As with any art form there are countless tips and tricks that novice photographers accrue to squeeze a bit more quality out of their shots. Luckily, especially thanks to the Internet, there is absolutely no shortage of such tricks that just about anyone can utilize (many of which we talk about right here on TogTech). But, have you ever stopped to wonder just how effective some of these tricks actually are, if at all?
One such trick that’s been making the rounds pretty much ever since autofocus was introduced is the theory of double focusing. If you’re not familiar with this process, it’s the notion that autofocusing on the same spot twice in a row will make for optimal focus. In other words, push the shutter button down half way, wait for the autofocus beep and then repeat the process over again. This is said to essentially fine tune the autofocus and make for more accurate results.
After having been taught this as a novice photographer, which can probably be said for many, Roger Cicala from LensRentals decided to put this theory to the test:
[If communication between a camera and a lens is one-way], AF may be more accurate if you ‘double focus’, meaning you push the shutter button halfway down until the AF beeps, then release and push it halfway down again. The idea is that you’re providing the camera a ‘recheck’ of the AF point and a chance to fine tune focus. I was taught to do this when I started photography but I have no idea if it really helps. So I thought we’d look at that [...]
If the two click AF method works better than one click AF, that might give us some indication that the system is open and without feedback. Maybe. If it isn’t I’m not sure it means there is a feedback loop. Maybe AF is as accurate as it gets no matter how many times you pre-focus.
What was the conclusion you ask? Well, after performing many different tests, Cicala and LensRental came to the conclusion that double focusing does, in fact, nothing at all when it comes to better focusing. Thus, performing a single autofocus operation will ultimately yield the best results and pressing it a second time will yield, you guessed it, the same exact results. For science![LensRentals via Gizmodo]