i started using my d70s as a back-up a while ago, and until now it's been a pretty reliable camera when in a bind. no glamour shots here. i tried to get an image of the sensor today whilst at work but compact cameras aren't good with reflections/specific shooting conditions. but, it looks like a patch of mold growing underneth the AA/IR filter. i noticed this the other day when i was cleaning my sensor, before i started cleaning. i took a bit of solution to the affected area, but it didn't lift. (sidenote: my cleaning technique isn't the issue, i was trained ) so that made me start thinking it was under the filter - but is there enough space for mold to grow between the filters and sensor? i can't see there being a lot of room to grow, but i know nothing about mold, and my sensor knowledge isn't extravagant. and also, i don't shoot in the rain. i've taken it out while it's been misty or wet out, but there hasn't been a collective amount of water in or on it. i realise it's not weather sealed, so it still could have some moisture inside to cause mold. next thing i did was some test shots. without a lens mounted, i get this (little scary): this doesn't look like the result of mold. it looks like a supernova of pixels. dead and dying. eek. here it is (top center, little black "dust" spot) @ 18mm/3.5. this is why i wanted to clean my sensor, looks like dust. not so much a huge deal - i can replace it in the near future. again @ 85mm/1.4 and flash. once more @ 85mm/8 and flash. now, as you expose less and less, it becomes a lot more noticeable. but if i properly expose a shot (particularly where the defect is) you can hardly see it. luckily, this isn't my main shooting rig, so i'm not really stressed about it. it had quite a good life for what i put it through. i'm just VERY curious to see what the hell it is. so i can either avoid it in the future (if i caused the problem) or, if its cheap and available, replace the sensor. i'm not sure if i'm going to send it in for repair/to see what's wrong. any info or theories would be helpful.