As someone who books freelance shooting/editing talent on a weekly basis and is also a shooter, I would offer a couple of things. Assuming that your skill set sets are developed enough to do what the project requires of you:
1) The whole corporate video industry is in flux due to an influx of shooter/editors, and will be for the forseeable future. Every project is different, and I don't have the same budget on every project. Your ability to continually get work depends entirely on your ability to bring value to the people who book you by being flex when needed and meeting each project's unique needs in any way you can. Start the conversation with the question, "What's the range in your budget for the role of DP?" and take it from there. This isn't the case with every agency/studio, but it's a much more common circumstance these days than it was 4 or 5 years ago, as more and more shooters are entering the mix.
2) "Going rates" are regional and even local. It depends on where you are and the level of talent in your area, divided by how saturated the market is with talent. Make a decision based your evaluation of where you stand in the marketplace. In a region where everybody is booked 24/7, you can charge more for your skill set because it's in high demand.