PM
dsjtecserv
Offline
• • •
Upload & Sell: Off
p.1 #18 · p.1 #18 · Burning a sensor


Folks, see Roland's and Photonadave's discussion above. As photographers, we should know that the f-number represented the light intensity (per unit area) of any subject (including light sources such as the sun) striking the sensor surface. Thus the intensity of the image of the sun through a 24 mm f/4 is the same as through a 300 mm f/4. The longer lens neither "spreads" nor "concentrates" the energy, when used at the same f-number.

However, as Roland explains very well, the TOTAL amount of energy incident on the sensor surface is a function of how big the image of the sun is; that is, its magnification. A longer focal length lens will produce a larger image of the sun, and thus when used at the same f-number as the shorter lens, will deliver more energy to the sensor surface. The energy per unit area (say, per square mm) is the same, but the total, over the greater number of square mm, can be much greater.

I raised this issue on an earlier thread related to the eclipse, since it is obvious that 1) many people have taken unfiltered pictures including the sun, even with the sensor uncovered during composition using live view, without damage; and 2) there have been documented cases of sensors and other internal surfaces being damaged. It is clear that any damage is not automatic or necessarily quick to happen, but it is also clear that it can happen. The interesting question is what variables influence the outcome of this -- what factors determine the risk or likelihood of damage occurring?

Since the temperature that a material reaches is a function not only of the rate of energy input but also the rate at which that energy can be dissipated, it would seem that long lenses may pose a greater risk simply because even at the same f-number (intensity) as a shorter lens, it is more difficult for the greater amount of total energy to be dissipated by the sensor or, to put it another way, the amount of time needed for energy to build up to a critical level on the sensor surface is less than with a shorter lens. The bigger the image of the sun, the more total energy that has to be removed form the sensor, and beyond a certain point, that cooling system is overwhelmed.

There are no doubt other variables that play a part, and different camera sensor systems may have different abilities to move energy from the sensor. But this would appear to partially explain why, in principle, longer lenses incur more risk.

Dave



Nov 01, 2017 at 05:45 PM
_manny_
Offline

Upload & Sell: Off
p.1 #19 · p.1 #19 · Burning a sensor


It's interesting to read this discussion.

One thing I have wondered about is whether sunlight can actually damage a lens if exposed for long enough to intense enough light. I realise aperture blades can be damaged if stepped down in the same way concentrated light can damage the sensor by burning.

But what about the lens coatings etc? Are they ever at risk? I have a number of old and strange lenses I rarely use but sometimes if it is a bright sunny day I would put them on the window sill and let the sunlight land on them for a while (standing up on end caps) as I read it's very good for making sure fungus doesn't grow. I never really gave it much thought until I got the Canon 35L II and a friend who is into photography said I ought not to do it because of the blue refractive element. It got me thinking as to whether enough direct harsh sunlight can bleach lens glass and coatings? I used to work in property management and would see that over the years sunlight can bleach almost everything but had never thought about it with lenses.

Probably not something one needs to worry about but I wonder if anyone has ever experienced anything like this.



Nov 03, 2017 at 05:15 PM
runamuck
Offline
• • • • •
Upload & Sell: On
p.1 #20 · p.1 #20 · Burning a sensor


Roger Cicala of lenrentals showed the damage done by people shooting the eclipse. It was considered negligence, and the photogs had to pay. If there is any co9ncern, don['t do it. A UWA will possibly burn a tiny hole in the shutter, but telephoto lenses can do serious damage. Just like burning ants with a magnifying glass as kids, the sun CAN DAMAGE gear.

https://www.lensrentals.com/blog/2017/09/rental-camera-gear-destroyed-by-the-solar-eclipse-of-2017/



Nov 03, 2017 at 05:33 PM







FM Forums | Canon Forum | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username     Reset password