400/6.8 vs. 180/3.4 APO w/ 2x

<p>This is an interesting question I haven't seen discussed. Other then the 10% decrease in focal length, do you lose anything by using a 180mm f/3.4 APO w/ 2x extender over the 400mm f/6.8? I understand the 180mm lens does well w/ the 2x extender, and for those mathematically challenged, the extender on the 180mm lens gives a 360mm/6.8.</p>

<p>I no longer have access to a 180mm f/3.4 APO so I can't do an optical test... but the biggest difference is handling. The 180 + extender would be best suited to use on a tripod, the 400mm f/6.8 is best without a tripod. The intended use of either lens would dictate which is more suitable much more than any optical differences.</p>

<p>I still have the 400 and 180/3.4 APO, but I don't have a 2x extender, hence cannot do a side by side test. However from from ease of operation, I agree with Doug, the push pull mechanism of 400/6.8 is much faster in focusing, the rotating ring focusing mechanism of<br>

180/3.4 is slow in action</p>

<p>I have used both these combinations. No longer have the 400/6.8 . This is what I remember. <br>

The 400/6.8 was an excellent lens ..high IQ and designed for hand held use. Lightweight and breaks down for transport.<br>

The 180/3.4 with the 2x lost quite a bit of contrast and resolution..personally I didn t like the IQ .<br>

The 180/2x handles poorly with slow focus. The older 180/2.8 67mm handles much better . <br>

The 180/2x was in my bag when I needed it at the 96 olympics and I got the gold medal winning vault from the 7th row .<br>

The 180 2.8 apo and the 1.4apo extender (a lot more expensive) is a best in class solution.</p>

 

<p>I have used both these combinations. No longer have the 400/6.8 . This is what I remember. <br>

The 400/6.8 was an excellent lens ..high IQ and designed for hand held use. Lightweight and breaks down for transport.<br>

The 180/3.4 with the 2x lost quite a bit of contrast and resolution..personally I didn t like the IQ .<br>

The 180/2x handles poorly with slow focus. The older 180/2.8 67mm handles much better . <br>

The 180/2x was in my bag when I needed it at the 96 olympics and I got the gold medal winning vault from the 7th row .<br>

The 180 2.8 apo and the 1.4apo extender (a lot more expensive) is a best in class solution.</p>

 

<p>I have used both these combinations. No longer have the 400/6.8 . This is what I remember. <br>

The 400/6.8 was an excellent lens ..high IQ and designed for hand held use. Lightweight and breaks down for transport.<br>

The 180/3.4 with the 2x lost quite a bit of contrast and resolution..personally I didn t like the IQ .<br>

The 180/2x handles poorly with slow focus. The older 180/2.8 67mm handles much better . <br>

The 180/2x was in my bag when I needed it at the 96 olympics and I got the gold medal winning vault from the 7th row .<br>

The 180 2.8 apo and the 1.4apo extender (a lot more expensive) is a best in class solution.</p>

 

<p>I have used both these combinations. No longer have the 400/6.8 . This is what I remember. <br>

The 400/6.8 was an excellent lens ..high IQ and designed for hand held use. Lightweight and breaks down for transport.<br>

The 180/3.4 with the 2x lost quite a bit of contrast and resolution..personally I didn t like the IQ .<br>

The 180/2x handles poorly with slow focus. The older 180/2.8 67mm handles much better . <br>

The 180/2x was in my bag when I needed it at the 96 olympics and I got the gold medal winning vault from the 7th row .<br>

The 180 2.8 apo and the 1.4apo extender (a lot more expensive) is a best in class solution.</p>

 

<p>Roger, you've had lots of lenses lots of times, apparently.</p>