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  1. #1
    LostBoyNZ's Avatar
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    Lightbulb Erm, was this a safe photo of the sun?



    Last year I took a photo of the Sun using my Canon 5D Mark II, 100-400mm lens, 2x extender and a B+W 1000 ND filter. The shutter speed was 1/8000th of a second, and it was set to f 20. The filter ensured only 1/1000th of the light that would normally get in did get in, but I assume that only covers the visible light.

    I never looked through the view finder (of course!), and I had something covering the lens for the entire time except for the couple of seconds around when the photo was taken.

    My question is though, was that safe? I believed it was, but never checked it with experts. I'm checking now as I was thinking it might be an ok way to take a photo of the Venus transit. Unless someone can recommend a filter for my 8" Meade LX200 that isn't too expensive?

    What do you think? Thanks guys I don't have the 100-400mm lens anymore, but I do have a 70-200mm lens, and with my 2x extender, I'd still be very happy with that shot I think.

    Also, when reviewing the photo on the camera I thought I must have some dust on my sensor, doh! But it turns out, I picked up some sun spots. I was so happy

    Here's the image, fully cropped, but resized by 50%.



  2. #2
    darethehair's Avatar
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    Nice 'clean' photo!

    I don't have a medical/scientific answer for your 'safety' question, but if you never look through the viewfinder yourself, then you should never personally be harmed -- the brightest/whitest display screen will not hurt your eyes. Do you mean safe for your camera? Well, since the photo was nicely exposed, my guess is that it would never harm the camera either.

    I *have* read that leaving a lens pointed towards the sun for too long can burn a hole in the camera shutter (?).
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  3. #3
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    If you were careful not to look through the optics, there was no personal safety risk. The risk is entirely to equpiment.

    The big thing is that you are dumping a large amount of solar heat onto the shutter curtain. With the filtering that you are doing, you probably won't burn a hole through the shutter. Still, all the heat collected by the lens ends up in the camera. You run the risk of thermal damage to various components - softening plastics, failing lubricants, damaged coatings, electronics acting up.

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  5. #4
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    Very nice photo. Thank you for sharing it!
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    Quote Originally Posted by LostBoyNZ View Post
    My question is though, was that safe?
    Maybe, but I'd err on the side of caution. As others have said you could fry something in the optical path. Use some Baader film in place of your ND filter and you're all set. You'll be able to safely look through the viewfinder.
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    Thanks for the replies That's mostly a relief but I'd rather not risk frying anything in my camera yeah. So after reading your comment, I looked up about Baader film and Seymour Solar film, and ended up ordering some of the Seymour stuff.

    Looking forward to giving that a test when it arrives, and I'll post the results

  8. #7
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    For the LX200, you could stop down the objective lens (corrector plate) to say 50mm then use a 50mm solar filter on it - I reckon that would be less expensive than a 200mm one!!
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  9. #8
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    On the burning a hole in the shutter bit - some SLRs had black cloth shutter blinds, so yes, that would be a possibility (at least if the mirror was up for long enough) though I think most cameras have metal shutter blinds nowadays. Possibly more likely is melting your viewing screen, or frying the LCD for the focus points
    Since the mirror is usually down and focussing the image on the viewing screen. However, I note the fact that it's not uncommon to have the sun visible in the viewfinder from time to time, and I've never heard anyone complaining about melted focusing screens, so I assume it's not an instant problem - especially since a lot of the light goes through the focusing screen so you can see it
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    Jerry is correct. With the mirror in place there is no chance of burning a hole in a shutter. The problem would be heat build up (just keep the lens covered until you are ready to shoot, shoot, then cover it back up), and make sure that there is nothing to burn behind the eyepiece since it will effectively be a magnifying glass.

    Personally, I would invest in a solar filter, or at least some Baader solar film and do it right just to be safe.

    Allan

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    I'm a wuss when it comes to safety (especially concerning the sun).
    If you have to ask if your method was safe, then maybe that's a good indication that you should consider different methods.
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