How to torture a Digicam

<p>A particularly egregrious example of CA, courtesy of the Sony DSC-

S85 (a pretty good little camera over all). <p/>

 

<p><img src=http://rogouski.net/loose-photos/purple-fringing.jpg>

 

What exactly are the reasons for this.

The sun is very, very, very bright.

Flare. Sun is just outside frame, the lens elements get many reflections and the contrast is too great for the CCD to handle, resulting in blooming. Solution: re-compose and/or use a lens hood.

 

Note that the situation is a torture test for any lens, but the purple glow is particularly bad here.

Lots of things get called "chromatic aberration" in digicams (and fim ones, too) that aren't.<P>

 

Chromatic aberration is when the lens focusses long wavelengths to a different point than short wavelengths. There are two reasons why the above doesn't look like CA to me:<P>

 

1. In true CA the long or short wavelenth component is still FOCUSSED , but its focus-point is just displaced. In the example you posted the magenta region is smeared over 2/3's of the frame.<P>

 

2. CA usually produces red or blue fringes, not magenta ones.<P>

 

I think what you're showing us is simple lens flare resulting from a cheap, low-quality zoom lens. Lens flare often comes in weird colors like magenta, yellow, or green, because the optical coatings designed to prevent it are designed to PASS all wavelengths evenly, but don't necessarily REFLECT all wavelengths evenly. For example MgF2 (magnesium fluoride), which is a common lens coating, has a purplish reflection, which may be what you're seeing in the above image.

did the aliens let you aboard their ship?

<p>20 Seconds later, same place. </p>

 

<p><img src=http://rogouski.net/loose-photos/graveyard.jpg></p>

It's because you're in a graveyard!

You zoomed. That's not fair.

don't burn out your sensor

 

 

in response to bob: "Waaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhhh!!!"

Yup, what other folks said. It's a combination of lens flare and sensor blooming. You'll get the same effect, on a smaller scale, by photographing a light bulb. Enlarge the image and study the bulb carefully - you'll see magenta fringing around the light source caused by the sensor going wacko.

dude u are shooting right on to the sun/ this behavior is not unexpected at all/this would also damage your sensor since direct exposure to sun might yield a larger current at the photosites and burn up the sensor/

<p>anyways even regular pro zooms are not made to be shot directly at the sun.