Raw file download of DualExposure+ feature (IQ4)

[Doug Peterson]

If you’d like to see the pros, cons, improvements, and limitations of capturing in DualExposure+ we have a writeup and free downloadable raws here:
https://www.dtcommercialphoto.com/dual-exposure/

[ben730]

That looks great, why isn't it possible for all Phase backs?
The real processing is made in Capture One.
It should also be possible to take two captures with an older back ...
Regards,
Ben

[Doug Peterson]

That looks great, why isn't it possible for all Phase backs?
The real processing is made in Capture One.
It should also be possible to take two captures with an older back ...
Regards,
Ben

It's not two captures in the traditional sense, though the sensor is read out twice.

The innovation here is that during one (longer) capture, part way through that capture the sensor reads out the exposure-accumulated-thus-far. That means the timespan of the first readout fully encompassed by the other. That is made possible by some advanced handling Phase One has finagled from circuitry on the BSI sensor in the IQ4 150mp and IQ4 150mp Achromatic. It is not possible with older sensors, including the one in the IQ4 100mp.

Of course, with any P1 back, or any camera at all really, you can capture bracketed raw files and do various forms of stacking/HDR. But in such cases, even with high frame-rate cameras, moving subjects will be in different locations between frames.

So the end goal of HDR bracketing and DualExposure+ are similar, but DualExposure+ provides a much faster, simpler, and more robust-to-subject-movement implementation.

As we wrote in our article, it's not a panacea, or a cure-all, and it has limitations, like any tool. That said, it is pretty freaking cool.

[erlingmmoe]

Does this work in a layer with masking? Let's say there is some movement in parts of the image, but you want to lift shadows in the stable part, and mask it in a layer, can shadows be lifted there and only there?

[Doug Peterson]

Does this work in a layer with masking? Let's say there is some movement in parts of the image, but you want to lift shadows in the stable part, and mask it in a layer, can shadows be lifted there and only there?

Think of this as a normal raw file with even more dynamic range in the shadows. So anything you can do on a normal raw file in C1 (including layer-based shadow/tone/push/pull/color adjustments) can be done on a DualExposure+ raw file. The only difference in that regard is that as you lift the shadows the amount of noise will be even less than a normal Phase One raw file would be.

[BernardLanguillier]

Think of this as a normal raw file with even more dynamic range in the shadows. So anything you can do on a normal raw file in C1 (including layer-based shadow/tone/push/pull/color adjustments) can be done on a DualExposure+ raw file. The only difference in that regard is that as you lift the shadows the amount of noise will be even less than a normal Phase One raw file would be.

Doug,

Since the 2 exposures appear to be stored within the raw file, is there any possibility to manually control in C1 Pro which file is used in which part of the image in case movement created some issues not handled correctly by the merging algorithm?

Cheers,
Bernard

[kirkt]

Hi Doug - interesting article.  The article indicates:

DualExposure+ relies on the electronic shutter, so a tripod is still critical, and rapid movements across large parts of the frame can cause rolling shutter effects, but subtle movements like water, leaves, and crowds render just fine (as you’ll see later). When the tool is activated, the first exposure is set by the user, while a second exposure, 3 stops brighter, is automatically captured before the first exposure ends. This results in two raw files, essentially exposed simultaneously.

Can you elaborate on how the "brighter" second exposure is completed before the user-selected base first exposure?  Is the "brighter" exposure started before the base exposure?  Otherwise, I am having a hard time appreciating how the exposure requiring a longer effective shutter speed for a brighter exposure is fully acquired during the, presumably shorter, base exposure time.

thanks!

kirk