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Old Jun 19, 2005, 10:28 PM   #1
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I'm using a Rebel XT and a Canon 70-200 F2.8 with a 1.4 extender. Sometimes I get nice sharp results but not today.

Should I use a faster shutter speed and let the camera decide aperture? If so, what speed to get restless subjects or birds in flight? What about higher ISO?

Here is a pictureI took today that isn't sharp.


Any advice is greatly appreciated.

//jim

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Old Jun 21, 2005, 7:22 PM   #2
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Hi Jim,

I am certainly not an expert in this matter, but I have almost the same equipment as you do. I shoot with the Canon EOS 20D and have had similar experiencesusing the EF 70-200 f2.8 IS lens and 1.4 X extender. I can think of a few possible reasons for the lack of sharpness. For starters though, knowing the shutter speed , aperature and ISOfor your posted photo would be very helpful.

If you are shooting handheld with the Rebel XT, at 280 MM. You are up to an equivalent of about 450 MM due to 1.6 X crop factor. Formany people, a shutter speed of atleast 1/500 would be required tohave a chance of atack sharp photo.This is using the 1/focal length rule. Some people can shoot at much slower speeds, but that isn't the norm. Plus I find my steadiness varies considerably from day to day. I try to use faster shutter speeds than that when possible by shooting wide open(f4) with 1.4 X teleconvertor attached , and increasing ISO when needed. This should give you a decent shutter speed.

If the problem isn't related to steadiness, it could be a focus problem. I have had simlar shots with the same lense and 1.4X convertor when the bird is sourounded by such a tangle of branches. If you had to crop tightly to post this shot, (such that the bird fills a very small portion of the frame at the time of the photo), the focus could easily have locked on a branch in front of or behind the birds position even though the center focus dot ispositioned directly on the bird. If you look carefully, you can often see this subtle off focus in the viewfinder .

I hope this helps some. Post your settings if you can. Otherwise, some of the contributors on the wildlife forum have amazing knowledge and talent to offer. If anyonecan help, it would be them. Good luck...

Thomas.
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Old Jul 9, 2005, 6:13 PM   #3
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killdeer0007 wrote:
Quote:
I'm using a Rebel XT and a Canon 70-200 F2.8 with a 1.4 extender. Sometimes I get nice sharp results but not today.

Should I use a faster shutter speed and let the camera decide aperture? If so, what speed to get restless subjects or birds in flight? What about higher ISO?

Here is a pictureI took today that isn't sharp.


Any advice is greatly appreciated.

//jim
As the other member suggested, posting the shot settings for that particular shot will help alot. Just looking at the shot it seems to be a low light shot since I see alot of noise which suggests a high ISO. Another issue is the distance from the bird. Is this a crop from original?

When focusing on the bird, especially in the side pose, try to use the eye as the focus point. That will put the eye near the center of your DOF. I have used several L lenses, and while they can be sharp wide open, it can also be hit and miss. Try to use a smaller aperture (larger F number) to increase the depth of field. Find the lenses sweet F/stop, probably around the f8 zone. Shutter speed has a lot to do with it as well. For example the below shot is a 100% crop from a inflight shot at equivalent of 305mm non IS, handheld but a nice 1/3000th took care of any movement.



Don't be afraid to shoot higher ISO settings to get higher shutter speeds when necessary. Shooting RAW and using C1 pro for processing renders excellent low noise shots even from 1600 iso. The below shots, while not ideal examples and just shot playing around while waiting at the hospital, were shot at 1600 ISO. The first is a reduced shot and the second is a 100% crop. The noise is minimal for a shot at such a high iso as you can see in the blank area on the wall.



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Old Jul 11, 2005, 9:16 AM   #4
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Iphotograph a lot of birds and have found with my camera (digital rebel, the first one 300D) that ISO 400 and set av at F8, I nearly always get good shots. For flight shots I use Tv mode. If there is enough light I will shoot at 2000. Otherwise I experiment with going to 1600, then 1250 and so on or increasing the ISO to 800. Most of the time neat image will sort out any grainy problems.
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Old Aug 25, 2005, 1:14 PM   #5
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Like veryone said, you need to tell what setting you used. I can't see any exif info in the shots that you posted. Did you use tripod or hand held? You would need atleast 1/500sec for hand held, maybe higher SS based on how steady you are. When I use my 70-200F4 hand held, I can't get good shots under 1/500sec.

You don't have to use f8 aperture all the time, main reason of having a fast lens is that you should be able to use it wide open. I use my 100-400 at f6.3 or f7.1 but I use the 400mm prime wide open at f5.6 all the time, even with 1.4xTC, unless I need more DOF, then I would stop down.

I also use center focussing point only on my 10D. I am always in aperture priority as using wide apertures gives me the fastest SS and i can control the DOF.
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Old Feb 5, 2006, 5:58 PM   #6
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Zoom browser has a feature that will let you see what focal points were turned on at the time the picture was taken. I was wondering why this photo was't too sharp. Now I know why.
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Old Mar 19, 2006, 5:50 AM   #7
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can photoshop come to the rescue......



hmmm not sure actually

is sharpness better>?


its wound prety hi, ther is distortion on the top end of the bird, just weird how even ps cant seem to see the sharpness. canon xt is a great series of cam. should be getting sharp images. u must have it on average focus mode. i think you need to put it to centre weighted or spot.


ken

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Old Apr 29, 2007, 8:22 PM   #8
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I guess I missed this thread. To get the fastest shutter speed and proper exposure, I use Av mode. Lens wide open and the camera sets the shutter speed. This allows for the fastest speed for the light conditions. Also, higher iso 800 and 1600 work well but really need to be properly exposed.

dennis
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