I was going to suggest you look into the Sigma 10-20 mm lens, but I see others have already mentioned this glass. I will just endorse those recommendations. I have used this lens on my D7100 for several years and am very satisfied with its performance.

You may get so many different opinions you may end up more confused than you were before posting the question! Here's my input. Having tried both flat bed scanners with slide adapters and dedicated slide-film scanners I definitely recommend the latter. I'm currently on my third such device -- my second Plustek OpticFilm 8200i. It scans at up to 3600 dpi (I have standardized on 2400 dpi). The quality of the digitized photo file is limited only by the quality of the original slide or negative. Some OptiFilm scanners have an infrared dust/scratch removal feature. This definitely helps, but some PP cleanup is always necessary. I have found that I like the bundled SilverFast scanning software better than the upgrade versions that carry a price tag. I have scanned images open directly in Photoshop CC, so I don't use the PP features of SilverFast. Since I am on my third scanner you may have surmised that they don't last forever. My experience is that they don't. I have had about 4-5 years of service from each scanner. Maybe I have just been unlucky in that regard.

Actually they did. Although never legally changed the Cincinnati baseball team was known as the "Redlegs" in the 1950s. This confused me as a kid.

After reading a few reviews that actually rated the Sigma 10-20 4-5.6 better than the comparable Nikon I decided to take a chance and save a few hundred bucks. I have never regretted the choice. The Sigma lens works great on my D7100. I have made transcontinental road trips when I never used another lens. Of course you will never go wrong with anything that says "Nikon" on it!

A gallery of great pictures. Thanks for the links.

You have some great glass in your bag! Consider sharing some of your captures with the 600 F4. I'll bet they are spectacular.

Agreed. You will need a long lens to photograph birds. It's just a matter of how "long" long is. An 18 to 135 lens is perfectly fine for use on my patio where the birds are 15 to 20 feet away. In the woods on International Migratory Bird Day I find that virtually all my shots are at 200 or 300 mm with an APS-c sensor DSLR.

Last year I had the opportunity to spend several days birding with one of the world's most famous birders. He recommended the Sigma 50-500 as the best affordable lens for bird and wildlife photography.

Was just in Arizona last month. Lots of prime photo sites around Sedona. If you have time consider taking a guided tour that can take you to sites you probably couldn't find and might be unable to reach on your own. Pink Jeep and other ATV tour companies in Sedona offer tours especially for photographers. To the south Saguaro National Park near Tucson offers many good photo capture possibilities. Sunset at Gates Pass west of Tucson is often spectacular, but get there early. Available parking fills up starting in late afternoon. If you go to Sedona stop at Montezuma's Castle while en route. It's a cliff dwelling that has nothing at all to do with Montezuma, but it's interesting, very photogenic, and it won't take you more than an hour.

Montezuma's Castle

(Download)

That is a great eagle shot!

I moved to the Nikon D7100 from a D80 a few years ago. Prior to that I had replaced the 18-55 mm D80 kit lens with the 18-105 mm. That lens continues to serve very well as my walking around glass. Since you already have an 18-200 mm lens I don't see a need to add an 19-200 to your gear bag. You might want to consider purchasing a fast "normal" prime lens.

As to newer lenses being better than legacy glass, they certainly have more bells and whistles, but as to optical quality I don't think much has changed. We have known how to produce excellent quality lenses for more than 100 years. Optically the best lens I have ever owned or ever expect to own was a 28 mm Canon Serenar I bought from a news photographer in 1959 along with a Canon III. I later sold this camera and the lens to a professional photographer, after raving about the quality of the glass. He called me a few weeks later to report: "That lens is everything you said it was."

For what it may be worth I moved from a D80 to a D7100. (A great decision, by the way.) I had previously purchased a Nikkor 18-105 VR lens, which is still my walking around glass. My bag now contains a 55-300 Nikkor VR and a newly-acquired Sigma 10-20. One of these days I am going to ask the community for advice on an upgrade to the 18-105, but I still find it to be a pretty great lens for the non-professional enthusiast.

Owls are great subjects since, unlike warblers, they don't move much! Every time I think I have a great owl picture someone comes along with a better one. Thanks for inspiring me to keep on trying.

I'll bet this shot would look great -- maybe even better -- in B/W. It depends on whether you're going for artistic or realistic scenic. Why don't you desaturate and see if you like the result?

Birds and cats are naturally photogenic, but some photos are better than others. These are great! Thanks for sharing.