Pentax 50mm Prime Lens Shootout

Design and Handling

Now, let us take a look at the build quality and handling of each lens.

Pentax DA 50mm F1.8

The Pentax DA 50mm F1.8 lens was introduced in 2012. It is designed for digital cameras, and as such not meant be used on film cameras because it does not cover the full-frame image circle. The DA 50mm field of view is like a 75mm on a film camera, because the APC-S sensor is 1.5x times smaller than a 35mm image. The DA 50mm is constructed with a plastic composite shell and mount.

The focus ring is located at the front of the lens and it requires 1/2 of a turn from the minimum focus distance of 18.9 inches to infinity. The focus ring is a little over 1/4 of an inch wide and does turn when you utilize the cameras slotted screw drive. The lens, unlike most DA lenses, does not allow Quick-Shift Focusing. The focus ring, when utilized manually, is a little noisy and not very smooth.

The lens is very light weight, and is quick and responsive when used with the K-5’s autofocus. The filter diameter is 52mm, which is different from the other two 50mm in this review.

Pentax DA 50mm F1.8 at minimum focus                                          

Pentax DA 50mm F1.8 focused at infinity

Pentax FA 50mm F1.4

The Pentax FA 50mm F1.4 lens was introduced in 1991. It can be used on both digital cameras and full frame cameras. When used with an APC-S sensor, the field of view will be like a 75mm on a film camera. The field of view will increase to 47 degrees diagonally or 50mm when used on a full frame camera. The Pentax FA 50mm is constructed with a plastic composite shell and a metal mount. The lens is almost twice as heavy as the DA 50mm F1.8.

The focus ring is located at the front of the lens and it requires a little less than 1/2 of a turn from the minimum focus distance of 18 inches to infinity. The focus ring is 3/16 of an inch wide and covered with soft rubber and does turn when you utilize the cameras slotted screw drive. At the back of the lens is a manual aperture ring. Once the ring has been moved off the “A” setting, it is possible to turn the aperture ring. The lens does not have Quick-Shift Focusing.

Pentax FA 50mm F1.4 at minimum focus

Pentax FA 50mm F1.4 focused at infinity

The lens has a small sealed window in the middle of the lens that displays the distance in feet and meters. Above is a picture of the sealed window. The lens takes 49mm filters. The front of the lens protrudes a little more than ½ inch when focusing at the minimum focus distance as you can see from the pictures above.

Pentax D FA 50mm F2.8 Macro

The Pentax D FA 50mm F2.8 Macro lens was introduced in 2009. It is designed for both digital cameras and full frame cameras. When used with an APS-C sensor, the field of view will be like a 75mm on a film camera. The field of view will increase to 47 degrees diagonally or 50mm when used on a full frame camera. The Pentax D FA 50mm F2.8 Macro is constructed with a plastic composite shell and a metal mount. The lens is the heaviest of the three lenses reviewed, at 9.3 oz.

The focus ring is located at the front of the lens and it requires a more than ¾ of a turn from the minimum focus distance of 7.7 inches (20 cm) to infinity. The focus ring is 3/4 of an inch wide and covered with soft rubber and does not turn when you utilize the cameras slotted screw drive. At the back of the lens is a manual aperture ring. Once the ring has been moved off the “A” setting, it is possible to turn the aperture ring. The lens has Quick-Shift Focusing, which permits you to manually focus the lens at any time.

Pentax D FA 50mm F2.8 Macro at minimum focus

At minimum focus distance the magnification is 1:1 (life size) hence the long extension compared to the other two lenses.

Pentax D FA 50mm F2.8 Macro focused at infinity

The lens has a small sealed window at the middle of the lens that displays the distance in feet and meters and the magnification of the lens. Above is a picture of the sealed window. The lens takes 49mm filters. The front of the lens protrudes a little more than 1 ¾ inch when focusing at the minimum focus distance as you can see from the pictures above. On the side of the lens is a clamp switch that allows you to lock the manual focus position.  Since the lens is designed as a macro you can use the Pentax AF160 ring light kit in conjunction with the lens.

Below is the lens with the lens hood installed.