D850 w/ Tamron 85mm f/1.8 VC v. D500 w/ Sigma 50-100mm f/1.8 Art

It's raining outside this morning, which gave me a chance to complete a comparison between my just acquired D850 and my trusty old D500 using a couple of fast lenses intended (by me anyway) for informal, shallow DOF candid photos. These comparisons are best viewed (using Chrome anyway) in a separate tab. On more thing, I can't edit the title of the thread, otherwise I would correct the f/2 on the Sigma Art lens, it's an f/1.8 lens.

I took a couple of approaches to comparing these camera/lens combos. First I did an equivalent series, and it's pretty clear to me that the D850/Tamron combo came out ahead of the D500/Sigma combo at 85mm, with an equivalent of 128mm being a tie, and an equivalent of 135mm putting the latter combo ahead:

Next, I did the 128mm and 135mm equivalent focal lengths but shot both lenses at f/2:

Here the Sigma really shines in terms of sharpness SOOC, though with a second pass of Smart Sharpening and the addition of a tonal curve to the Tamron shot (whereas the Sigma shots had one pass of Smart Sharpening and no added curve) the differences become more negligible even when viewed at 100%. It should be noted that in all my testing so far that even at 4K, after some judicious PP, the two cameras are practically indistinguishable AFAIC -- YMMV.

Unfortunately for me, your representations here are much too small to give a good idea of your results
In the end, are you sorry for the lack of difference, or satisfied knowing that your D500 can stand up to the D850?

Are you viewing the results in a separate tab? I did mention that in the first paragraph. I see a difference.

In the wide open shots, after being processed, there's a small difference with these lenses using the same focal length, so that's not going to be something to see no matter how large I make the display. Should I upsize to 300% to make it more evident? The softness of the Tamron SOOC at f/2 is plainly visible, to me.

It's as much about the lenses as it is about the cameras here. The Sigma 50-100mm f/1.8 Art is a larger and more expensive lens than the Tamron 85mm f/1.8 VC, so it's not surprising to me that the Sigma which goes wider and narrower than the Tamron also outperforms it wide open. The thing is that there is also a question of equivalence, so the Tamron mounted on the D850 at f/2.8 matches the Sigma mounted on the D500 at f/2, and at that particular FOV and aperture diameter the D850/Tamron combo does significantly better than the D500/Sigma combo. I would add that I think the bokeh of the Tamron is much nicer than the bokeh of the Sigma (which I consider to be often problematic).

Another test I did that I didn't bother sharing here was between the D850 using the AF-S NIKKOR 24-70mm f/2.8G and the D500 using the Tokina ATX-Pro 14-20mm f/2. At f/11 and 24mm on the former and f/8 and 16mm on the latter there is practically no difference between them. I think the reason for that is similar to what I think is going on in the comparison I showed, and that is the qualities of the lenses being used and the benefit of the lens engineered for the smaller format covering a smaller image circle. However, at f/11 and 29mm compared to f/8 and 20mm the D850 pulled way ahead of the D500, and a couple of days ago I stopped to get a shot with the D850 and the aforementioned NIKKOR and I think I was able to make a rather nice photo with excellent image quality (it turned out that I had zoomed the NIKKOR to 42mm):

A more relevant question might be how the image quality of my D850 compares to my D800. Depending on the lens, the difference can range from none at all to marginal. Still, the shooting experience is better with the D850 and I expect that to yield some better results above and beyond the bare image quality offered by these cameras. After all, I've had the D800 and D500 side-by-side for awhile now, and I had found myself consistently reaching for the D500 over the D800 just because it is a more versatile and enjoyable camera.

Ok, I just realized that you have to force it (right-click) to open your photos in another tab.
It's much better, bigger thank you.