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Old Feb 20, 2005, 1:17 PM   #1
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First off I have nothing bad to say about my D-70. I have taken the time to research all the websites and books I could get my hands on to learn about my new camera and now I can take about 95 percent of in-focus,sharp and well saturated photos. But the one question I have not been able to get an answer to is this. Why cant I get sharp and in-focus fotos of a subject within the auto focus area of my camera as well as the surrounding area at 2.8 aperture? I went back to some fotos that I took with my Olympus C-750 UZ and checked the exif info and all my family fotos were taken at 2.8 aperture at focal lengths of 24mm and up. And everything from the little dog at my feet to the clock on the wall 50 or so feet away were comepletely infocus and sharp. With my D-70 I cant even begin to get everything in focus untill I go to atleast f/16 and its best at f/22. But by then there so little light left its immpossible to get a good foto. So mabey I am missing something, so any help or info would be greatly appreciated. And just in case you need to know I have tried this with my Kit lense 18-70 nikkor, 50mm 1.8 nikkor, and my tamron 28-300mm 3.5-6.3 lenses with and without my sb800 flash all with the same results.

thanks again

joey


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Old Feb 22, 2005, 9:07 PM   #2
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I would take it to the dealer you got it from and have them check the lens.
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Old Feb 22, 2005, 9:57 PM   #3
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arowana wrote:
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With my D-70 I cant even begin to get everything in focus untill I go to atleast f/16 and its best at f/22. But by then there so little light left its immpossible to get a good foto. So mabey I am missing something, so any help or info would be greatly appreciated.


Hi Joey - I'm in the learning stages as well so I hope I'm not too far off the mark here. But at f/2.8, how far away is the main subject that you're focusing on? Moreso at high zooms but to a degree even at 24mm, you have to have some distance between your cameraand your subject if you want everything to be in focus. Small cameras with small optics have a much greater depth of field. Though...are you sure you want everything from the wall clock to the dog to be in focus? It was the thing that drove me mad about less capable cameras until I purchased a dSLR.

One more tip...assuming the lens is wide-open at f/2.8, what you see through the viewfinder focus-wise is (supposed to be) what will be taken by the camera. Do you find this isn't the case?

Take care,

-Doug
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Old Feb 22, 2005, 10:08 PM   #4
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I bought my lenses at durys here in tennessee except the 18-70 kit lense that came with my camera. And I dont think it is possible that all three lenses I have suffer from the same problems. And i am not blaming this problem on my camera or lenses. I am sure its something I am doing wrong. Thanks for the reply.
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Old Feb 22, 2005, 10:21 PM   #5
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1st off I dont have 20/20 vision but it seems that everything in my veiwfinder is in focus. That is one of the things that aggrevates me. I compose my shot and see everything in focus but when I download my pictures that is not the case.

2nd yes, sometimes when I take pictures of groups of family and friends I do want the entire frame in focus. I hate looking at a foto where the people are in focus but you cant tell what that is on the table or what time the clock says on the wall. If i am taking a portrait picture, all I want is the subject in focus, of course. I just wanted to know if there was a way to correct this or if this was another of the great digital compact features I can kiss goodbuy.

And I have tried taking pictures from 4 or 5 feet away up to 20 to 50 feet away. All with the same result unless I raise the apreture to f/16 to f/22. Then everything is In focus but I have to have a lot of light or my SB800 on. Never had any of these problems with my Olympus.I love my D-70 and would never go back to a compact. Was just wondering if I was missing something.

Thanks for the response.

joey
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Old Feb 23, 2005, 11:38 AM   #6
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This may be a small point, but what focusing matrix are you using? Single, dynamic or closest subject? That will affect things badly while things will still appear in focus through the viewfinder. Try changing the settings and let us know if the results are different
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Old Feb 23, 2005, 5:15 PM   #7
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You've hit the depth of field issue. I don't know anything about the Olympus. What category of camera is it? Is it a 'small' format? You mention 24mm focal length which is wide (36mm on a 35mm camera). Generally f/2.8 doesn't offer much DOF no matter what the focal length. Also sharpening could be an issue. Are the image really out of focus or just soft? The Olympus could be doing more in camera processing than your current D70 setup.

Here are some DOF values based on the D70, point of focus is 5 meters out.
focal length 50mm, f/8 DOF = 3.15 meters
focal length 35mm f/8 DOF = 9 meters

If you change the point of focus to 1 meter, the DOF for the 35mm focal length drops to 0.24 meters! These numbers would get worse at f/2.8. DOF = 0.13 meters.

Also rule of thumb 1/3 of the DOF in front of the point of focus, 2/3 behind.
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Old Feb 23, 2005, 7:02 PM   #8
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Mainly single and sometimes matrix. But its the same with both. I will try closest and let you know.

thanks

joey
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Old Feb 23, 2005, 7:16 PM   #9
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The Olympus is the C-750 ultra zoom. It is a compact camera. And the pictures are out of focus and not soft on the D-70. I took 5 fotos with the D-70. One foto aimed directly foward at about 5 feet from the ground on a subject at about 15 feet away. And 4 more to the left,right, up and down on subjects at about the same distance. With focus set to single and matrix. In every foto the center of the frame was completely in focus and the surrounding area was not. That was at 18mm to 70mm and aperaturs of 2.8 to 5.6. Then I tried all the same fotos again with all the same settings except I used aperatures of 16 to 22 and all was in focus but noticeably darker. I dont have my C-750 any longer to retest it but the exif info from old pictures says all the fotos were taken at 2.8 aperature.Iwas just wondering if it was possible to achieve the same all in focus frame at 2.8 aperature with the D-70.

Thanks for the reply

joey
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Old Feb 27, 2005, 8:15 AM   #10
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Your best bet is to do a search on google for "Hyperfocal distance".

Read a few articles and your questions will be answered.

If u want everything in a photo to be sharp then you focus at the hyperfocal distance.


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