A6000, what else do I need to start?

Well I dove with the SEL16mm pancake, back when the NEX 5n was new and you had the choice between the 16, 18-55, 50, 30macro, 55-210 and Zeiss 24mm plus Sigma 19 and 30mm.

For me 16mm felt too wide, but I didn't want to be limited by going full macro (always the chance to see a turtle or manta ray where I went diving ). My 30mm are a compromise I learned to live with and got some decent results for my purposes. Of course there are always better photos, but I currently don't feel like my gear is the problem.

Now kelp diving is something I really want to do when I get the chance.

DigiPainter wrote:

I thought the Sigma 16mm f1.4 would have been a good option to given its wide angle and lots of light via f1.4? I know guys shooting rx100s with no zoom underwater and thats 28mm.

So what is the problem with wide angle?

Several:

1. small subjects (of which there are lots)

2. forced to deal with ambient lighting most of the time

3. corners, especially with flat ports.  (IQ)

4. corners again, except in relation to the size of dome ports you have to carry.

5. less than crystal clear water

Macro tends to have none of those issues, or to a much smaller degree.

Also, an F1.4 wide angle lens would not do you much good underwater as you typically stop down a lot to try to have decent corner and edge quality.  F8 is common starting point for my wide angle, and many stop down a few more f stops.   If exposing for ambient, you can see why ISO climbs rapidly as you descend.