I need to do a time lapse in a pitch black room. I'm down-shooting onto a reflective black surface, which is a problem because my built-in, external flash creates a massive glare across my shots. I know that I can increase my ISO and widen the aperture to get better shots, but that doesn't really cut it. I tried a diffuser that goes over my flash, but it left a glare as well.
How do I modify my setup to eliminate the glare and get better shots? I'm currently using the built-flash on my Pentax K3. Because I'm down-shooting, I can't just angle the built in flash away from the surface I'm shooting. If it's necessary to know, shots will be taken at 30 min. intervals. I will not be there every 30 min. to adjust anything, so whatever setup I have must be automated. Also, I'm using an 18-55mm WR Pentax lens.