Just bought a used lens, looked fine in the shop and got it home to find three dust specs on the inside of the lens. the condition of the lens was apparently mint.
My questions would be
- would I notice the dust in the pictures?
- how frequently do lens get dust inside of them. None of my other lenses have this issue?
- if it is not that common and this lens already has dust inside then is it more likely to get more dust inside?

I am thinking about taking the lens back but as i've never had dust inside a lens before thought i'd find out a bit more about it first.

I've inherited a few old items that used to be used with an ME super (which I’m keeping). If any of the below is interesting to anyone I would prefer to hand over in person rather than post but we can discuss. I live in London (Dalston) and work nearish monument station.

Items include:
Sirius 28-200mm lens (I believe this is similar to the vivitar) – offers welcome
Vivitar zoom thyristor 285 flash with vari sensor adapter – offers welcome
Sunpak auto 170 flash– offers welcome
Sunpak auto 200 flash– offers welcome
Cokin P375 creative filter set – offers welcome
Cokin P160 linear polarizer - £30

Thanks guys.

I've been coming to the conclusion that to upgrade I'll need to buy two lenses. I've toyed with the idea of the sigma 150-500mm (for 599 from srs) and then saving up for a marco but have the feeling it would be too heavy a lens without regular use of a tripod. Does anyone currently use this lens?

Bit of advice needed. I’m currently looking to upgrade this lens but not sure what with. I have mainly used it for wildlife photos, so anything from deer to birds to insects, with decent results but I think it's time to upgrade so am considering my options and would like a bit of help. I do occasionally use a tripod but generally don't so am conscious of weight. Price wise I would say I would be willing to spend up to £600, whether that is on one lens that can replace the telephoto and macro (although not true) capability of the Sigma or two lenses which can do either task. What do you think my options are?

Thanks for your help. i've done some more research and the Pentax 100mm f2.8 SMC D-FA WR Macro Lens gets really good reviews. As it's only 100mm i was thinking of getting extension tubes as well to help with smaller insects/distance issues. Do you think this is a good idea and what make would you go for?

I need a bit of help. i'd like to get more involved in macro photography, mainly in the plants and insects field. I currently have a K10D and have historically used my sigma 70-300 macro which has some pretty decent results but i'd like to get a better lens to improve my shots.

I'm considering either the sigma 105mm or the 150mm macros. The 150mm is twice the price but seems to be the better choice. Is this right? This will be the most expensive lens i own so wan to make the right decision. are there any other lenses I should consider? will they work well with my K10D as well?