The 5 Lens Autofocus Drive Types Explained

Pentax AF technologoy overview and comparison

By beholder3 in Articles and Tips on Aug 19, 2018

Camera lenses today use many different technologies to facilitate autofocus.  Under the hood, there needs to be some way for the camera to move elements inside the lens, which in turn changes what's in focus.  In this article, we'll be taking a look at the different types of focusing implementations currently in use by Pentax.  In addition, you'll learn more about some of the terminology used by Pentax and other manufacturers.

Pentax users currently have access to both manual focus lenses and lenses with one of 5 different autofocus drive technologies. 

These have evolved over many years, and as almost everything in life, each comes with its pros and cons.  For example, fast focusing in single autofocus mode (AF.S) is not the same as fast continuous autofocus (AF.C).  In-lens motors can fail.  Gears in drive mechanisms can shatter.  Powerful motors take up space.  Modern, larger drives allow more torque.  The list goes on!

It is important to stress from the very beginning that many of the designations given to the drive types (e.g. SDM or DC) are generalizations. Different lens models can have different autofocus implementations even if they go by the same name.  Ultimately, this can mean that a drive type that is commonly known to be fast may actually appear slow in a certain lens and much quicker in another.

2018 Pentax K-mount DSLR User Survey

The results are in!

By beholder3 in Photo Industry News on Aug 9, 2018

Between February 26th and March 10th, we conducted a detailed survey via e-mail to gauge the current and future interests of Pentax K-mount DSLR users.  Given the broad scope of the survey, we never would have expected to receive over 1,600 responses!

Thanks to you, we are now ready to share the results of the survey, which was intended for people who user Pentax as their primary camera brand.

Guide: DSLR Lens Resolution Testing at Home

Using freeware programs and charts

By beholder3 in Articles and Tips on Sep 21, 2017

Many enthusiasts spend a lot of money on camera gear and then want to know how good it is. While every experienced photographer can tell the optical qualities of a lens from fitting sample images there are ways beyond subjective quality evaluations. These are about testing lens sharpness and resolution using either an optical bench (which costs more than the average new car, so not really a good fit for "homegrown" testing), or shooting test charts and analyzing the results mathematically.

The article is about the latter: resolution testing at home using freely available test charts and software to analyze it.

DSLR Guide for Shooting Sports II: Horse Racing

How to set up autofocus and other DSLR settings

By beholder3 in Articles and Tips on Sep 11, 2017

Horse Racing

In our second article on how to shoot sports type subjects with Pentax gear we will again try to showcase one way to approach a certain type of subject scenario. The previous article can be found here: Guide to Camera and Autofocus Settings for Shooting Sports.

Again this is intended to get interested users going quicker and to provide an easy reference for you, regardless if you use a Pentax, Canon, or Nikon DSLR. Most of the tips in this article should help you out with shooting sports, perhaps after converting some Pentax-specific terms.

How to Check Your Lens for Decentering

A quick and easy decentering test

By beholder3 in Articles and Tips on Jul 20, 2017

When we invest our money in high-quality camera lenses, we expect them to be able to capture sharp, clear photos.  One of the production quality aspects of lenses is how well they are "centered"; a decentered lens can lead to inconsistent sharpness and should be exchanged or repaired.

This article describes a quick, easy, and reliable way to check for lens decentering all by yourself.

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