Do we still need a TC?

Started Nov 11, 2013 | Discussions thread
JNR Veteran Member • Posts: 3,331
Re: Do we still need a TC?

viking79 wrote:

I did a resolution test of an SMCP-A 50mm f/1.7 and a Vivitar 2x macro focusing extender, and the TC was much better than cropping to 100 mm field of view. This was on a 16 MP Sony NEX camera, K-3 might differ for crop, but not enough to match the TC.

I haven't posted results for it, will try to soon. Been doing some other lens reviews.

However, the TC was only decent above f/4 on lens (f/8 including TC). This combination was similar resolution to the SMCP 100mm f/4 macro, but not at equivalent apertures. The macro at f/4 was more like TC+50mm at f/8 (set at f/4 - 2 stops for TC).

My point is, with a good sharp prime and quality TC should still be a little better than cropping. The trade off point with K-3 will mean you need even better TC and lens to get better results than cropping. TC on small aperture lens is probably no gain, but I haven't tested as I can't get that far away from my chart. Your best bet is get a lens of the needed focal length of course, it might not be sharper than lens with TC but should be larger aperture.


Seems to confirm the conventional wisdom. That is, a good, fast prime will benefit most. I suspect a few good zooms can benefit if they are fast. Diffusion limits are going to pose a problem as much as dark screen issues on the slower lenses. The resolution question is a real factor. I never hesitated to use a TC when shooting the Canon 5D - which had a larger pixel pitch than the original 6 mp sensors on Pentax and Nikon.

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