Andaman Sea Blackwater

kelpdiver wrote:

ugh....I have to echo B's remarks - if you didn't know what a blackwater dive is, you have no business lecturing him on what his settings should be.

I do. I've dived hundreds of times at night, capturing moving objects. If something is wrong, it is wrong, it doesn't change the right that many people do wrong.

A key reason why you need all the DoF you can get is that your targets are not static. You're floating in open water and it is floating or swimming in open water, and may respond adversely to the focus light. This works against full frame sensors, and may force manual focus only.

I suspect also that the images are crops., rather than a full frame composition, for the same reasons. So TTL is unlikely to do a lick of good. And for the same reasons, needs all the light possible.

Squid are among the most frustrating targets as they rarely stay still for more than a second or two. The translucent jellies are more difficult to focus on, but they are more likely to be drifters, or can't move very fast.

Objects that move after focusing do not stay in focus in DOF until the moment of shooting.

If the object is moving, f32 won't give you a DOF. The important thing is to shoot as soon as you focus. There is no point in using f20-32 instead of f8-11.

High ISO won't help you freeze the image. 100 iso and 100000 iso freeze images with the same success. High iso only helps to make background images more distinct and you do not have such a purpose in blackwater shooting. TTL always works well at ISO 100.

An image is frozen when the flash light hits the object and therefore the sensor. If the speed of the moving objects is more than the shutter lag, blurry will occur behind the image. The only thing that matters is the shutter speed. There is no reason to do 160 instead of 200. If you can do HSS, you should.