Image quality: Extender on FF vs crop

Wilt wrote in post #16780379
I
This also really is the 'optical vs. digital zoom' issue! Should I crop to leave (fewer than captured) pixels, or should I use a telextender that zooms in a comparable amount...optical zoom is always better than lopping off pixels.

As I see it, it's an issue of optical cropping verses optical tele-converting.
Either you are cropping the image circle, or you are expanding the image circle with additional glass. It is not obvious which method should work better. As placing double the amount of pixels in a smaller area, as APS-C does, also demands more resolving power of the lens.

Canon 5D Mark III - Leica M240
EF 16-35mm F/4 IS L - EF 14mm f/2.8 L II - - EF 17mm TS-E L - EF 24-70mm f/2.8 L II - EF 70-200mm IS II f/2.8 L - Sigma 35mm f/1.4 Art - Sigma 85mm f/1.4 EX
Voigtlander 15mm III - 28mm Elmarit-M ASPH - 35mm f/1.4 Summilux-M FLE - 50mm f/1.4 Summilux-M ASPH
500px

Canon G1X II, 1D MKIV, 5DSR, 5DIV, 5D MKII, 16-35/2.8L II, 24-70/2.8L II, 70-200/2.8L IS II, IS, 100-400/4.5-5.6 L IS II, 500/4 L IS II, 24-105/4 IS, 50/2.5 macro, 1.4x MKII, 1.4X MKIII, 2X MKIII,580EX II, 550EXs(2), ST-E2.
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Canon 5D Mark III - Leica M240
EF 16-35mm F/4 IS L - EF 14mm f/2.8 L II - - EF 17mm TS-E L - EF 24-70mm f/2.8 L II - EF 70-200mm IS II f/2.8 L - Sigma 35mm f/1.4 Art - Sigma 85mm f/1.4 EX
Voigtlander 15mm III - 28mm Elmarit-M ASPH - 35mm f/1.4 Summilux-M FLE - 50mm f/1.4 Summilux-M ASPH
500px

Here's a comparison between a crop and a FF body, having the exact same MP count (70D and 6D)

70D with a 1.4x TC, while 6D has a 2x TC on. Shot from the same spot. Lens: Sigma 120-300 2.8 OS at 230mm
Yes, I know the 6D +2x was at wide open, but I wanted to compare f/5.6

SONY A7RIII | SONY A7III | SONY RX10 IV | SONY RX100 | 24-70 2.8 GM | 70-200 2.8 GM | 16-35 F/4 | PZ 18-105 F/4 | FE 85 1.8 | FE 28-70 | SIGMA 35 1.4 ART | SIGMA 150-600 C | ROKINON 14 2.8
Gabe Balazs Photo
Nature Shots Portfolio

A couple more samples with a different target and this time at roughly 200mm, similar to a 70-200mm II at 200mm. (The 2 lenses have similar sharpness at 200mm)
In the 1.4x vs 2x image I did stop down 1 stop both combos.
100% crops

SONY A7RIII | SONY A7III | SONY RX10 IV | SONY RX100 | 24-70 2.8 GM | 70-200 2.8 GM | 16-35 F/4 | PZ 18-105 F/4 | FE 85 1.8 | FE 28-70 | SIGMA 35 1.4 ART | SIGMA 150-600 C | ROKINON 14 2.8
Gabe Balazs Photo
Nature Shots Portfolio

I've posted these before, but let's do it again.

Two images of same subject, both at ISO 6400, one with a 7D + EF 70-200 mm f/2.8L IS II USM and the other with the 1DX + EF 70-200 mm f/2.8L IS II USM + EF Extender 1.4X III in that order.

Here's another pair with the same hardware.

Anders

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Canon dSLR system, Olympus OM 35mm system, Bronica ETRSi 645 system, Horseman LS 4x5 system, Metz flashes, Dynalite studio lighting, and too many accessories to mention

Wilt wrote in post #16782205
Can folks please put a label next to a shot, so in A-B comparison series one can determine which is which, with certainty? Or at least preface the two, stating which comes first.

I thought on this page everything was labeled or indicated in the text. At least mine were.

SONY A7RIII | SONY A7III | SONY RX10 IV | SONY RX100 | 24-70 2.8 GM | 70-200 2.8 GM | 16-35 F/4 | PZ 18-105 F/4 | FE 85 1.8 | FE 28-70 | SIGMA 35 1.4 ART | SIGMA 150-600 C | ROKINON 14 2.8
Gabe Balazs Photo
Nature Shots Portfolio

gabebalazs wrote in post #16782229
I thought on this page everything was labeled or indicated in the text. At least mine were.

I am guessing about which photo is which in the pairs seen in post 21...I see the same issue in other threads a lot.

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Anders

My findings are (at least between the 7D and 5D3) that the 7D plus lens is better than FF with same lens (then cropped and resized up to match), but the FF with a 1.4x TC was very, very close to the 7D with same lens no TC.

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They look near identical to me.

Hmm, lets take a look at Digital Picture.

1D3 + 2x Extender III + 70-200 IS II 2.8

60D + 70-200 IS II 2.8

Canon 5D Mark III - Leica M240
EF 16-35mm F/4 IS L - EF 14mm f/2.8 L II - - EF 17mm TS-E L - EF 24-70mm f/2.8 L II - EF 70-200mm IS II f/2.8 L - Sigma 35mm f/1.4 Art - Sigma 85mm f/1.4 EX
Voigtlander 15mm III - 28mm Elmarit-M ASPH - 35mm f/1.4 Summilux-M FLE - 50mm f/1.4 Summilux-M ASPH
500px

Canon 5D Mark III - Leica M240
EF 16-35mm F/4 IS L - EF 14mm f/2.8 L II - - EF 17mm TS-E L - EF 24-70mm f/2.8 L II - EF 70-200mm IS II f/2.8 L - Sigma 35mm f/1.4 Art - Sigma 85mm f/1.4 EX
Voigtlander 15mm III - 28mm Elmarit-M ASPH - 35mm f/1.4 Summilux-M FLE - 50mm f/1.4 Summilux-M ASPH
500px

SONY A7RIII | SONY A7III | SONY RX10 IV | SONY RX100 | 24-70 2.8 GM | 70-200 2.8 GM | 16-35 F/4 | PZ 18-105 F/4 | FE 85 1.8 | FE 28-70 | SIGMA 35 1.4 ART | SIGMA 150-600 C | ROKINON 14 2.8
Gabe Balazs Photo
Nature Shots Portfolio

gabebalazs wrote in post #16783116
That loss of sharpness on the crop is not typical.

I suspect this may be because the resolving power of the 200mm f/2 is much higher than the 70-200mm IS II. It exceeds the resolving power of a 20MP FF sensor and can provide enough resolution for the pixel density of a APS-C sensor! Yet it doesn't seem to suffer a teleconverter well...

Canon 5D Mark III - Leica M240
EF 16-35mm F/4 IS L - EF 14mm f/2.8 L II - - EF 17mm TS-E L - EF 24-70mm f/2.8 L II - EF 70-200mm IS II f/2.8 L - Sigma 35mm f/1.4 Art - Sigma 85mm f/1.4 EX
Voigtlander 15mm III - 28mm Elmarit-M ASPH - 35mm f/1.4 Summilux-M FLE - 50mm f/1.4 Summilux-M ASPH
500px