I was doing a test HDR panorama at dusk in a park near my house today, and using the M8 since I haven't got a DB for my Contax 645 yet, and was shocked to find that my longest exposure time was 32 seconds, and I wasn't even really getting the shadows, it wasn't fully dark yet, and this at the M8's base ISO of 160.
The back I am planning to buy is the Sinar eMotion 54 LV, but it has a longest exposure time of 32s, which today would not have been enough. I am now wondering if I have done something wrong, or if there is some way to get around this.
I was shooting three images of each location, in a 360 degree panorama, one at 1s, one at 4s, and I was supposed to shoot one at 32s for the darker areas ( but not the shadows in those areas), but I didn't have a stopwatch nor a cable release, so I settled for 4s at ISO 640, and was hoping that the HDR blend would iron out some of the minor noise this would introduce. This was at f8 with the 28 Cron, at dusk, in a park with a view of the three streets surrounding it, with restaurants and cafés. Annoyingly my battery conked out about 1/2 way through the last pass, so I was never able to complete it, but this was a dry-run anyway, in anticipation of the panorama work I will do soon with the kit I have ordered.
So, given the above information, is there some way I could have worked around the darkness, with a maximum exposure time of 32s? Should I just have accepted the noise resulting from jacking up the ISO to 200 for the last sweep? How do you guys do the long exposures on a camera which doesn't allow setting a speed of slower than 8s (Contax 645)?