“I’ve heard that 720p can be sharper than 1080i. Is this true?”
In general you could say that 720p produces sharper still frames while 1080ihas more overall detail with smoother motion, but a lot depends on the specific camera you’re using and how you’re processing and playing the footage. Among inexpensive HD cameras the ones with the sharpest images are the Sony EX1, then the Canon HDV cameras, followed by the JVC andSony HDV modelsand finally the Panasonic HVX200. But image sharpness isn’t everything either, and a lot of people like the Panasonic camera because of the overall “look” it produces.
“What is HDV like to edit? Can you edit it in realtime using Adobe Premiere or Final Cut? Also, how is the render time? “
Depending on who you ask HDV editing is manageable on a modern dual-core or multi-processor computer, but it helps a lot to convert it first to an “intermediate” editing codec like Cineform Aspect HD, Edius HQ or Apple ProRes. This increases the file sizes by about 3X from 12 GB/hour to ~40 GB/hour, and takes a lot of load off the processors to smooth out the editing. Rendering your final HD output can be painfully time-consuming depending on the software you’re using and your choice of output formats. I just made my first Blu-ray disc this week and it took a full day to render and transcode the video and author and burn the first disc, but it can be evenworse than that if you’re rendering to formats like WMV-HD or H.264. All things considered HD production is more time-consuming than SD production, so you need to be smart about how to handle that.
