Uncle Ken Rockwell, if you pay much attention to him, doesn't much rate the D80 suggesting you saved your money for the later D90... when current, which was a good while back.... its an 'old' Digital offering. It's also, according to specs, a Cop-Sensor camera, so you already have an effective 1.5x tele-converter effect from the crop-factor on lenses you used on 35mm.
Personally in simlar situation half a decade back; I had dodged the 35mm AF vogue... I had used Olympus OM's all through uni 'cos they were 'cheap', and continued to do so into the millennium. Around 1993, I DID price up and get almost as far as a credit agreement on a second hand Nikon F801, to system switch to both Nikon and Auto-Focus.... but a Month of Sundays sat in the launderette eventually saw a washing machine 'win' my 'first' tax paid pay-cheque!
Around the millennium, a healthy redundancy cheque, saw me re-visit the notion, but early Widgetal tempted, as I had packed up the dark room 'cos Kids, and bought a computer! Early Widgetal though was pretty dire and utra expensive and often both... so I ultimately bought a dedicated 35mm film scanner, dug out the dev-tank & changing bag, and bought some E6 chems and slide film! I STILL use that film scanner...... chucking out 10Mpix scans at a high colour depth, it out-performed most direct-digital for est part of a decade!!! And STILL offers a resolution far higher than necessary for 99% of everything I am likely to do... its just not as 'convenient'.
A 'cheap' Digtal P&S was bought when they fell to the under £100 range cira 2003/4... it died circa 2006... another was bought, that took AA's, mostly because I was fed up with the 'old one' costing me more in alkaline batteries than my film cameras had film, ... that one I will say still works! If you carry enough AA batteries! So circa 2009, a new 'zoom' compact that used a lith-ion was procured. I call it the Franken-Camera! That has died at least three times! And flat batteries you couldn't replace on the hoof from a kiosk was annoying! Grandad all enthused by wdgetal, actually bought a bunch of them for the family that year, hence the 'Franken-Camera' made from the component remains of two or three of them! Which sort of still 'works'! BUT! They DONT make'em like they used to!
Hence five years ago, Digi-SLR was plumped on because 'entry' level examples had fallen into the £300 price range; whilst consumer compacts had dssapeared ito smart-phones. I was utterly over-whelmed by the electric offerings; and the compatibility issues.. trying to get to grips with what's what... For simplicity I bought a Nikon D3200 kit 'off the shelf', and treated it as a complete new system.... Though I did buy an M42 adapter early on to try using my old M42 screw fit lenses on it, whilst I saved up to get the same sort of lens range I had for film..... That experiment quickly lead to me saving faster!
Its a hinter-land of in-compatibility, using legacy lenses. Using M42 screw on my D3200, I had not only no AF but also no TTL metering, and had to be careful manually setting apertures on the lens. Trying an AF50 from a late film-era camera showed up the niggle between camera driven AF and lens motored AF, and looking at an old 'AI' slot coupled lens off a mates Nikormat, had me hand it back hurriedly!
The 'Famed' Nikkor 'back-wards/fore-wards' F-Mount compatability between cameras from 1948 to date or whatever, IS I think as much of a curse as a boon! IMO!
Anyway... up-shot was, that after expanding the Wdgetal 'kit' with Nik 55-300, the Sigma 4.5 fish, and Sigma 6-16 UWA, that all work on digetal as they aught to... I sort of had the 'range' I had for film.... and was left deliberating whether to swap out the 18-55 kit for something better, or the 55-300 kit for a more serouse long zoom.... etc etc etc...
B-U-T.... actual upshot of the entire exercise, was curouse... where in days past, the 'big guns' sat in the gadget bag with spare film and winders and schit, and the little Digi-Compact had sort of replaced my trusty old Olympus XA2 film 'compact' in my pocket for incidental shots....With an all singing all dancing Widgtal SLR and host of electric lenses in the gadget bag... that little XA2 was BACK in my pocket, doing what it had always done... MORE, the 'convenience' of all singing all dancing direct to digital display DSLR's.. actually got shunned in favour of me pickng up my old Sgma Mik1 'Rchoch' copy, M42 clock-work camera. All manual, all primes, the only 'easement' its non-coupled TTL CWA light-meter.... that DID offer the photo-making 'engagement' and begged me think and work a lot harder for a photo.. and consequently more often get better results and enjoy the process a lot more.
Which takes us where?
Your D80.. was not that well rated even in it's own era, of early Digital offerings. So it may not be the 'best' start point to leap into wdgetal.
The D80, is also a crop sensor camera. Using full-frame lenses for 35mm on that, you will get very flattering results, the D80's crop sensor only taking data from the center of the image circle... but, its older electronics, probably choke that some-what.
Meanwile, the D80, as a crop-sensor camera has that aprox 1.5x crop-factor stretching effetive lens lengths. As I found, its 'cheap-reach' going telephoto, but it does make going wider, harder and more expensive. Anything much under 24mm was rare/expensive for film; most common and more affordably available then are modern electric lenses for wdgetal, hence my choice of the Sggy 4.5mm fish, where I had used 12mm fish on film.
On the long-side; on 35mmfilm, I pretty much covered everything with a 70-210 zoom. I had a 3x tele-con in the gadget bag, but seldom used. This is where you my have more departure shooting nature, begging longer lenses, but still...The 55-300 'kit' was for me 'cheap-reach' and with 1.5 crop factor took that lens well into the 'long' realms of 450mm, I would only have occasionally wanted or got with the 3x tele on 210 on film. It is NOT the 'best' long lens for widgetal by a long stretch, and I have to say, I got far more pleasing results using my old Prinz-Galaxy M42 screw 300mm on adapter... with a site more 'faff'...
But, 300mm with 1.5 times crop factor, that 450mm ish 'equivalence' is a LOT of zoom, when many nature snappers of the film era hummed and harred over 300, 500 & 1000mm miror lenses... and my personal experience with ulta-long lenses has always been the incredibly narrow angle of view making it SO tricky to frame and hold subject 'in' frame.
Seems that the old 70-300, on a crop sensor widgetal, givng 450mm equivalence, is a favored combination with nature photographers these days, and seems they aren't ashamed to frame wide, and crop in post to get a bit more... hint!
On that notion, I had similar reasoning behind buying my 24Mpix D3200 over then cheaper 15Mpix D3100... the extra pixies giving that bit more margin to crop down, especially from half masked full-round fish-shots, and retain pixie count in the resultant display image. Your D80, a generation or so behind ether of those with just 10Mpix sensor, it may lack scope there for digi-zoom or cropping.. but its still a very capable camera.
Which brings us back around.....
I don't have the biggest budget, and at this point in time, it just a hobby I'm getting back into
Warning!: Photography, like most hobbys, will consume as much time and money as you let it... plus a bit more...
Beware Gadget-Acquisition-Syndrome and the tendency to try 'Buy' solutions rather than learn them.
and on my old film camera I took some amazing pics
So why cant you STILL take amazing photo's on your film camera?
You can still buy film. And you can buy a HECK of a lot of film for the price of electric-picture-makers and thier accesories. High end film scanners, if you want dgtal renditions of your photo's, are also very very cheap. That £500 dedicated film scanner I bought in Y2K, would be lucky to command £50 on e-bay, and as said, chucks out scans with as many mega-pixies and far better colour depth than you get from your D80.
Do you really NEED or WANT to get more serous about widgetal, or make big investment in it?
Remember the old adage;
if it ant broke, dont fix it!
I wanted to make use of the lenses I already had for my F55
See comments vis this being a doule edged sword. They may 'ft' the D80, but they were optmsed for full frame, and you have a 1.5x crop factor to consider, before teleconverters.
but I would like to get more zoom, and a converter
See above, you already have an effective 1.5 tele-converter in the crop factor... and there's a contradiction in your comments that if you were happy with 300mm on film, and already have 450mm equiv on digital, why now do you think you need more still?
Avoid GAS... dont buy it unless you REALLY need it.
I'm still getting used to the camera, and am a complete novice with using settings (all a bit over my head at the minute!)
THIS I think s probably the 'nub'.... the know-how.
I knew how to use settings and stuff before I picked up a digital camera... trusting to automation and getting the best from that was actually my problem, a-n-d as often STILL revert to first principles, switching 'off' the auto-focus and focusing manually; turning 'off' the auto-exposure and metering by eye, and setting aperture and shutter speed by educated guess-work... I struggled to 'trust' the electrickery.
The electronic automation in a modern electric picture maker, is significantly 'easements'.. which most of the time DO make the job easy. Hence comments above about reverting to my clock-work film cameras to get that missing user 'engagement'... but I have to say, that easement IS appreciated in a lot of situations where I need to work fast and loose, or just don't want to 'faff'.
So! Whats the solution? Tele-converters, alternate lenses, DON'T immediately spring to mind here;
LEARNING to use the camera, properly, what it can do, what it cant, what it might do well, and what you might do 'better' and learning to exploit that as suits, would be the logical answer, I think.
At the minute I'm basically flicking between settings to get used to how things work/look!!
See above! This supports the suggestion you need know-how not gadgets.
Here perseverance with effectively cost-less digital, could be useful to give you more chance to 'play' and see the results and find out what does/doesn't work... but its perseverance and patience that's needed not lenses or tele-converters.
I am getting so muddled up with all the jargon
Trouble wth the terratory 'Jargon'.. no real answer to that one really, other than don't sweat it. Ignore tutorials that talk in jargonese, you don't understand, back up start lower down, where its in more 'plain English'.
and knowing what will fit on my camera
You have camera. You have lenses that fit it. This is only a problem if you persevere looking for other gear to solve your problems, which given above will only get worse, with more permutations and combinations to try and get to grips with.
Keep-It-Smple-Silly!
Dont make the job any more convoluted or complicated than you need to. Don't try and run before you can walk. Don't try do six things badly when you can do one well... and all those sort of platitudes... they hold truth!
My question is: would a teleconverter be a good option?
If you haven't worked this one out by now... NO! I don't really think this would help you much, if at all, at this stage, or any other, IF you were getting good results with those lenses on film camera without!
Alternatively, would a different lens be better; one specifically for a D80?
again.. no, not really. You have lenses. You have achieved good results with them, you are looking the wrong place for 'something' to solve problems you only 'think' you have.
I am getting pretty obsessed with photography again!
Err.. at this juncture I would have to disagree... you are getting obsessed with
CAMERAS... not
PHOTOGRAPHY... its an easy distinction to miss , and so many do... but what do you want, great photo's or a gadget bag full of fancy cameras?
Yup... its confusng, and confounding, and theres a dozen folk, ALL with thier hands out ready to take your money to make themselves happy, and another twenty (probably already having handed over their own cash for an off the shelf solution!) to tell you why its a brilliant way to go... BUT...
Its your money... and
your photo's that matter... and the reveal, here is you are floundering, in not so deep water, clutching for life-lines, when all you REALLY need do is STAND UP!
Remember,
Keep-It-Simple-Silly!
MY suggestions?
1/ go buy a roll of film! Its cheap! Do what you USED to do, see if you enjoy it!
A dededicated film scanner, a dev-tank and chems, an alternative film camera, maybe even a full-manual one, MAY be a completely different route to take, and with only 36 frames at a time, enforce the discipline to get it 'right' rather than loose it in the 'faff' of prodding buttons.
But, KEEP-IT-SIMPLE-SILLY! You did it wth film, you enjoyed it with film, you reckon you got good results with film.. you STILL COULD... pick up where you left off, rather than try some-thing 'different',and wonder why ts t the same!
2/ The D80, has a question mark over it, being an early generation Digital Camera. It may be doing you few favours. But, it's old fashioned lower tech does help KISS somewhat; to get to grips with wdgetal its as good a place to start as any...
but there is a lot to learn... and by the sounds of it you are not just trying to learn digital, but stuff you didn't learn with film, vis traditional full manual, manual focus, manual exposure settings kind of operation to get the most from it.
Treated as a free-film-less training tool, that could help you learn such intricacies, and not waste large sums on film and processing along the way... BUT that's what's needed is the learning. Not a new lens or tele-converter or even a new camera.
How you get that, by way of trial ad error, u-tube tuts, formal photo-classes, etc etc is up to you... BUT that's where I would suggest you look for what you hope, not in brochures or catalogs or e-bay!
That's my probably large 4-penneth FWIW and not explicit answer you hoped for, telling you exactly what you should buy... BUT... I hope, helps point a different way to hopefully achieve more of what you hope to, WITHOUT spending so much money!