Phase One IQ4 - Automated Frame Averaging

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Chris Dodkin
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Phase One IQ4 - Automated Frame Averaging

This just in from Commercial Photo/PhaseOne:

Take the Photographic Triangle and throw it in the garbage; Automated Frame Averaging officially arrives to the IQ4 this week and it represents a fundamental change in the array of choices photographers have for determining their exposure.

The result is a Photographic Pyramid with an entire new dimension of exposure control.

Originally discussed at the time of launch, Automated Frame Averaging allows for long exposures (e.g. several minutes long) in bright daylight without the use of strong ND filters, reduces (the already very low level of) noise in shadows, and adds interesting aesthetic options to the toolkit of the photographer.

It works on any kind of body or camera that the IQ4 can mount to including the world’s only modern medium format SLR, the Phase One XF, and tech cameras such as the Arca Swiss RMD3Di and Cambo Wide RS series.

Best of all it’s incredibly simple to use and generates a standard raw file (in camera) ready for immediate use.

  • Improved Shadow Flexibility in Challenging Scenes: The Phase One IQ4 150mp full-frame-645 sensor has the most dynamic range of any camera available today, but some scenes are so challenging that even the IQ4’s dynamic range is not enough. Frame Averaging drastically decreases shadow noise, allowing even more aggressive shadow recovery without introducing noise or losing highlight detail.
  • “Total Time” and “Shutter Speed” decoupled: For approximately 193 years of photographic history “shutter speed” and “total time” over which the camera exposed were the same thing. With the IQ4 you can now independently set both attributes; you have another axis along which to manipulate the photographic triangle. Do you want a waterfall with smooth silky water that comes with a multi minute exposure, but find yourself in lighting that calls for 1/8th of a second shutter speed for proper exposure? With the IQ4 Automated Frame Averaging you can select a 1/8th of a second shutter speed for the exposure brightness, but 3 minutes as the Total Time for the blurred rendering of the waterfall.
  • Replace your Strong ND filters: Many photographers carry a very strong ND filter (e.g. ten stops) to do long exposures in bright light. These nearly opaque filters allow the photographer to drag the shutter speed out to seconds or minutes or even hours long even in broad daylight, creating rivers and ocean that are glassy-smooth (since all waves and turbulence average out), surreal scenes of city streets that appear as a ghosted river (since any cars that flow with traffic average out to a sea of “smoke”), sidewalks that appear empty, and clouded skies that blur with an effect straight out of science fiction. The IQ4 can now do this without strong ND filters.
  • Special Effects: Multiple Exposure is a time-honored special effect in still photography. This tool will allow you to generate a single raw file in-camera from multiple exposures.

The Technical Underpinnings: How does it work?

At its heart, this tool works by averaging two or more (often many more) sequential captures together, generating a single raw file. This has the effect of evening out noise in the shadows.

With four samples the noise should be roughly half as much as a single capture (which is already extraordinarily low), with sixteen samples it should be roughly half as much again. In theory this technique can be used by anyone with any camera by capturing more than one image of the same scene and layering them with a low opacity in Photoshop or via specialized software.

However, manual frame averaging requires capturing many gigs worth of raws, processing even more gigs worth of TIFFs, and minutes (or even hours) worth of computer time; just to generate a single output image.

The IQ4 does exposure stacking internally, on the fly, and generates a single raw file ready for immediate use. Moreover, the IQ4 can do it entirely free of temporal gaps and entirely free of vibration.

Free of Gaps and Vibration

The IQ4 uses its best-in-class sensor-based Electronic Shutter system and generous internal ram to capture frames in immediate succession during frame averaging. In fact, at many shutter speeds the IQ4 Frame Averaging allows successive captures with no meaningful temporal gap.

Traditional mechanical shutters (focal plane shutters or leaf shutters) must reset between exposures, so even the cameras with mechanical shutters capable of very high frame rates, cannot have the entire frame exposed all the time, which leads to gaps of time (aka “temporal gaps”) when the scene is not being recorded.

For example, in a scene of a car driving across the desert at night, a temporal gap leads to the headlights being rendered as a series of dots rather than a continuous long blurred line.

With the IQ4 each capture cycle immediately follows the previous, allowing gapless frame averaging.

The ES is also beneficial to frame averaging because it generates zero vibration. With a traditional mechanical shutter (focal plane shutters or leaf shutters) there is a small amount of vibration created each time the camera captures. When averaging several or many captures together that vibration can reduce sharpness and cause visual artifacts. ES creates no vibration, so many captures can be averaged together and retain the same sharpness as a single capture.

Contact CommercialPhoto for RAW file examples of Frame Averaging or for a free demo of the IQ4.

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Your time is limited, so don't waste it arguing about camera features - go out and capture memories - Oh, and size does matter - shoot MF

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