John, maybe you missed my previous posts, so I will summarise.

I referenced The Focal Encyclopedia of Photography 4th Edition, which is a standard reference work I hope you recognise. Nowhere in that vast tome could I find anything that said macro lenses are sharper than non-macro. Of course this could be an error of omission on the part of the editors.

I secondly referenced Erwin Puts and two articles on his website The Tao of Leica. Puts is the respected author of the Leica Lens Compendium, a book that is acknowledged as the best on its topic (it now fetches many hundreds of dollars). His quotes directly support my contention.

Furthermore I can reference all of the Pentax lens tests at Photozone, which do not show macros to be across-the-board sharper than other lenses. Quite the opposite, in fact. Possibly the only macro that does come out on top would be the 50mm, but they, alas, have not tested that one. As far as I can tell, the sharpest lens they have tested is the FA43mm Limited.

And I'll add yet another reference. The respected EF Lens Work documentation (Eighth edition, 2006) Canon produced for their lens system likewise does not make any special sharpness claims for macros, stating instead that they "maintain high image quality" (p. 146) while providing "maximum photographic magnification" (p. 145). They then go on to discuss choosing a macro based on desired working distance and magnification.

Can you reduce the "mass of literature from a lifetime" to a couple of specific references that might refute what I have assembled here? Otherwise I take your claim as a perfect example of the pervasive myth I am arguing against, a myth fed by the compelling experience of viewing images of small details we never normally get to see.

I have supported my claim with references and reasoning. You have supported your claim with nothing at all. What work are you looking for that might change your mind?

Algi, I am not suggesting using a lens for a purpose for which it was not designed. I am merely substantiating my claim that macro lenses are not necessarily sharper than others. And that the common belief otherwise is a myth.

I have done some further research.

The Focal Encyclopedia of Photography 4th Edition states that "a macro lens has been designed to control aberrations at close working distances" (p. 725). This says nothing about increased resolution, but the article may simply be omitting information.

However Erwin Puts, respected author of Leica Lens Compendium, is more forthcoming. His article "Reflections on current optical designs" (The Tao of Leica website) states that "these macro designs are optimized for the near focus region. To be more accurate it should be noted that the performance at close range is not as good as that at infinity (contrast drops a bit), but the loss of contrast and definition of fine detail is much less than what we get when using a standard 50mm lens at closer distances."

In other words macros do not magically become better at close distances. They simply do not degrade as much as other lenses.

Elsewhere on the site Puts plainly states: "Here one falls into the trap of assuming that a macro lens must have superior resolution above other lenses by definition. And by repeating this statement over and over again, readers do assume that it is true, because everybody tells the same story." This is exactly my claim.

My understanding is that a macro lens retains or even optimises its resolving power at macro distances. This does not necessarily mean that the resolution is better than what other lenses achieve at their own optimal working distances. I would love to see some hard data on this one way or another. Does anyone have a reference?

Yet other lenses have higher resolution, contrast that is just as good and close to zero flare. I guess that's because lots of people also like their non-macro lenses to have good IQ.

I've already noted that a flat field is a design aim of macros, but many telephotos in similar focal lengths match them in that regard. The only necessary distinguishing feature of a macro is the high magnification. This does not imply any superiority in other respects.

P.S. You can call me Robin. I'll update my sig so people stop spelling my name incorrectly.

So this means that the Vivitars, Sigmas, Cosina and Pentax offerings (other than the most expensive lens no-one can even find to buy) are not "proper" macros somehow?

Er, no. Though I grant the 50mm example might be sharper than the other Pentax lenses this actually proves my contention that the idea that macros are de facto sharper is a myth.

The OP is not using full frame.

In many cases I am happy to go out with just my FA77 (eFOV close to 120mm) but this would be rather restrictive on a once-in-a-lifetime trip. Even the 31mm (eFOV 47mm) is not what anyone would call wide.

True enough. The difference is that the DA15 gives you this quality at 15mm. The DA12-24mm also gives you this quality at 12mm, 13mm, 14mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, and 24mm.

I do not normally argue for zoom lenses, but in this case every mm makes a distinct difference in the image captured. Some use the same argument in favour of the Sigma 10-20mm, but I prefer the availability of 24mm and the IQ. It makes even more sense given that the OP already owns it!

And something else: macro lenses have a flatter image plane so the peak value (inevitably in the centre of the lens) is likely to be similar to the edge value. This is a big boon for their intended use.

On lenses like the DA16-45 the MTF value diminishes significantly towards the edge, though it is still high enough to make that an excellent landscape lens. It doesn't hurt that its best values are obtained at wide focal lengths. The DA* 16-50mm border values are best at 24mm, not 16mm, for example.