Protecting Digital Camera (Canon Powershot SX 50 HS) against Sun burn in.

Build yourself a sun tracker and instruct the camera to point elsewhere. Or just cover the lens when the sun approaches the "burn angle".

The video security camera chips I've designed switch in a day/night neutral filter, BUT they're also not aimed skyward. ...Jim Thompson

If you point the lens straight up, the solar zenith (sun height) will never be higher than 90 degrees minus your latitude. For example, in my area, at latitude 36 degrees, the maximum elevation will be 90-36 =

24mm widest angle (35mm equivalent) lens. That yields a viewing angle of about 73.7 degree. The lowest solar elevation where the sun can illuminate the sensor directly will be 90 degrees min 1/2 of the 73.7 degree viewing angle: 90 - 73.7/2 = 53 degrees.

Therefore, if you point the camera straight up, open the lens to the widest 24mm FL, ignore the 0.5 degree width of the sun, and live at latitude 36 or higher, the sun will never shine directly onto the sensor. However, 1 degree is not a good safety factor, and you should install a lens hood on the camera.

Canon cameras can be hacked. (I have several): Write or find a program that retracts the lens when the iris is fully closed and/or the sensor detects too much light.

No. The sun has risen and fallen daily and quite reliably for millions of years. Other than biblical accounts of the sun going into overtime for a few hours during a battle (Joshua 10:13), there is no known method of preventing the sun from trashing yet another of your electronic devices. I suggest that you purchase an extended warranty.

However, if your voodoo or magic incantations fail to stop the sun, you could also just install a dark filter on the lens.

The dynamic range of the CMOS sensor is not sufficient to maintain quality at high light levels. You'll need a dark filter to photograph the sun or any manner of super bright light. A fully closed iris is probably insufficient.

I wouldn't worry much about the night. Your camera is likely to have been stolen by then.

A motorized sun blocker. I've built a solar tracker from 4 matched solar cells, two diff amps, and two toy motors. The solar panel is gimbal mounted and can swing up/down and left/right. The cells are arranged symmetrically around a center post, that casts a shadow on some of the cells when NOT pointed at the sun. You can also do the balance trick with optics or just black tubes around LED sensors. The motors move the gimbal mounted platform, until the shadow is minimized, which is when the center post is pointed directly at the sun. All you need to do is build one of these, and position it so that an attached umbrella shields the camera from the sun. You'll find 2 axis solar trackers and sun sensors all over the web and eBay:

Incidentally, I made mine sensitive enough to function with light from a flashlight, so I can do indoor demonstrations. A side effect is that when passing car headlights shine on the solar panel, it will try to swing in the direction of the car. My next model will have end of travel sensors to prevent embarrassing excursions and crashes.

Disclaimer: Please note that I have no idea what I'm doing. However, please don't let that stop you from reproducing my mistakes.

Not to change the subject, but I'm thinking that you could rip the lens off a cheap USB camera (they start at $1) and replace it with a pinhole, for full sunlight outdoor use. Most cheap web cams go snowblind in daylight.

Good idea. Pinhole security cameras are quite common because it's easy to hide the camera, with only a small hole needed for a picture: I have a few lens caps that have been converted with a needle into pinhole lenses. That's the way I test night vision devices during daylight hours.

Diverting further from the subject, I see the problem as how to increase the dynamic range of the camera system. There are photochromic (and electrochromic) plastic and glass materials available, as used in eyeglasses that darken in sunlight, but I couldn't find any filters that could be placed over the camera lens. I've wanted to try this to extend the light range of a cheap security camera but as usual, no time. One obvious problem is that such lenses are usually only good for a few hundred transitions, before they remain permanently transparent.

However, the OP wants to wreck his $400 camera and I wouldn't want to offer any suggestions that might prevent him from achieving his goal.

that's only correct twice a year.

the annual max is 113.5 - lattitude

Oops. I forgot the earths 23.5 degree axial tilt. Max_elevation = 90 + 23.5 - Latitude

That means that unless Skybuck lives north of 60.3N, a simple lens hood isn't going to work.

Thanks (grumble...).

Actually no. That is only true at the equinoxes. The altitude of the sun at transit varies with the time of year from the nominal equinox altitude by +/- 23.5 degrees which is the angle between the Earths orbital motion and its axis of rotation. So for your latitude of 36 degrees the range is 90-36+23.5 = 76.5 summer and -23.5 = 20.5 winter.

At my latitude of 54.5N the sun gets to only 59 degrees in summer and a pathetic 12 degrees in winter. This makes solar power unattractive!

The definition of the tropics is the region of the Earth where at some time of year the sun will be directly overhead at transit.

Silicon CCDs are fairly robust but continuous sun on one will eventually bleach the dyes in the Bayer mask.

The standard for this is Baader solar film - photographic grade.

Depends what you are trying to do. Stopping the lens down to a largish pinhole should be good enough to avoid damage to a CCD.

Plenty of people run whole sky cameras but tend to live in very dark areas. They seem to survive daytime OK despite having fast lenses and

A couple of new serious amateur ones have been launched fairly recently although details online are surprisingly scant. Try it with a sacrificial webcam and see if it does what you want.

take

It is also correct at two longitudes all year 'round. Plus how much to 'add' to 90 degrees varies by longitude.

?-)