The Good and the Bad of Big Glass Depth of Field

Greetings all! I am finally getting back on my feet after the month from hell. Once all the adrenaline and excitement wore off from the race and party I started realizing what a toll it all took on my body. Even with my customary week off relaxing (yep, no running, and no work on Project Auuunoold) I still couldn’t shake the aches and pains. The next week started and I was beginning to get concerned. Figured I’d start the rebuilding process this week … back on the core to get the body fixed up and stretched and a little biking for cardio is starting to work their magic. Still not ready to run yet but due time, due time. In the meantime, thought I’d toss out a quick post.

Tonight’s topic is that very tricky subject of Depth of Field (DoF). To be honest, this is one of those photography topics I am trying to get a better understanding of – primarily because I’m constantly fighting it out in the field especially with the Beast. My quick and dirty definition of DoF is the measurement of how much distance will be in focus (sharp) for a given set of exposure, glass and camera specs. I still have a lot of learning to do on this subject so there will not be any expert advice here – I’ll certainly come back on this subject once I get read up on it some more. The good, or the bad depending on your point of view, is that you can see the effect pretty easily.

Take a look at some shots from a shoot Linda and I took back in July. We were out at Jubilee and due to lack of birds was spending my time on anything else I could find that had wings.

So there I was with my standard birding setup which consists of the Beast (200-400mm) coupled with the 1.4 Tele on the D7000 (1.5 crop sensor).  These shots were taken at around the 3.6 to 3.8 m range hand held… and people wonder why I continually workout.  These dragonflies were all over the place darting to and fro so I decided to get a little small subject focusing practice in.  When the subject is smaller than the central focus region, the glass tends to walk a lot, especially the long glass.  So there I stood happily shooting away.  That happiness lasted until I got home and started assessing the output.  Notice anything glaring wrong with the first shot?

The right wings are nice and crispy, but what the hell is up with the left side?  Was that particular wing moving at the time … doubtful, they tend to move both sets of wings in unison from what I have experienced and the 16oo ISO would have compensated for that anyway.  The problem is in the focus parameters.   My depth of field is not encompassing the full thickness of the subject.

I was fighting the glass to keep it on target and firing away on fast multi-shot so there were plenty of other examples to explore.  Hit the jump to see more examples of DoF.

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