| Joined: | Wed Apr 18th, 2012 |
| Location: | United Kingdom |
| Posts: | 4186 |
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Using (some cameras) internal crop feature (eg D500/D850 and other FX bodies) means you keep the fstop/shutterspeed/iso advantage that's lost with a TC. Of course that may only be a stop, but that could be significant when exposure parameters are being pushed by lighting and subject movement. The same applies to a post process crop, I assume.
Of course there's the question of whether the cropped image, with reduced mp and enlarged noise, is acceptable quality. But the perceived wisdom is that using a TC not only loses exposure latitude but image quality.
Until I got the Nikon 1.4 III, I had tried and finally discarded every TC I owned That includes, the Sigma, KenkoPro3000, Nikon earlier versions...and a few Canon versions back in the day. It's not that they weren't good, more that they all created images that needed more post processing to attempt to bring out the detail seen in the bare lens images. In addition the responsiveness of the focusing suffered, albeit only a tad.
The Nikon 1.4 III is something different ....image IQ seems to be uncompromised. But the above exposure loss discussion still applies and to some extent there is some loss of focus responsiveness.
I've yet to personally evaluate the perceived advantage of in camera cropping as opposed to using the TC, but looking back, I've often preferred a photoshop crop of a bare lens photo over the TC straight image. Similarly, cropping an FX photo compared to a DX photo.
The final point on TCs is they are best used on prime lenses. Maybe it was the quality of my zooms (there is inherent variability in zoom lenses) but I always found that a TC seemed to find out the limitations in my zooms...invariably at the long end where it was needed.
Just my 2 cents
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Eric