Top positive review
5.0 out of 5 starsA bit expensive but ultimate image quality
Reviewed in the United States on July 25, 2022
DISCLAIMER: This is based on my experience with a USED copy of the camera.
TL;DR While some features are quite gimmicky (e.g., the screen tilt mechanism), if you are after the ultimate image quality, insane dynamic range, great low-light performance, this is the camera for you. If you're going for fast action, look at the Pentax's latest APS-C bodies.
Image quality is simply amazing. Dynamic range allows you 2.5 stops of highlight recovery and 4 stops of *very clean* shadow recovery. Noise at ISO 6400 is acceptable under normal indoor lighting conditions, but may developer color shifts in very poor light. Color rendition is great with the camera Jpegs, but the SATOBI color profile from one of the latest firmware versions really hit it out of the park for me.
The sensor stabilizer is effective down to 1/8s at focal lengths between 28mm and 105mm (I haven't tested wider or longer yet). Below that the keeper rate drops significantly. I would say it's comparable to the performance of the IBIS in something like a Fujifilm X-S10, but it's certainly no Olympus.
Viewfinder is average. I've used bigger and brighter. The LCD used for the AF point markings and similar are sometimes invisible in the dark, and there is no way to turn their illumination on either permanently or based on the lighting condition. It has digital levels in the viewfinder which is my first for a DSLR and a highly appreciated feature.
The back LCD is clear and crisp. The brightness can go high for better viewing in direct sun. The free-tilting mechanism is appreciated but there is no added benefit from the way it can be oriented at any angle. The standard angles work well enough. It's a cool party trick to impress friends, though.
Ergonomics are fantastic. Much better than Nikon's semi-pro bodies that I've used before, and on par with a double-gripped body like Olympus E-M1X. Button layout is somewhat cramped in some areas, but otherwise well laid out and easy to reach.
The lens selection includes the current Pentax K mount full frame lenses (D FA series) as well as the older FA, F, A, M, and K lenses. With an inexpensive adapter, you can also use the vintage M42 lenses. Note, however, that most camera features are only available with D FA and FA lenses, while F lenses only have autofocus and no in-camera corrections, and manual focusing with A, M, K, and M42 lenses is unreliable at the best of times. In particular, there are no contemporary affordable fast lenses. The cheaper zoom (yes, only one) is around $500, and it is a slow lens for indoor use. There are plenty of vintage fast-aperture lenses in various focal lengths, but not many zooms, and they are... well... vintage lenses.
Build quality is top-notch, but if you are after weather-sealing, be prepare to limit yourself to the latest pro-grade lenses only (the D FA F2.8 zoom trio). The cheaper lenses are somewhat splash-proof (fine in light to moderate rain, for example) but not at the same level as the camera itself (you can't expect to put it under faucets or get splashed by waves on the beach).
Camera isn't very customizable, but the controls are well laid out and easy to use. Be sure to understand how you might use the camera and check the manual before purchasing. If the command layout does not suit your needs, there isn't much you can do about it.
AF is average. It's generally precise and fast enough, but not as good as some of the latest mirrorless cameras or even some older DSLRs. However, it's decent in low light, even with a slow lens.
Battery life is not great for a DSLR (I get around 400 shots, maybe a bit more), and replacement batteries are not readily available and are expensive. There are some 3rd party batteries, but do check the reviews because some are rated quite poorly. I ended up getting used batteries on eBay.
Pentax makes great use of the sensor stabilizer and GPS with features like Pixel-shift resolution, automatic horizon correction, astrotracer, etc. Pixel-shift (called Real resolution in some markets) which gives you enough detail to potentially match a 144Mpx image from a sensor that does not have this feature. It requires a tripod and relatively still subject, but it's amazing when it works. Automatic horizon correction can straighten the image automatically if the horizon is off by up to a few degrees. The astrotracer can track stars on a tripod for exposures up to a several minutes (depends on the lens).
Overall, K-1 (mark 1) is a very compelling package for those that aren't sports and action shooters.
