Depth of Field

D.O.F. or Depth of Field, What is it? Is it the distance from home plate to the center field fence? Is it the height of the wild grass in an unmowed meadow or field? No, it is none of these.

Depth of Field is a term used in photography to describe the focal distance between the nearest object and the farthest object in focus in the focal plane. Here is a simple example of how D.O.F. works. If you are standing on a street corner and you are looking down the street a sign. You notice that most everything is in focus between you and the sign, but the sign itself seem to be a bit out of focus. However, if you squint you notice that it bring more objects into focus including the sign.

This happens because as we squint we close down the iris in our eyes. Just like a camera lens we can close down our aperture and create the same affect, increasing the focal distance. If you have a 50mm lens with the aperture adjustments of f2.8 to f22 the larger the number the smaller the aperture opening and the greater focal distance is created. The smaller the number the short the focal distance and the wider the aperture opening is.

Keep in mind that the aperture does increase or decrease the amount of light allowed through the lens of the camera. So you will have to adjust the shutter speed to compensate, and make a properly exposed image.

If you have a point-n-shoot camera without all these adjustments, don’t fear. It is possible to achieve the same results even when you are using a point-n-shoot style digital camera. On the top or back of the camera is a dial. On that dial are many different settings represented usually with little pictures.

The mountain picture is used for taking scenic pictures. This is the setting you should use for the greater depth of field. When this setting is selected the camera knows you need the greatest focal range and will select the proper aperture and shutter speed.

For a shallower depth of field choose the picture of the flower. This is for close up photography. This setting will allow you to take a sharp picture of a subject and allow the background to be out of focus.

Give this a try, let me know how it works out for you…

Green Sea Turtle

Green Sea Turtle
Originally uploaded by Kirk Howard

This was taken with my new Canon PowerShot G10 camera and Canon WP-DC28 underwater housing. It took a week to get somewhat familar with all the controls and buttons and knobs.

However by the end of my vacation I was able to capture moments like this free diving with an very buoyant housing. I need to get the weights to help make the camera neutrally buoyant.

Aloha...

Aloha, we all made it back from Maui, Hawaii in one piece. I think I speak for all that went (Kathlene, Karla, Krista, Kirk) we are none too pleased to be back on the mainland.

Vacations no matter how long they are, they never seem long enough. It felt like yesterday we were on our way to Hawaii. Unfortunately all good things come to an end and so did our Maui vacation.

If you didn't know and you may not really care I have a travel blog on TravelPod.com. If anyone is interested to read more about our trip you can follow this link to the My TravelPod Blog.

Here is a little video I shot on Saturday our last full day on Maui. I had been snorkeling earlier in the day at Black Rock Point with Kathlene and Krista. During that snorkel session we saw some Green Sea Turtles. The turtles had surfaced for air while we were there.

I decide I would go for one last snorkel session during the evening before dinner. I walked to Black Rock and slipped into the water at 5:30 PM. I was the only person in the water.

I swam over to where I had last seen the turtles earlier in the day. I was pleased to see that one turtle was in his little hidy hole.

Now I would just wait for him to surface for air, which could be a 30 minute wait. Fortunately I only had to wait about five minutes. The turtle surfaced and then proceeded swim along the face of Black Rock...

I will let the video tell the rest of the story. I hope you can enjoy it half as much as I did filming it.

Mahalo

Hawaiian Green Sea Turtle from KiHo on Vimeo.