Brent Ramsey
Brent Ramsey

Brent Ramsey has spent over thirty years in the cinematography field where he has worked on television programs, films and commercials. He is currently a Canon Technical Advisor for our motion picture equipment.

Cinema EOS C100 Feature Upgrade to Offer Optional Dual Pixel CMOS AF

November 05, 2013

A new optional feature upgrade will be available for the Cinema EOS C100 in February, 2014. The upgrade activates Dual Pixel CMOS AF technology, which significantly improves the EOS C100’s focus search and acquisition performance, and which was recently introduced in the EOS 70D DSLR in September of 2013. Dual Pixel CMOS AF delivers more natural focus action for video, with less hunting, by utilizing a combination of phase detection and contrast based autofocus technologies. An added benefit of the new optional feature upgrade, when paired with Canon’s latest STM equipped EF lenses, is virtually silent lens drive, eliminating audio interference while recording with the camera’s on-board microphone.

A new assignable button option, called “Focus Lock,” will be added with this upgrade. Programming it to an external button will allow the operator to interrupt continuous auto focus, acquire a quick focus mark in the center of the frame and lock it in. By pushing the Focus Lock button again, the focus mark will be released and a new Focus Lock point can be acquired with a smooth focus adjustment. Acquiring focus marks in this fashion should greatly enhance the quality of “live,” focus transitions – excellent for live venues – like concerts, events or documentary work where a quick, natural focus transition is desired.

Additionally, One-Shot AF will see huge improvements with this upgrade. Focus can be achieved about twice as fast than without Dual Pixel CMOS AF. Quick focus checks made with One-Shot AF can be counted on to look natural – without excessive adjustments and lens blurring as it searches for the correct direction to roll focus.

Also, this feature will work with every Canon EF lens that is capable of autofocus. Beginning in February 2014 and for a fee of $500, an EOS C100 can be modified to activate Dual Pixel CMOS AF. There are currently no plans to ship new EOS C100’s with this feature built-in. Adding this feature upgrade will require that cameras be shipped to an authorized service center to have the work performed.

How does Dual Pixel CMOS AF work?

The individual pixels on the CMOS sensor in the EOS C100 are capable of both capturing light and performing phase-difference autofocus. Each pixel has two separate photodiodes to receive light. Image plane-phase detection requires signals from two locations.

Each signal is detected during AF and is used as a phase-difference detection AF sensor. During imaging, they are combined as one pixel when outputting the image.

What are the advantages of adding Dual Pixel CMOS AF to the EOS C100?
  • Continuous AF will be available in the EOS C100 with all EF lenses – except for manual lenses, of course. An AF LOCK function will allow users to change the framing while holding the desired focus point. Continuous AF will only be available in the center of the frame.
  • AF is tuned for shooting video. This new feature places a high priority on image quality and natural, smooth focus movement, thus resulting in stable AF movement – essential for avoiding undesired blurring.
  • Improved One-Shot AF (supported by Canon STM lenses). Achieving sharp focus with the One-Shot AF feature will be about twice as fast with this upgrade, and the focus will be natural without overshooting the focus point.
How will the EOS C100’s continuous AF work?

The continuous AF portion of the shot will be located in the center of the frame and will represent 20% of the overall frame vertically, and 25% horizontally.

A new AF LOCK function will allow the operator to set the focus point and lock it, making it possible to change the framing while maintaining the same focus position.

How does this change the functionality of the EOS C100?

Beginning with Firmware, the EOS C100’s camera setup menu has had an “AF Mode” selection available. This offers the options of “One-Shot” or “Continuous” autofocus.

A new AF LOCK function will now be an option for the EOS C100’s assignable buttons. While filming, users can push the assigned AF LOCK button to stop the Continuous AF from changing, and then push the button again to re-enable the Continuous AF feature’s functionality.

How does the EOS C100 avoid blurring while focusing?

By using the signal from Contrast AF as supplementary to the Dual Pixel CMOS AF, users will avoid major blurring that may be caused by the Dual Pixel CMOS Auto Focus’ inability to detect the direction the focus must move to achieve proper focus.

Without the addition of Contrast AF to Dual Pixel CMOS AF, the focus could move in the wrong direction, only to hit the end of its range and then change directions to find the correct focus point. Contrast AF can detect the correct direction, eliminating a random search for focus.

How has One-Shot AF been improved in the EOS C100?

By changing the EOS C100’s One-Shot AF feature from only using Contrast AF to using One-Shot AF by Dual Pixel CMOS AF, the EOS C100’s focusing will be twice as fast than it is currently. Focus will be more natural and won’t overshoot or blur while the camera performs an autofocus adjustment.

Who will benefit from these upgrades?

The EOS C100 has quickly become established as the ultimate single-operator, digital cinema camera. With these service upgrade improvements, operators should see a vast improvement in the ease of obtaining fast and reliable focus marks, while confidently making smooth, natural focus transitions within the scene.

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