100-400 mfd with extension?

[jeff_nolten]

Can someone tell me what the minimum focus distance, or working focus

range, of the Canon 100-400 L lens is using the 12 or 25 mm extension

tubes? I have the 500D but I'd like a working distance between its

18" max focus distance and the 100-400's normal 6' mfd.

 

Thanks in advance -Jeff

[eosdoc]

EF 100-400 IS USM<BR>

<table>

<TR><TH></TH><TD rowspan=4> </TD><TH>Max<BR>Magnification</TH><TD rowspan=4> </TD><TH>Focus<BR>Distance</TH></TR>

<TR><TD>Lens alone</TD><TD align=center>0.20x</TD><TD align=center>1.8m</TD></TR>

<TR><TD>with 12mm extension</TD><TD align=center>0.25x</TD><TD align=center>1.5m</TD></TR>

<TR><TD>with 27.25 extension</TD><TD align=center>0.31x</TD><TD align=center>1.3m</TD></TR>

</table>

[jimdavis]

Dunno about those figures from the book, but distance is way different at different focal lengths. I only have a 25mm tube and it's the best one for long lenses. At 100mm, I can focus pretty close for higher magnification. At 400mm, focus is further out from camera and good for stuff you can't get very close to. Nothing scientific here but you can ger quite close at 100mm. From memoery, at 100mm, focus from about 12 to 24 inches. At 400mm from about 5 feet to 12 feet. And of course focal lengths between fill in the distances. I have got a few good bug closeups, not frame filling but nice at 100mm, while I've shot butterflies at 400mm from quite a distance.

[karl_lehmann]

Julian's figures are for 400mm, you will do much better at 100mm. The 25mm tube will cover the whole range at 100mm but both tubes will give you more flexibility. You get the highest magnification (not just the closest focus) at 100mm.<P>Here are some quick empirical measurements:<P>

 

<table>

<TR><TH></TH><TD rowspan=5> </TD><TH>Min Distance<BR>from<BR>Front Element</TH><TD rowspan=5> </TD><TH>Min Distance<BR>from<BR>Film Plane</TH></TR>

 

<TR><TD>100mm, EF25 tube</TD><TD align=center>11.4" (30cm)</TD><TD align=center>21.5" (55cm)</TD></TR>

 

<TR><TD>100mm, EF12 tube</TD><TD align=center>19.75" (50cm)</TD><TD align=center>21.5" (75cm)</TD></TR>

 

<TR><TD>100mm, both tubes</TD><TD align=center>8.25" (21cm)</TD><TD align=center>19" (48cm)</TD></TR>

 

<TR><TD>400mm, both tubes</TD><TD align=center>36" (91cm)</TD><TD align=center>50" (1.27m)</TD></TR>

 

</table></div><P>You can also get a set of three tubes from Kenko for less than the price of the two from Canon, and the Kenko tubes are probably just as good.<p>Karl Lehmann <a href="http://www.lostworldarts.com/new_page_3.htm">Lost World

Arts</a>

[eosdoc]

Taking up Karl's suggestion, I mounted my 100-400 IS lens on a

set of Kenko extension tubes and measured:

<table>

<tr><th>Zoom</th>

<th rowspan=8> </th>

<th>Extension</th>

<th rowspan=8> </th>

<th>Working<br>distance</th>

<th rowspan=8> </th>

<th>Focus<br>distance</th></tr>

<tr><td>100mm</td>

<td> </td>

<td align=center>1.47m</td>

<td align=center>1.70m</td></tr>

<tr><td>100mm</td>

<td>12mm</td>

<td align=center>0.53m</td>

<td align=center>0.77m</td></tr>

<tr><td>100mm</td>

<td>12+20+36mm</td>

<td align=center>0.13m</td>

<td align=center>0.43m</td></tr>

<tr><td> </td>

<td> </td>

<td align=center> </td>

<td align=center> </td></tr>

<tr><td>400mm</td>

<td> </td>

<td align=center>1.44m</td>

<td align=center>1.74m</td></tr>

<tr><td>400mm</td>

<td>12mm</td>

<td align=center>1.2m</td>

<td align=center>1.52m</td></tr>

<tr><td>400mm</td>

<td>12+20+36mm</td>

<td align=center>0.07m</td>

<td align=center>0.45m</td></tr>

</table>

<P>

The following tables is for those who need the measurements in inches:

<table>

<tr><th>Zoom</th>

<th rowspan=8> </th>

<th>Extension</th>

<th rowspan=8> </th>

<th>Working<br>distance</th>

<th rowspan=8> </th>

<th>Focus<br>distance</th></tr>

<tr><td>3" ^{<small>15</small>}/<small><small>16</small></small></td>

<td> </td>

<td align=center>58"</td>

<td align=center>67"</td></tr>

<tr><td>3" ^{<small>15</small>}/<small><small>16</small></small></td>

<td>^{<small>15</small>}/<small><small>32</small></small>"</td>

<td align=center>21"</td>

<td align=center>30"</td></tr>

<tr><td>3" ^{<small>15</small>}/<small><small>16</small></small></td>

<td>^{<small>15</small>}/<small><small>32</small></small>"+^{<small>25</small>}/<small><small>32</small></small>"+1" ^{<small>13</small>}/<small><small>32</small></small></td>

<td align=center>5" ^{<small>1</small>}/<small><small>8</small></small></td>

<td align=center>16" ^{<small>15</small>}/<small><small>16</small></small></td></tr>

<tr><td> </td>

<td> </td>

<td align=center> </td>

<td align=center> </td></tr>

<tr><td>15" ^{<small>3</small>}/<small><small>4</small></small></td>

<td> </td>

<td align=center>57"</td>

<td align=center>68.5"</td></tr>

<tr><td>15" ^{<small>3</small>}/<small><small>4</small></small></td>

<td>^{<small>15</small>}/<small><small>32</small></small>"</td>

<td align=center>47"</td>

<td align=center>60"</td></tr>

<tr><td>15" ^{<small>3</small>}/<small><small>4</small></small></td>

<td>^{<small>15</small>}/<small><small>32</small></small>"+^{<small>25</small>}/<small><small>32</small></small>"+1" ^{<small>13</small>}/<small><small>32</small></small></td>

<td align=center>2" ^{<small>3</small>}/<small><small>4</small></small></td>

<td align=center>17" ^{<small>11</small>}/<small><small>16</small></small></td></tr>

</table>

[eosdoc]

Formatting in this thread was broken because of an unbalanced

<DIV> tag in Karl's last post.<P>

For future reference, close focus and magnification data can

be found at the eosdoc page for the 100-400 IS USM lens:<BR>

 <a target=eosdoc href=

http://eosdoc.com/manuals.asp?q=EF100-400LIS

>http://eosdoc.com/manuals.asp?q=EF100-400LIS</a>