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General Photography
Macro
1:1 at f/36 Versus 1:2 at F/8 Cropped
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<blockquote data-quote="Eyelight" data-source="post: 424702" data-attributes="member: 24753"><p>Something here I tried to point out a few posts (pages back). First, I'll reiterate that calculations get you to the ballpark, but then comes subjectivity.</p><p></p><p>Here is the formula for calculating close focus DOF using f/stop, magnification and CoC (same as shown on Wikipedia):</p><p></p><p>[ATTACH]143910[/ATTACH]</p><p></p><p>Here then are calculations using this formula for a DX:</p><p></p><p></p><table style='width: 100%'><tr><td>f/stop</td><td>N</td><td><strong>36<br /> </strong></td><td><strong>32<br /> </strong></td><td><strong>8</strong></td></tr><tr><td>CoC</td><td>c</td><td>0.02</td><td>0.02</td><td>0.02</td></tr><tr><td>Magnification</td><td>m</td><td>1</td><td>1</td><td>0.5</td></tr><tr><td></td><td></td><td></td><td></td><td></td></tr><tr><td></td><td><strong>DOF</strong></td><td><strong>2.88</strong></td><td><strong>2.56</strong></td><td><strong>1.92</strong></td></tr></table> <table style='width: 100%'><tr><td></td></tr></table><p></p><p>And for the FX:</p><p></p><table style='width: 100%'><tr><td>f/stop</td><td>N</td><td><strong>32<br /> </strong></td><td><strong>8<br /> </strong></td></tr><tr><td>CoC</td><td>c</td><td>0.03</td><td>0.03</td></tr><tr><td>Magnification</td><td>m</td><td>1</td><td>0.5</td></tr><tr><td></td><td></td><td></td><td></td></tr><tr><td></td><td><strong>DOF</strong></td><td><strong>3.84</strong></td><td><strong>2.88</strong></td></tr></table><p></p><p>Using this formula, the calculated DOFs are not the same for 1:1 at f/32 and 1:2 at f/8.</p></blockquote><p></p>
[QUOTE="Eyelight, post: 424702, member: 24753"] Something here I tried to point out a few posts (pages back). First, I'll reiterate that calculations get you to the ballpark, but then comes subjectivity. Here is the formula for calculating close focus DOF using f/stop, magnification and CoC (same as shown on Wikipedia): [ATTACH=CONFIG]143910._xfImport[/ATTACH] Here then are calculations using this formula for a DX: [TABLE="width: 320"] [TR] [TD]f/stop[/TD] [TD]N[/TD] [TD="align: right"][B]36 [/B][/TD] [TD="align: right"][B]32 [/B][/TD] [TD="align: right"][B]8[/B][/TD] [/TR] [TR] [TD]CoC[/TD] [TD]c[/TD] [TD="align: right"]0.02[/TD] [TD="align: right"]0.02[/TD] [TD="align: right"]0.02[/TD] [/TR] [TR] [TD]Magnification[/TD] [TD]m[/TD] [TD="align: right"]1[/TD] [TD="align: right"]1[/TD] [TD="align: right"]0.5[/TD] [/TR] [TR] [TD][/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD][/TD] [TD][B]DOF[/B][/TD] [TD="align: right"][B]2.88[/B][/TD] [TD="align: right"][B]2.56[/B][/TD] [TD="align: right"][B]1.92[/B][/TD] [/TR] [/TABLE] [TABLE="width: 256"] [TR] [TD="align: right"][/TD] [/TR] [/TABLE] And for the FX: [TABLE="width: 267"] [TR] [TD]f/stop[/TD] [TD]N[/TD] [TD="align: right"][B]32 [/B][/TD] [TD="align: right"][B]8 [/B][/TD] [/TR] [TR] [TD]CoC[/TD] [TD]c[/TD] [TD="align: right"]0.03[/TD] [TD="align: right"]0.03[/TD] [/TR] [TR] [TD]Magnification[/TD] [TD]m[/TD] [TD="align: right"]1[/TD] [TD="align: right"]0.5[/TD] [/TR] [TR] [TD][/TD] [TD][/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD][/TD] [TD][B]DOF[/B][/TD] [TD="align: right"][B]3.84[/B][/TD] [TD="align: right"][B]2.88[/B][/TD] [/TR] [/TABLE] Using this formula, the calculated DOFs are not the same for 1:1 at f/32 and 1:2 at f/8. [/QUOTE]
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1:1 at f/36 Versus 1:2 at F/8 Cropped
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