Because they have higher-than-average incidence of front/back-focusing problems. That and brand snobbery (it's sharper wide open than the DA*16-50 for example).

The DA 40 and FA 50 have different purposes.

The DA40 is an almost ludicrously compact lens (it looks like a body cap!), very sharp indeed right from wide open (f2.. The FA50 gives very shallow depth of field (good for blurring the background) and is also good in low light. The latter of these isn't terribly relevant because 50mm isn't the "do everything" focal length that it was on the film cameras the FA50 was designed for (if you want a very low light lens, get the Sigma 30mm f1.4). The Sigma 50 has much better image quality than the FA50 (especially sharpness wide open, and much less vignetting), and also has a silent AF motor. It is however much bigger and heavier than the FA50.

Those do look quite good, and also don't scream "camera bag". I'm acquainted with the quality of Lowepro's bags (have one of their Stealth Reporters as my "carry everything" bag) so no concerns in that regard either.

At that price it's 90% likely to be MF

With all the travelling done by folks on here I imagine this issue has come up for a few of you. Can anyone suggest a combined 'camera gear/stuff-which-isn't-camera-gear' bag which fits within airport hand luggage restrictions? It'd need to hold my K20D with a Sigma 10-20, DA35 Limited, and another lens (either a DA18-135, or the 50 and 100 Macros*). Essentially what I'm looking for is a bag which has camera inserts, but also has an undivided chasm for the other stuff I'm likely to want with me.

Also, I'm going to a city so I want a shoulder bag rather than a backpack.

Cheers

In what circumstances would uploading a (20Mb or so) RAW file to this website be quicker than opening the RAW file in PhotoMe?

Also (with due caution about being labelled a witch for mentioning other brands) Canon's 50mm f1.8 has a plastic mount and is probably their best-selling lens outwith the two kit lenses. If there were problems with plastic mounts eventually wearing out/breaking then we'd have seen lots and lots of complaints about that lens.

The older version of the Sigma 10-20 (f4-5.6) is reported to be noticeably sharper. Of course, the newer version is nearly a stop-and-a-half faster at 20mm so it's up to you which is the priority.

Or buy from an online retailer who'll pay return postage on faulty items.

That's a good point, though in my case I'm not sure that the 18-135 would be so much as ousting the FA77 (though buying the former would certainly exclude buying the latter). It's more that the FA77 these days is £800 (give or take) - I'm not sure I could justify spending that on a single camera lens (even if I had the money, which I don't!), beautiful though the FA77 is.