Took this regular picture of of a compact fluorescent lamp in my office. I used the ND setting on my camera and added some flash to get some of the background in. Now I have the picture I realise that the darn thing is dirty and probably needs a clean! You can lose up to 10% of the light output from a lamp just to dust and dirt...!
Bit of a feeble blip today, and as you can see a little late in the day and even the backblipped!