For macro photography you want a prime (non zoom) lens and set of extension tubes or a bellows. An older, used, manual focus lens is fine as you will likely lose metering and focusing with the tubes/bellows anyway.
The tubes/bellows allow the lens to focus closer--at the cost of distance focusing.
The 105mm f4 micro nikkor ais; is an excellent macro lens and cost about half what the f2.8 costs--and you NEVER shoot macro under f4, trust me.
My "go to" camera for macro is the one I got in 1978....A Mamiya Sekor DTL 1000. This is a pure manual screw mount rather like a Spotmatic BUT the DTL 1000 has spot and avg meter, which helps in Macro. I have auto extension tubes, an Auto bellows, a tiny Kopil folding bellows, Novoflexar 100 mm + 135 mm Bellows lenses, a Schneider Keutznach 50 mm enlarger lens glued to a m42 extension tube and a SMC Takumar 135 Screw Mt, plus a LOT of other lenses.
Long ago I got a Sigma 135 1.8 in YS mount,and YS adapters for PK and Pentax screw (M-42) and found that anything screw mt screws into the PK adapter and becomes a virtual K Mount...so I CAN use my screw mt stuff on my ZX-5 Pentax...which enables me to also employ the TTL autoflash and slave my 283 Vivatar.
I Also use a Tamron SP 35-80 which is a great macro zoom,and sometimes the Tamron SP 60-300. These can be used on my M42, Pentax K or Nikon bodies......and are why if and when I get a DSLR..it's a Pentax. The Pentax K 10 D can use the full spectrum of Pentax type lenses including K mount and M42. Naturally.... you go Manual or aperture priority and man focus.
Virtually every other maker more or less abandoned early mounts...and those who used them. When Canon and Minolta went AF...all new mount and no good adapter. Nikon...SOME af bodies can use a N-ai lens. SOME digitals can use "film" AF lenses.
Pentax? Screw mt,K Mt,PK-A , F, FA, you can have Pentax's, a Chinon/Ricoh/Cosina...old screw mt Practica or Mamiya.....and swap lenses around.
If you don't go Pentax or Film.....Check out Tamron's 90 mm macro,the originals were adaptal mount,later versions added AF but were a specific mount. Great resolution. Actually.....if you DO go Film, the original SP 90 mm 2.5 is a GREAT macro. Vivitar Series One also had a great Macro 90 for film, and good Macro zooms.
I started out talking Mamiya DTL 1000. A DTL 1000, a set of auto extension tubes, a NON auto bellows and a SMC Takumar screw mt 135 can out macro MOST stuff you spend $500+ for.....and would total UNDER $100 on
ebay,maybe as little as $80 including shipping. I've won blue ribbons with that stuff.