I love my Fuji X-T1 but it is no replacement for my Nikon gear except as the camera I take when I am not planning on taking important shots. I had a D3s and now the D750 and am amazed each time I use it. My suggestion is to stick with the Nikon gear.

Although the cameras you are looking at have the same number of pixels, the difference is the size of the pixels. They are much bigger on the FF D750 because they need to be to fill the size of sensor. The advantage is that the larger pixels allow more light to enter, thus are superior in low light situations.
I love my D750.

The problem with f1.8 is getting what you want in focus. If the subject is moving, you could get a knee in focus and the face out of focus, even with continuous focus set on the camera. f5 to f8 insures moving subjects remain in focus with sufficient DOF.

I often shoot sports in a gym without flash with some success. My lens of choice is the Nikon 24-70 2.8 because the action can go from close to far quickly and although I have used my 70-200 f2.8, I have often found I am too close, if I am at ring side. For me, shooting at f2.8 can narrow the DOF such that I can miss good opportunities so I set aperture to at least f4 or f5, shutter to minimum of 1/250 but prefer 1/320 depending on the speed of the competition and ISO at least 3200 and at times 6400. If the sport is a bit slower I would choose a lower ISO to eliminate some of the grain.
I found if you want to get the actions shots, you need to push to the limits. Some grain can be taken out in Lightroom.

Fast Action


Taekwon-Do

Congratulations on going macro, it can be a lot of fun in a whole new world. I chose the Nikon 105mm; f2.8 for a few reasons: the longer focal length allows you to be a bit farther from the subject, instead of on top of it; the 2.8 allows a bit faster shutter speed; it is a 1:1 ratio lens and the Image Quality is extremely high.
Good luck with your decision.

I can see where you are getting the wrong information by reading McLean's Magazine. :D
Actually, Scotland has a higher violent crime rate than Northern Ireland and Glasgow and London have higher rates than Belfast. If we were worried about violent crime, tourism would die in the US. (No pun intended)

Northern Ireland is also filled with many friendly people and after travelling extensively in the North this year, I saw no signs of "active" trouble. Northern Ireland needs tourism to help move it forward after a very long history of unrest. Any people I met were more than accommodating to my inquiries. Derry, Belfast, Giant's Causeway and everywhere in between have incredible opportunities for a photo enthusiast.

There are a lot of great comments here. The only things I can add is to bring smaller size memory cards so if one is lost or stolen, you do not lose a ton of images. The second suggestion is to bring a beanbag to use indoors when you need longer exposures. It is easy to make. Fill a plastic zip lock sandwich bag with rice, and then sew it into some kind of cloth. I used denim.
This is the perfect support for your camera when you need a longer exposure, say on the back of a church pew instead of a tripod and it is no larger than a sandwich. I use mine often when I travel as many places do not allow a tripod and getting long exposures or multiple exposures for HDR is not always easy, handheld.

We were in Ireland in May this year and had a great time. Just remember, no one goes to Ireland for the weather because it is very unpredictable. What should have been the nicest month, we were there for the worst weather. It rained every day of our 12 days. We still had a great time.

Enjoy your trip

I think you are on the right track with your thinking. I learned long ago that if you become serious with your photography, the camera and lens you buy today will likely not be adequate as your skills and expectations improve.
With that in mind, any of your choices are fine for you as a new photographer.
Go out with your new camera and lens and take a ton of photos, experiment a lot with all different types of images, read lots of material, keep in touch with sites like this one and learn, learn, learn. As you get better, you will realize what type of photography you enjoy the most and what limitations your gear will have to fully enjoy the type of photography you enjoy. That will help you determine where you go next. Right now you only have an idea of what you want to do. It is only once you learn and take lots of photos that your journey will become clearer.
One of my favorite sayings is: "If you don't know where you are going, any road will take you there".
You won't know what gear is the best for you until you start shooting with something and find your passion.
Good luck on your journey.

Why is it that these types of discussions always lead to the argument that mine is better than yours when it is never true as a definitive statement. The 810 is not a superior camera to the 750 nor vice versa. They both have different uses and are the best for those uses. To say your sports car is better than my SUV doesn't make any sense if I am going off road.
The D750 is the superior camera for me and I am sure for those that have the 810 or the 7200 their camera is superior for them. So to the OP, determine what you want to do with your camera and then go and buy the one that will be superior to you. You can't go wrong with any choice if you do your homework. People spouting off statistics and technical numbers that will very likely make zero difference to your images does not help you in your decision.
Go to a camera store with a memory card, put it in each of the cameras and take a bunch of shots in the store. Take the card home and see if there is enough difference to warrant any extra cost. At least then you will know if the camera is superior for your needs and not someone else's.

Listen to the Nikon Rep. Both cameras are extremely good. I am sure you can easily find many discussions on this site with people supporting their model and they are absolutely right....for them. Decide what type of photos you take now and want to take in the future. If you are going to take mostly landscape and blow the images up to large sizes then the D810 is probably your best bet. If you don't do that and you are looking for a very good, all round full frame camera that will last you a long time, the D750 is right for you.
I love my D750 and for the types of images I take, I could not be happier while others love their 810 and for the types of images they take, they could not be happier. I don't think you can go wrong.
My only comment is that if you do not know why you would need to spend $900 more for the 810, then you should get the 750 and put your money towards some good full frame glass.

Thank you Houdel. That's a great summary.

Thank you everyone who has responded. I see there are clearly two camps regarding this issue.
Could I use PSP with Lightroom as a cataloguing program? Since LR and PS do not actually alter the original file, how do I keep the changes to the images I have taken in the last 5 years or so? I find it frustrating being a 'technodope' and not fully understanding the ramifications if I move away from LR.

Thanks for the info. I will look Lynda up.

I currently use Lightroom with the NIK suite of programs for almost all of my post processing and I am quite proficient with them. I also have Photoshop Elements which I am mediocre with at best. I am now ready to move up and start using layers/masks and more creative techniques for my photography but I struggle with the monthly leasing fee for the full version of Photoshop so I could use your help. If you use either Photoshop or Paintshop I would appreciate knowing why you chose that program; given my experience what sort of learning curve will I have and how should I move forward.
I really don't want this to get into a mine is bigger argument, please tell me why you like one over the other? What challenges will I have moving my existing files and processing over to Printshop? If I go with Photoshop am I not now married to it and changing back would create a very messy divorce? What are the pros/cons of using neither and getting more use of my Elements?
Thank you for your help.