Pentax K-1 Review


The optical viewfinder is one of the most important components of any DSLR.  The K-1 has a bright pentaprism viewfinder with 100% field coverage and 0.70x magnification.  This is a fairly typical size for a full-frame DSLR; only flagship models from competitors, such as the Nikon D5 (0.72x) and Canon 1D X (0.76x), offer larger viewfinders.  Cameras such as the Nikon D800 and Canon 5D have roughly the same viewfinder size as the K-1.  Since Pentax has historically been class-leading in terms of viewfinder size, there is still some room for improvement in this respect.

With the standard eyecup, looking at the edges or corners of K-1's viewfinder size does not cause any eye discomfort.  Many other Pentax film-era SLRs have larger viewfinders than the K-1, but those viewfinders do not cover the full image area.

The K-1's full-frame sized pentaprism (0.70x magnification, 100% coverage)

Despite having a lower magnification, the fact that the full-frame format has more than twice the sensor area than APS-C means that the K-1's viewfinder is about 65% larger than that of the K-3.

Diopter knob and eyecup mount

An easily-accessible knob to the left of the viewfinder lets you dial in a diopter adjustment between -3.5 to +1.2.  This is a slightly larger than the -2.5 to +1.5 range of the K-3, but with an unfortunate loss of positive compensation.

Stock eyecup Fk

The K-1 comes with the Fk eyecup and it is also compatible with viewfinder attachments such as the O-ME53 magnifying eyecup, diopters, magnifiers, and refconverters.  The attachments easily slide onto the rails on either side of the viewfinder eyepiece.  Some of these attachments are hard to come by new, though.

LCD Overlay

The K-1 is the first Pentax DSLR to feature an LCD overlay in the viewfinder.  We see this as a very important improvement, as the LCD enables viewfinder customization without the need to replace focusing screens.  In addition, multiple focus points can be displayed simultaneously, there is an APS-C crop frame in crop mode, and there are indicators for both axes of the electronic level.

Viewfinder with all components enabled and AF on

Users of Nikon cameras will find the LCD overlay very familiar.

Pentax K-1 Viewfinder Diagram Pentax K-1 Viewfinder Customization

Pentax K-1 viewfinder diagram and customization menu

The K-1's viewfinder customization options are found in the 5th tab of the main menu.  The grid and electronic level display can also be controlled directly from the Control Panel.

Note that changes to the AF Frame and Spot Metering Frame settings will not be reflected in the viewfinder until you half-press the shutter button.  We contacted Ricoh and learned that this is by design.

The photos below show the individual components in the viewfinder.

Electronic level Spot metering frame
AF frame Grid
APS-C frame always shown in crop mode Default viewfinder setting
A-33 point mode A-9 point mode
SEL-1 mode Center AF point reporting in-focus

As suggested by the diagram and photos above, the LCD overlay features two indicators for each AF point.  The larger indicator means that the point is in focus, whereas the smaller indicated is used to show active points while AF is on. The smaller indicators only come on in Spot, SEL and A-9 mode.

The indicator for the central AF point is larger than the other indicators.

AF on, illumination on Viewfinder light setting

When shooting in dark conditions (or if permanently enabled via the C9 setting), a red light illuminates during AF to make the viewfinder overlay easier to see.  This light is also illuminated whenever the AF Mode button is pressed.

1:1 Crop Mode

Firmware version 1.30 unlocks a 1:1 crop mode which utilizes four extra line segments not previously used in the viewfinder.  The screenshot above depicts the viewfinder in this mode.


The Pentax K-1 has a state-of-the-art viewfinder and we greatly enjoyed the addition of the LCD overlay.  Arguably, this is a crucial enhancement, as without it, advancements in AF indicators and visible crop frames would not be possible.

While using the K-1 in the field, we occasionally found the viewfinder darker than we would like.  This was primarily an issue with slower variable-aperture zooms such as the D FA 28-105mm.  One might initially place the blame on the camera itself, but the primary reason for this is that full-frame lenses tend to exhibit a larger degree of vignetting than comparable crop lenses.

After comparing the K-1 to the K-3, we can conclude that the K-1 viewfinder itself is only very marginally darker with the same lens.  Ultimately, the K-1 still clearly pulls ahead simply because of the larger viewfinder size.

We strongly recommend fast primes and wide-aperture zooms for users who exclusively shoot through the viewfinder. PentaxForums @PentaxForums News | Reviews | Forum

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