Busy day, and so I am behind, but I have a new crown for the disintegrated molar.
Kudos to PhaseOne. I’ve alluded to multi-frame averaging for dynamic range purposes in the past, this includes the possibility of varying exposures across frames. This is another variant.
It is so obvious that I just have to shake my head and wonder WTF Sony/Canon/Nikon are doing (Pentax has done frame averaging for years)—not going full bore on features like this—not going at all—while at least the Panasonic S1R style Multi-Shot High-Res mode is a killer feature (in itself a form of frame averaging with a resolution bonus). Most all cameras today are like iPhones with very few apps burned into firmware and you'd better like it that way.
It looks like PhaseOne has done it right.
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, in-camera, a standard raw file.
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 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.