Pentax-DA 50mm F1.8

Construction and Handling

If you're not in a position to try before you buy, you will probably enjoy this little virtual tour of the DA 50mm F1.8, where we analyze it from all angles. Let's do this!

Front Element

The front of the lens is completely unadorned, showing nothing except the front glass and a ring of plastic. This is somewhat atypical, but in line with the look of the DA 35mm F2.4.

The front element is covered by the Super Protect (SP) coating, which allows easier cleaning and helps to repel dirt and oil. This is no mere gimmick; the SP coating really is an improvement over regular coatings.

The lens uses the common 52mm filter thread size. Many Pentax primes instead use the smaller 49mm size instead, meaning that filters will not be automatically usable. However, many compact zooms (such as the 18-55mm) and a few primes do use 52mm filters.

Lens body and external focus

The body of the lens is made entirely of plastic. While some Pentax lenses tend to show the same finish found on camera bodies, the DA 50mm is smooth, without texture.

The only markings of interest are found on the barrel of the lens, grouped together in the front. In keeping with the style of recent DA lenses, the name Pentax and the focal length are marked in large letters near the lens mount, separated by an alignment line. Textured ridges surround most of the barrel to facilitate mounting and removal of the lens.

The recognizable Pentax green ring sits just above. Until 2015, a green ring meant that a lens used SMC coatings (as opposed to the newer HD coatings, indicated by a red ring). The most recent lenses, starting with the 18-50mm kit lens, returned to the green ring even though they use HD coatings.

Higher on the barrel, the complete name of the lens is written (repeating the focal length information). There are no engravings on the body, markings are all printed. After all, this is a budget lens.

The last part of the lens is the focus ring. Repeating the pattern of the ridges near the mount, this ring encircles the whole barrel. There are no distance markings of any kind. This will not be a problem in most situations, though a distance scale can be a huge help for manual focusing. In addition to guessing the approximate distance before fine-tuning, a distance scale indicates the orientations of both infinity and close focus.

Changing the focus distance does not extend the total length of the lens. The lens still isn’t a true “internal focus” lens, because the lens elements themselves move inside the barrel, as can be seen in the animated image below.

The focus ring comes to hard stops at both ends of the range.

The side of the lens shows the ubiquitous “SMC DA” plate, and the back sports the serial number filter diameter. The other side is empty.

Aperture

The DA 50mm uses 7 rounded aperture blades.  The rounding is likely to improve out-of-focus rendering (bokeh).

Lens Mount

The lens mount is plastic, which is to be expected on such a budget product. While the use of plastic instead of metal can be worrisome for some users, we must stress that the very light weight of the lens means that the level of stress on the lens mount is negligible. Moreover, plastic lens mounts have been used on lenses for more than 20 years, and to our knowledge there has been no report of a plastic lens mount breaking due to the material itself.

Lens Hood

No lens hood is supplied with the DA 50mm. A hood (RH-RA52) can be purchased as an accessory, however note that this model is a rubber hood screwing on the filter thread. Many generic third-party replacements are also available from various online stores.

Compared to Other Lenses

Here is the DA 50mm dwarfed by the HD 16-85mm, a walkaround zoom lens.  Even compared to the 18-55mm kit lens zooms, the DA 50mm can be seen as tiny.  It is also smaller and considerably lighter than the film-era FA 50mm F1.4.

The following image shows the DA 50mm sitting between two other Pentax pancake primes, the DA 40mm Limited and the DA 21mm Limited. while larger than both pancake lenses, the DA 50mm is still in the same size range, and lighter.  This is a nice bonus for those who wish to travel light.

Verdict

After a while using the DA 50mm, we can't help but like this cute little lens. When considering that this lens regularly sells for about $100, it's hard to find anything to complain about. The lens is made well, feels light yet solid, and at no point did we feel we were using an inferior product. There is no wobbling or loose parts.

There are a few things missing, of course. In particular, the lack of a focus distance is an unfortunate, if unsurprising, omission. The lack of a lens hood or a metal mount is also to be expected.

For the asked price, we feel that the build quality of the DA 50mm delivers above our expectations.