As far as differences in a hog thermal and a coyote thermal, it all depends on terrain and the type of hunting style. If a hunter is walking up close to a large sounder of hogs, they want a wider field of view and less zoom, so when they shoot the first shot, they can get on the other animals quickly. The person who is hunting over a feeder and shooting singles, may want a higher base magnification and less fov to be able to take longer shots.
For coyotes, a person coyote hunting in open plains and typically calling in singles may want a higher base and smaller fov. While a person hunting coyotes in heavy timber or often calling in multiple coyotes, may want a wider fov and less base mag.
Almost all thermals will allow you to shoot to 200 yards. Even the entry level Flir PTS233 and RXQ30 will get you easily to 150 yards. The issue with the entry level thermals is they struggle in high humidity. All thermals do, but these entry level thermals are more prone to it.
I shoot a Flir PTS536. It has a 4x base magnification and I have made shots to 400 yards on base magnification. I will admit the 400 yard shot was a bit lucky. It will shoot to 250 yards easily on base magnification. Virtually all currently produced stand alone thermal scopes have a zoom capability. It is digital zoom, so each time you zoom, you are losing image quality but as long as the reticle is on the animal, it can help. Pulsars have PIP, so you get the base image plus the magnified view on the same screen. Some hunters really like this because they can have a wide field of view due to a low base magnification and then have the higher zoom in the PIP.
Think about what power you use during the day on your glass scope. I would say for a thermal, you may want to be close to that or a little less. The reason for a little less is that during the day, you know where the coyote is when you pull up to shoot. At night, when you move from scanner to gun, it isn't as easy to pick up the incoming coyote.
If a thermal can't shoot to 200 yards, I wouldn't own it. Most of today's thermals can get you to 200 yards and beyond. I have included a video of some kill shots from the 18-19 calling season. To give you an idea of range, the coyote at .23 seconds is roughly 60 yards, at :26 is 150 yards, and at :42 is 200 yards. The one at 3:07 is the long bomb at 400 yards. Yes, I could have digitally zoomed the scope, but my partner had missed this coyote, and he stopped one last time before leaving, and I only had once chance. If I had waited and zoomed the scope, he would have been gone. Every coyote on this video, shot with the PTS536, was taken on base mag. There is some PTS233 video (start at 4:49) from my hunting partner on this video, and there is some instances where the scope is on 2x zoom on his scope because of the lower 1.6x base mag.
At times, the fuzziness of a thermal image can be because of humidity but it could also be an issue with focus. The higher your base magnification of your scope, the more precise the focus has to be. Some thermals have automatic focus and some require manual focus. On many coyotes, I set my focus to be around 100 yards and when a coyote is coming, I don't want to move to adjust my focus. The image is good enough, so I leave it and worry about making the kill shot.
Another factor to mention is most hunters will tell you the actual image through the eyepiece is better than the video shows. You lose video quality on the recording, so this plays a factor in what you will see when watching videos on youtube, etc.
There is so much more to this that could be discussed including 640 vs 320 resolution, 17 micron vs 12 micron, 19mm up to 100mm objective lenses, and more. All of these and more play a factor in what the base mag, field of view, detection, and image quality is of a thermal scope. Hard to talk about all these in a forum post. I would recommend giving Tom Austin (909-312-5424 X531) at Night Goggles a call, and he can help you through narrow down your choices based on budget and need.
