Birds... Fast Birds... Focus Help Needed w/7D 70-200 f2.8 USM IS II

Started Jan 22, 2013 | Discussions thread
OP tvstaff Senior Member • Posts: 1,897
Re: Fast Birds... Focusw/7D 70-200 f2.8 USM IS II... MF!!! know your subject/FoV goal...

Steve D Yue wrote:

tvstaff wrote:

I'm trying to capture FAST birds in flight and feel like I'm skeet shooting and shooting blanks

7D with 70-200 f2.8 USM IS II

know your subject... (how big is your subject, really... do you know, even approximately?)

and know your desired FoV (subject composed within the frame)

that is, KNOW what you consider a good 'capture size' within the frame of your subject

this also means REALIZING the birds can ONLY be at a particular distance (ideal for composition), and you can adjust your Zoom FL accordingly.

know your LENS FoV/DoF limitations (yes, f5.6-f8 is great for more light, and higher shutter speeds to minimize blur for 'fastest birds', yet DoF not too deep to isolate background)

Need some advice on optimal 7D setting for focus on really fast moving objects.

once you isolate the above 'you know it' parameters, resort to MF... not AF (especially if the background starts to get 'pattern clutter', and not 'clear blank patternless skies')

IF you know the relative size of your subject, how it would be 'ideally sized in a composition' for YOUR LENS FL/FOV... then you have actually NARROWED the POSSIBLE subject distances needed for REPEAT SHOTS 'at the right size'. YES, this means ignoring FOV Scenarios where the composition is 'wrong sized'. HINT: shoot consistently a bit wider for FOV so you have more flexibility in 'creative cropping' your shots.

For two days I've been sitting on the edge of the FDR Drive in NYC trying to get a shot of a seagull up close in flight with the 59th Street Bridge in the background.

UP CLOSE is RELATIVE... if you are trying to kill the bird, 'fill the frame' would be the objective, BUT instead, you are trying to capture AESTHETICALLY the bird 'composed within the frame', so it can easily be OFF CENTER and the subject (fast bird in flight) definitely smaller (a fraction) of the framed composition. HOW CLOSE is of any use to you? HOW FAR OUT is it 'useless' to you? If you know both, you can MF accordingly.

The 7D keeps focusing on everything but the birds. I know it's my fault. HELP!

this assumes you want only AF to do the focusing work in the scenario...

at some point, when you master the MF, you are more likely 'well practiced' to gauge whether AF will 'do better' or 'do worse' given the background that may fill in behind your subject (pattern clutter vs blank clear backgrounds)

Happy New Year all,


e.g. start with 'hypothethical flying bird wings-open size' (say 1m across), now calculate 'ideal composition', how big is 1m if, say covering 1/4 to less than half, your frame (FOV)?

calculate according to the fact you have a 7D (APS-C) sensor w/ 70-200 (FF 112-480mm FOV)

a 1m sized wing-open flying bird would fill:

the WHOLE FoV, at exactly: 4.667m (@70mm FL) to 13.333m (@200mm FL)
HALF FoV, at exactly: 9.333m (@70mm FL) to 26.667m (@200mm FL)
THIRD FoV, at exactly: 14m (@70mm FL) to 40m (@200mm FL)
QUARTER FoV, at exactly: 18.667m (@70mm FL) to 53.333m (@200mm FL)
once you spot a singular/group of birds flying at a particular distance [with lots of contrasty background pattern clutter] (you can gauge this by shifting your Zoom FL to an approximate 'appropriate composition size' FoV) for your 'BIF', you then can even NARROW your focus range, because NOW you know which FL to 'settle' on, for shooting, say your birds 'look a good size' around 120mm FL: then the 'ideal' distance is 8m (set MF to 8m; if you ever master your AF, it's important to at least get an MF 'distance' close to ideal, too)

So, with MF, set at exactly: 8m (@120mm FL)... would the subject size in the FoV be what YOU want, or another size instead (another FL?)?

it's said, that when guys try to thread a needle, they try to bring the thread point to the eye of the needle, and often MISS, whereas girls will bring the eye of the needle to the thread point instead... and get it threaded...


-- hide signature --

(not 'Steve D Yue' (my husband (RIP)))

Thank you for taking the time to write and offer your advice.  I will try MF too....  With a little sweat on my brow, perhaps I'll catch these critters!  Best, TVSTAFF

 tvstaff's gear list:tvstaff's gear list
Canon EOS-1D X Canon EOS-1D X Mark II Canon EF 70-200mm f/2.8L IS II USM Canon EF 300mm f/2.8L IS II USM Canon EF 24-70mm f/4L IS USM +25 more
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