A Site for Photographers by Photographers

Home > Equipment > Pentax System Explained

Featured Equipment Deals

Getting Started in Video Read More

Getting Started in Video

Photographer Ted Kawalerski made the transition from still to motion and has never looked back. Ted takes you through the steps to get started in a medium that will open your photography business to...

Latest Equipment Articles

4 Outdoor & Adventure Photo Packs Read More

4 Outdoor & Adventure Photo Packs

Photo packs have come a long way in the past decade, especially those that are targeted toward outdoor and adventure photographers. Alaska-based adventure photographer Dan Bailey takes a closer look...

Latest Learning Articles

Getting Started in Video Read More

Getting Started in Video

Photographer Ted Kawalerski made the transition from still to motion and has never looked back. Ted takes you through the steps to get started in a medium that will open your photography business to...


Pentax Digital SLR Cameras and Lenses

a photo.net guide by Hannah Thiem, August 2007 (updated May 2008)


All Pentax digital SLR bodies are compatible with older Pentax film lenses (FA, F and A mounts) as well as newer lenses (DA and DA* mounts). The Pentax K10D is the cheapest weather-sealed digital SLR body on the market. Pentax offers a different approach to image stabilization than market leaders Canon and Nikon. The Pentax DSLR bodies electronically shake their sensors to compensate for camera shake, rather than adding image stabilization to specific lenses. The Pentax system is not as effective as in-lens image stabilization and it isn't very effective for long telephoto lenses, but it does work with all lenses, including old designs from the film years.

This article covers every current Pentax product and some good third-party components.

If you are new to photography, you might want to read "Building a Digital SLR System". The same principles can be applied to the Pentax DSLR system.

Bodies

All Pentax digital SLR bodies incorporate an APS-C sized sensor. The sensor size is 23.5x15.7mm, smaller than the standard 35mm film frame (36x24mm). The small or "crop" sensor on the Pentax DSLR bodies means that lenses don't function the way that they do on a film camera. Multiply focal lengths by 1.5x to calculate the "35mm equivalent". A 50mm lens that would be "normal" for a film camera, for example, will function as a good portrait lens on a Pentax digital body. This magnification will be welcomed by wildlife photographers and cursed by owners of high-quality high-speed wide-angle lenses (a dramatic 21mm gives a boring 31mm equivalent perspective).

Nomenclature

"DR" is the Pentax-original Dust Removal system, which helps keep the CCD surface dust-free.

"DA" refers to the series of lenses engineered exclusively for digital cameras. All DA-series lenses feature a responsive "Quick-Shift Focus System" that allows photographers to instantly switch the focus mode from auto to manual with a slight twist of the focus ring.

"DA*" refers to the series of lenses designed for exclusive use with Pentax digital SLR cameras. The DA* lenses feature tightly sealed, weather-resistant and dust-resistant construction for use in rain or dusty conditions.

"FA" specifies the autofocus lens series compatible with both film and digital SLR bodies.

"AL" stands for "aspherical lens."

"FA-J" designates a line of cheaper autofocus lenses without an aperture ring, compatible with both film and digital SLR bodies.

"A" designates a line of old manual focus lenses.

"SP" refers to a Super Protect lens coating applied on all Pentax lenses, where the surface is coated with a special fluorine compound to repel dust, water and grease, making it easy to wipe off fingerprints and cosmetics.

"ED" is "extra-low dispersion" glass, a more expensive and higher quality glass that reduces chromatic aberration, in which light of different colors takes different paths through the lens, which would result in a dot of white light being fuzzed up by the time it reaches the film or sensor.

"IF" is internal focus, meaning that the lens does not change physical length as you focus on subjects that are closer or farther away.

"SDM" is "Supersonic Drive Motor", the Pentax equivalent to Canon's in-lens ultrasonic motor. SDM makes autofocus faster and facilitates simultaneous use of manual and autofocus, which Canon calls "full-time manual focus" and what Pentax calls "quick-shift focus system".

Normal Lenses

A normal lens is light in weight and approximates the perspective of the human eye. Normal lenses generally have large maximum apertures, indicated by small f-numbers such as f/1.4 or f/1.8, and thereby gather much more light than zoom lenses. It may be possible to take a photo with a normal lens in light only 1/8th or 1/16th as bright as would be required for the same photo with a consumer-priced zoom lens. Also, the viewfinder will be brighter and therefore easier to use in dim light, due to the fact that the large maximum aperture stays open for viewing and stops down to whatever aperture you have set just before taking the picture.

Wide-to-Telephoto Zoom Lenses

A wide-to-tele zoom is what you get as a standard "kit" lens with a consumer-grade digital SLR body. The range goes from moderately wide through normal to moderately telephoto. They are good when you are too busy to change lenses, e.g., at a wedding reception. A 16mm focal length at the wide end will capture a table of guests; the 45-55mm long end is good for a flattering portrait. The main weakness of these lenses is that the cheaper ones have a very small maximum aperture, e.g., f/4 or f/5.6, and can only be used in bright light, on a tripod, or with a blast of on-camera flash that gives everyone a moon face.

Wide-angle Zoom Lenses

Telephoto Zoom Lenses

  • Pentax DA* 50-135mm f/2.8 ED IF SDM, (compare prices), (effective 75-202.5mm), 685g, the function of a standard full-frame 70-200/2.8 lenses at less than half the weight (Canon's 70-200/2.8 is a shoulder-breaking 1470g); Canon and Nikon should be ashamed of themselves for not making a lens like this for their small sensor bodies.
  • Pentax DA 50-200mm f/4-5.6 ED WR, (compare prices) (review), (effective 75-300mm), 260g, longer reach and much lighter weight at the cost of two f-stops in light-gathering ability; bring a tripod unless you're going to use this in bright sunlight.
  • cheap slow low-quality lenses from Pentax's film years

  • Pentax FA-J 28-80mm f3.5-5.6 AL, (compare prices), (effective 42-120mm on a full-frame camera), this provides an unusual normal-to-telephoto range.
  • Pentax FA-J 75-300mm f/4.5-5.8 AL, (compare prices), (effective 112.5-450mm), potentially useful for wildlife photographers on a budget, as long as the wildlife is standing in very bright sunlight.

Wide-angle Prime Lenses

Wide-angle lenses let you get close to your subject while still showing a lot of background information. A dramatic wide angle for a small sensor Pentax DSLR is 16mm or shorter.

Telephoto Prime Lenses

A telephoto prime lens offers excellent image quality at long focal lengths due to a large maximum aperture and magnification of the subject, and can be handheld in low-light situations. When comparing a telephoto prime to a normal-to-telephoto zoom, although zoom lenses cover wide ranges, they usually have a smaller maximum aperture on the long end. Keep in mind that on a small sensor, the effective focal length of a telephoto prime is multiplied by 1.5.

Note that Pentax does not make any teleconverters for its autofocus lenses.

Macro Lenses

Macro lenses let you photograph physically small objects. The longer the focal length of the macro lens, the more space you can put between the camera and the subject. Extra working distance is helpful in lighting scenes or keeping insects calm. A macro lens that goes down to "1:1" can be used to take a frame-filling photo of something that is roughly 23x16mm in size, the dimensions of the APS-C sized sensor on a Pentax digital body. The macro lenses below can be used for ordinary photographic projects as well, i.e., they will focus out to infinity if desired.

Flashes

Straight ahead on-camera flash blasts the subject with an unflattering light. Pictures will look just as you saw them with your eyes... assuming you are in the habit of walking around with a spotlight on top of your head. The built-in flash of Pentax bodies only points forward and is therefore mostly useful outdoors for filling in harsh shadows. The accessory flashes below can be titled up towards the ceiling or used at a distance from the camera for more natural-looking lighting.

Accessories

For a camera body and one lens, the average professional photographer would not use a case at all. To hold a camera system, it is best to visit a nearby professional camera shop and see how your gear fits in various bags. See the photo.net camera bag article for some ideas.

The tight budget:

The average family:

The serious photographer on a trip:

More

Links to Photo.net Reviews of Discontinued Pentax Cameras and Lenses

Digital Cameras • *istDS

Film Cameras • MZ5

Lenses • 200mm/4 Macro A • 300mm/2.8 A • 100/2.8 FA • 28-200mm/3.8-5.6 FA • 28-80/3.5-4.7 FA • 50/1.7 FA • 24/2 FA • 300/4.5 FA • 85/1.4 FA


Text © 2007 Hannah Thiem. All photos, except as otherwise indicated, © 2007 Josh Root. Most of the photos were taken with the Pentax K10D, (compare prices) (review), Pentax DFA 100mm f/2.8 Macro, (compare prices), Pentax DA 50-200mm f/4-5.6 ED WR, (compare prices) (review), and the Pentax DA 16-45mm f/4.0 ED AL, (compare prices) (review).

Article revised May 2008.