Sensor mark?

[Galaxy66]

Here is one of a few pics I took with my Sigma 10 -22 wide open, as you can see I have a few specs of dust showing but what concerns me most is the elongated vertical mark showing in the centre.
The rather thick polariser is leaving it's mark also.

 

[HuntingMartians]

take a picture at a high F value of white paper

 

[Galaxy66]

take a picture at a high F value of white paper

Thanks, will do, will any lens do so long as it if f22 ?.

 

[hyakuhei]

yup

 

[Canon Bob]

If I remember correctly Mal, you haven't cleaned the sensor yet have you?

Bob

 

[Galaxy66]

If I remember correctly Mal, you haven't cleaned the sensor yet have you?

Bob

Correct, and I am not looking forward to cleaning it.
Anyway, off to take a pic of an A4 sheet of paper now

 

[mercmanuk]

Hi i believe you can use 18% graded gray card as well, well it says that in the instruction booklet

Regards Mark

 

[Canon Bob]

Correct, and I am not looking forward to cleaning it.
Anyway, off to take a pic of an A4 sheet of paper now

I asked because it looks more like a residue mark than dust.

Bob

 

[Galaxy66]

Before I uploaded it I could see a few at the top but they are not showing up now on the page, nothing like it was on the pic. I had a look at the two previous images from the same spot same lens and they are not on those
Maybe the in house sensor cleaning gismo is doing it's job.
sorry, not into doing borders yet but you can just make it out on the left.