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Photography Question 

Elaine Davis 		 

far distance not in focus


When I take a picture of a river and trees behind the river, trees are blurry. Lens is new canon 24-105 on a new Dig.Rebel XTi Thanks so much.


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November 14, 2006

 

Bob Cammarata 		  Can you post an example?
...might be as simple as a smaller aperture setting.


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November 14, 2006

 

Elaine Davis 		 
 
 
I forgot to mention, it was a sunny day with aperture setting at 22, speed at 250 and iso at 100. I guess I wasn't sure when to initially start focusing. Do I start 1/3 into the shot or on the woods. I'll try to upload a picture or 2


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November 14, 2006

 

Bob Cammarata 		  At that shutter/aperture/ISO setting, you probably under-exposed your shot a little.

That point aside,...what was the extension of your zoom lens when you composed your shot?
At 24 mm, everything should have been in apparent focus at f-22.
As you increase your zoom toward 105 mm, your depth of field from the foreground to infinity (the background) will decrease exponentially.

Typically, focusing manually just beyond the foreground will yield the results you seek.


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November 14, 2006

 

Pete H 		 
DOF (Depth of Field) is a possibility.

Another possibility is pixel coverage.
As objects increase distance from your lens, the image projection upon the sensor is smaller.

For example, a ball, let's say 2 feet in diameter is photographed from 2 feet away. The same ball is then photographed at 100 feet.

The image made from 2 feet away will occupy (more) pixels compared to the one shot at 100 feet, assuming you do not change the focal ratio.

This effect does not produce "blur", but rather "pixelation" which you may be seeing.

As Bob requested, an example would be helpful in analyzing the geometry of your shooting situation.
Overall, if you are shooting at f/22, the DOF is very high at 24mm, quite low at 105mm.

Let us know,

Pete


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November 14, 2006

 
- Gregory LaGrange

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Gregory LaGrange's Gallery 		  Could also be that the lens is not that good at that focal length, as zooms have good spots and not so good. The 75-300 is not that sharp at the 300mm length. Not a bad lens, but you'll see a difference with the L lenses.
Depth from f/22 at 100mm focal length would have a good distance range if it's not a close up or macro.


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November 15, 2006

 

Ed Heaton 		  Hello Elaine,
Not to take anything away from your already responses, but If I had to guess I would say it’s a hyper-focus issue. I’m assuming you are using a tripod too. When you compose your scene make a conscious decision as to where you want your focus point to be. More times than not you can get away with focusing one third of the way into your scene. This will give you 1/3 sharp focus in front and 2/3 behind that point…
Give it a try and good luck…

P.S. It wasn’t a windy day was it??? (just asking)

Ed


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November 15, 2006

 

Elaine Davis 		  Thank you so much everyone. I'm going to remember what everyone here told me, and when I go to the river again I'll take pictures exactly as I was told and post them here. Yes, I did use a tripod ... I don't think it was windy but I thought at 250-500 speed, that would be ok?????


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November 15, 2006

 
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