Dirty Sensor

[BenAllen94]

Today a hired 70-300mm VR arived in the post. I put it on my camera almost straight away and took a few photos to check it was fine, which it was. Later on i had another go with it looking for anything that might put me off buying one, and i got crisp images all the time. Then suddenly the next image was covered in black dots (dust on the sensor) that wasnt there before. Cant really see where it came from so if anyone has an idea please let me know.
Thanks

 

[sep9001]

May happened when you changed the lens.

 

[BenAllen94]

Hadnt changed the lens. It was, take a photo and it was clean, then next photo it was dirty.

 

[RobertP]

You only see sensor dust spots at small apertures like f11 - f16. They have to be quite bad spots to show at f5.6 or wider.

Check the pictures to see what aperture setting was used.

 

[Mark_C]

Try the smallest aperture on a white backrground or blue sky, will show you exactly where all the dust lies, if it is indeed that. Mine has loads but only show up once I really stop the lens down.