Monday, November 12, 2012

Today's Meeting 12.11.12

We had another well attended meeting today, starting with a slideshow of members' photos from our last field trip to Cleveland Point.

Photos: Alan Brown

After that Diane told us all about street photography which included several topics such as urban photography, architectural photography as well as cityscapes. 
Diane's notes on Street photography will be posted on the sidebar of this blog soon.

Then Kathy Roman told us about the forthcoming solar eclipse on Wednesday morning and what we should do to protect our eyes and our cameras from the sun's harmful rays. 

Here is Kathy's presentation:

Kathy sent me the following information after the meeting:

Hi Bill
Could you please add these notes to the blog. I hope they are okay-I have just cut and paste from different articles.

Also could you mention that if anyone would like solar glasses $4 or solar film to use on their camera lensD, $3 to $5 depending on size, these can be bought from Astro Petes Café in Palmdale Shopping Centre (Across from Garden City). He appears to have sufficient numbers of both. Phone 0412 085 224.
Many thanks

See below:

Notes About Photographing Solar Eclipses

Your camera lens is not protection enough
The biggest challenge with photographing a solar eclipse is that this is the sun itself that you're looking at. As we've all been told since we were little, looking directly at the sun is a bad idea. Not only can doing so permanently damage your eyes, it can also damage your camera's image sensor. For that reason, you need to take special precautions to protect both your camera and your eyes. Never, ever look directly at the sun without looking through a filter.
Your camera's optical viewfinder does not offer any protection from the sun's harmful rays, so you can't just watch through your camera. If you have a compact camera with an LCD screen, you could, in theory, watch the eclipse on the screen, but it will still probably damage the camera's image sensor, so we wouldn't recommend it., how-to guides and more at to help you get the most out of your technology.
The easiest and cheapest filter you can get that will allow you (and your camera) to safely view the eclipse is a simple pair of eclipse glasses. If you have a point-and-shoot camera, get two pairs — one for you and one for the camera. Then you can attach one lens of the camera's pair to the camera's lens, and you'll be good to go. It's not the most elegant solution, but it works.
If you've got a DLSR camera, things get a bit trickier, since the lenses of the eclipse glasses probably won't be big enough to cover your entire camera lens. You'll need to find a special solar filter for your particular lens size. These are usually made of Mylar or glass and can be purchased through various dealers, including Amazon.
Setting your settings
The best advice we can offer about photographing a solar eclipse is to practice before it happens. For many people, a solar eclipse is a once-in-a-lifetime experience, and you'll only have one chance to get the photos you're hoping for.
What you can do, though, is go out and take some photos of the sun on a non-eclipse day. Make note of which settings work best, so you can easily go back to them when the big moment comes. The settings you use for pre- and post-totality will be different from those you'll use for the brief time when the sun is completely eclipsed, so practice switching between them — or better yet, have two cameras available.
When it comes to choosing a lens to use, remember that the sun is, of course, extremely far away. Even when viewed through a 200mm telephoto lens, the sun itself will still look pretty darn small. Ideally, you should aim for around an 800 to 900mm focal length so that the sun's disc fills a good portion of your viewing area.
Using your camera's manual settings will work best, since your camera will likely be very confused about what to focus on and what aperture and shutter settings to use. Since the sun gives off plenty of light, set the ISO to a low number such as 100. Before and during the period when the sun is only partially eclipsed, use a small aperture such as f/16. When the eclipse reaches totality, the intensity of the available light will drop dramatically, so try using larger apertures.
What eclipse types mean to your photography
The eclipse that occurs on May 20 is an annular eclipse, which is a little different from a total eclipse. During an annular eclipse, the moon is at the farthest point in its orbit around the earth, and its relative size isn't enough to completely cover the sun. Thus, even when the moon is dead center in front of the sun, a thin ring of the sun itself will be visible around the moon.
Even during the height of an annular eclipse, don't take off your solar filter or glasses. The ambient light will go way down, but it's still not safe to look at the sun because there will still be a ring of direct sunlight. During a total solar eclipse, you'd have to take the solar filter off your camera to get a decent photo, but that's not the case during an annular eclipse.
While you can plan for and practice your settings for the partial phases of an eclipse, the total phase requires either a lot of math or some guesswork. Both NASA's and Mr. Eclipse's websites have extensive tables that will help you figure out the optimum exposure settings for various phases of the eclipse. It can all be very confusing.
The salient point you should remember is bracket, bracket, bracket. For every photo you take, take at least one or two with your aperture and/or shutter speed set higher and lower than the setting you think you should use. Yes, you'll end up with hundreds of photos you'll have to sift through when all is said and done, but you also stand a much higher chance of getting that great shot you're looking for.
Ideas for viewing method alternatives
If you don't have the time or money to purchase expensive lenses for your camera (and your eyes!), you can still get some great photos of the eclipse. The best way is to use a lens or create a pinhole camera to project an image of the eclipse onto a piece of white cardboard (or any other smooth surface), and then take a photo of the projected image. You can use a pair of binoculars with one lens covered or a telescope, or create your own simple pinhole camera by poking a very small hole (about 1mm in diameter, about the size of a pen tip) in a piece of cardboard.

A solar eclipse begins as a small notch slowly appears along one edge of the sun. During the next hour, the moon will gradually cover more and more of the sun’s bright disk. If the eclipse is a total solar eclipse, the last remaining minutes of the partial phases can be dramatic. The crescent of the sun grows thinner as the moon’s shadow approaches. The abrupt darkness of totality is stunning to view, and the solar corona is an awe-inspiring sight. The sun’s corona can only be seen during the few brief minutes of totality.

Starting Exposure (Nikon cameras)
Solar eclipses may be viewed and photographed, provided certain precautions are taken. You can photograph a solar eclipse with any type of camera: D-SLR, COOLPIX or Nikon 1. The longer the focal length of the lens, the larger the images of the sun you’ll be able to make. While you can also use film cameras to photograph eclipses, this article specifically discusses digital camera use.
With a D-SLR, you can also combine a super telephoto lens with a teleconverter to increase the focal length. You can also increase the relative size of the eclipse image by selecting an FX camera’s "DX Crop Mode". If you’re photographing the solar eclipse using a COOLPIX compact digital camera, turn the built-in flash to OFF.
How large you want the sun to be in the frame will determine what focal length lens to use. For a D-SLR camera with a full frame FX sensor, choose a focal length of 2000mm or less. For a D-SLR camera that has a DX sensor, the maximum focal length is about 1300mm; any longer and you won’t be able to get the entire sun in the frame.
However, if you also want to capture the sun’s corona during the phase of totality, then you should choose a focal length that’s shorter still—no more than 1400mm for an FX (full frame sensor) camera, or 900mm for a Nikon DX camera.
Place your camera on a sturdy tripod, and manually focus the camera, setting it to infinity.
If you are using a telescope on an equatorial mount, the electric drive will track the sun keeping it centered in your camera throughout the eclipse.
A solar filter must be used on the lens throughout the partial phases for both photography and safe viewing. These filters typically attenuate the sun’s visible and infrared energy by a factor of 100,000. Almost any ISO can be used because the sun gives off abundant light. The actual filter factor and choice of ISO will play critical roles in determining the correct exposure.
The easiest way to determine exposure is to run a calibration test on the un-eclipsed sun on a clear day prior to the eclipse. Digital cameras are ideal as you can see your results almost instantaneously. Shoot the mid-day sun at a fixed aperture, (choose an aperture between f/8 and f/16) using every shutter speed from 1/4000 second to 1/30 second. Looking at the exposures, choose the best shutter speed/aperture combination and use them to photograph the partial phases of the solar eclipse. Your camera’s histogram function is an excellent way to evaluate the best exposure. The histogram should not be clipped but should lie toward the upper end of brightness values. Because the sun’s brightness stays the same throughout the partial phases, no exposure compensation will be needed. You may also decide to bracket your exposures to ensure that you photograph the solar eclipse with a perfect exposure. If you ran your test on a sunny day and the eclipse occurs on a hazy day, increase the bracket of exposures an additional f/stop

1) The Danger of Viewing and Photographing a Solar Eclipse
Before I talk about the process of photographing a solar eclipse, let me first talk about the dangers of doing it. First of all, you should never look directly at the sun with your eyes, especially through a DSLR viewfinder that shows the sun much more magnified. Remember Galileo or those crazy Indians that stared at the sun and went blind? You surely do not want the same faith. Looking at the sun through the viewfinder without blocking any light, especially UV can result in immediate blindness. See this article on Wikipedia for more details.
So what do you do? If you prefer to see the eclipse with your naked eyes, then get a pair of eclipse glasses. If you cannot find them or it is too late to get them now, then there are two things you can do:
  1. Build a small pinhole camera/projector
  2. Use the camera’s liveview/LCD for viewing the sun
Building a small pinhole camera/projector is very simple. Just grab two pieces of cards, make a small hole in one card, then hold the card above the other one and align them with the sun. The sun’s image will be projected through the hole into the second card. If you want something more advanced, check this tutorial out.
The second method to view the sun through the camera LCD is what I did. First, make sure to mount a very dense/strong neutral density filter in front of your lens. Then, use your camera’s LiveView function to look at the sun. It is ideal to have a camera that allows manual exposure control, so that you could stop down the lens and increase the shutter speed while looking at the sun through live view. Bear in mind that if the ND filter is not strong enough, viewing the sun through the LCD could actually damage your camera. Either way, I would not use LiveView for more than a minute or two, since it could overheat the image sensor. I only used LiveView when taking pictures and turned the camera off in between. When the sun is too bright during partial eclipse, unless you have something like Hoodman loupe, you might not see much when looking at the LCD though.
If you have a point and shoot camera with a relatively small lens, the same eclipse glasses you war could be used as neutral density filters. Just hold one in front of the lens and it should work great.
2) Photographing the Sequence
One thing you need to decide on, is whether you want to shoot the entire sequence of the solar eclipse, or just the middle of the process (period of totality) when the moon blocks most of the sun, creating a “ring of fire”. I would personally recommend to document the whole process from the beginning to the end, so that you have pictures of all the phases – from partial eclipse to totality and then back to partial eclipse. The nice thing about having the entire sequence in pictures, is that you can later combine images together, creating a nice sequence.
Bear in mind, you will have to be very patient though, as the process could take a while. If for whatever reason you cannot stay for the entire duration of the eclipse, then I would just stay for the total eclipse to capture the “ring of fire”.
3) Camera Equipment and Lenses
When it comes to photographing a solar eclipse, the type of equipment you are using plays a huge role. Using a camera with a bare lens is not going to work, because the sun is way too bright (especially during partial eclipse) – it will be totally blown out. Even stopping down to a very small aperture like f/22 and lowering ISO to the lowest value might result in an exposure faster than what your camera allows. Therefore, you need a very strong neutral density filter that would block most of the light from the sun, allowing you to use slower shutter speeds and larger apertures. If the neutral density filter is not strong enough, you might need a couple – in my case, I had a 6 stop ND filter stacked with a 3 stop ND filter together, but a 10 stop ND filter would be better. Stacking multiple filters is not a problem, because you will be shooting with your longest lens at its longest focal length anyway.
Talking about lenses, the longer the lens, the better. I used the Nikon 300mm f/4 AF-S with a 1.4x teleconverter, because I had it handy. Longer lenses are ideal, so if you have a 600mm lens with a teleconverter in your arsenal, then get them ready! My 300mm was already mounted to my Nikon D700, so I did not bother changing the camera body.
Camera does not matter, because you will be capturing the solar eclipse at the lowest ISO. Cropped-sensor/DX cameras would work great, because they provide better magnification on the pixel level.
4) Camera Settings
Camera settings are quite simple. Here is what I recommend:
  1. Set your camera and lens on a tripod.
  2. Set your ISO to the lowest value like 100.
  3. Set your camera mode to Manual.
  4. Start out at the fastest shutter speed your camera has to offer, such as 1/8000 and see if you need to lower it.
  5. Start out at f/8 and stop down a little more if the shutter speed is too fast. If the sun comes out too bright and overexposed, it means that you are using a weak ND filter.
Depending on what ND filter you are using, your shutter speed should be fast enough to not cause any vibration issues. I was shooting between 1/500 to 1/8000, depending on the phase of the eclipse and how bright I wanted to sun to come out.
5) Focus Accuracy and Sharpness
No matter what lens you are using, getting a very accurate focus on the sun and moon is extremely important. I know that some photographers suggest to shoot at infinity using the lens marks, but since many lenses now allow focusing “beyond infinity”, getting a true infinity focus is not that easy – a slight inaccuracy in focus will make the sun and moon appear blurry. Forget about trying to acquire focus on the sun without an ND filter – it is too bright and could be too small in the frame for that. What I would do, is point your lens at a really far object and focus on that object (either through viewfinder or LiveView). Instead of dealing with refocusing every time you take a picture, I highly recommend to switch off autofocus once you get an accurate focus. Take a picture and use the LCD screen of the camera to see how sharp the sun is. Zoom in all the way and make sure that the sun appears sharp.
One more thing I would like to point out, is if you are using a lens with a teleconverter, or if you are using a consumer zoom lens, the optics are probably not very sharp when shooting at large apertures. Stopping down the lens aperture to f/8-f/11 should give you the sharpest results. Don’t use apertures larger than f/16 – diffraction will kick in and make the moon appear even softer.
6) Composition
Unless you are shooting at short focal lengths with a foreground object or some sort of a scene, don’t worry about composition – place the sun anywhere in your frame. The location does not matter, since you can easily crop the sun out in post-processing. If you have some thick clouds in your frame, then play with the exposure a little and see if you can use clouds as part of your composition. Here is an image that I captured with the clouds, when clouds opened up a little bit during the start of the eclipse:
7) Post-processing
As for post-processing, aside from cropping and playing with white balance and saturation levels, the only issue you might have is dealing with some noise that might show up even at the lowest ISO levels. Noise levels will increase if you underexpose and try to brighten up in post-processing, so try to expose the sun correctly (you can also bracket your shots). If noise is an issue, see my “noise reduction tutorial” that I posted a while ago – there are plenty of tips in that article on how to clean up noise in Photoshop and Lightroom
1. Use a proper solar filter: Never look at the sun with your naked eyes, or through a telescope, binocular or camera viewfinder without a safe solar filter. Failure to do so can result in serious eye injury or blindness. [How to Safely Photograph the Sun (Photo Guide)]
Use a No. 14 welder's glass filter, or purchase special solar filters from companies such as Thousand Oaks, Kendrick Astro Instruments, or Orion Telescopes & Binoculars, and fit them securely in front of your equipment.
2. Use a telescope or telephoto lens with a focal length of 400 millimeters or more: This helps to get detailed, close-up shots of the eclipse. This will give you a reasonably large image of the sun's disk in the frame.
The best way to attach your digital SLR camera to the telescope is to use an appropriate T ring and T adapter for your camera brand. (Check with your local camera retailer.) Other helpful accessories include an electronic cable release to operate the shutter and a right-angle magnifier that attaches to the camera’s viewfinder to assist you in focusing.
CREDIT: Imelda Joson and Edwin Aguirre
3. Use a sturdy tripod or mount: Make sure your tripod and head are strong and stable enough to support your camera gear. Keep your setup as portable, light and easy to assemble as possible in case you need to relocate in a hurry to escape clouds.
4. Set the camera to its highest resolution: To record as much detail and color information as possible, use your camera's highest-quality (least-compressed) JPEG setting or "lossless" (uncompressed) image formats, such as TIFF or RAW.
5. Use a high ISO setting: Set your camera to ISO 400 (or higher) to keep exposures very short and prevent blurring from vibrations.
6. Switch to manual: Set your camera to "manual" (M) so you'll be able to control its focus as well as exposure and white-balance settings.
7. Focus carefully: Don't let poor focus ruin your images. If possible, prefocus your camera the night before the eclipse using a bright star. Otherwise, focus carefully on the sun's edge (or on sunspots, if some are visible). Place a piece of adhesive tape on your telephoto's focus ring (or lock the telescope focuser) to keep it from accidentally being moved during the eclipse. Be sure to recheck your focus as the eclipse progresses and refine it if needed.
If you don’t have a DSLR camera, don’t worry — you can use your automatic “point-and-shoot” camera to take decent pictures of the eclipse through a filtered telescope. Insert a wide-field eyepiece and hold the camera lens close to it. Use the camera’s built-in LCD screen to center the sun and compose your shot. Zoom in as needed.
CREDIT: Imelda Joson and Edwin Aguirre
8. Minimize vibrations: The mirror slap in DSLRs can cause blurred images. If possible, use the camera's mirror lock-up feature before each shot to keep vibrations to a minimum. You should also operate the shutter with an electronic cable release to eliminate camera shake. Lastly, choose an observing spot that is shielded from the wind.
9. "Bracket" your exposures: It's a challenge to determine the correct exposure beforehand, so shoot the eclipse at various shutter speeds.
10. Use a fresh battery: DSLRs can easily drain their batteries, especially if you use the LCD screen continuously. Make sure you have a fully charged battery right before the eclipse begins, and have a spare one handy, just in case.
11. Test your imaging setup: Be sure to try out your actual setup before the eclipse. This will reveal any potential problems with focusing and vibrations, as well as internal reflections or vignetting in the optics. Take some test shots of the sun to give you an idea of what exposure to use with your solar filter.
12. Try to shoot the sun in hydrogen-alpha: Unlike "white light," the plain, visible light from the sun, H-alpha is the red light given off by hydrogen atoms in the sun's atmosphere. A portable H-alpha telescope offers a wealth of stunning details of the sun at a wavelength of 656.3 nanometers.
13. Process your images: Since the camera's output is already in digital format, it's easy to enhance the images' brightness, contrast, sharpness and color balance using image-editing software such as Adobe Photoshop. You can also "stitch" the frames together to create a movie.
Shooting the Eclipse with Video
As with digital cameras, you need a proper solar filter over your camcorder when recording the sun.
The color of the solar image will depend on the type of solar filter used. Metal-coated glass and black polymer filters produce a pleasing yellow or orange image of the sun, while aluminized Mylar filters show a bluish sun. Welder’s No. 14 glass filters give a greenish image (not shown).
CREDIT: Imelda Joson and Edwin Aguirre
Today's camcorders have zoom lenses with up to 40x (or more) optical magnification. To videotape the eclipse, simply mount the camcorder on a tripod and zoom in on the filtered sun to the lens's highest power. (Hand-holding the camcorder can result in shaky footage.) High-end camcorders have manual controls for adjusting the gain, f-stop and shutter speed so you don't overexpose the sun's disk.
Again, it is best to test your setup before the eclipse. On the day of the event, be sure to use a fully charged battery and bring a spare one as backup. Take two- to three-second clips every two to five minutes to produce a time-lapse sequence that compresses the eclipse's hourlong partial phase into just under a minute.
High-end DSLRs are capable of shooting HD video. (Check your camera manual.) In a pinch, you also can use your cell phone camera to shoot video (or still images) through a filtered telescope. Low-cost webcams can also be useful.

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