Originally posted by TheDocAUS Looking at the old and new model, the specs are very similar. Differences include:
-10g heavier;
-one more diaphragm blade;
-a few changes to the external design of the lens (looks more like the 55mm); and
-different coatings on the glass.
Overall not much difference.
Tests will tell if it is better optically. Without testing it is very minimal upgrade.
Originally posted by Ed Hurst Some questions that occur to me are:
1. How does it compare optically with the 35mm FA and A lenses?;
2. Specifically has the field curvature generally found with the FA been remedied?;
3. How does it compare optically with the 28-45 at apertures from f4.5 (and smaller) (because this might mean anyone owning the zoom might not want this lens, unless it be because it's smaller)?;
4. What's it like from f3.5 - f4.5 (because this would represent an area where it can do something the zoom cannot)?
The optical formula is said to be the same, the difference is in aspherical glass used, low dispersion glass used and a new coating. This could take care of image aberrations, possibly of field curvature, definitely flare as well as improve contrast. However, until we see one it's difficult to tell exactly.
As far as the 28-45mm, I can't see how the new lens will replace it, for the work I do at least, and at least until Pentax will give us a true WA to go with it. For my landscape work, I use the 28-45mm 90% of the time, and a longer lens for the remaining 10%; plus, I don't particularly need a fast lens for what I do. I wouldn't be able to replace the 28-45mm with the 35 + 55mm, which is the alternative today (the 45mm is not a great performer, sadly). However, if Pentax will give me a 20-something lens, I might consider using only primes: that, the 35mm and the 55mm would make for a nice, light kit. Of course, YMMV according to your focal length preferences, the subjects you shoot and the look you are after...
Best,
Vieri