How much dust is too much?

eddyc · 26 Jan 2012 at 21:56

I just bought a second hand lens from the auction site and it was listed as being in "very good condition".

It has arrived and does look to be in a reasonable state externally but examining the inside it looks like there is a fair amount of dust.

I managed to take a photo which illustrates it fairly well:

What do you guys think? Will this affect image quality? Should I send it back?

I'm new to SLR so I don't know how much I need to worry about this kind of thing.

eddyc · 26 Jan 2012 at 22:57

Paid £45 + P&P.

Yes, beginning to think I am going to send it back. No point putting up with a dusty lens if I can get another that isn't.

eddyc · 26 Jan 2012 at 23:30

Back it goes to the seller I reckon. Just got to find another.

That model is actually supposed to be pretty good. It is a SMC Pentax-a 50mm 1.7. Cheap but pretty decent is the reputation. Hope I can find a clean one.

Thanks for all the advice

eddyc · 27 Jan 2012 at 10:08

ManCuBuS said:
To see how much dust shows on a shot just take a pic of a white piece of paper at the smallest aperture. (f22+)

Any dust spots in the shot will be very obvious.

That's a good test to know. I'll have a try, thanks.

eddyc · 27 Jan 2012 at 11:38

sbi5ar said:
The answer the question in the thread title...

That! is too much dust.

I'm convinced. Sending back.

eddyc · 27 Jan 2012 at 15:36

Not really had a chance to test it properly yet (it is always dark when I am at home during the week

).

I have found another one from a seller that I trust much more (from a dedicated pentax obsessives forum) so I think I am just going to get that and send the old one back. Not worth the bother of trying to check images etc - also will affect resale value.