Questions - Good to know
"Are diopters a must with dome ports?"
When taking a picture through a dome glass it works like a lens. This lens creates a virtual image on which you focus. The smaller the dome glass radius the closer you need to focus. SEACAM has constructed its dome glass such that diopters only become necessary when lenses have a too large short focus limit. For this and also in order to retain the actual short focus even under water, we recommend the use of a premium diopter. In general this should be avoided since additional elements always deteriorate the image quality.