Maybe look at TCs?

I think the focal distance and cost mix is about right but wondered if there would be value in looking at some of the medium focal length lenses (200-300mm range) with 1.4X or even 2X "teleconvertors"?

For some of us less wealthy and / or new wildlife photographers these can appear very tempting. It would be nice to have a definitive view on how effective (or not) they are.

It is something that I have been working on Brian, however, there are some complications with actual test figures and results.

For instance, the same problems with different sensors arise, so getting meaningful data to compare one brand against another is difficult.
I suppose that I could do the 'independent brands against the main brands if the independents are willing to play ball and supply converters in (both) the main brand fittings.

I'll look into it.

Ian

I have never seen a clear review comparing the third party TC like Kenko/Tamron to a Nikon or Canon converter

I like to see the comparison of a 1.4 converter first, since those provide the least degradation. I am Nikon fan, so a TC14E vs the comparable Kenko/Tamron SP would be nice.

This would be great - however the difficulty I see is that performance seems to vary with each lens/TC/body combination.

There are also lots and lots of compatability issues. Maybe you could start a user maintained database of compatibility and user comments. For instance, the Kenko Pro's work fine on my Sigma 400mm APO f5.6 Tele Macro with a D70, but on a D200 it underexposes one f-stop. On a Sigma 500mm f4.5 EX APO HSM on a D200 the Kenkos won't AF reliably, the Sigma 1.4x doesn't even try to AF, but a modified TC-14E II AF's and exposes fine, but the focal length and aperture are reported as if the TC is not there. Etc, etc, etc. . .

I have both the Nikon AF 180mm f2.8 and the AF 300mm f4 and the Tamron 1.4x SP does not noticebly effect the autofocus on both lenses on my F100. I get correct exposures on both leneses with the F100. I would like to see the results for the TC-14E to see if I want to spend the extra money.

BTW, I read that autofocus on Nikon above is 5.6 is marginal, that may explain the result that you get, but the 14E working better is interesting.

I am expecting a similar tests to be done soon. Regardless of the sensors, body and lens, I still think this is a possible projecto to be carried out. For me I have been noticing the disatrous degradation of optical quality for 2.0TC but not so with 1.4.