I'd do a demo with a Phase One dealer and have them show you the following options for exposure evaluation with an XF IQ3 kit:
- Handheld meter
- In-Camera Meter
- Highlight Warning
- Clipping Warning (not the same as highlight warning)
- Zone System Heatmap
- Exposure calculator (very useful for rapidly finding the right exposure when the shutter speed will be a minute or longer)
- Histogram after capture on camera body LCD (good for when you're above the camera)
- Histogram after capture on digital back LCD (notably, does not obscure or interrupt the view of the image)
- Histogram after capture on iOS device (good for a digital tech, or when the camera is mounted out of reach)
- Histogram after capture in Capture One (good for a digital tech, or when the camera is mounted out of reach)
- Bracket and figure it out later (The
XF HDR mode tags associated files for easy sorting in Capture One)
The clipping warning, zone system heatmap, and exposure calculator are (as far as I know) unique to the IQ2/IQ3 platform. Since I
shoot weddings more often than landscape it is the clipping warning I personally use most often, followed by the zone system heatmap, followed by the grip histogram. When shooting
nudes I tend to use Capture One more than anything on the camera.
Alternatively you can Stop worrying and Learn to Love the Dynamic Range that the 100mp Sensor plus Capture One Raw Processing Provides. When at low ISO in IIQ-L 16 bit mode, even if you're
several stops under exposed, the real-world impact on shadows is extremely minor, even for those who are very picky about image quality. It's still always "best" to get it right in-camera (both for quality and workflow reasons) but when you don't, for whatever reason, the flexibility/pliability of the file from the IQ3 100mp is unmatched.
During the review of the images you can also rate the image using the digital back interface (or iOS device) such that when you import the images back at home you'll see which images you've already rated as poor exposures; that's a great way to use some downtime. You could also delete them from the digital back interface, but I find it best to wait until after the images are imported to delete anything. Storage is cheap; trips into the field are costly (both in time and $).
If you're in the US we'd be glad to be that dealer that shows you the above features in practice and helps you arrange a test drive for you to try them in the field. We live and breath Phase One.