Two relatively minor things are bothering me on the K-3 - that I haven't seen discussed. First, maximum aperture settings on variable aperture zooms are not exact and can skip 2/3rds of a stop when stopping down. Second, unlike the older Q which allows for entering the exact focal length of a manual lens on startup, you have to choose among what the menu offers (therefore I can't get 14mm in EXIF or as my SR setting).
This hasn't been noticed much in the past - as I shoot a lot with primes or constant aperture zooms. However, I recently acquired the Sigma 12-24 f/4.5-5.6 which will be a high-demand lens when FF comes out. I also have the 18-55 WR for occasional use in inclement weather, and the old F 70-210 f/4-5.6. Normally, I shoot at one-third EV stop down settings (rarely use flash at 1/180th requiring half stops). With all of these lenses, you tend to see the lenses stay at the claimed at f/4.5 all the way as you zoom up to f/5.6 - skipping the f/5 setting, and the same as you zoom toward open. Sometimes you can get the f/5 to register (especially on the 18-55), sometimes not (almost never can get it with the other two lenses - and on the Sigma most of its range is around f/5 as maximum). Moving the aperture setting on a lens that should have f/5 available as maximum will result in skipping between f/4.5 and f/5.6; if you start the lens at the widest focal length you can set f/5 but when you reach the range of the zoom that is f/4.5 it jumps down to that setting and will not allow f/5. Frustrating! By the way, I notice that half stops are also using f/4.5 at the supposed midpoint between f/4 and f/5.6 - which most certainly it is not. Also, testing out the situation fully, I checked on the other end of the variable spectrum to minimum aperture (not that I ever use that setting) and found the behavior to be similar - often in the middle of the range the minimum aperture - such as f/25 is skipped entirely and the aperture shown moves from f/22 to 29.
At first blush, this shouldn't be a big deal, but I do feel that most zoom lenses tend to improve greatly when stopped down by only one-third of a stop. A few years ago, I would have chalked this up to my general view that variable aperture zooms aren't worth the worry (although the 70-210 shot in the middle of its range is impressive even wide open). Now, the best available walk-around zoom lenses - IMHO - are the 16-85 and the Sigma 17-70 (C) - both of which happen to be variable aperture. The skipping aperture settings is enough to discourage me from moving to one of those lenses from the venerable 16-45 where I always have access to every third of a stop. I get the strong sense that constant aperture lenses tend to yield more consistently accurate exposures than the variable aperture lenses, as well.
The issue with setting the exact focal length is more inconvenience than anything that will have a direct impact on image quality. Acquiring the Sigma 12-24 means that it will be more difficult to discern shots taken with it vs. the Samyang 14mm (which is usually stopped down to at least f/5.6 for IQ purposes) in the EXIF. I set it at 12mm on startup, as I'd rather undercompensate SR than overcompensate - it likely is closer to a 13mm anyways. I do know how to rewrite the EXIF using EXIF Pilot, but there just isn't enough incentive for me to go through that process. Obviously, Pentax already has the ability to program to exact focal length and precision SR because the Q allows for it. Apparently the Q requires greater precision than the larger format models (sarcasm).
For those who are bothered by either of these issues (especially the variable aperture problem), I'd be interested in your reaction and experiences. I certainly understand that many users don't see either of these items as a concern, but I wasn't intending to post the thread as a poll or opportunity to be defensive. I view the K-3 as a great camera, but these two concerns would prompt me to lower its rating by a total of 1 point on a 100 point scale.
Last edited by ScooterMaxi Jim; 09-03-2015 at 11:00 AM.