Pentax-DA 50mm F1.8

General Image Quality

50mm lenses are usually regarded as "safe" designs; even the worst 50mm can be expected to perform better than many other lenses. The DA 50mm is a budget lens, but should follow suit and deliver excellent results in most situations. In the following pages, we will look in detail at every measurable parameter, but for the moment we will consider those subjective elements that can make or break an image.

Field of View

50mm was considered the "normal" focal length during the film era. The reason being that the image seen in the viewfinder of a full-frame camera equipped with a 50mm lens closely resembles that of the naked eye. However, the field of view is obviously narrower with a digital APS-C sensor, so we would regard the DA 50mm as a short tele or portrait lens on digital bodies. Some might find the focal length a bit tight for many scenes, especially indoors.

This might be a reason why Pentax (and recently, other manufacturers) have released 40mm lenses to match their APS-C sensors. 40mm (and, for that matter, 35mm) more closely approaches the "normal" field of view of the 50mm on a full frame body.

The DA 50mm still offers a focal length that is considered the de facto value for most people, and either it or the DA 35mm are often the first prime that users purchase after the kit lens.

According to reports from users, the DA 50mm does cover the full-frame image circle with only moderate vignetting and corner softness.  This testing is beyong the scope of our review and we will be focusing on performance exclusively on Pentax APS-C bodies.

Color and Contrast

The following image involves a scene with a high level of contrast, and illustrates how the lens performs in difficult situations.

Colors remain true and accurate, with the tonal response that can be expected from a Pentax lens. As will be obvious from our samples image gallery, the DA 50mm can deliver rich colors that might not reach the level of a Limited, but should please most users.

The shadows retain a good amount of information, and there is no clipping. In our testing, the lens performed evenly at all apertures regarding colour rendition. 

Metering and Exposure

The lens exposes well in most circumstances when tested on a K-3. In particular, with bright light sources in the frame, we found the lens and camera combo to perform admirably.

Lens Corrections and EXIF Data

The DA 50mm 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 DA 50mm is a very compact lens. As such, there is no shadowing with the on-board flash with any of the current Pentax camera bodies.

In the following section we will look at the sharpness measurements.