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Old Mar 17, 2008, 5:25 PM   #1
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I am trying to get a particular type of shot and I would like some advice with the best settings to use with my canon 20d and EF-S 17-85mm f/4-5.6 IS USM lens.

I do a lot of pike fishing in ireland and I am trying to get a good shot of pike tail walking or jumping when been caught. At the moment I only have the above lense which isn't as fast as I would like, but I will have to make do with it for now. I also have the problem that I have to shoot with out the use of a tripod and on a moving boat at a fish that moves faster than I can.

I will be taking these shots in light ranging from sunny to very cloudy as I am out in all weathers.

Below is a picture that I took yesterday to give you an idea of the shot that I am trying to get. (I know it is a terrible shot but it gives you an idea of what I am looking for) I made a lot of mistakes with the shot, but I didn't have me camera at the ready. Next time I will be shooting at the widest angle wich will give me more chance of getting the whole fish in the shot and will make the lense a little faster.

Does anyone have any tips for getting this type of shot?


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Old Mar 17, 2008, 6:59 PM   #2
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The biggest issue you're running into is motion blur. The fish is moving pretty fast. The posted shot was 1/25 at ISO 400 and 5.6. So not the best lighting.

Given the same equipment I would suggest bumping the ISO up to 1600. That would stsill only give you a shtute speed of 1/100 which ain't great. You'd probably need around 1/800 to freeze the motion so you're going to need a lot more light.

One thing you might try is using the flash. It might not work well - you might get too much reflection of light but it's worth a try. Set exposure to manual and make sure you're about 2 stops underexposed. I.E. in this exposure, set the shutter speed to 1/100 at 5.6 and ISO 400. The flash will freeze the motion of the fish. But it will take a while to re-cycle so you'll have to get it on the first shot.

Also shoot a little looser until you get your technique down so you don't lose the fish out of the frame.


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Old Mar 18, 2008, 8:26 AM   #3
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Your shutter speeds should have been much faster than that for ISO 400 and f/5.6 in daylight, even if it's overcast.

Are you using any filters on that lens that would be restricting the amount of light getting through (for example, a Neutral Density Filter or a Polarizer)?
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Old Mar 18, 2008, 12:54 PM   #4
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Thanks for the replys,

John, I will give it a try with the flash, but I don't like my chances for getting the shot.

Jim, I just have a clear UV filter on to protect the camera lense, will that slow things down much?

Whay sort of difference to shutter speed would a faster lense make, for example the the EF-S 17-55mm f/2.8 IS USM or the EF 28-70mm f/2.8L USM?

Would it be possible to get faster shutter speeds with a 40d, or is it all about the lense?
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Old Mar 18, 2008, 1:05 PM   #5
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ryanfawcett wrote:
Quote:
Would it be possible to get faster shutter speeds with a 40d, or is it all about the lense?
shutter speeds are one of three parts to the exposure triangle. Exposure is determined by:

Shutter speed, ISO and aperture

Shutter speed determines how long light is let in to the sensor

ISO determines how sensitive to light the sensor is made

Aperture refers to how MUCH light is let in.



Your shot was 1/25 shutter, ISO 400 and 5.6 aperture.

A 2.8 lens is 'two stops' faster. So keeping ISO the same would increase shutter speed by 4 - from 1/25 to 1/100.

A 40d has ISO of 3200. That's 1 stop better than the 1600 your current camera has. If you shot at 5.6 but increased ISO from 400 to 1600 (2 stops) you'd get 1/100. Increase it to ISO 3200 and it doubles again to 1/200.

Jim's point is - it seems very odd to have such a slow exposure. The only thing I can think of is the boat is casting a shadow on the water in the shot above.

For example on heavily overcast conditions for baseball I would expect about 1/100 at ISO 400 or 3 stops brighter than what you were getting.

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Old Mar 18, 2008, 2:24 PM   #6
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I'd yank the filter.

No, it should not be impacting light transmission. Even mediocre quality UV filters should have > 90% light transmission with any decent coating at all. But, there are probably some bad ones out there that may not handle reflections as well.

Perhaps that was just a "fluke", with the metering overexposing a bit due to the white splash of water in the center (which would be unusual, as you'd expect the opposite), and the camera still handling other highlights OK by adjusting the tone curve.

But, something's not quite right with 1/25 second at ISO 400 and f/5.6 in mid afternoon.

Shoot in Aperture Priority Mode versus Auto, make sure your Aperture is set to the smallest f/stop value (which represents the widest opening of the aperture iris).

The camera was already using f/5.6 (which is the brightest your lens can go when zoomed in much). But, in some conditions you want faster shutter speeds to stop action, it may not choose an aperture that wide (instead, using mid range apertures designed only for camera shake).

Then, I'd use Exposure Compensation to give it a 1/3 stop darker exposure. Basically, set it to where the needle in the viewfinder is one click left of center). Then, the camera will use a slightly faster shutter speed for a given lightig, ISO speed and aperture.

I'd be hesitant to go any more with Exposure Compensation (you don't want to make it too dark in case it was just some kind of odd problem you wouldn't normally experience).

Then, increase your ISO speed to ISO 800 and take some test shots to see what shutter speed you're getting, increasing it another stop to ISO 1600 if you need to.

Or, use a lower ISO speed if conditions are sunny and better than that (for example, ISO 400 where it was before).

P.S. -- if my post didn't make sense the first time around, I edited it. lol

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Old Mar 18, 2008, 4:11 PM   #7
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Thanks for the replys, they have given me a lot more to think about.

I don't know when I will be out fishing again, but hopfuly I will be able to post some improved results in the future.




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