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DPChallenge Forums >> Photography Discussion >> Solar Eclipse and camera sensor
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05/16/2012 03:31:04 PM · #1
I was hoping to do a timelapse of the eclipse...was wondering if i should be worrying about my camera sensor at all?
05/16/2012 03:38:20 PM · #2
Probably some of the details are pertinent. Are you going to be zoomed in on the sun and track it with a mount or manually? Is it going to be within a wide angle view? Are you going to have mega ND-filter help?

I had similar questions, although I'm not planning on doing a time lapse. I can tell you that my sensor wasn't hurt shooting straight into the full sun at 200mm. I wouldn't recommend looking through the viewer though (I had the lens closed down the f/36, used the aperture preview button so I could look through with my eye, closed my eyes, released the aperture preview, and then shot the picture).
05/16/2012 03:43:37 PM · #3
Your sensor will not be exposed to the image of the Sun except during the (short) periods when the shutter is open, so that won't represent a problem. The vast majority of the light passes up through the mirror box and out through the viewfinder, except during exposures. The one exception is if you were to use Live View. Don't do that. :-)

Leaving a camera pointed directly at the sun, without significant filtration, will introduce quite a bit of heat into the optical system, and I would be concerned about that. There is also the risk of looking into the viewfinder, which could lead to eye damage. So always use appropriate filtration, preferably a screw-on filter (can't be knocked off).

05/16/2012 04:04:22 PM · #4
Anyone ever used a gel IR filter? I am tempted to see what comes out.

I am paranoid because I actually burned a cameras sensor to oblivion and I was at 100mm and short exposure. Just bad luck on that one.
05/16/2012 04:34:38 PM · #5
Originally posted by kirbic:

Your sensor will not be exposed to the image of the Sun except during the (short) periods when the shutter is open, so that won't represent a problem. The vast majority of the light passes up through the mirror box and out through the viewfinder, except during exposures. The one exception is if you were to use Live View. Don't do that. :-)

This also applies to anyone with a camera with an electronic viewfinder (EVF), i.e. almost all non-dSLR cameras these days.
05/16/2012 04:40:29 PM · #6
In the Nikon D7000 manual, in the section about "live view", it clearly says;
"When shooting in live view mode, avoid pointing the camera at the sun or other strong light sources. Failure to observe this precaution could result in damage to the camera's internal circuitry. "
I'm curious about Sophia's sensor burn. Was that a P&S or DSLR, and if DSLR, were you using live view?
05/16/2012 10:47:39 PM · #7
It was a pentax K10. I really liked that camera. I was not using live view, it was close to sunset and a very short exposure and not a high mm (100). I was shocked. They did cover it with the warranty thank goodness.

Originally posted by MelonMusketeer:

In the Nikon D7000 manual, in the section about "live view", it clearly says;
"When shooting in live view mode, avoid pointing the camera at the sun or other strong light sources. Failure to observe this precaution could result in damage to the camera's internal circuitry. "
I'm curious about Sophia's sensor burn. Was that a P&S or DSLR, and if DSLR, were you using live view?


Message edited by author 2012-05-16 22:47:56.
05/16/2012 11:26:01 PM · #8
Thanks Sophia. I shoot sunsets quite often, and have never had any problems, even with long lenses. I rarely use live view.
I'm glad to hear that it was a warranty repair.
05/17/2012 12:17:57 AM · #9
I am going to see how my IR filter does. Let you know the results.
05/17/2012 12:33:27 AM · #10
Originally posted by MelonMusketeer:

Thanks Sophia. I shoot sunsets quite often, and have never had any problems, even with long lenses. I rarely use live view.
I'm glad to hear that it was a warranty repair.


I might be wrong here, but wouldn't short lenses be a more risky configuration? Given that the power density of the sun on any given spot on the sensor would be much higher with a short focal length?

Or am I just completely wrong about this one?
05/17/2012 01:01:58 AM · #11
”Even though as much as 94% of the Sun’s disk will be covered, you still need to use a solar filter or some type of projection technique. A #14 welder’s glass is a good choice. There are also many commercially-available solar filters.”

Doesn't sound like we'll get to see it in Seattle..see the map on this link to see where the best chances are, of seeing it.

//science.nasa.gov/science-news/science-at-nasa/2012/15may_sunday/

It seems many places are sold out of the solar filters, or filter sheets?
05/17/2012 08:07:49 AM · #12
Originally posted by Cory:

Originally posted by MelonMusketeer:

Thanks Sophia. I shoot sunsets quite often, and have never had any problems, even with long lenses. I rarely use live view.
I'm glad to hear that it was a warranty repair.


I might be wrong here, but wouldn't short lenses be a more risky configuration? Given that the power density of the sun on any given spot on the sensor would be much higher with a short focal length?

Or am I just completely wrong about this one?


Actually, I've been thinking about this too. I believe the answer is, "the power density is the same given the same f-ratio." If we consider that the sun has an invariant surface brightness, then for any given f-ratio the only thing that varies is the area covered by the subject. The brightness does not change.
This leads to an increase in the total power dissipated into the sensor that varies approximately with the square of the focal length, for a given f-ratio. Make sense?
05/17/2012 08:37:07 AM · #13
Re 21.gif Cory,21.gif kirbic, These are good questions. My thoughts about this is that watt density would be equal at similar apertures.
If you shoot a scene with a 100 mm lens at f2.8, and correct EV, you could move closer and shoot the same scene with a 35mm lens at f2.8 and the same shutter speed/iso combination, and the brightness levels would be the same in both images.
The thing with the sun though, is that you don't move closer, so with the longer lens, it's image covers a larger area on the sensor, so the "hot spot" is much larger. The result is that with two lenses with the same max aperture, you can roast a lot more ants at one time with the longer lens because the spot is larger and at the same power level.
I guess that there are two ways it could damage a digital camera. One would be the heat damages the actual sensor, and the other would be if the output overload or voltage from the sensor cells fries the electronics that "read" the sensor output.
In any case, it's probably a good idea to keep the aperture small, and iso low any time when shooting with the sun in the frame.

As a side note, with "live view" on the D7000, I observe that the aperture is closed to the chosen setting when the mirror goes up, and stays that way until live view is ended.

05/17/2012 09:20:24 AM · #14
Makes sense to me - but not my area of expertise. Lets just say that when I want to look at the sun, I usually use a telescope with the right filter.

My burn out happened when it hit the background through the trees, I definitely wasn't "shooting" for that.

Very interesting discussion.

Originally posted by kirbic:

Originally posted by Cory:

Originally posted by MelonMusketeer:

Thanks Sophia. I shoot sunsets quite often, and have never had any problems, even with long lenses. I rarely use live view.
I'm glad to hear that it was a warranty repair.


I might be wrong here, but wouldn't short lenses be a more risky configuration? Given that the power density of the sun on any given spot on the sensor would be much higher with a short focal length?

Or am I just completely wrong about this one?


Actually, I've been thinking about this too. I believe the answer is, "the power density is the same given the same f-ratio." If we consider that the sun has an invariant surface brightness, then for any given f-ratio the only thing that varies is the area covered by the subject. The brightness does not change.
This leads to an increase in the total power dissipated into the sensor that varies approximately with the square of the focal length, for a given f-ratio. Make sense?
05/17/2012 03:50:52 PM · #15
Some tips about the event here
05/18/2012 12:44:25 AM · #16
//news.yahoo.com/sunday-solar-eclipse-safely-photograph-ring-fire-180800451.html

This may help...
05/20/2012 06:41:24 PM · #17
Well, it is just passing right now, past its point of most annularity. I didn't get any good photos, though.
05/20/2012 11:43:39 PM · #18
Here is a shot with my IR filter:

//www.dpchallenge.com/image.php?IMAGE_ID=1016571



Message edited by author 2012-05-20 23:44:51.
05/21/2012 12:39:39 AM · #19
Not that sharp, shot through high-density film* at 432mm (35mm EQ) ... near time of maximum coverage in the Bay Area; 100 crop, no adjustments or sharpening ... Copyrighted_Image_Reuse_Prohibited_1016584.jpg

*The film I was using has a density near 4.0 on a logarithmic scale, meaning it was letting through about 1/10,000th of the available light. I had to shoot at ISO 80, f/3.5, and between 1/15-1/30th of a second exposure length. I guess I should have tried a higher ISO setting combined with a faster shutter to trade some sharpness for noise ...

Message edited by author 2012-05-21 00:50:14.
05/21/2012 08:57:24 AM · #20
Here are all of the shots I got:

//www.sophiaimages.com/ArtCollections/Eclipse-2012/

They are about the same quality.
05/21/2012 10:31:49 AM · #21
Originally posted by sophiawood:

Here are all of the shots I got:

//www.sophiaimages.com/ArtCollections/Eclipse-2012/

They are about the same quality.


Those are very nice, and no burned sensor this time?
I bet that it seemed like hours while you waited for that cloud to move out of the way.
05/21/2012 10:34:25 AM · #22
No burned sensor!!! The exposures weren't bright to my eye so I figured they weren't bright to the sensor. Thanks!

It did seem like forever. The pic as it is coming down from the cloud and mostly covered was the "peak" time for the eclipse. So I am happy I didn't miss that.
05/21/2012 11:59:31 AM · #23
Sophia, those are awesome. The shots between 11 and 17 are really, really neat.

Originally posted by sophiawood:

Here are all of the shots I got:

//www.sophiaimages.com/ArtCollections/Eclipse-2012/

They are about the same quality.
05/21/2012 01:23:00 PM · #24
Thanks! - I need to post that last couple as the sun sets over the mountains. Will do tonight.
05/21/2012 01:33:06 PM · #25
I stupidly was in live view to see the light flares in real time. I was stopped all the way down, but quickly realized this was probably a bad idea so I turned it off. I think I was lucky because everything still appears fine.

Message edited by author 2012-05-21 13:34:05.
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