Here are some comparison shots using a 1Dmk2 with 1.3x crop factor.  <hr><br><Br>

<TABLE WIDTH="90%"  CELLSPACING="1" CELLPADDING="4" BORDER="1">

<h1>Lens test @ 12mm Center Crop</h1> 
<TR>
<TD>Simga 12-24mm f/4.5 - 5.6 @ 12mm
</TR>



<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/full.jpg">
<br>full image </TD>
</TR>

<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/cen/HP8F0487.JPG">
<br>Sigma f/4.5 </TD>
</TR>



<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/cen/HP8F0488.JPG">
<br> Sigma f/6.3 </TD>
</TR>


<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/cen/HP8F0489.JPG">
<br> Sigma f/9 </TD>
</TR>

<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/cen/HP8F0490.JPG">
<br> Sigma f/13 </TD>
</TR>



<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/cen/HP8F0491.JPG">
<br>Sigma f/22 </TD>
</TR>
</table><br><br><hr>



<TABLE WIDTH="90%"  CELLSPACING="1" CELLPADDING="4" BORDER="1">

<h1>Lens test @ 12mm Edge Crop</h1> 
<TR>
<TD>Simga 12-24mm f/4.5 - 5.6 @ 12mm
</TR>



<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/full.jpg">
<br>full image </TD>
</TR>

<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/edge/HP8F0487.JPG">
<br>Sigma f/4.5 </TD>
</TR>



<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/edge/HP8F0488.JPG">
<br> Sigma f/6.3 </TD>
</TR>


<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/edge/HP8F0489.JPG">
<br> Sigma f/9 </TD>
</TR>

<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/edge/HP8F0490.JPG">
<br> Sigma f/13 </TD>
</TR>



<TR>
<TD><img src =  "http://etischer.com/1dmk2/lenstests/12mm/edge/HP8F0491.JPG">
<br>Sigma f/22 </TD>
</TR>
</table><br><br><hr>