@brapodam
I understand fully what you are saying.
I'm suggesting that with ETTR we have another workflow.
Taking an ETTR reading is seconds.
To be clear, my ideal workflow would be as follows (based on having a fixed ND 'stack':
1. Compose & focus, of course;
2. Put on the filter(s) you have - for most of us having one or two is a luxury, ie we don't normally use the ND as a 'variable' in LE shooting (no pun intended wrt variable NDs);
3. Set ISO 100 and a mid aperture and get ML to estimate the LE shutter speed;
4. Adjust aperture and ISO to get a shuuter speed nearer to your artist desire, assuming you weren't lucky first time.
As I say, if ETTR could be enhanced to give us a shutter speed, for a given ISO and aperture, I believe it will greatly help with LE, as you wony need any apps!
Hmm, perhaps a ND calculator integrated with ETTR? Workflow will be as follows:
1. Go into live view, compose, focus and
press set to activate ETTR
2. Go into ML menu, set ND filter stops and target shutter speed (maybe even have an exposure offset function to compensate for changing light or the ND filter blocking off more light than specified)
2a. The ML menu shows you the ISO and aperture settings required for the target shutter speed (this is just a calculator based on the current exposure settings, no metering required)
3. Go back to live view,
double press half shutter to set exposure settings, put on ND filter
As I have mentioned before, I usually want a specific shutter speed, so I want to lock that first before I care about aperture or ISO. I also try to use the lowest ISO, so unless I still don't have enough light when I have my lens wide open, I won't raise the ISO.