Do we still need a TC?

Started 10 months ago | Discussions thread
JNR
JNR
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Re: Do we still need a TC?
In reply to viking79, 10 months ago

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.

Eric

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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JNR
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