All photographs © Rick Sammon

This is the third in a series of posts I am writing aboard the Northern Song, the boat the Light Photographic Institute is using for its first Alaska photo workshop of 2011. I'm co-leading the workshop with fellow Canon shooter Hal "Bull" Schmitt, the lead instructor and director of Light - which also produces the California Photo Fest – the must-attend photo event of the year.

Each day, we chased the light, as photographers do every day - and night.

(I hope to see you on one of my workshops - perhaps in Alaska in 2012. Shoot me an email to get on my workshop list.)

Because there is no internet on the boat, I'll actually be posting when I get back on land - so each Alaska post you read was actually written about a week ago.

I'll be including some of these photographs (with composition tips) in my next Kelby Training class: Composition - the Strongest Way of Seeing, which is scheduled for release later this year. For info on all my Kelby Training classes, click here.

Today's tip:

Never underestimate the importance of cropping.

Yes, there is something to be said for negative space, but when you want to emphasize the subject, follow this tip: The name of the game is to fill the frame.

I photographed these Dall's porpoises (the cheetah of the ocean – the fastest marine mammal in the world) while leaning over the bow of the boat. I used a polarizing filter to reduce the glare on the water.

These animals are graceful and beautiful. If you need a reason as to why we should protect these animals and the marine environment, click here and scroll down.

Dall's porpoise (Phocoenoides dalli) is a species of porpoise found on the North Pacific. It came to worldwide attention in the 1970s when it was disclosed for the first time to the public that salmon fishing trawls were killing thousands of Dall's porpoise and other cetaceans each year by accidentally capturing them in their nets. The Dall's porpoise is the only member of the Phocoenoides genus. It was named after American naturalist W. H. Dall.