If your phone and phone mounted filters ain’t doing it a dslr is a great choice! I will try to be as unbiased as possible but I am a canon lover. The perfect setup for what we all want in a coral photography is a full frame sensor with at least 18 megapixels (more the better) paired with a 100mm Macro lens with an orange or yellow gel filter( the 2 colors depends on what light spectrum you run). But that setup does cost money. So for a beginner I’d recommend a the Canon Rebel sl3 ( I have the sl2) the kit Lens is eh but I’d invest in the glass( Lens) any macro Lens will work but best is 85mm prime or 100mm prime (prime means it’s only has 1 focal length so it doesn’t have a zoom) my top 2 recommendations for lens under $600 are the Tonkina 100mm macro f2.8 @$399 and the Sigma 70mm Art macro lens @$469. Both these brands are really good glass that doesn’t break the bank. Now if your curious the best Macro Lens it’s the Canon 100mm f2.8 Macro L series Lens thats at $899. The best canon macro lens!! But it’s expensive
. As far as filters I can’t really recommend one I haven’t tried out anyother ones than my K&F brown filter.
Here’s why I reccomend the sl3 it has a 24 megapixel sensor it is aps-c which btw adds a 1.6x crop on all lens, it records 4K which even tho I know your asking for photography but the video will be sweet, you could always steal some frames from a video.
So even after all that still do your research to see what brand fits you. Nikon isn’t bad, Sony is actually pretty good but the body’s and Lens are kinda pricey. Hope this helps lol. Happy Reefing!