Saturday, July 28, 2012

Saturday Evening Creature Feature and some Tips

Tonight’s Saturday Evening Creature Feature is a Slaty Skimmer that I happened upon in Dogtown. He’s on a Staghorn Sumac branch. I would like to share some techniques that I use and some of the though processes I go through when I’m in the field. 

Like many photographers, I shoot in Aperture Priority mode. First, let me define aperture for you. In optics, an aperture is a hole or an opening through which light travels. (There, that wasn’t so bad.) If you are not sure about this, go look in the mirror, see the black circle in your iris? That’s your eye’s aperture.

The aperture does a couple of things for you. It regulates that amount of light that hits your detector. The second thing it does is it helps determine how deep the focus region is.

To get you oriented to this lesson, look at this shot here. I focused on the back of the dragon’s head. For a theoretically perfect lens, everything that the camera sees that is at the same distance as the dragon’s head will be in focus. You can see stuff closer to the camera become fuzzy. The dragonfly’s head and forewings are sharp. As we go further up the stem, things get fuzzy. That’s depth of field, some of my buddies out there call it DOF.
   ©2012 Steve Borichevsky

Now depth of field is a very important artistic tool. It’s so important, that camera manufacturers give us a semi-automatic method of dictating whether we get a shallow DOF or a deep one. It’s called Aperture Priority. This is a program mode that lets us set the desired aperture and the camera will figure out the correct shutter speed depending on the ISO setting. DOF is one of the most important considerations when I compose a picture. I may want it shallow or I may want it deep.

Skip this if you’re mathematically squeamish
Here is another bit of trivia. The f-number of a lens is the ratio of the lens's focal length (in my case, 300mm) to the diameter if the aperture. It is a dimensionless number that is a quantitative measure of lens “speed”. Just to take some of the mystery out of that. So for my lens, 300mm f/4, my maximum opening

D = 300mm / 4 = 75mm.

At f/8,

D = 300mm / 8 = 37.5 mm.

Note that the diameter gets smaller as we sent from f/4 to f/8. This cuts the amount of light, but increases the depth of field. What is going on in the lens is with the smaller opening, you are restricting light from the outer areas of the lens from hitting the sensor. This “sharpens” the photo. Thus the perfect lens would have a miniscule pin hole for an aperture. But, you’d have to wait a long time for your exposure and your subject going to fly away and you may get a distracting background!

Alright, I’m done.
I just wanted to give you some information so you could get some deeper understandings about what I’m going to show you.

I came across this Slaty Skimmer on a Sumac branch. Pretty cool. In these shots, I’ve done a minimal amount of fussing with the photos. I’ve made not attempt at white balance adjustment. These are all full frame. These were all shot with a tripod and a remote shutter release to reduce camera shake. (This is a fricken heavy lens and I going for some relatively long exposures here.) I had my camera set on ISO 320 for all shots.

First up, when I came upon the bug, I knew I had enough time to compose a shot.  Here’s the boring stuff: 1/250 sec at f/7.1. The sun was behind the clouds.

©2012 Steve Borichevsky

There was a slight breeze, so I waited for the sun to come out. Note that the color temperature is a little warmer? 1/640 sec at f/7.1.

©2012 Steve Borichevsky

See that distracting brown stick in the bottom of the frame? I going to sneak up on the bug and get it out of the frame. Now I’m still focusing on the back of the head. Note that as I move up closer, my DOF gets shallower. You can see it in the sharpness in the back muscles where the wings attach. I’m still shooting with lots of light, 1/640 sec at f/7.1

©2012 Steve Borichevsky

Now it’s hard to tell, but what I’ve done is extended my tripod up so that more of the dragon is at the same distance from the lens. I want looks straight on the bug my line of sight to be perpendicular to the wings and abdomen. This will put a lot more in focus. I’ve got a little more sunlight from the clouds parting. 1/800 sec at f/7.1.

©2012 Steve Borichevsky

Now I’ve got plenty of light, plenty of shutter speed to trade in for a tighter aperture. This is going to be a documentary shot more than an artistic shot. Let’s see how much we can push this. I dialed in f/14. So the boring stuff, 1/160 sec at f/14. Notice that the tail is getting sharper?

©2012 Steve Borichevsky

Now I’m losing some sun behind the clouds. I’ve lost some shutter speed, but I’ve still got a good result. Here is a killer tip for shooting dragons: Note that in the shot below, the shadow of the wings is gone?  Compare it to the one above. Which do you like? 1/80 sec at f/14.

©2012 Steve Borichevsky

The sun is coming back out, 1/100 sec at f14. See the wing shadows?

©2012 Steve Borichevsky

Okay, let’s push this scene. Let’s cut the aperture again. With lots of sun we get 1/80th sec at f/22. Now I have to be careful to wait for the breeze to die down or I get a fuzzy shot.

©2012 Steve Borichevsky

My minimum aperture on this lens is f/32. With lots of light the result is 1/30 sec at f/32.

©2012 Steve Borichevsky

Okay, if I haven’t got a good shot by now, I’m not going to. Let’s just open the lens all the way and get a comparison shot. 1/2000 sec at f/4.0.

©2012 Steve Borichevsky

Well, that was one dose of photography lesson. You have to decide what you like and what you don’t like for yourself. On this blog, I have a mixture of art and documentary photography. I take photos for different reasons. And I hope you do too.

Depth of field is an important tool. Items in focus and out of focus create interest in an image. I hope that this is helpful to many of you.

For those of you that dig the art scene, yet yearn to take more art inspired dragon shots, check out my high key, low key dragon post.

Visit Camera Critters for more photos from the animal kingdom.


chubskulit said...

Beautiful series of images! Hopping by from camera critters.

Some Cardinal shots, come and see.

Anonymous said...

Muy buena explicación, sí señor...Y buenísimo macro...Se puede ver inclusive la sombra que producen las alas...Son muy buenas capturas...Muchísimas gracias...

Un saludo


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