Will the sun damage lens or sensor?

Discussion in 'Canon EOS' started by davyjo, Jan 6, 2007.

  1. I have a nice view of a tidal river and am considering taking a timelapse of the
    view for a day which would involve sunrise and a couple of hours of exposures
    with the sun in the image. I'd set the camera up in a window and automatically
    shoot with my computer. The tidal range is dramatic as the river at high tide is
    a mile wide and at low is 100 feet wide. I have done some test test runs on a
    cloudy day but that gives much less interesting shots. Ideally a mix of clouds
    and sunshine and shooting every two or three minutes would produce a set of
    images. <P>
    I'd be shooting with my 30D with either a 50mm f/1.8 II or a 28-135mm IS
    somewhere near 50-60mm.<P>My concern is about possible damage to the lens and
    sensor taking that many images of the sun and the lens objective being exposed
    to sunlight for that long. <P>Another question might be: Can this be done with a
    camcorder?<P>
    Thanks for any help.
     
  2. Never heard of such a possibility. Only warning I read in Canon documentation was not to shoot pictures toward the sun when there is no lense mounted on the camera.
     
  3. There will be no damage done to your sensor or your lens.
     
  4. Afaik sensors (so those in camcorders too) get damaged if exposed to the sun for
    prolonged times. What are 'prolonged times'? Imo anything longer than 3 seconds qualifies
    as 'prolonged times'.

    FYI 1: 'time lapse photography' doesn't neccessarily mean extremely long exposures. It
    means an exposure every X seconds or minutes. But those can all have different exposures
    (shutter speed and aperture combo's) if you set the camera on Auto.
    Time lapse photography is best done under even lighting. So a whole day with all its
    differences in light intensity and continuously changing angles is the opposite of an ideal
    subject for time lapse photography!

    FYI 2: if you let the camera auto expose, the frames with the sun in them will have terribly
    underexposed landscapes. Because the difference in brightness between the sun and the
    landscape is too great and your cam will expose for the sun.
    For those photos you need either a graduated Neutral Density filter, or you need to employ
    HDRI (High Dynamic Range Imaging; http://en.wikipedia.org/wiki/HDRI).
     
  5. The sun rises over the river so the light is reflected off the water/mudflats(dependinig on tide) so the exposure isn't horribly underexposed. The tests I did were on auto setting, P. I imported the images into iMovie and the results were quite interesting. The biggest drawback is the image size from the 30D. Even the smallest image size is huge for a movie frame.
     
  6. If you're happy with the exposures with the sun in them, fine.

    "The biggest drawback is the image size from the 30D. Even the smallest image size is
    huge for a movie frame."

    What's the prob? Those can be batch shrunk to any size you want, can't they?
     
  7. <<Afaik sensors (so those in camcorders too) get damaged if exposed to the sun for prolonged times. What are 'prolonged times'? Imo anything longer than 3 seconds qualifies as 'prolonged times'.>>

    IMO making up numbers out of thin air makes you look silly.
     
  8. I'd rather look silly than destroy a 2,000 dollar camera, Rob. But apparently money is no
    object to you...
     
  9. The easiest answer is this: if you are very uncomfortable because the sun is too strong or too hot for too long, then protect your camera. You are not exposing the sensor to anything unusual.
    I think some people do not read posts carefully enough.
    Camcorder would be great, but what not if you want decent prints.
    Doug
     
  10. jbq

    jbq

    The lens certainly won't have any damage, nor will the sensor (it'll be hidden behind the shutter most of the time) or the shutter (it'll be behind the mirror most of the time).

    The screen and the AF sensor might not be as happy.

    Let's call R the power density of the sun (1000 W/m^2), f the focal length, a the f-stop and O the apparent angle of the sun (half a degree).

    The power received from the sun is R*pi*(f/a/2)^2.

    The area of the sun's image is pi*(f*tan(O)/2)^2.

    The power density of the overall image is R/(a*tan(O))^2, i.e. potentially a whole lot (4MW/m^2 at f/1.8). I would recommend a lens that you can keep stopped down (i.e. a non-EF lens, a Nikon 50/1.8 will do just fine), at f/11, with a 3-stop ND filter. That'll bring you down to 13kW/m^2, split approximately 8kW/m^2 on the screen and 5kW/m^2 on the AF sensor, which could be within an acceptable range (though I'm not sure). By comparison, a 486 processor dissipates about 30kW/m^2 in normal operation, and typically comes with a heat sink and a fan.
     
  11. Thanks everyone. I'm not interested in prints so a camcorder might be an option if it can be automated to take a few frames every 30 seconds or so. I'll look into it. I don't supposes there is any way to hold an EF lens at f/10 between shots is there? Other than holding down the DOF Preview button. Batch proccessing several hundred images can be quite a chore for a iBook G4!
    Thanks again.
     
  12. jbq

    jbq

    You could in theory unmount the lens while holding down the DoF preview, and tape the pins.

    I don't know whether that'd damage the lens or not.
     
  13. I think Jean Baptiste's calcuations are a little conservative. The intensity of solar radiation at dawn and for the next couple of hours will be substantially less than at midday under a clear blue sky (his 1kW/m^2 figure) because the sun's rays pass through a much greater thickness of atmosphere and suffer much more scattering (hence the colours of the dawn sky). It will also depend on your latitude, the time of year, and the turbidity and moisture content of the atmosphere. Moreover, the sun moves through its diameter approximately every two minutes, so the area being subject to an image of the sun is changing. I don't think the focus screen is at much risk because it actually transmits most of the light rather than absorbs it.

    http://www.jgsee.kmutt.ac.th/exell/Solar/Intensity.html

    http://edmall.gsfc.nasa.gov/inv99Project.Site/Pages/science-briefs/ed-stickler/ed-irradiance.html
     
  14. In an SLR the sensor is protected by the shutter and mirror: The sunlight is reflected to the viewfinder and most of the light will leave the camera without doing any damage to the camera.

    With a camcorder the situation is different: All of the sunlight goes straight to the sensor. And when the camera is mounted on a tripod the sun has plenty of time to damage the sensor.

    So overall I would think that a camcorder is more likely to be damaged than an SLR.
     
  15. "The biggest drawback is the image size from the 30D. Even the smallest image size is huge for a movie frame."

    Faststone photo resizer, I swear by it. It's free for home use too.
    http://www.faststone.org/FSResizerDetail.htm
     
  16. <<I'd rather look silly than destroy a 2,000 dollar camera, Rob. But apparently money is no object to you...>>

    I'm interested in facts, Smith, not the ramblings of someone who makes stuff up.
     
  17. I've been shooting sunsets (5:30 pm to 6 pm) and sunrises (about 6:20 am to 6:40 pm). I use a micro 4/3 camera, will it or will it not damage the image sensor? I'm confused.
     

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