On Tuesday, 5 June 2012, at 6:03 PM EDT. this will not happen again until 2117. Looking for suggestions on how to capture this event. If the sun is out, I will use an ND filter, but that is as far as I have gotten.
I saw this on the Weather Network a couple of days ago. They didn't really say not too look at the sun though. I'm thinking there might be a few more blind people by the end of the day.
Good idea with the ND filter. Maybe I'll give my new polarizing filter a go!
to get an image of the transit of Venus you will need a telescope fitted with a solar film filter ND filters are a bad idea to get any sort of decent image you will have to have at least a 12 stop ND filter just to get an image even then it would be a bad idea to look through the camera as ND filters dont filter out UV or IR radiation leading to possible solar retinopathy, solar film reflects back most of the light including IR and UV radiation, you will definately need to take the shot through a telescope though or a huge lense as Venus compared with the sun is tiny so anything other than that and you may find you just get a picture of the sun
here is a link with some more info http://www.space.com/15987-venus-transit-2012-lunar-eclipse-photography-tips.html
I've got two ND filters I'm stacking (4 & 8), along with two polarizing filters set at opposing angles. I have solar glasses for myself, so there's no worry about that. I'm just hoping the clouds clear out!
@petaqui because it can blind you, if you look at any bright light source for more than a second or 2 you will find that part of your vision goes and you are left with black spaces, this is because damage has occured to the rod and cone cells in the eye, this is especially dangerous when viewing the sun through a lense as anyone who has started a fire using a magnifying glass will tell you, just imagine the same thing happening on the back of your eye, pretty nasty the reason its not a problem most of the time is because the light we see by is reflected light and not direct light.
I know how the damage happen, I studied that one year ago (here there is a pharmacy student xD), but I can't understand why if I look 2 seconds to the sun in a normal day the damage is low; and during the transit cand blind me in just 2 seconds :S
Sorry if you told me and I didn't understand you, right now I'm tired, exam tomorrow, Monster Energy in blood xDDDD
@hjbenson@shutterbugger@petaqui@petaqui As Lee ( @asrai ) says, you shouldn't trust standard ND filters at all for trying to photograph the Sun. I did some Google searching and eventually went to a blog site called DigiBorg (http://digiborg.wordpress.com/). IDAS solar filters are high-quality (manufactured in Japan) glass filters designed for safe (high UV and IR rejection) visual and photographic use. The supplier is Astro Hutech. Technical details and filter comparisons can be found here:
http://www.sciencecenter.net/hutech/idas/solar/index.htm. Basically think of a magnifying glass and starting a fire through the optics...you eye being at the receiving end of the focused light. It is safe to take pictures of the Sun with the right solar filters that block harmful UV and IR lightwaves, and it will not harm your camera sensor. Place solar filters at the leading edge of your optics not at the eyepiece. Here are shots I took of the Sun and recent eclipse.
@petaqui The way I understand it is your camera lense that works like a magnifying glass and therefore magnifys the intensity of the already bright sun and thus can cause sever damage. I also heard that you can ruin the sensor in your camera, that somehow the sun can burn it as well???
@hjbenson Harry, I heard this was not a good idea unless you have all the proper equipment. You should try for the lunar eclips tonight and in the morning as it set is you have no clouds.
Oh, right now I understand that with the camera you can "burn" your eyes, but not looking derectly xD
And, what do you think... putting the camera in "Live mode" (my Canon EOS450D calls Live mode viewing what you want to capture as you usually do with your mobile or compact camera", will protect your eyes because you just look the LCD screen, BUT, Could the camera broke with this? Maybe the rays can burn teh sensor or damage it in any way?
@asrai I have a 200mm all lined up and ready! I used it for taking eclipse photos, and they turned out great. I'm not looking through the viewfinder much at all, but using it as a pinhole instead. I close the shutter down to around f32 at ISO 100. That reduces the amount of light hitting my sensor.
@petaqui I dont think you get my point I am not saying that damage to the eyes is higher or lower looking at the sun for a second or 2 causes the same damage regardless, and although a quick glance in the majority of cases may only cause temporary solar retinopathy (Retina burn) the time you need to observe and photograph something like the transit of Venus is a fair bit longer than a couple of seconds and it is this this that can cause permanent damage to the eyes especially if the direct light is being focused into the eye by a lens
@pschtyckque hmm you may be lucky a bit of browsing has come up with a minimum size lens to get the transit as 500mm and ideally 1000mm+ I would be interested to see what you get though
It should be possible to resolve the transit with a 200mm lens on a modern crop sensor camera.
Luckily Venus is currently about as close to Earth as it gets, and so the angular diameter as seen from Earth is about 60 arcseconds, or roughly 0.015 degrees. A 200mm lens on a crop-sensor camera will see approximately 6.3 degrees, so the diameter of Venus should be approximately 0.23% of the frame.
Taking a modern 15 megapixel camera with approximately 4,700 pixels in the long axis, that means that Venus should occupy a circle approximately 11 pixels across.
However, note that setting the aperture as small as possible (e.g. f/32) will significantly reduce the chance of resolving it, due to lens diffraction. This is an effect that causes a reduction in the overall sharpness of the image as the aperture is reduced. This can result in small details being effectively lost when using very small aperture diameters.
If we use the calculator with our example 15 megapixel camera (e.g. a Canon 50D), we can see that at f/32 the Airy diameter is about 10 times the pixel pitch of this camera. This is likely to virtually obliterate the 11 pixel wide silhouette that Venus projects on the sensor.
For best results you need to be below the point where diffraction starts to have a significant effect, which is around f/11 on our 15 megapixel camera.
However, without increasing the filtering, this will obviously result in much more light being captured by the camera. If the camera has an insufficiently high shutter speed, then the silhouette of Venus will again likely be obscured due to overexposure and bloom.
In conclusion, if you have a nice dense ND1000 filter, or can make one out of suitable materials (e.g. X-ray film), then with the right settings you probably can capture this. Without those ingredients, you may need a longer focal length. Oh, and do I need to mention that correctly focusing the lens to infinity is critical? No, I didn't think so :)
With regards to sensor damage, I will re-iterate what I said in my post regarding the Eclipse a couple of weeks ago -- with an SLR it's very difficult to damage the sensor, as it will only be exposed to the sun for a few thousandths of a second. Only in the case of error (accidentally using a several-second exposure) is there any chance of damage, and even then it is unlikely. Note that I would, however, be cautious of using a non-SLR camera, or using Live View, as both of these will expose the sensor to the sun for a long period. Realistically damage is unlikely (see below), but it's probably safer not to risk it.
Finally, with regards to eyesight, the question of the duration of exposure required to cause solar retinopathy is unclear -- some people have voluntarily and intentionally stared directly at the sun for several minutes, and suffered no damage apart from a very bad after-image which faded after a few minutes, whereas others have received long-term damage with much shorter exposures.
Note that describing it as 'retina burn' is misleading -- the actual temperature increase to the retina is only approximately 4 degrees Celsius, which is nowhere near enough to cause thermal damage to the retina. Instead it appears to be a chemical reaction within the eye to the strong UV light that causes the damage. This also explains why it's unlikely to damage a camera sensor -- they are not typically permanently damaged by high levels of UV, only by thermal damage.
Regardless of all of this, you only have two eyes, so take the proper precautions -- do not look directly at the sun, and certainly don't attempt to use the viewfinder of a camera pointed at the sun with a telephoto lens.
@asrai Here is the test shot I took. The color is due to the polarized lenses. I tried removing the blue tint, but the sunspots disappeared. Still playing with grayscale options. That was just a quick post.
@mikew Yup, it's easy to think that Venus is tiny and hence requires serious magnification, until you do the maths.
Looking at a previous transit gives a good illustration as to why not much magnification is required:
As can be seen, Venus actually covers a surprisingly large amount of the Sun's surface. If we compare this to the shot that @pschtyckque posted earlier, you can see it's going to be fairly easily visible, given the size of the sun in his photo.
Incidentally, NASA claim that you'll be able to see the transit by eye (with proper solar protection) -- no magnification needed.
@petaqui If you have the proper gear, BY ALL MEANS try and take a picture of it! i know my lens is too short to get a decent shot, but I'm not going to pass up the opportunity. You won't get another chance. ;-)
@darrenellis I tried playing with my color balance, but bringing up the yellow reduces the visibility of the sunspots. I'm thinking grayscale is the way to go.
Wow, this reminds me of living in Tennessee in 2004 and hearing about the transit on the radio, waking the kids up early and going to a parking lot where a bunch of people gathered with telescopes and cameras. I didn't even take a camera, but people were SO kind to let the kids look through telescopes.
Here is my test shot from lunchtime. There have been no modifications to this other than cropping. My #12 welder's glass is good for viewing directly, but not good as a camera filter. It's not optically pure.
These are great shots! We couldn't watch it here (eastern Pennsylvania USA) because we had clouds today. I'm so glad I could see your shots though. In some way now I feel I've seen it.
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Good idea with the ND filter. Maybe I'll give my new polarizing filter a go!
here is a link with some more info http://www.space.com/15987-venus-transit-2012-lunar-eclipse-photography-tips.html
Sorry if you told me and I didn't understand you, right now I'm tired, exam tomorrow, Monster Energy in blood xDDDD
http://www.sciencecenter.net/hutech/idas/solar/index.htm. Basically think of a magnifying glass and starting a fire through the optics...you eye being at the receiving end of the focused light. It is safe to take pictures of the Sun with the right solar filters that block harmful UV and IR lightwaves, and it will not harm your camera sensor. Place solar filters at the leading edge of your optics not at the eyepiece. Here are shots I took of the Sun and recent eclipse.
And, what do you think... putting the camera in "Live mode" (my Canon EOS450D calls Live mode viewing what you want to capture as you usually do with your mobile or compact camera", will protect your eyes because you just look the LCD screen, BUT, Could the camera broke with this? Maybe the rays can burn teh sensor or damage it in any way?
http://www.thousandoaksoptical.com/solar.html http://stores.ebay.com/Seymour-Solar-Filters http://www.sciencecenter.net/hutech/filters.htm
Luckily Venus is currently about as close to Earth as it gets, and so the angular diameter as seen from Earth is about 60 arcseconds, or roughly 0.015 degrees. A 200mm lens on a crop-sensor camera will see approximately 6.3 degrees, so the diameter of Venus should be approximately 0.23% of the frame.
Taking a modern 15 megapixel camera with approximately 4,700 pixels in the long axis, that means that Venus should occupy a circle approximately 11 pixels across.
However, note that setting the aperture as small as possible (e.g. f/32) will significantly reduce the chance of resolving it, due to lens diffraction. This is an effect that causes a reduction in the overall sharpness of the image as the aperture is reduced. This can result in small details being effectively lost when using very small aperture diameters.
Further explanation can be seen here, along with a calculator:
http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
If we use the calculator with our example 15 megapixel camera (e.g. a Canon 50D), we can see that at f/32 the Airy diameter is about 10 times the pixel pitch of this camera. This is likely to virtually obliterate the 11 pixel wide silhouette that Venus projects on the sensor.
For best results you need to be below the point where diffraction starts to have a significant effect, which is around f/11 on our 15 megapixel camera.
However, without increasing the filtering, this will obviously result in much more light being captured by the camera. If the camera has an insufficiently high shutter speed, then the silhouette of Venus will again likely be obscured due to overexposure and bloom.
In conclusion, if you have a nice dense ND1000 filter, or can make one out of suitable materials (e.g. X-ray film), then with the right settings you probably can capture this. Without those ingredients, you may need a longer focal length. Oh, and do I need to mention that correctly focusing the lens to infinity is critical? No, I didn't think so :)
With regards to sensor damage, I will re-iterate what I said in my post regarding the Eclipse a couple of weeks ago -- with an SLR it's very difficult to damage the sensor, as it will only be exposed to the sun for a few thousandths of a second. Only in the case of error (accidentally using a several-second exposure) is there any chance of damage, and even then it is unlikely. Note that I would, however, be cautious of using a non-SLR camera, or using Live View, as both of these will expose the sensor to the sun for a long period. Realistically damage is unlikely (see below), but it's probably safer not to risk it.
Finally, with regards to eyesight, the question of the duration of exposure required to cause solar retinopathy is unclear -- some people have voluntarily and intentionally stared directly at the sun for several minutes, and suffered no damage apart from a very bad after-image which faded after a few minutes, whereas others have received long-term damage with much shorter exposures.
Note that describing it as 'retina burn' is misleading -- the actual temperature increase to the retina is only approximately 4 degrees Celsius, which is nowhere near enough to cause thermal damage to the retina. Instead it appears to be a chemical reaction within the eye to the strong UV light that causes the damage. This also explains why it's unlikely to damage a camera sensor -- they are not typically permanently damaged by high levels of UV, only by thermal damage.
Regardless of all of this, you only have two eyes, so take the proper precautions -- do not look directly at the sun, and certainly don't attempt to use the viewfinder of a camera pointed at the sun with a telephoto lens.
Looking at a previous transit gives a good illustration as to why not much magnification is required:
As can be seen, Venus actually covers a surprisingly large amount of the Sun's surface. If we compare this to the shot that @pschtyckque posted earlier, you can see it's going to be fairly easily visible, given the size of the sun in his photo.
Incidentally, NASA claim that you'll be able to see the transit by eye (with proper solar protection) -- no magnification needed.
http://eclipse.gsfc.nasa.gov/OH/transit12.html
Good luck guys!
http://www.flickr.com/photos/stweedle/7289603796/in/photostream
@darrenellis I tried playing with my color balance, but bringing up the yellow reduces the visibility of the sunspots. I'm thinking grayscale is the way to go.
F/14 * 1/400 * ISO100 * 200mm * ND4 + ND8 + 2 POL
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Here is mine
400mm lens, ND4 + ND8 + CPL, plus a grey studio gel, 100ISO, 1/8000s @ f/22, processed in Lightroom
F/32 * 1/400 * ISO100 * 200mm * ND4 + ND8 + 2 POL