When I first started learning portraiture, I went out and picked up an 85mm lens. Everything I read said for headshots and above-the-waist portraits, 85mm was the lens to use. I eventually picked up a 50mm prime as well for full body shots. I was happy with the results with both lenses, and used them for years. The only catch was I was shooting on a crop sensor body, first with a Nikon D5100, then with a D500. Other than needing more space to shoot, I didn't think much of it. Having recently switched to full frame (Nikon Z6), I figured the same guidance applied, but I could stand a little closer to my subjects, and obtain a shallower depth of field with the same lenses if desired. However I decided to take some test shots, and the results weren't quite what I expected. First, I compared headshots taken at 50mm and 85mm, both on my D500. I typically don't take tight portraits at 50mm, but also didn't think it would be terrible. The results were as expected, albeit a bit more exaggerated than I would have thought. It is pretty clear that the face gets quite distorted shooting this tight with the 50mm. Since 50mm on a crop sensor is roughly the same field of view as 85mm on full frame (technically 75mm), I figured I would compare the two. Below, we can see that despite 85mm being the "ideal" focal length for portraits, it isn't all that different from 50mm on a crop sensor in terms of facial distortion. So does that mean same 85mm lens on both cameras would look significantly different? It turns out it does, with 85mm on the Z6 showing the same distortion as the 50mm did on the D500. Note that the D500 was a bit further from the subject to accomplish the same framing. Thenext logical step was to perform the same test with equivalent focal lengths from the same distance again. That meant 85mm on the D500, and 135mm (70-300 zoomed to 135) on the Z6. And look at that, the facial distortion is gone on both. Please excuse the head position at 135mm, I must have bumped it at some point. Lastly, I wanted to see if the difference really was so significant between 85mm and 135mm on the Z6. While not quite as pronounced as the difference between 50mm and 85mm on the D500, the facial distortion is still noticeable. That leaves me with two questions. Is 85mm really the best focal length for headshots and above-the-waist portraits? Is the facial distortion something to be concerned about, or is that a normal perspective of how we see people from 4-6' away? Would a longer focal length be more flattering if I have the space to support it? I've heard great things about some of Sigma's Art glass, particularly the 135mm f/1.8. I've also been curious about their 105mm f/1.4 and its comically large size, particularly on a smaller mirrorless body. It's worth noting that 85mm is currently the longest native Z-mount prime. I would love to hear from portrait photographers on here - what you typically shoot with, what you would recommend, and your thoughts on whether or not the perspective at these focal lengths is pleasing.