[UncleVanya]

Look 50mm is close to the focal plane distance making these not telephoto OR retrofocal. A simple design with high levels of softness and vignetting make tge 50mm 1.4 design smaller - but look at tge FA 35 f2 or an older 1.4 35mm. Those are also much smaller than modern 35mm 1.4 lenses. The 85 f1.4 designs had higher expectstions and more glass I'm sure they could have been a little smaller with more modest goals.

Look at apples to apples. The modern fat fifty lenses are all large or have significant compromises. The difference is glass, sharpness wide open, and vignetting.

[subidoc]

These comments above are the sum of cummulative knowledge and experience... It never ceases to amaze me how inclusive and helpful all of you are.

Keep up the good work. Cheers!

[Rondec]

I think the big questions are whether you plan to use the lens on full frame (the DA 40 isn't very compatible with full frame) and if you shoot a lot of wide apertures (the DA 40 only goes to f2.8).

In general, the DA limiteds are created to have good contrast, excellent flare resistance, and nice colors in a small size. They do this by having slow-ish apertures and typically great Pentax coatings. I use my DA 15 and DA 40 mainly for landscape situations and have been pleased with both of them, but I don't think they could take the place of f1.4 lenses. I mainly got the DA 40 because I bought a K-01 and wanted a couple of small lenses to mount on it -- the DA 15 and 40 seemed to fit the bill quite nicely.

[johnha]

I really like my M40/2.8 or Voigtlander 40/1.4 (Leica M4) or 43/1.9 Ltd on film or FF, but I struggle to make the focal length work on APS-C (too long and not really long enough). I do use a 28mm as an equivalent on APS-C.

The M40/2.8 really does make an MX or Super-A very compact, this and the focal length easily makes up for the slower aperture.