HD Pentax-D FA 24-70mm F2.8 ED SDM WR
General Image Quality
On the following pages we will look in detail at every measurable performance parameter, but for the moment we will consider those subjective elements that can make or break an image.
Field of View
As most as long as zoom lenses have existed, the "walkaround" range has been popular. Its boundaries have extended more or less towards both end, with a vast number of offerings using focal ranges like 35-70mm, 28-80mm, 28-70mm to name a few. On digital, 17-70 is a popular range with many products on the market.
For the K mount, it is only with the advent of the FA line that a high-quality zoom, with a fast aperture, became available over that range. The FA* 28-70mm F2.8 from the mid 90's is still regarded as a remarkable lens today.
When Pentax released the DA line, optimized for APS-C sensors, they naturally released an upgrade to that lens. The DA* 16-50mm F2.8 covers approximately the same fields of view on APS-C, being a bit wider. With the announcement of the Pentax K-1, the company released yet another version of the fast walkaround. The field of view of the 24-70mm closely matches that of the 16-50mm.
The 24-70mm range is extremely versatile, especially when coupled with a fast aperture. Such a lens can be used for landscapes and cityscapes, where it is expected to excel. It can also serve in a studio, covering most needs from group shots to portraits. It can be used in low light, and is well-adapted to candids and street shooting.
On APS-C, the 24-70mm gives an equivalent focal range of 36-105mm on full frame, an interesting range with less wide angle coverage but a longer reach, which can still be useful in many situations.
Color and Contrast
The 24-70mm's color and contrast are consistent with other Pentax lenses. Shadows and dark areas transition smoothly from black to gray, with a good level of details preserved. It works well as a portrait lens, delivering good subject isolation and pleasing contrast, as can be seen on the image below.
With a little bit of post-processing, it can also be very effective as a landscape lens.
Metering and Exposure
We did not experiment any real exposure errors with the lens. Exposure is even at all focal lengths, which is to be expected.
Starbursts
As can be seen on the image below, the 9 curved aperture blades do not help in creating particularly remarkable starbursts. Click on the image to see a partial crop showing that the starbursts are in fact present, but very small and hard to notice.
Lens Corrections and EXIF Data
The HD D FA* 24-70mm is a lens made for digital, and as such it includes all the necessary data for modern camera bodies to apply in-camera lens correction when required. Vignetting, diffraction, aberration, and distortion can be adjusted in-camera.
EXIF data is complete and accurate, and Pentax camera bodies are able to record every relevant parameter into the file. Note that it is up to your software to properly decode this data when an image is viewed on a PC.
On-Board Flash Usage
The K-1 does not have an on-board flash. When testing on a K-S2 (a compact APS-C DSLR), we observed a small shadow at 24mm even without the hood, with the test surface approximately 1.5m from the camera body. The shadow is gone when zooming to approximately 30mm.
User Report
The HD D FA* 24-70mm is a hefty lens. It is actually heavier on its own than all recent entry-level Pentax DSLRs (such as the K-70, K-S2, K-S1 or K-50). It looks more at home on a K-1, and would probably fit well with an older body such as a K20D (which is actually larger than a K-1).
The weight can be off-putting at first since Pentax trained its users to enjoy small, compact lenses. Given the length and diameter, it will be a tight fit in some camera bags. In use, the lens feels well balanced, and its size is not a hindrance. It is easy to handhold and manipulate, though of course two hands will be needed for proper handling.
The lens is a good match for the D FA* 70-200mm F2.8 in terms of size, performance and coverage.
The position of the zoom ring, near the front, is becoming the new standard. It is intuitive and natural in use, and the friction means that resting your hand on the bottom of the ring for support should not cause unwanted movement. However, veteran Pentax users might wish the ring had remained near the body, where the focus ring now rests. There is not a lot of available space on the lens shaft to rest the hand without touching one of the two rings.
In general terms, the lens gives the user a feeling of quality and reliability. Images have a nice punch, good subject isolation and fast AF. This is a lens that begs to be used wide open, where it probably is not at its sharpest, but where subjects seem to pop.
In the next sections we will look at the optical performances of the HD D FA 24-70mm F2.8.