How to shoot an eclipse

What's the preparation for shooting the solar eclipse with an ordinary digital camera?

July 22nd this year is a once-in-a-lifetime total solar eclipse. Friends who don't have professional equipment can use ordinary digital cameras to keep this rare commemoration. In order to take a better picture, adequate preparation is indispensable. ?

the camera I use is Kodak 743, which is an old camera with 4 million pixels and a focal length of 34-12 mm, with 3-light and 4-number zoom and no manual function. ?

1, lens filter?

① filter is essential?

A friend said that a camera with manual function can control the exposure with low sensitivity, small aperture and high speed without a filter. I don't think this method is advisable. The sunlight is very powerful. Even if you don't take pictures, it is easy to damage the camera if the lens is directly facing the sun! Filters must be used to block most of the sunlight to ensure safety. ?

② what is the material of lens filter?

There are two kinds of plastic and glass. Plastic films used to be sensitive negatives, but now it is hard to find them. I use medical X-rays, and choose the one with colorless film base. ?

the glass material is easy to get, which is the welding filter. It's available in the hardware and electrical accessories store. The price of the electric welding filter I bought in Shenyang is 1 yuan Money (retail price) for your reference. ?

The advantage of the glass filter is that the transmitted sunlight is basically parallel light, so the captured sun has high definition. The disadvantage is that the welding sheet is dark green instead of black, and the photos taken are green and have large color difference. ?

the plastic sheet will diffuse to a certain extent, which will reduce the definition of the photo. The advantage is small color difference. ?

③ what is the transmittance of the lens filter?

which welding pads can I buy here are No.7 (lightest) to No.12 (deepest)?

a friend said that the lightest welding is enough, but I found that the darkest welding is not enough! ?

obviously, we should have an objective standard to select the transmittance of the filter. ?

Open Shoot's photos with potoshop and look at their "histograms". ?

Figure 1 is the sun shot with "8+8" filter, and Figure 2 is its histogram.

Figure 3 shows the sun shot with a "12" filter, and Figure 4 shows its histogram.

fig. 5 is the sun shot with a "4X" filter, and fig. 6 is its histogram.

fig. 7 shows the sun shot with a "3X" filter, and fig. 8 shows its histogram.

The above-mentioned "8+8" filter refers to the overlapping use of two No.8 welding plates; ?

"12" filter refers to a 12 # welding plate; ?

"4x" filter means that four X-rays are overlapped. The first one is fully exposed pure black, the second one is Zhang Shen gray, the third one is light gray, and the fourth one is unexposed; ?

the "3x" filter is the above-mentioned "4X", and the fourth one is the unexposed one. ?

The dense part on the left side of the histogram is the sky; Some vertical lines on the right are the brightness of the sun. ?

The brightness line representing the sun in Figure 2 and Figure 6 is not close to the right line of the histogram, which is a relatively "normal" exposure. ?

The vertical line representing the sun in Figure 4 and Figure 8 is close to the right line of the histogram, which is actually beyond the histogram range, indicating overexposure. ?

However, from the photos, the "normal" exposure looks a bit like the moon, lacking the bright and dazzling feeling that the sun should have. I think it is appropriate to overexpose the sun. In fact, Figure 8 only lacks an unexposed "transparent" X-ray film compared with Figure 6, but the effect is quite different. ?

the color difference of the welding pads in fig. 1 and fig. 3 is unpleasant. ?

After comprehensive comparison and many experiments, I finally recommend 3X film, that is, a slightly overexposed filter composed of X-rays. ?

If everyone's X-ray concentration is appropriate, "2X" will certainly be better than my "3X". ?

In order to ensure success, friends are advised to visit Shoot several times. There may be some differences between different cameras, and the transmittance of X-rays cannot be quantified. ?

④ lens filter sleeve?

for convenience, I made a sleeve out of paper and put it on the lens, and the top of the sleeve was stuck with the cut 3X? Film. This is not only convenient to use, but also can prevent the scattered light nearby. ?

2. Side view window filter?

If it's not the viewfinder of a SLR, you need to add a filter, so long as its light transmittance can ensure that you don't look dazzling. Of course, it's more convenient to make a plastic sheet. ?

I used the fully sensitive black part of the medical X-ray, cut a small piece and stuck it on the camera to cover the viewfinder. ?

3, focal length?

In order to make the sun as big as possible, we must use the maximum focal length. My camera has 3 times optical zoom and 4 times digital zoom. ?

Some friends think that digital zoom is useless. I have made a contrast experiment: the text in the newspaper was shot with 3 times optical zoom and 4 times digital zoom, compared with only optical zoom and PS amplification, or the former was clearer. Therefore, I think we should make full use of digital zoom instead of rejecting it. ?

the diameter of the sun shot at this focal length is about 1/1 of the length of the photo? Figures 1, 3, 5 and 7 all take the whole photo without cutting directly. ?

4, shooting mode?

use landscape (distant view) mode and turn off the flash. ?

5, tripod?

The focal length of 3 times optical zoom and 4 times digital zoom is equivalent to more than 4 mm! Hand-held camera is easy to shake, which makes the surrounding of the sun blurred or out of shape. A tripod should be used. ?

Friends who don't have a tripod can put their cameras close to corners, colonnades, railings, etc. to reduce shaking, but avoid the lampposts, because the lights may be turned on during the solar eclipse! ?

6, date and time calibration?

In order to leave an accurate time in the photo, we should pay attention to the time of calibrating the digital camera. Based on the standard time of the National Astronomical Website National Time Service Center, the website is:/&; nbsp;

The specific operation method is: adjust the time of the digital camera to one or two minutes after the current time, and when the standard time reaches this time, press the "OK" button to start synchronous walking. The time error of the calibrated digital camera should be within .1 second. ?

the last time calibration should be done on the evening of July 21st. ?

of course, your watch should also be calibrated to accurately grasp the time of the eclipse. ?

7. Have enough batteries?

without further ado, of course, the battery should be sufficient.

8, what else can I see? ?

watching the total solar eclipse is not only about the changes of the sun's garden, but also something worth seeing:

① Bailey beads: like a beautiful diamond ring, they can only be seen in two very short moments when the total solar eclipse begins and ends. ?

② Mercury: Mercury, which many people have seen all their lives, is just to the east of the sun. The area of total solar eclipse may be photographed. Don't miss it! Venus, Mars, Jupiter and Sirius, the brightest star, are also in the sky. Figure 9 is the all-sky star map during the total solar eclipse. It is not difficult to identify according to this star map. ?

You are welcome to put forward different opinions and learn from each other, so as to make better preparations for the solar eclipse! ?

I hope we can catch a good weather! ?

(a little boat, a bamboo cloak? Finalized on May 26, 29)