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Subject: "RE: Where is the focus?" Previous topic | Next topic
grnzbra Silver Member Nikonian since 28th Sep 2011Thu 23-Aug-12 10:10 PM
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#5. "RE: Where is the focus?"
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Thu 23-Aug-12 10:25 PM by grnzbra

Springfield, US
          

>You also need a very flat clearly printed and high contrast
>target. And this would be start of process for testing the AF
>system.
>
>You shutter speed formula is for the FX or 35mm full frame
>camera. For a DX sensor, you need to adjust the focal length
>for the crop factor.
>

Got one. While one can see approximately where the focus is, there is no point where the picture is crisp. It's soft everywhere. Yet when I take some pictures, it seems that I can sometimes see an area behind the point on which I focused that is sharper than the focus point. For example, in this picture ( http://images.nikonians.org/galleries/showphoto.php/photo/388775/size/big/cat/22196 ), the bug was the point of focus, but it is obvious that the point in focus is the on the flower, about an inch behind the bug. (I know, it's only 1/80th of a second, not 1/200 but I was taking pix of a yellow flower in the sun just before this and the shutter speed was 1/360)

OK. You lost me on the second part. From what I've been reading in forums relative to focus, shutter speed should equal or exceed the focal length. I set the focal length as high as it will go much of the time because I am shooting small things like flowers, or rather the small pollen stalks within the flowers. What is "crop factor" and how should it be related to focal length?

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A general, generic topicWhere is the focus? [View all] , grnzbra Silver Member, Tue 21-Aug-12 12:22 PM
 
Subject Author Message Date ID
Reply message RE: Where is the focus?
JosephK Silver Member
21st Aug 2012
1
Reply message RE: Where is the focus?
gkaiseril Gold Member
21st Aug 2012
2
Reply message RE: Where is the focus?
grnzbra Silver Member
23rd Aug 2012
3
     Reply message RE: Where is the focus?
gkaiseril Gold Member
23rd Aug 2012
4
     Reply message RE: Where is the focus?
grnzbra Silver Member
23rd Aug 2012
5
          Reply message RE: Where is the focus?
Skyco Silver Member
24th Aug 2012
6
          Reply message RE: Where is the focus?
grnzbra Silver Member
25th Aug 2012
10
               Reply message RE: Where is the focus?
Skyco Silver Member
25th Aug 2012
11
          Reply message RE: Where is the focus?
pjonesCET Gold Member
24th Aug 2012
8
          Reply message RE: Where is the focus?
gkaiseril Gold Member
24th Aug 2012
9
     Reply message RE: Where is the focus?
pjonesCET Gold Member
24th Aug 2012
7
          Reply message RE: Where is the focus?
Stonecherub Silver Member
26th Aug 2012
12
               Reply message RE: Where is the focus?
gkaiseril Gold Member
26th Aug 2012
13
                    Reply message RE: Where is the focus?
grnzbra Silver Member
26th Aug 2012
14

Forums Lobby GET TO KNOW YOUR CAMERA & MASTER IT Nikon D5300/D5200/D5100/D5000/D3300/D3200/D3100/D3000 (Public) topic #6560 Previous topic | Next topic


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