Without seeing them it's a little difficult to offer a reason.

Are they all similar settings ? (by which I mean aperture, shutter speed & iso) & are they handheld ?

Could be down to a number of factors, but if you know the lens is capable of producing sharp results at a given aperture then the answer is nearly always down to photographer error, whether that be settings selection or handholding technique.

Higher iso's can lose a little detail especially if you are using higher noise reduction as the pixels are (for want of a lengthy & detailed description) "smudged together a little" to reduce noise.

Very nice shots indeed.

I'm afraid our pentaxian friend is mixing brands though. That's quite clearly a Canon L-series stepladder.

Firstly Cosmo, apologies for going OT & good luck with your sale.

Secondly, mpg - I've held my tongue long enough, why criticise peoples pricings, declare your interest in virtually every lens that goes on sale here, then pull out as your "friend" doesn't want it or can get one cheaper.

You say it's impossible to pay £110 less for a used lens over new price ? Then may I remind you of your post of only a month ago HERE where you are asking only £50 less than the new price. Please practice what you preach !

Careful or he could work it out by a process of elimination.

In the interest of uselessness I can confirm that they are not available at Jessops... hope this doesn't help

I would tell you where I have seen them at a similar price but that would be useful & thus prohibited in this thread.

For anyone interested there's a series of programs on BBC4 tonight beginning at 9.30.
Docs on Lee Miller, Annie Leibovitz, Linda McCartney, Eve Arnold and Sharon Chazan.

I've not seen these before so this is not a recommendation, just a heads up. I think I'll set my sky+ & can then watch them at leisure.

P.S. disclaimer: don't blame me if you delete "love boat" to make room on your recorder & they subsequently turn out to be rubbish !

How about you share the answer then

Simon, as much as I rate the Sigma 30mm, it isn't well suited to landscape really as the colours are a little muted - if 35mm is a suitable focal length for you then I'd snap up the Da macro whilst it's priced as it is.

I'm glad you're getting on with it Lilly,
I told you I thought it'd suit your style very well & I have no reason to change my mind now. It doesn't give the saturated colours that the Pentax primes seem to give, but it does generate a great depth in tones (great for B&W).

I see you've just outgrown the novelty of shooting everything at f1.4 - f2 is where it starts to get into its stride.

I fancy getting the 20mm f1.8 also. I can deal with the bulk, but not the price