Shooting Mode

I haven't been able to find exactly what I'm looking for but here's my question. 

I've decided to get a Nikon D300 as my underwater camera. I want to use a Tokina fish eye or Nikon 17-24mm 

I've been reading a lot of articles about how to get the best shots and the ones I've read all say shoot in manual mode.  The articles suggest ISO 100/200, F8 and up and then toggle with your shutter speed and then shoot away. 

My question becomes how do I then adjust the focus of the lens? Am I not thinking about this correctly or is there something I'm missing? 

You'll rely on autofocus to focus the lens.  Your housing needs to accommodate a zoom ring for a zoom lens.  For a prime (macro) lens, you can get focus rings instead.

How you shoot depends a lot on whether you are using strobes or not.   If I'm shooting with strobes, I'm pretty much always in manual mode, playing with aperture for depth of field and strobe power for exposure.  I've gotten used to manual strobe exposure too, after years of TTL.  Not that hard, but be prepared in any case to do a lot of post-processing, so shoot in RAW.

When I shoot ambient, typically with a wide zoom, I'm sometimes in aperture mode, but often I'm in manual mode just like with macro with one exception - I turn on auto-ISO.   Which is the same thing as playing with strobe power in a way.

The reason why I shoot manual is that I really want to set certain minimums and control them.   I don't want shutter speed below 1/160th typically, in order to reduce blurred fish.  Over 1/200th I get banding in the strobes, and that also means less ambient exposure.  1/160th is where I end up in compromising between strobe, ambient and ISO.   Aperture I almost always use for depth of field in macro and corner control in wide.  I never have enough depth of field in macro, and even at F5.6 I pretty much have huge depth of field at 16mm.  But getting those corners sharp.... (I'm shooting a D850 with Nikon 16-35vr behind a huge 230mm dome port.  I had to always crop edges until I added a Sea & Sea Internal Correction lens/filter.   Now I can shoot at F5.6).

And I want to control my ISO very, very much, especially with macro.  I want my ISO set to 64 if I have enough light.   I use the extreme dynamic range to give me options in post-processing.   Those options disappear rapidly as the ISO rises.

So there you have it - fix shutter speed, fix ISO (except ambient if you have to), fix aperture to the scene, and ... you're shooting in manual.  Except maybe TTL flash.

3 hours ago, underwaternoir said:

My question becomes how do I then adjust the focus of the lens? Am I not thinking about this correctly or is there something I'm missing? 

As phxazcraig explains, the camera will do the autofocus for you if you have it set on Autofocus.

I had a D300 for many years with both the Tokina 10-17 and the Nikkor 12-24. Loved it! It's a great system. I found the Tokina more useful a lens than the Nikkor. Horrible topside, the 10-17 is a treasure underwater and I'm still using one now with my D500 based system.

2 hours ago, TimG said:

As phxazcraig explains, the camera will do the autofocus for you if you have it set on Autofocus.

I had a D300 for many years with both the Tokina 10-17 and the Nikkor 12-24. Loved it! It's a great system. I found the Tokina more useful a lens than the Nikkor. Horrible topside, the 10-17 is a treasure underwater and I'm still using one now with my D500 based system.

What housing and strobes did you use? Also thanks for the Tokina tip, what kind of dome did you have also? 

Also I feel like such an idiot, when I read "set your camera to manual" I immediately thought use my manual lenses. I have a couple zeiss manuals that I use from time to time 

3 hours ago, underwaternoir said:

What housing and strobes did you use? Also thanks for the Tokina tip, what kind of dome did you have also? 

I had a Subal housing (and have had for my D800 and D500). They are superb! If you can find one in good condition and in your budget, grab it! (You can thank me later ) 

I had Inon Z240 strobes. Again, I can recommend them highly although the Z240 model is now out of production (the Z330 is the replacement and is getting very good reviews). You can find the Z240 from time-to-time in the Classifieds usually for about $350-$400 a piece. 

On the dome,  I started with an 8" and then bought a 4" as well. Both work perfectly with the Tokina. You'll probably need an extension ring for each dome depending on the housing you end up buying. This fits between the housing and the dome port and ensures the lens is positioned in the right position inside the curvature of the dome.

The 8" is an excellent all-purpose dome and will let you do good over/under shots. The 4" is very good for "CFWA" (close focus, wide-angle) which allows you to get very close to the subject (with the Tokina) but shows the subject against its habitat in wide-angle. The advantage of the small size dome is that it allows you to tuck the strobes in closely which helps light the subject well. An 8" dome is very tricky for this.

By contrast, a 4" dome is hopeless for over/unders!

Hope this helps.

3 hours ago, underwaternoir said:

Also I feel like such an idiot, when I read "set your camera to manual" I immediately thought use my manual lenses. I have a couple zeiss manuals that I use from time to time 

LOL, no worries. We've all been there at one time or another. The beauty of this forum is you can ask any question you like and you'll usually get a very good, helpful reply. There are no dumb questions.