Troubleshoot Issue of light smear on right side (only) of frame

[jswnz]

Not really a beginner - been using my Nikon D7000 + Sigma 11.16 wide-angle for years
yesterday I discovered what might be described as a light smear on right side of the image

photos settings
ISO 250 f8 1/60th second

something is wrong - never encountered this before

 

[wfooshee]

That kinda looks like fogging in the lens. Did the camera go to a different temperature environment before you took the picture?

 

[paigew]

I'd be sure to clean your lens well and see if it happens again.

 

[480sparky]

A smear on the lens.

 

[Soocom1]

That or a something on the sensor.