Photo Experiment - Don't Do -- OR PERHAPS DO -- This At Home
Jun 18, 2020 13:50:43 #
I have this 18-140 zoom lens that I usually just keep on the D90 Infrared camera body. That is a DX or APS-C setup regarding sensor size, i.e. "DX" in Nikon terms being smaller than the "FX" or full-size sensor in my D700.
I got to wondering what would happen if I attached my 1.4X TC (teleconverter) to the lens and used it on my D700. I already knew the DX lens wouldn't fill the entire FX frame. So why do it? That lens is the only one I have that has image stabilization and I thought it might be okay for a small distant subject where I'd crop down and only use the center pixels of the frame anyway. Surprise, surprise! It not only filled the FX frame on the D700, but did so at full zoom on the 140 mm end of its range where that arrangement would usually yield the smallest image circle. Depending on the particular lens, the wide-angle end of the zoom range can fill or almost fill the FX frame with this kind of setup.
No, I don't recommend this as sound practice to follow. I was just surprised and wanted to pass it along. I would suspect that the "unexpectedly filled" edges are probably not as sharp as a "correct" lens would produce, etc., but that's beside the point.
The attached full-frame photo from the D700/TC/DX lens combo (max zoom & not cropped) was just a quick hand-held test shot above the roofs of some houses at the end of the street. I used Photoshop to remove part of a transformer near the bottom left side of the photo and a cluster of wires leading to it. I also removed a couple of overhead wires that went from the lower left side of the photo toward the red-colored tree on the right, plus the top of a vent or chimney that was at the bottom center of the photo. For illustrative purposes I didn't want to crop the photo but didn't like that kind of junk in a scenic view either. There was a little bit of vignetting at the corners, but no more than some lenses normally do. View the download for a closer look (full frame but reduced in size for web and e-Mail -- it displays approx. 12" x 8" on my monitor).
I got to wondering what would happen if I attached my 1.4X TC (teleconverter) to the lens and used it on my D700. I already knew the DX lens wouldn't fill the entire FX frame. So why do it? That lens is the only one I have that has image stabilization and I thought it might be okay for a small distant subject where I'd crop down and only use the center pixels of the frame anyway. Surprise, surprise! It not only filled the FX frame on the D700, but did so at full zoom on the 140 mm end of its range where that arrangement would usually yield the smallest image circle. Depending on the particular lens, the wide-angle end of the zoom range can fill or almost fill the FX frame with this kind of setup.
No, I don't recommend this as sound practice to follow. I was just surprised and wanted to pass it along. I would suspect that the "unexpectedly filled" edges are probably not as sharp as a "correct" lens would produce, etc., but that's beside the point.
The attached full-frame photo from the D700/TC/DX lens combo (max zoom & not cropped) was just a quick hand-held test shot above the roofs of some houses at the end of the street. I used Photoshop to remove part of a transformer near the bottom left side of the photo and a cluster of wires leading to it. I also removed a couple of overhead wires that went from the lower left side of the photo toward the red-colored tree on the right, plus the top of a vent or chimney that was at the bottom center of the photo. For illustrative purposes I didn't want to crop the photo but didn't like that kind of junk in a scenic view either. There was a little bit of vignetting at the corners, but no more than some lenses normally do. View the download for a closer look (full frame but reduced in size for web and e-Mail -- it displays approx. 12" x 8" on my monitor).
Jun 18, 2020 15:02:38 #
Jun 18, 2020 16:50:13 #
dar_clicks wrote:
I have this 18-140 zoom lens that I usually just k... (show quote)
Edit: I have an error in my original entry -- The last time I had experimented with this was at a family gathering in 2012 when a couple of us swapped lenses and I had not remembered the results correctly.
The frame coverage is more complete at the telephoto end of the zoom's range. The circle of coverage gets smaller toward the wide-angle end. I apologize for getting that wrong earlier. My experimenting this time was using the maximum telephoto setting which had resulted in fairly decent coverage of the frame.
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