This gallery is dedicated to showing the difference in final results shooting scenic telephoto with a Kenko 2X extender using the Nikkor AF 300mm F4 lens along with four different bodies representing four different resolutions. In addition, comparisons are made available of the lens' performance without telextender, and of its performance compared to the faster and more expensive AF-S 300mm F2.8, the "Gold Standard" of 300mm lenses.

The first row of photos approximates 8x10" print size (although obviously only at screen resolution). The second row approximates 13x19" print size.

The first page is recent and was done on several different reasonably sunny days. All bodies proved to be sharp with the 300mm f/4 plus Kenko combination, with the exception of the Nikon D300. The D300 shots, taking the best of the bunch, were woefully short of the D50 and D1X shots in per-pixel clarity. I repeated the tests twice more with the same results. I've included here the best shot, focused manually. It is still soft and smeared at the pixel-level. Most recently I've added shots from the D7000 at almost identical time of year and conditions. I've concluded that the AF 300mm f/4 along with the 2X TC is simply not sharp enough for these high resolution bodies, even when shot on a tripod and with mirror up. This lens used with the D1X and D50 (larger photostites)is clearly much less fussy.

All photos were taken at F8 on a Manfrotto tripod using the RC2 system. Cameras were optimized as best possible for lack of vibration (remote - D50, timer - D1H and D1X, mirror up - D300, mirror up - D7000). Focus was single area, single shot, and metering was centerweighted.

On the second page, I've included shots of the same target taken in prior years with the AF-S 300mm f/2.8 using the D50 body. This lens is the holy grail of lenses when using telextenders, and so this shot is a good comparison standard for the AF F4 lens with D50 combination. I've also included shots of another target - the Summit House - taken with the D300 and the AF 300mm F4 without TC, showing this (pixel-dense) combination's improved performance without telextender. The AF 300mm apparently just passes muster without the TC added, as this shot is not far behind that done with the AF-S 300mm f/2.8.

Finally I've printed these photos at 8x10" on a Canon MP610 printer, using a TIFF that has been expanded to 4800x6000 pixels and printed at 600ppi. Viewed this way, the D1X and the D50 lead in apparent resolution, the D300 is still a noticeable tiche behind. Not surprisingly, at this size the D1H begins to have problems.

All in all, this testing has shown me that this older, less expensive telephot lens used on tripod is still a fine performer, and mates well with 5-6mp bodies, even used with a TC. With DX bodies above 6mp the gains in resolution of lens alone (without TC) are really very tiny, and when a TC is added, the smaller photostites (as in the D300) see the resolution limit of the lens combo, resulting in pixel-smear and a higher percentage of slightly OOF shots. In light of this, my current advice would be to stay with 6MP DX unless you are using Nikon's finest telephoto lenses, and when upgrading to more pixels, then move to the large photostite 12mp full frame Nikons (D3, D700) rather than to the 12mp D300, D90, or D5000 DX bodies. The 12mp DX sensors can create wonderful pictures, but they can also cause many to be less than optimally sharp.