AF-S VR Micro NIKKOR 105mm 1:2.8G ED

[erik_christensen3]

<p>Is there any difference between the above lens (wording from my lens- no IF) and<br>

AF-S VR Micro NIKKOR 105mm 1:2,8G <strong>IF-</strong>ED lens?<br>

The reason I am asking is that I have just got a TC-20 III, and the user manual states it can be used with the 105mm with no limitation, whereas Nikon's teleconverter compatibility table states that auto-focus is not possible. I just tried it on my 105mm and AF functions like normal. Is it Nikon's table which has not been updated or am I missing something? </p>

[Michael R Freeman]

<blockquote>

<p><em>"...or am I missing something?"</em></p>

</blockquote>

<p>Same lens.</p>

<p>But it may not autofocus all that well <strong>at minimum focus</strong>, where the effective aperture of the combo will be much smaller than f/5.6. That's the reason for it being listed by Nikon as "incompatible" re: autofocus.</p>

[ShunCheung]

<p>There is only one version of Nikon's 105mm/f2.8 macro lens that has AF-S and VR. Any version prior to that did not have AF-S.</p>

[joseph_wisniewski]

<p>No. The only G 105m is the IF.</p>

<p>Remember, AF is based on angles and exit pupil sizes, it only works on lenses f5.6 and faster, even if there's a lot of light.The 105mm drops its aperture to f3.8 at 1:1, and on a 2x converter, that's f7.6. AF accuracy and performance fall as you pass f5.6, so Nikon isn't going to guarantee AF performance beyond that. You may think it's working, but it will end up off, by enough to be annoying, frequently.</p>

<p>At least Nikon leaves it in your hands whether to try or not. Another famous camera maker disengages AF when lenses go beyond f5.6, you can't even try. ;)</p>

[erik_christensen3]

<p>Thanks for your clarification - I thought that the AF would be disengaged, when lenses go beyond f5.6</p>

[ShunCheung]

<blockquote>

<p>Thanks for your clarification - I thought that the AF would be disengaged, when lenses go beyond f5.6</p>

</blockquote>

<p>That would be the case on certain C-brand models. Nikons will attempt to auto focus as Joseph describes, but it tends to AF hunt when your max aperture drops below f5.6, especially under dim light.</p>