autofocus technologies

August 27, 2017

I knew nothing about autofocus technologies. This is the reason why I procrastinated for about a year and a half not writing about phase-detect autofocus (PDAF) for AmanzMY. I was notified in January 2016 to get a primer in Bahasa on this. Now I got about a week before starting my Ph.D. at the University of Rochester, I thought I could actually give it a shot.

I did. It took me an immense and immersive amount of reading, sweating, and thinking. The first problem that came to me was how to actually make it easier for the general public to understand. To be honest with you, translating some terminologies to Bahasa was a gruesome experience.

The struggle to find factually correct contents was daunting. It was different than fact-checking biological advancements like I did for the Zika article, to which I could cross-check some papers pretty easily. In this case, most of the facts came from press releases so there would not be tons of details about the juicy details regarding the autofocus technologies. I had to rely on blogs to which I had a little less wiggle room to actually care about the facts. But hey, someone has to write an article about autofocus.

I would like to say thank you to whoever is behind the blog Exclusive Architecture because I happened to rely on their materials about DSLR Technology quite a lot. Thank you man! I also relied on B&H’s material regarding autofocus. The GIFs that they have on that page are great, they eased my understanding. I also relied on Stack Exchange Photography. A search keyword like “how does phase detection autofocus work” brought me there and sometimes the answers were dumbed down into bite-size chunks, which made it easier to digest a somewhat overly complex material. I learned about practical differences between PDAF and CDAF on Stack Exchange and this site also provided a general overview of the Hybrid CMOS AF technology. But, I could’ve never gone deeper without Linus. This Techquickie video gave a short 3-minutes video on what I should know beforehand. From there, I crawled the web for more specific information. The Creative Photographer also got an explainer about the differences between PDAF and CDAF.

The coolest thing (probably) is that I found a schematic diagram of the first camera with autofocus technology, the Correfot. Produced by Leitz (now Leica), Correfot sported a PDAF-like mechanism for detecting the sharpest focus of the object, then assisted with an infrared lamp. The downside? Correfot drew too much power and photographers didn’t like that. That was probably why photographers back then ditched autofocus technology, and Leitz was right when they said their consumers preferred manual focusing.

correfot schematic The schematic diagram of the Correfot AF. Source

In the end, I managed to get everything written down. The article for AmanzMY in Bahasa was at 4 pages long (9 pt font, single-spaced). That took me about 3 days (with breaks in between, of course) to write and to draw some diagrams. This is the first time an article for AmanzMY has so many charts that I made in Inkscape. Learning how to draw simple objects in Inkscape was the right decision I made couple months ago.