Camera lens smear/smudge causes lighting issues?

[msg7529]

I recently noticed that the camera captures these "light lines" when facing towards a light source. I thought it was a hardware issue until I realized the camera lens (glass cover) was actually what caused this problem.

This photo is from Google, not taken by me or the M8

If the lens is dirty (fingerprint smear and such), those light lines start showing up.
Even if I tried to use my finger to "clean" it, the lines become not as obvious but still somehow visible. I would need a cloth or my shirt to wipe the lens clean for those light lines to disappear.

I never actually noticed such problem when I used my previous phone (Droid DNA). The same thing happens with my friend's M7 when I smeared the camera lens with fingerprints.

Does this usually happen? I mean, I never knew that the smartphone camera is so sensitive about the smudge on the glass.

 

[notacoach]

That would happen with most cameras shooting into the light, phone or otherwise - called lens flare. A dirty lens and/or filter will emphasise it, but it will happen even with high end dSLR lenses in similar conditions..........