Looking for a recommendation: AF teleconverter for non AF-I or AF-S prime

[martinangus]

<p>I have the older 300mm AF ED 1:4 prime lens and I'd like to teleconvert it to 1.4X <strong>WITH</strong> the AF function.<br />The Nikon TC-14E won't work on anything other than AF-I or AF-S lenses. So, what Tamron, Sigma etc TC will do the job for me?<br />Thanks</p>

[martinangus]

<p>A pic</p><div></div>

[frank_skomial]

<p>Kenko PRO 300 latest versions of teleconverter work with both AF and AF-S lenses. (focusing motor in the camera or in the lens).</p>

<p>They do Auto focus with lenses f=4 or 2.8 in average lighting conditions.<br>

Lenses with f=5.6 require good lighting. In dark places none works well with auto focus teleconverters.</p>

<p>Older Kenko were only AF (mechanical shaft focusing) converters, so make sure you get both features in one converter. </p>

[elliot1]

<p>Considering the pixel peeping you did on the thread you posted earlier this week, I have to assume IQ is of prime concern to you. As such, any TC will degrade IQ to a level you will probably not be satisfied with. If you are making small prints without cropping (4 x 6, 5 x 7), the Kenko converter will work for you. If you are making larger prints or cropping your images, there are better options if you have the budget for them.</p>

<p>The best teleconverter you can get for this lens without any loss in IQ would be a D7000 (unless you already are using this body) - its increase in resolution will allow you to easily crop your pictures to the 420mm equivalent and maintain high IQ quality in every regard. Plus you have the advantage of maintaining the f4 aperture. And AF speed. And AF accuracy. Any teleconverter you use with this lens will compromise all of these important attributes.</p>

<p>Another option for longer reach would be Nikon's 80-400mm VR lens. AF speed will be comparable to the 400/f4 and the IQ at 400mm will certainly be better than your lens with a TC.</p>

<p> </p>

[elliot1]

<p>Typo: that last sentence should read " AF speed will be comparable to the <strong>300/f4</strong>"</p>

[rodeo_joe1]

<p>Someone will doubtless suggest digital zooming or interpolation, but I'm not entirely convinced that interpolation gives results equal to those from a teleconverter. I tested this theory out a few months back and came to the conclusion that a <em>good</em> teleconverter was slightly better than digital zooming, especially with a low TC multiplication factor like 1.4. However a poor converter can be a complete IQ destroyer and introduce chromatic fringing that you just wouldn't get from digital enlargement.</p>

<p>There's no doubt in my mind that one of Nikon's TC-14 series converters would give excellent image quality, but you'd lose AF in the process. The protruding front elements of the converter are important in this respect, since they allow the converter to approach closer to the primary lens elements to reduce vignetting and chromatic errors. However, I'm not familiar enough with Sigma or Tamron's converter products to say how good they are - sorry. The best 3rd party converter I have personal experience with is an old Vivitar 2x macro/teleconverter, but these are no longer made, and anyway it's a manual focus converter. Worst was a 2x Komura "Telemore" without going into no-name off brand territory.</p>

[cwphoto]

<blockquote>

<p>T<em>he best teleconverter you can get for this lens without any loss in IQ would be a D7000 (unless you already are using this body) - its increase in resolution will allow you to easily crop your pictures to the 420mm equivalent and maintain high IQ quality in every regard. Plus you have the advantage of maintaining the f4 aperture. And AF speed. And AF accuracy. Any teleconverter you use with this lens will compromise all of these important attributes.</em></p>

<p><strong>I had the same dilemma. USe a D700. Thanks to you I just ordered a D7000 rather then a TC-14e. Makes sense, darn it. </strong><em><br /></em></p>

</blockquote>

[munim]

<p>Whether D7000 is a better choice depends on what you have now.<br>

I have the same lens, a Kenko 300 DGX 1.4 and a D90. I notice a significant decrease in contrast when using TC, so at times I take the TC off. A brighter lens, eg f/2.8, can tolerate TCs better. Many of my birding friends permanently attach Kenko TCs to their longer/brighter/more expensive lenses.<br>

Not sure if I have this right, so do comment. D7000 has 16.2 Mpix and D90 is at 12.3 Mpix. Going from D90 to D700 will get me a 1.3x increase in horizontal x vertical resolution. But using a TC1.4 gets me a 1.4 H x1 .4 W ~ 2.0x equivalent increase. IMHO, a D90/D300/D300s user is better off using a TC. I may get the D7000 later as the price drops, though.</p>