What are these lines?

[Rachelsne]

a couple of times now I have taken pictures and seen a kind of hatching accross my pictures-is this normal?

Today it happened while I was trying to correctly expose a white rose, I under exposed (forgetting I had my view screen turned up high) I thought my icture was exposed correctly when in actual fact it was underexposed, when I corrected this in elements raw thinging I got these lines:

The same thing happened to this one a while back, I under exposed, I went from the sunny giraffe pen to the shady (what ever this animal is) pen and didnt change any settings DOH! so I had the same problem

am i correct to think because it was so underexposed it just cant find the information, and I am seeing some kind of marks on the sensor?

I know its probably my fault, but i want to make sure this is normal and my insides of the camera is ok...

 

[Overread]

Yep this is what you get when you underexpose and try to boost the brightness to get the details back - its a simple case that the data is not there in the camera to resonstrucst from. RAW will help a little, but even in RAW a really underexposed shot won't be salvegable.
out of interest what mode and settings were you using?

 

[Big Mike]

I think that is just a pattern in the digital noise and it probably has to do with the sensor.

You can reduce or avoid noise by shooting at low ISO settings and properly exposing your shots. The more/farther you have to adjust the levels/brightness in post, the more you will bring out the noise.

I once had a crappy little P&S digicam for work; it crapped out on me and gave me images that looked more like cartoons. I was playing with the images to see if I could save them...and when I cranked the sliders all the way...I found a very weird pattern in the clear areas (sky)...it was certainly a geometric shape and was repeated in a pattern. It must have been the sensor but it was really weird.

 

[Rachelsne]

My hubby had some flowers delivered to me (he has been away this week) so I was just playing around in my poorly lit livingroom, I used a tripod f5.6 (lowest for that lens) and shutter 1/40, for the rose-like I said my viewing screen was turned up high so even though I was looking at my meter and I kept changing my values I was thinking I was over exposing even though I wasnt, Im silly!

I had actualy thought I would need a slower shutterspeed-hence the tripod

I dont see the lines anywhen else-only on extreemly underexposed pics, so I shouldnt worry I guess,

Also I only asociated noise with ISO which was set at 100 so it didnt cross my mind---Oh so much to learn

 

[dslrchat]

I experience the same, with the flower pic that was very dark and then bumped up the exposure when converting from raw.

 

[*Mike*]

...my viewing screen was turned up high...

The LCD's on cameras are notoriously inaccurate... Histograms are the place to be. )

 

[tim.bennett]

I've recently started using the histogram as mike said. And it's great! Do some reading online on how to read it effectively. really makes a difference specially when using an of camera flash without the outo control.