1- Astrotracer : only proposed in Pentax SLRs, since K-3II (K-1, KP, K-1II) ; previously and otherwise available with O-GPS-1 add-on module
I'm very interested in this, but I have a KP and no O-GPS-1. I do wish that the KP had been made like the K3ii, since I have no use for the built-in flash.
2- Pixel-shift : only on Pentax SLRS, since K-3II (
K-1, KP, K-1II ; some other makers produce resolution enhancement via multi-exposure like Olympus and Fuji)
I've yet to run into a situation that really begs for pixel-shift to be used, but that's because I rarely do static shots or tripod landscapes. I'm glad it's there though, and since I use Rawtherapee I'm already prepared to develop pixel-shift shots once I finally make one.
3- Composition adjustment : only on Pentax SLR, since
K-5 Again, I've yet to be in a situation that demands it, but I'm glad it's there.
4- AF precise adjustment : first on Pentax SLR, since K-10D
I'm surprised Pentax was first to implement this, considering everyone else had always supposedly been ahead in PDAF tech. It's invaluable for anyone who wants to ensure AF accuracy, so I don't understand why other manufacturers withhold it from lower end models.
5- TAV mode : only on Pentax SLR, since K-10D (equiv. to M mode + ISO auto on
GR III ; and other brands)
It's a great idea in theory, though technically it's not unique. I do prefer Pentax's implementation as a separate exposure mode, as it makes M mode exclusively a manual mode. Semantics, but UX is an important aspect that Pentax usually gets more right than others.
6- Green button : only on Pentax SLR, since MZ series
Another great idea. Hearing about this is what first piqued my interest in Pentax, because it had such high praise from people on reddit. I don't quite understand how other brands handle this function when using manual lenses or modes, as it seems so natural. Nikon also requires stop-down metering with legacy glass, so what button do they use then?
7- Sensor shake reduction : first on Pentax K-10D (and Minolta 7D)
Obviously this is a huge plus for DSLRs. As soon as I heard Pentax had this alongside native legacy glass support, I was hooked. I understand that some people are hesitant to call IBIS invaluable (owners of Fuji and other DLSR brands), but going forward I see IBIS as a standard feature that introduces more value than it costs (considering the addition of astrotracer, pixelshift, composition adjust, and horizon correction).
8- Effective "all weather"/"weather resistant" sealing : systematic on Pentax SLR, after
K-S1 ; and in Pentax new lenses since a few years
This is a strange feature, as technically it's not always effective since not all lenses are WR, but when other brands withhold WR from cheaper camera models, it devalues their whole line of WR lenses. Like with IBIS, I think WR should simply be a standard body feature so that only lens features should be variables. It would have been nice though if Pentax had produced more standard WR primes, and WR Limited lenses.
9- Pentaprism versus pentamirroir : systematic on Pentax SLR, since
K-S1 Pentamirrors are nothing but a cheap imitation of pentaprisms. Apart from their weight reduction, they have no practical benefit over prisms, which I hardly consider to be important since those who are looking for lighter cameras can just go mirrorless now. Pentax made the right choice to go all-in on prisms, which is especially appropriate considering they're Pentax's namesake.
10- In-body raw development : first on Pentax SLR, since K-10D
Again, I'm surprised Pentax was the first, or that it wasn't even standard to begin with when DSLRs were first made. I have no use for it, but it's better to be there than not.
11- DNG raw format : first on Pentax, since
K-5 (and Leica)
Nice and practical. Propriety formats make no sense and only serve to splinter the camera market (and not even effectively). It's better for the whole industry to accept a single Raw standard and treat it like film (that is to say, compatible with any developer (barring the difference between colour and b&w film of course)).
Beyond all these features, what attracted me to Pentax was that I could get all this at a lower price than comparable models from other brands, only at the loss of a few things that I don't even need to mention because every Pentax user already knows the arguments. Nonetheless, those lost features were the least important things to me and were easily made up in the value of the Pentax brand. Hyper modes, legacy lens support, and the KP's three dials were all also features that I considered useful for my purposes, as when I was shooting with a cheap Nikon, all I could think about was what my ideal camera controls would be, which the KP turned out to provide exactly.