For full WA coverage you want the dome port. Flat port will cut down coverage by about 25% due to water refraction.
The vignetting is caused by the Raynox lens. You may or may not have the problem. The vignette does not show up on my camcorder lcd or when the footage is shown on a HDTV. WA adapters for camcorders can be tricky. The same lens can work well on 1 camcorder but not another. If possible you want to try out the adapter before buying or find footage on the web with the same camcorder adapter combination.
The vignetting is caused by the Raynox lens. You may or may not have the problem. The vignette does not show up on my camcorder lcd or when the footage is shown on a HDTV. WA adapters for camcorders can be tricky. The same lens can work well on 1 camcorder but not another. If possible you want to try out the adapter before buying or find footage on the web with the same camcorder adapter combination.