October 31, 2014, 03:35:39 PM

Author Topic: Trouble finding focus  (Read 1382 times)

ideaworx

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Trouble finding focus
« on: March 11, 2013, 12:31:40 PM »
Hi All, been awhile since I posted here, been out trying to spend more time behind the lens than behind my keyboard. I have a certain shot I have been trying to get for the past weeks that is plaguing me, just not able to focus or get my setup correct to nail the shot. Let me paint a picture.

We are shooting Tarpon underneath bridges in Tampa, FL. The timing on the shot is essentially right when the fish hits the bug (we are fly fisherman), they realize the hook is set, and BAMM, they come jumping out of the water. Typically we get 5-10 jumps on each tarpon. We have very very limited light underneath the bridge and with the fish we are targetting, having a bunch of fill light would spook the fish. So I am trying to capture the moment the fish jumps in the proximity of 10-25ft and running into issues where I am unable to get the AF to pick up the subject fast enough.

My Setup: 5DMIII + 600EX(x2). I have captured the subject, but always is blurry, so wondering what some of the experts here might have as tricks to assist on this. Typically we are in a rough tide, so the boat bounces, so my chances of using a tripod/monopod is not great, but I do have both of these options available. As well I have tried higher ISOs and slower shutter speed, both which yield less than desirable results.

I appreciate any and all feedback and thanks again for a wonderful place for photogs to chat on our passion!

Cheers,

Shane
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Trouble finding focus
« on: March 11, 2013, 12:31:40 PM »

Mt Spokane Photography

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Re: Trouble finding focus
« Reply #1 on: March 11, 2013, 12:44:34 PM »
Try taking the flash unit off, it slows down AF if the AF assist light is on.  Canon has promised a fix, but its not here yet.  Also try turning off the AF Assist light.  Its not going to help in any event.
The lens you use might have a affect on AF speed as well, hopefully its a fast AF lens.  Third party lenses cam be slow to autofocus.

ideaworx

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Re: Trouble finding focus
« Reply #2 on: March 11, 2013, 01:05:03 PM »
Try taking the flash unit off, it slows down AF if the AF assist light is on.  Canon has promised a fix, but its not here yet.  Also try turning off the AF Assist light.  Its not going to help in any event.
The lens you use might have a affect on AF speed as well, hopefully its a fast AF lens.  Third party lenses cam be slow to autofocus.

I am shooting with 70-200mm II 2.8 and 85mm 1.2, both pretty snappy lenses. I got the email on the af assist light being addressed in a future firmware upgrade, I hope it helps a bit. Is there any value in using the likes of a flash bracket with a flashlight mounted to it that i can trigger on and off before taking the shot w/o it blowing out the image. I have found a couple flashlights that mount to the bottom of handguns that have pressure sensitive on/off functionality. I have a decent flash bracket I was considering using to do all this, but really not sure how I can avoid having the blown out shot from a giant flashlight glaring into the frame. Also wanted to mention I do have the ST-E3-RT as well, so if you think this would be helpful in this instance, please let me know.

Thanks again,

Shane
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RLPhoto

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Re: Trouble finding focus
« Reply #3 on: March 11, 2013, 01:11:50 PM »
Try Pre-focusing and holding until the correct composition comes into the frame.

Sometime the very best AF systems just aren't smart enough to stick the focus where its needed. It's worked for me quite well in other areas of photography and could see it working here.

Mt Spokane Photography

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Re: Trouble finding focus
« Reply #4 on: March 11, 2013, 01:30:46 PM »
There are LED video lights that might help, they are not very expensive and might add some fill light.
 
http://www.amazon.com/s?ie=UTF8&keywords=led%20video%20light&page=1&rh=i%3Aaps%2Ck%3Aled%20video%20light

RS2021

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Re: Trouble finding focus
« Reply #5 on: March 11, 2013, 04:17:23 PM »
I am shooting with 70-200mm II 2.8 and 85mm 1.2, both pretty snappy lenses.

Dump the 85L f/1.2;  it is probably the worst lens for what you are describing.... though very high quality, it is notoriously slow in AF performance.  70-200 f/2.8 II you list is a good fit. If you absolutely must use a prime, then use the ones with faster AF's depending on what is available to you.... 85 f/1.8 or 135L or 200 f/2 etc all come to mind. 200 f/2 is rather pricey and not in everyone's bag; the other two, especially 135L  autofocuses quickly and is a longer medium tele.

But putting autofocus aside, as RLphoto suggested, prefocusing in the zone may be a better bet.

And, take shots in burst mode. While 5D3's 6FPS may not be blazing fast... it is probably better than taking single shots. Best of luck!
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Re: Trouble finding focus
« Reply #5 on: March 11, 2013, 04:17:23 PM »