Saturday, 19 of May of 2012

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Auto-Focus Options – Which is Best?

Today’s DSLRs offer many auto-focus options and people often ask me which is best. Of course that depends on the situation and personal preference. I have settled in on one or two basic combinations of auto-focus settings that work for me 99% of the time. Before I get into the specifics, let me disclose that I am a Canon shooter and the descriptions that follow are based on Canon’s feature set and terminology. I think it is safe to assume that all major DSLR brands have similar options but their terminology may vary a bit.

First, for me it all starts with switching the auto-focus from the shutter button to the AF button on the back of the camera. Whether shooting wildlife or landscapes, I have fewer focus errors when using “Back-Button AF”. I takes a bit of practice to reprogram your brain to focus with the AF button rather than the shutter button. But the nice thing about using Back-Button AF is you can set your focus point, recompose the scene if necessary, and fire the shutter without the risk of inadvertantly changing your focus. I know you can depress the front shutter button half way and re-position without changing your focus, but if you take your finger off the shutter button you will likely change your focus when you finally trip the shutter.

Back-button AF is turned on by setting the appropriate Custom Function for your camera. Remember, Custom Functions are locked-out if you’re in the full-auto or a picture-icon setting like the Portrait mode or Landscape mode. The particular Custom Function number varies with the particular model. Here are the C.Fn menu selection for my current cameras:

  • EOS 7D: C.Fn IV-1 (Custom Controls — Shutter, AF-ON, AEL buttons)
  • EOS 5D Mark II: C.Fn IV-1 (option 2 or 3)

Ok, with that messy business out of the way, we can move on. For nearly every photo shoot, there are two basic auto-focus considerations. First is the auto-focus MODE and the second is the auto-focus AREA. Canon DSLRs have three focus MODES; One Shot, AI Focus, and AI Servo. Let’s keep this simple by eliminating AI Focus from our discussion because all it does is automatically switch between the other two. AI Focus switches from One Shot to AI Servo if a stationary object begins to move. I have never found AI Focus to be useful and simply don’t use it. I suppose some of you will think I’m crazy but I have just never found a reason to use AI Focus – so let’s throw it out of the discussion and focus (no pun intended) only on One Shot and AI Servo modes.

At the risk of over simplification, One Shot is good for landscapes and AI Servo is good for moving objects such as wildlife and kids. AI Servo allows you to lock onto a moving subject and keep it in focus while you track it along its path. In theory all you have to do, if your focus mode is set to AI Servo, is concentrate on keeping the subject in the frame while the camera keeps the subject in focus.

One Shot mode is for still objects and landscapes. If you never shoot moving subjects, One Shot is probably the mode for you. But there is no disadvantage as far as I know to shooting landscapes in AI Servo mode so most of the time, my focus mode is set to AI Servo.

After deciding between One Shot and AI Servo, the other focus consideration is which focus AREA to use. Canon has three default AREA selection modes with two additional added with Custom Functions. The default modes are Single-Point AF (manual selection), Zone AF (manual selection), and Auto Select 19-AF Point. The two custom modes are Spot AF (manual selection) and AF Point Expansion (manual selection). On the 7D, these additional two modes can be turned on with the Custom menu C.Fn III -6 Select AF area selection mode.

I don’t like Auto-Select AF or Zone AF because I want total control of the focus point – I don’t want the camera making those decisions for me. Single Point AF and Spot AF are very similar however, Spot (according the the Canon manual) is more precise. For landscapes I use Spot AF. I choose the subject for critical focus, press the AF Back button and then recompose the scene if necessary. If it is a “big” landscape, I will pick a focus point about two-thirds into the scene and then recompose.

For wildlife, especially birds in flight, I use AF Point Expansion. AF Point Expansion is a lot like Spot AF, except that in Expansion, the adjacent focus points are used to help lock in on the moving subject. Intuitively, the Auto-Select 19-AF point mode would seem to be the best for fast moving wildlife. However Auto-Select 19-AF is problematic with shallow depth of field produced by long lenses. I found the auto selection point chosen by the camera would usually be the closet object to the camera, like a wing tip, rather than the eye or head. For wildlife, the eye MUST be tack sharp, anything less gets deleted. Since the Auto-Select 19-AF point doesn’t always make the best decisions, I rarely use it.

Therefore to sum up, here are the auto-focus methodologies that work best for me:

  • Landscapes: One-Shot AF mode with Spot AF
  • Wildlife: AI Servo AF mode with AF Point Expansion
Like just about everything in photography, with auto-focus there are no absolutes. Everything is a compromise and there is always more than one way to skin a cat. The most important thing is to read your manual and understand the vast number of options manufacturers provide on today’s cameras. And then practice, practice, practice to find out which options and techniques work best for your and your style of shooting.
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Questions and comments, of course, are welcome.

 

 


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Happy Arbor Day

Here’s a nice collection of trees in honor of Arbor day. Please stop by the  NWF photography contest web site to vote for your favorites.


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Sandhill Cranes – Canon 5D MK II Video

This video of sand hill cranes on the Platte River in Nebraska was shot with the Canon 5D Mark II and the Canon EF70-200 f/2.8. If you’ve got a fast internet connection check it out full-screen in 1080p.


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Sandhill Cranes 2012 – Rowe Sanctuary

Sandhill Cranes

Canon 7D with Canon EF600mm f/4.0

This year marks my sixth consecutive year photographing the spring migration of Sandhill Cranes in Nebraska. I just wrapped up three days shooting from Rowe Sanctuary, various points along the Platte River, and nearby cornfields. Rowe Sanctuary is owned and operation by the National Audubon Society.

Each year has certain similarities but also unique aspects. This year was unique for two reasons. First, it was really hot. I’ve never shot cranes in 88 degree heat!  Normally after an afternoon shoot your fingers and toes are numb from the cold. This year we needed a cold drink and a shower. Second, this year for the first time in my experience, the Rowe Sanctuary blind was not photographer-friendly. Never before have I felt unwelcome in the public viewing blinds. This year however, it was clear that serious photographers were to be tolerated but severely restricted. Granted, Rowe has specialized photography blinds, but for many photographers, the public viewing blind is a better alternative.

It’s not clear if the new photography restrictions were a result of new policy or just one over-enthusiastic volunteer. Rowe is clear about their mission – conservation of Sandhill Cranes and their habitat – not the care and nurturing of a photographer’s habit. However, in years past, I felt sanctuary staff  was welcoming and accommodating.  This year, in addition to previous rules, high-speed continuous shutter bursts were prohibited and LCDs were required to be turned off or covered. I’m no crane expert, but I find it hard to believe the cranes’ well being requires such restrictive measures. More importantly, disparaging comments from the Rowe Sanctuary staff  made the experience uncomfortable. I am fully aware the Sanctuary is privately owned by the National Audubon Society and as such they get to set the rules. I appreciate what they do and am grateful I have an opportunity to visit their facility each year. However, it seems to me they could further their cause by being a little more supportive and accommodating to nature photographers. Just one photographer’s humble opinion FWIW.

Ok, the rant is finished. Now on to more important matters; photography. Despite the heat and hostile attitude, I must say this year was quite productive. We were treated to some fantastic sunrises and sunsets and even though the number of birds were down about 50% from their peak a few weeks ago, there were plenty of photo opportunities. One of my goals this year was to capture cranes engaged in courtship dancing. Sandhill Cranes are monogamous and mate for life. They dance and call to to their partners during the mating season (and other times I’m told). The dance involves jumping, bowing, and extending their wings. You will also frequently see them throw a stick or corn cob into the air. I guess to a crane, all this dancing and stick throwing is quite a turn-on.  Any way, I wanted to come home with some quality images of these rituals, not only from the river, but also from nearby fields.

I spent considerable time cruising the back roads south of the Platte working on “dance” photos. I learned many years ago that cranes are quite skittish when approached. However, moving cars don’t bother them. Cars, even travelling at 75 mph on the Interstate don’t inhibit their dance. But getting out of ones car to setup a tripod and camera does disturb them. They will walk or fly away if you so much as open your car door. So using your car as a blind minimizes disturbance and gives you the best opportunity to capture their  behavior.  I’ve tried bean bags of many types for in-car camera support and until now have not found one that works for me (the top of the door is too low with the window all the way down or the support is unstable with the window partially up). However, a newly discovered gadget, the Puffin Pad, made shooting from a car a breeze, even with a 600mm lens. It is contoured to fit over the top of the door when the window is fully open (which is still too low for me) and it has a slit that fits nicely over a partially extended window for a very stable and sturdy support which of course allows you to adjust the height to suit your needs. The Puffin Pad worked great. It allowed me to get the shots I hoped for without disturbing the cranes. I highly recommend it to any wildlife photographer.

Here are a few 2012 favorites:

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Sandhill Cranes 2012

[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_2719-web.jpg]a
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_2742-web.jpg]b
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_2810-web.jpg]c
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3205-web.jpg]d
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3148-web.jpg]e
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3118-web.jpg]f
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3180-web.jpg]g
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3058-web.jpg]h
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3025-web.jpg]j
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3734-web.jpg]k
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3718-web.jpg]l
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3753-web.jpg]m
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3788-web.jpg]n
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3856-web.jpg]o
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3885-web.jpg]p
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3959-web.jpg]q
[img src=http://scenicaperture.com/wp-content/flagallery/sandhill-cranes-2012/thumbs/thumbs_mg_3402-web.jpg]r
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Florida Birding Wrap Up

Florida is a wildlife photographer’s paradise. Over the course of just two days (about 14 hours really) I shot over 20 species of birds – and I don’t mean I just caught a glimpse, rather I was able to spend considerable time photographing each of them. In this, my fourth and final post on the topic I will simply show a few of those species and favorites from two productive days of photography.

Possibly the most interesting (not necessarily the best photo) of the group is number two below; a Reddish Egret White Morph. I’m not an expert birder, but I’m told it is very rare. While shooting it I didn’t notice the pink beak and thought it was merely a Great Egret. Not until afterwards did I learn from a fellow shooter what it was. Cool.

As they say, even a blind squirrel finds an acorn now and then.

As always, thanks for looking. I’d love to hear from you about your Florida experiences.

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snowy egret

Snowy Egret - 7D with EF70-200mm f/2.8 @ 85mm 1/1600s -1.0 f/4.0 iso160

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reddish egret white morph

Reddish Egret White Morph - 7D w/ EF600mm+1.4TC 1/1250s @ f/5.6 +0.67 iso400

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bald eagle

Bald Eagle 7D w/ EF600mm 1/1000s @ f/8.0 -1.0 iso200

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White Pelican

White Pelican 7D w/ EF600mm 1/2000s @ f/8.0 -1.0 iso200

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Osprey - 7D w/ EF600mm 1/1600s @ f/8.0 -0.67 iso200

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wood stork

Wood Stork - 7D w/ EF400mm 1/1250s @ f/8.0 -0.33 iso200

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oyster catcher

Oyster Catcher - 7D w/ EF600mm 1/1250s @ F/8.0 -0.33 iso200

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Great Blue Heron

Great Blue Heron - 7D w/ EF400mm 1/1000s @ f/5.6 -0.33 iso200

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