Purplish Tint on Sensor Picture

[hador7]

Hi guys,

I recently purchased a Canon Digital Rebel XTI and had to get it replaced by the retailer since the first XTI had an issue. Anyways, I took a sensor picture of both the cameras to identify any problems/scratches/dirt with the sensor.

I took a photo of a white background (computer lcd) using my Canon 70-200mm @ 70mm focal length, 2s shutterspeed, at f22 to test the sensor and then used Adobe Photoshop and used the Auto-levels function to help better identify the dirt.

The picture of the First Camera (one with problems) is here:

The picture of the Second Camera (replacement camera) is here:

Both sensors seem to be relatively clean but Camera 2 (replacement) has more uneven purplish tint compared to the first. My questions are:

1) What causes this?
2) Will it affect my pictures? (e.g. colour accuracy)
3) Is it a defect?

Thanks guys for the help

 

[DHammer]

Most likely its the computer screen. Try shooting a white wall or back drop.

 

[Big Mike]

Don't shoot a computer screen

 

[Alpha]

^Agreed. And don't use auto levels. It's worthless-- like surgery with a butcher's knife.

 

[Sideburns]

LOL.

Computer screen, dude. That's your problem. Shoot an evenly lit white wall.

OR. Go and shoot PICTURES!

 

[Garbz]

Also the effects there can be caused by posterisation. It may just be noise pronounced by post processing, but unless it shows up on a normal un-edited pic don't worry.

It's just like those people complaining about the lines the early D200s made even though the only way to get these is to horribly overexpose the photo beyond any use.