Kim, great photos! Beautiful work!

I'm really looking forward to the Z9, and I am happy to hear your experience with it. I do love my Z7 and Z6 II for most static subjects, the Z7 especially for landscapes and seascapes. https://capephoto.net

Yeah, currently I rely on the Z7 for landscapes and seascapes, whenever DR is needed. I think the Z9 will be more for that genre than for shots like the above, but I love playing with them all and seeing what they can do. I do think the D5 will be a keeper over the D850 once I have the Z9.

Ha! This topic is pretty well beaten to a pulp, but I have to add my tuppence because just last week I bought a D5 (with less than 3K clicks) and have been shooting and comparing it to my other three cameras: the Z7, Z6 II and the D850. So far, what I can see from real world shooting of backyard wildlife in low light, in trees, and on the wing, is the D5 is superior to the others, not so much for the low-light aspect of noise, although the D5 does seem to be better (see image attached); they are all pretty close in that respect and the noise can be mitigated in post. What's more amazing is the ability of the D5 to grab focus almost instantly and hold that focus on distant subjects, with the two long lenses I've been shooting with (Nikon 500mm PF and Sigma 60-600mm S). Shooting a bird in a tree behind or through branches, the D850 is slow and hunts, the Z6 II fails and the bird is gone, and I don't even bother trying those same shots with the Z7.

The other unexpected beauty of the D5 is the incredible sharpness of the photos I've been getting with it. It really reminds me of the D500: the camera performs much better than the specs say it should. The D5 images are easily equal to the D850 especially when processed with DxO PureRAW 2 and Enhanced in Lightroom to double the resolution. But again, it's the D5's focusing and tracking ability that wins me over. The D850 is good, the D5 is better.

As for the FPS, I don't like blasting off 120 frames in 10 seconds and have to deal with hundreds of images to sort through and rate or delete—it's a waste of time. Most birds in flight aren't going to be around much longer than 15-20 frames, and static subjects, well what's the point of shooting 12 fps when something is barely moving?

All that said, I do have a Z9 on order and if it ever gets here I'll have a heck of time deciding which one of the other cameras to keep as backup, because the IQ differences between the Z7, Z6 II, D850 and D5 are not a criteria for making that decision. And I really don't need 5 great cameras.

In case anyone is wondering, the workflow I used on the attached images is this: Make exposure adjustments in Lightroom Develop, and Crop > Enhance in Lightroom w/o Super Resolution > Process in DxO PureRAW 2 (an amazing plugin/app) > Enhance again in Lightroom for Super Resolution > Edit in Photoshop for final little tweaks and reduce for Web using Steve Perry's PS Action for doing so.

If you want the absolute best lens for your Nikon D7100, buy the Nikon AF-P 70-300 FX version. It is one of the sharpest and finest lenses Nikon has ever made; it's not a pro-grade build, but the optics are superior as is the AF and the VR. It is small-ish and lightweight compared to most other lenses in that room range. The difference between it and the older AF-S version can be measured in lightyears, don't waste your money on the old one. You can find a good used one at B&H for under $500.

Keep in mind that on your D7100 it is the equivalent of a 105-450mm. If you can afford a few more bucks, the Sigma 100-400mm is a good choice, and for more money still, the Tamron 100-400mm offers better weather-sealing than the Sigma with similar performance. Those will give you the equivalent of 150-600mm on your D7100.

As far as I can see, there are no other choices under $800 new. I do agree that the Sigma 150-600mm is also a good choice if you can find a really good one in your price range, however you may want to invest in a good tripod to go with it if you don't already have one.

I have bought refurb Nikons from both B&H and Adorama and have never been disappointed. Most often they are brand new cameras that haven't been selling so every once in a while they offer them as refurbs in white boxes with a shorter warranty period, 90 days vs 1 year. I bought my Z7 about a year ago as refurb from B&H for $2,100—it was brand spanking new with zero shutter count and have had no problems with it. I bought my refurbished D500 from B&H for $1,100 and it totally looked like new but had 517 shutter clicks—not a big deal. I bought a Z6 refurb that was also brand spanking new with zero shutter count for $1,299 about six months ago.

These deals don't happen all the time, and the refurb may not always be brand new, but they are usually close to it, especially cosmetically. I would NOT buy refurb Nikon lenses for one reason: you do not get the benefit of the 5 year warranty, and usually the price difference is not that great on lenses, which from my experience are just "used" lenses as there really isn't much to refurbish on a lens.

I've owned the Nikon 200-500mm as well as the Tamron 150-600mm G2 and the Sigma 150-600mm C, in my opinion none of them are really sharp enough consistently across the image. I suggest you read all the reviews of the Sigma 60-600mm S or the Sigma 150-600mm S, both are exceptional lenses with the 60-600mm being ever-so-slightly smaller and lighter than the 150-600mm (still both much heavier than the Nikon). The Sigma Sports lenses are well worth the extra money. The 60-600mm is simply amazing. Buy from B&H or Adorama, not, as everyone tells you, from Abe's, or 6th Ave, or various other online retailers who are not authorized US sellers. This goes for Nikon as well as Tamron and Sigma. The factory warranties are much better than the "store warranties."

Cooper's Hawk.

The text is smaller the higher the resolution. I find 1920 x 1080 Resolution (16:9) best for me; it is the same as the 1920 x 1200 (3:2) resolution of a 24" regular (non-widescreen) display, like this one: https://www.bhphotovideo.com/c/product/829236-REG/Dell_469_1137_U2412M_UltraSharp_24_LED.html/specs. The 24" is about the same height as the 27" 16:9 but not as wide.

Crazy! When I bought it about a month ago the price was $249, now it has gone up $100. Check for it at Amazon, Adorama or other online sellers, but they probably all fix the price the same.

I just recently bought this for my 2012 Mac Pro for use with Lightroom and Photoshop. I researched extensively and this is the best display for the price. It has USB 3.1 hub on the side, no speakers (who needs them, they're always crap anyhow) and the resolution is perfect for editing. You do not want too high resolution. Get it from B&H https://www.bhphotovideo.com/c/product/1430186-REG/dell_27_p2719h_full_hd.html

The only advantage of the D500 is its great focussing, tracking, and low-light capabilities—big advantages if you're shooting birds in flight or fast-action sports. Otherwise, the many, many advantages of the Z6 or Z7 far outweigh the D500. You get IBIS that will add another level of VR to your F-mount lenses, especially those without VR; you get much better signal-to-noise performance and the ability to shoot at higher ISOs if you need to. You get OSPDF that eliminates the need to fine-tune your lenses, including your F-mount lenses. All the other features that I am sure you have explored just make a Z body all the more appealing. Not to mention it's the latest technology and certainly where digital photography is heading in the future.

Although I own both the Z6 and Z7, and although I think it's bit of a toss-up as to which is really better for which type of photography, I recommend the Z7 for studio work. I shoot almost all my studio work with the Z7 in DX mode—essentially the equivalent of a DX body like the D500, unless I need to make huge prints or need to make non-standard crop-size.

rmorrison1116 got it exactly right, as did some other replies. I come from the film era. For digital I shot APS Canon EOS cameras for some years before switching to a Canon full-frame EOS 6D, and I really wish I had switched a couple years earlier before I took hundreds of great shots of shorebirds. They're great, but they have a fair amount of noise that they wouldn't have had I been shooting full-frame, and printing them 48" wide reveals too much of it. In a nutshell, if you're serious about photography and are likely to go forward with it for a long while, and if you can afford it, buy a full frame camera. You won't regret it. If you do buy a DX camera and lenses to go with it, buy full-frame lenses so that you will be ready for full-frame when you realize you have to move up to it.

Precisely. We don't get to choose, unless we buy a dozen or two different cameras.

My first 35mm was a Nikkormat; after a year or so I sold it and bought a Nikon FM and later added an FE2. Those two cameras served my 35mm needs as a pro for many years, but I also had an F2AS as well as medium format Hasselblad and an Arca-Swiss 4x5. In all three formats the number of models was pretty limited, and that made it easy to choose, and mostly they were all pretty much "best." Nowadays, you not only have the extreme complexity of DSLRs, with various sensor sizes and various sensor qualities, you have many models with many different features.

As Bob has pointed out, any given year of the 35mm film era Nikon only offered perhaps a couple 2-3 models and the differences made some sense: the F2 being a heavy rugged pro camera with interchangeable finders and so on; the FM, a lightweight easy to handle manual camera, and an auto exposure version of the FM, the FE. All used 35mm, no APS (yet), all took the same photographs when mounted with the same lens. If you wanted some different quality you used a different film. I used an Ilford ASA/ISO 1000 color transparency film occasionally, specifically for the graininess of it. Kodachrome 64 for portraiture, fine grain and for red tones; Ektachrome 100 or 200 for some landscapes, for a gain in speed and blue tones, Tri-X 400 for low-light and action black and white. Film made the difference, not the camera.

So why do we need so danged many different models? Sensor/lens combinations lock us into a particular quality, and there are many combinations with many different qualities. If you want low noise you need full-frame and amongst full-frame offerings there can be a lot of difference. My Canon 6D is better than my Nikon D810 at ISO 200, 400, 800 or above. The D810 is sharper than any of them at f/5.6 or below. It's almost as if you have to have a different camera in the same way we used to have different films, to achieve different results or for different shooting situations.

I tend to think that it would be better for the manufacturers to have fewer models and focus (pun intended) strictly on achieving only the highest quality photos. All full-frame, one high resolution model like the D810 for dynamic range and large prints; another model for high-speed action photography; one for high ISO shooting in extreme low light, and so on. Much correction and different effects are now easily achieved in post with all the various applications and plugins now available from folks like NIK Dfine (highly recommended), DxO and ON1. Limited models would bring the manufacturing costs down and make quality cameras and lenses more affordable for more people.

For me, there are three or four best DSLRs: The Nikon D810, The Nikon D750, the Canon 6D, and maybe the Nikon D7200 or Canon 80D for APS-C, but then I haven't tried the many, many different brands and models. I am sure there are many other cameras that would serve the purpose; I agree with the sentiment of others— it's not the camera so much as it's the eye behind it.