This is one of several conversations going on right now in which members are being chided for wanting to upgrade from a D3xxx camera. Many of the arguments being posted are, quite frankly, misinformed and really pretty arrogant. I've used both D3400s and D3500s and helped students with them at school, and. quite frankly, these are very problematic cameras for people wanting to progress beyond pointing and shooting. Physical controls are absent, and menus are, to say the least, obtuse and awkward. It is correct to say that they can capture good images in middle-of-the-road situations, but they are very difficult to use in more marginal conditions. Yes...kids do OK with them, but kids have a sort of innate ability to get past most obstacles (and obstacles of many types).

One respected member here went so far to say something like that the D3xxx is a professional grade camera that is every bit as good as a D7500 or D750 or even a D500. This comment belies either a profound level of ignorance about the camera or a profound disrespect for the inquirer's question. Quite frankly, replies of this sort are becoming very tiresome here. And 10 other members fell right in line behind.

Now that my blood pressure is down a little bit, some words to the OP...

Yes...the D3400 is capable of capturing similar images to those captured by other digital cameras in a lot of cases. But you will find that as you move to more capable models, the ability to capture images in more difficult situations expands significantly. Not only that but the ease with which you can capture those images increases drastically, once you have learned the capabilities of the camera and how to access them. I have not used the D7xxx Nikons, so will not address them. I have worked with rollout of the D5xxx Nikons at school, and I am completely unimpressed with them as an "upgrade" to the D3400. They do offer some additional capabilities that I would class as mostly just cosmetic, while retaining most of the operational shortcomings that frustrate me with the D3xxx cameras.

Depending on what you would like to accomplish with a different camera, there are many viable paths available to you. If you want to learn how to use a camera with better menus, better controls, and much better ergonomics, you could find a nice used D300 or D300s. Cost would be very low. The disadvantage is that thneither of these cameras are supported by Nikon now, so you may have a harder time getting good repairs done if necessary. Used D500s are also available, but may be beyond your budget. There are also a number of used full frame models available, and I endorse your willingness to use DX lenses for a while as you are saving for other lenses.

I'm not sure what battery that your D3400 uses, but if buying used, you might want to do some research and see if any of the full frame models use the same battery as that camera. Being able to bring your batteries along could also be a money saver, at least in the short term. (I don't know if this is even an option, and don't let it be your primary criterion for selecting a camera.)

So...there's quite a bit to think about. Have fun doing it. And good luck.

Please be assured. I am not trying to be unkind, The kids at school have produced yearbooks for several years using D3300 and D3400 cameras, I AM saying FROM EXPERIENCE that those are NOT professional grade cameras, and they are not appropriate recommendations for someone wanting to upgrade. My wife still shoots happily with a D40x, which is what...12 years old? She is perfectly happy with it. I am happy that she is happy with it. I still have and occasionally use a D200, which is maybe a little older. But the OP is not happy with his D3400 and has expressed that he would like something different. That is a very big difference.

Some of the responses have been politely trying to say you shouldn't be worrying about a new camera in your current situation. If you didn't pick up on it already, the population is this site is an overwhelming majority of retirees with lots of disposable income, lots of free time and ample encouragement to play 'can you top this?'

If you can't break your gear lust, have you made any serious assessments of your needs? Do you shoot in RAW? Do you use commercial-grade editing software? Do you own a tripod? An external flash? Have you really reached the limits of your current gear? Have you posted any example images and asked for feedback on your work and ideas to consider? Where / how do you use your digital images? Do you have a realistic and effective back-up strategy for your images and computer hardware in general?

All the ideas above involve money, time and effort, some simply more time & effort rather than money.

I shoot in raw, sometimes RAW+JPEG. I use Lightroom CC, on mobile and desktop with 1 TB cloud storage. Almost all of my photos go there to be edited. If they don't go into Lightroom cloud, they go into the 4TB external hard drive plugged into my desktop. I own two tripods, a Camopro 62", and a JOBY gorilla pod(which is the stuff of the heavens I love that thing). I have a 3rd party external flash I don't remember which brand, but it works wonderfully. I try to push my gear to the absolute limit without breaking it, but sometimes I am physically limited by my camera. I was uploading to flikr, but then it but a cap on the number of photos I could upload. Now I mainly upload to Instagram, but I am slowly starting to discover new places to put my photos. Maybe I'll put some on here.

I love my D3400, but I need to move forward and expand my capabilities. This next purchase will probably be my only camera purchase for 10+ years. The law of diminishing returns is present in cameras more than in many other places. The leap between a Canon powershot SX 530 HS and a Nikon D3400 is absolutely huge, and only $250 apart. The gap between a D3400 and a D750 is about 900-1000 dollars, but its a jump from entry to pro. The only things I stand to gain past the 750 is more battery, more megapixels, and a somewhat better auto focus. Maybe I don't need to upgrade just yet, but that what I'm trying to figure out.

If I found the right IG account, your image quality isn't going to improve in an obvious way from a full-frame camera. In fact, the candidate D750 is the same 24MP resolution as your D3400 when an FX lens is used on either body. The D750 is 'larger' pixels, not 'more' pixels.

The more obvious changes with a higher-end model are the camera controls and overall ruggedness of the body. They are meant to last 10+ years of heavy use. Improved autofocus comes from the size of the AF array, total number of AF points, the AF tracking abilities, capabilities must useful for action shooting. For static subjects, they don't make a difference. A full-frame camera will tend to have better low-light / high ISO performance, but that general comment applies less and less with each new DX-style model.

Lenses always make the bigger difference and they last the longer, if not forever. I've been shooting almost exclusively with a 24mm prime for all of 2020, so I was interested to see that idea as your first FX lens. Of course, that FX lens on a DX body doesn't get you 24mm 'wide'. If you step back from the body-first approach, you may find a number of Nikon's excellent lens are a better first step, whether FX or DX options. Those external controls and advanced AF exist for higher-end DX models as well, that don't invalidate your existing DX lenses.

Currently, I have a Nikon D3400 (which is pretty beat up), with a couple of DX lenses. I am looking to upgrade to full frame, and for a while it looked like the D750 was the best option. However, the D780 just came out, and it looks like its packed with extra features. As it is a new camera though, it's significantly more expensive, and there are some seriously sweet deals for the d750 on eBay. Is it worth it to spend the extra couple hundred dollars for the D780? (Currently I don't have a budget, and if I did it would be at around 100 bucks. Any money spent will take a lot of time to save for, especially considering the pandemic right now.) Thanks.

Frankly, I was responding to your assessment of the 3XXX and 5XXX series of cameras rather than the OP's desires. You stated, "Physical controls are absent, and menus are, to say the least, obtuse and awkward." I won't discuss the physical controls because much of that is very personal. Some people prefer physical controls while others prefer that choices be embedded in the menus. However, if you look at Nikon's menus across the gamut of cameras produced by Nikon, you will find that one camera's menus are nearly identical to the next. If you find Nikon's menu system obtuse and awkward, you can always try another brand of camera. Now understand, I'm not a Nikon fanboy. I shoot Nikon, Canon, Sony, Pansonic, and Olympus so I have no ax to grind.

Currently, I have a Nikon D3400 (which is pretty beat up), with a couple of DX lenses. I am looking to upgrade to full frame, and for a while it looked like the D750 was the best option. However, the D780 just came out, and it looks like its packed with extra features. As it is a new camera though, it's significantly more expensive, and there are some seriously sweet deals for the d750 on eBay. Is it worth it to spend the extra couple hundred dollars for the D780? (Currently I don't have a budget, and if I did it would be at around 100 bucks. Any money spent will take a lot of time to save for, especially considering the pandemic right now.) Thanks.

Currently, I have a Nikon D3400 (which is pretty beat up), with a couple of DX lenses. I am looking to upgrade to full frame, and for a while it looked like the D750 was the best option. However, the D780 just came out, and it looks like its packed with extra features. As it is a new camera though, it's significantly more expensive, and there are some seriously sweet deals for the d750 on eBay. Is it worth it to spend the extra couple hundred dollars for the D780? (Currently I don't have a budget, and if I did it would be at around 100 bucks. Any money spent will take a lot of time to save for, especially considering the pandemic right now.) Thanks.

I don't know how extensive your review of the cameras in question has been, but if you have not yet done so you might want to go to a site such as cameradecision.com and actually compare the D750 and the D780. It is interesting to note that although there are additional bells and whistles with the D780, its overall rating is 86 versus 85 for the D750 on the site mentioned. Look at the additional features and decide for what you do whether the extra money spent for the D780 gives you what you want. If it were I making decision, I think the D750 would be preferable, perhaps a Nikon-refurbished one (currently out of stock at both B&H and Adorama--but more coming) at less than 50% of the cost of a new D780. But let me hasten to add that I am not you, and sometimes you just want the better of the two regardless of the extra expense. That's one of the main reasons I upgraded to the Nikon D850 at Christmas. I don't think that in a 100 years I would become fully conversant with all the features of my camera, but it makes me happy, so that is sufficient reason for me. Good luck with your decision.