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Old Aug 16, 2006, 4:33 PM   #1
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I have a 75-300mm Canon lens that seems to be blurry when I focus at full zoom.

It seems to be worse when my subject is farther away then close up.

It does it even at faster shutter speeds. No tripod. Is it me or is it that I am trying to do more than the lens can do?
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Old Aug 16, 2006, 6:00 PM   #2
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It would help if you posted an example of your problem. A 100% crop around 400 by 800 pixils would be great.
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Old Aug 16, 2006, 7:15 PM   #3
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Here is a crop

It just does not look right to me.

What do you think?
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Old Aug 16, 2006, 7:21 PM   #4
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Here is one more
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Old Aug 17, 2006, 1:57 AM   #5
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Is that a 100% crop?

If so then I think you're expecting a bit much from your camera and lens.

For squirrels or little birds what you really want to do is fill the frame with them. If you're not doing that then you're too far away. Not easy I know, but that's why being a wildlife photographer is so challenging.

The lens you're talking about is not particularly sharp, and 1/100s is probably just a little bit slow for the firstshot. 70mm*1.6=112 which is pretty marginal. 1/250 would be better.

Don't forget that a 100% crop is like looking at a print under a pretty strong magnifying glass.

Also those crops look a bit underexposed to me, which makes noise worse, and "cheaper" lenses struggle more with contrast in low light too.


I checked the levels on the first and it was somewhat underexposed, so I adjusted the levels, applied some local contrast enhancement and a bit of sharpening.

Doesn't look too bad to me.

Your second shot though at 300mm*1.6= 480 - you should be using at least 1/500s and you were at 1/320.

Also - although it's not exactly underexposed it could certainly benefit from abit of exposing to the right.

And honestly - pictures of small birds are VERY VERY VERY difficult, they move fast, often sit on branches that are swaying, ruffle their feathers, etc. People who shoot this sort of stuff well need either to get very close - think 2 or 3 meters. Or use some very big and expensive lenses. Preferably both.


NHL and Eric can help.


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Old Aug 17, 2006, 4:31 AM   #6
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I kind of agree too...

If those images are already cropped that mean the objects are too small for the AF point to pick out -> the AF sensor can't pick out the squirrel from the roof or the bird from the branches in which case the shingles on the roof look more in focus to me, ditto with the humming bird from the branches in front

The low contrast didn't help either (i.e. the camera can't tell the subject from the background like your brain does), and like peripatetic said that Canon 75-300 is also not particular sharp at 300mm and you're magnifying it by cropping on top! (Plus you can notice the purple fringing on the white areas of the squirrel)

--> Get closer to fill the focus point and if you can't then you need a longer lens:


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Old Aug 17, 2006, 9:36 AM   #7
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peripatetic
What is the formula you are using to figure the shutter speed needed?
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Old Aug 17, 2006, 10:35 AM   #8
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RP33 wrote:
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peripatetic
What is the formula you are using to figure the shutter speed needed?
Simple rule of shutter speed > 1/focal length. So for 300mm, and 1.6x crop camera, you get 300x1.6 = 480. So 1/480 shutter which will translate to 1/500 as there is no 1/480 ss.

To some simple test. take some shots in good outdoor light. use a tripod and if no tripod, make sure you have high enough shutter speed for hand holding, say like 1/1000. take shots of some signs and post 100% crops. That will show if your lens is ok or not.

Here is what a good lenses will do at 100% without any sharpening at all.



Another real life 100% crop of 800x600.




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Old Aug 17, 2006, 12:14 PM   #9
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That helps.

I will do some experimenting.

Thanks

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Old Aug 26, 2006, 1:11 AM   #10
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I see a lot of the pictures in the wildlife area of this forum use a lot slower shutter than the formula that was posted. Are they using a tripod to get sharp pictures, better equipment, or just lucky? It also looks like good light makes a huge difference in getting a sharp picture, at least from what I am seeing. Is that a true statement?
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