Auto Focus

[Scott Lamoreaux]

Can anyone explain or point me to a source that properly explains the different auto-focus options? Do you guys use them or pull focus manually? I've always pulled manually but heard a lot of people use the auto for basic non technical shots. I was playing around and my Canon still 50mm seemed to hunt quite a while which to me seemed unreliable.

There are a few different modes. Any help would be awesome!

Thank you,

Scott

 

[Maik Müller]

Can anyone explain or point me to a source that properly explains the different auto-focus options? Do you guys use them or pull focus manually? I've always pulled manually but heard a lot of people use the auto for basic non technical shots. I was playing around and my Canon still 50mm seemed to hunt quite a while which to me seemed unreliable.

There are a few different modes. Any help would be awesome!

From the DSMC Operation Guid 6.0, page 129, chapter: "Autofocus Modes":

Single: When you press the key mapped to AF: Start, the camera performs single-shot AF. Optimized for rapid focus even under low-contrast conditions. Works with both Center and Spot zones.
Continuous: When you press the key mapped to AF: Start, the camera attempts to keep objects in the target in focus. Works best with good lighting and contrast. Works with both Center and Spot zones.
Touch Track: Dynamically updates a positionable AF point using the touchscreen. Only works with Spot zone. Keep target on subject while moving across frame, as the lens continuously focuses on that target.
Rack: Enables rack focus. Only works with Spot zone. For more information, go to “Rack Focus” on page 131.

You should keep "Enhanced AF" on as long as you don't need the HDMI and SDI for something else. It improves AF-performance and enables better visuals for AF-confirmation. In general, AF on RED is contrast-based (think like older DSLRs in liveview). AF-performance has improved from firmware to firmware, it's much better now. But it is still slow and hunts, it is not comparable with the Phase Detection AF on DSLRs or the Dual-Pixel stuff found in Canon's 70D and some other cameras.

You can't properly track a fast moving subject. It works best with still subjects in good light and contrasty details. It also helps to not shoot wide open and have shorter exposure times/higher shutterspeeds. 1/48th on a 50mm, maybe handheld? That delivers lots of motion-blur and makes searching for contrasty details difficult.

RED's AF is absolutely not useless, you just have to know its limits. You can use it to get a starting point and for shots of still subjects, it's pretty good for that. I most often use it for shooting stills on RED and sometimes have Single AF enabled for motion, but with another button assigned on the Sidehandle (a bit like back-button focus configuration on a DSLR). I don't want me to randomly start/stop recording when triggering AF.

I also love the rack-focus feature, this is to date the coolest way to use the lens-internal AF-motors on a RED.

But in the end, manual focus-pulling is what you will and should do 99% of the time.

 

[Scott Lamoreaux]

THANKS MAIK!