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Old Jul 18, 2008, 10:42 PM   #1
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I recently bought a Canon XSi and have been playing around with the 75-300mm lens that came with the package and I'm trying to figure out why they don't look so great on my computer.

An example is this photo:


It doesn't look horrible but then when you view the full size photo it looks quite pixelated: http://farm4.static.flickr.com/3198/...49bc3a3e_o.jpg

But then I found out I was set to using ISO-800 so I would think that would account for the Grainyness right?

Then the next day I went out and took some more photos of the Ospey with using ISO-100 and using the same 75-300 III USM lens I was thinking the birds were in focus as they look in focus when I view them with the computer. But when I click on the 'view full size' they are not in focus.



You can view the full sized photo: http://farm4.static.flickr.com/3013/...09f88714_o.jpg

Am I doing something wrong?
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Old Jul 18, 2008, 10:43 PM   #2
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The last full sized photo can be viewed via: http://farm4.static.flickr.com/3013/...0191f1f6_o.jpg
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Old Jul 19, 2008, 12:38 AM   #3
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Did you hand hold the camera for that second shot at ISO 100? It looks like you were using a shutter speed of 1/60 @ 300mm.
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Old Jul 19, 2008, 3:24 AM   #4
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I will agree with dr_spock here. It probably is camera movement you see. Way to slow of shutter speed. You will find that you are going to need at the very least a Monopod when you shoot with that lens.
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Old Jul 19, 2008, 4:46 AM   #5
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Gimli wrote:
Quote:
I was thinking the birds were in focus as they look in focus when I view them with the computer. But when I click on the 'view full size' they are not in focus.

You can view the full sized photo: http://farm4.static.flickr.com/3013/...09f88714_o.jpg

Am I doing something wrong?
The first picture especially looks very good for a hand-held shot, on my 17-inch 1280x1024 monitor, and the image size is thenapprox. 10 inches by 7 inches.

But when you ask in 'flickr' to 'view full size image', they give it you pixel for pixel, so I'm seeing only 1280 of the 4272 pixels across at a time. This is the equivalent of viewing a 10*4272/1280 inch print, i.e., a 33-inch wide poster from a normal reading distance of about a foot, when you'd have to turn your head to see it all. Expecting that to look sharp is asking rather a lot.

Hope this helps, if that's what you meant. I think your shots will be fine if you stick the camera on a solid support. I usea little Kodak Z712 'superzoom' camera with excellent image stabilisation, but detail, hand-held, at that sort of distance won't be good.

Here is a peregrine falcon chick sitting on a church tower, a 3072x2304 frame at 432mm equiv. 1/160s, f/4.8, resized to 600x450, and sharpened, which appears on my monitor as a 6x4 inch image, and looks fine The 'reply' that follows is a 600x450 clip from the same image at 1:1, 'full-size' which looks pretty fuzzy, the equivalent of a print 36 inches wide. Your results, with a much better camera and a tripod would be better, but it illustrates the point.


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Old Jul 19, 2008, 4:47 AM   #6
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'Full-size' clip...
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Old Jul 19, 2008, 5:06 AM   #7
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What you see in the first image isn't pixelation; it's noise. And, yes, dropping the ISO will clear that up.

And I agree with dr_spock and Old Jim that the image is probably soft from camera shake.

I think I see some chromatic aberration on the piling as well. Which 75-300 lens do you have?
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Old Jul 19, 2008, 9:53 AM   #8
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TCav yes I meant noise not pixelation oops.

Both shots were taken with a Tripod. The lens is a f4-5.6 75-300mm III USM.

I guess clicking the button still made the camera shake on the tripod then. Guess it be best to invest in a heavier tripod? It seems sturdy, perhaps the head and it being as tall as it can (with a wide base) isn't sturdy enough?

Would it be better if I shot with the mirror lock and see if that improve the camera shake? That why when i hit the shutter button, it locks the mirror up partially, waits 2 seconds and then takes the photo?

I'm think I'm just expecting better I guess from a lens even though it's a relatively inexpensive one.

I am coming from using a Canon PS750 and wanted to try something a bit better than it's optical zoom ability. Learning as I go though!
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Old Jul 19, 2008, 10:59 AM   #9
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  • Spread the tripod legs as far as possible.[/*]
  • Keep thehead at it's lowest position.[/*]
  • Try the self-timer, then the mirror lock-up, then bothif possible.[/*]
  • Keep the tripod legs at their shortest. That is, don't extend them from their stored position. That will keep the camera closer to the ground making it harder to use, but the tripod will be a lot more steady.
[/*]
The piling with the water in the background is a high contrast subject, and that's where chromatic aberration will be most evident. I think the Minolta 75-300 I got rid of hadCA that bad, but it was also pretty soft at 300mm. That might be what you're seeing here as well. You could try backing off the zoom a little and see what effect that has.
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Old Jul 20, 2008, 7:29 PM   #10
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It really doesn't look to me like motion blur is much of a factor with these shots. Motion blur is usually quite directional, and these are just a bit soft .

style="BACKGROUND-COLOR: #000000"Given that you are taking pictures over water, at a fairly long telephoto, they aren't bad at all. Using the timer and MLU might help some, but I think you would see more improvement from using a polarizing filter. This would remove some of the haze, and improve contrast, giving at least the appearance of sharper images.

style="BACKGROUND-COLOR: #000000"brian
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