My foray into cult lens territory:
Vivitar 2x Macro Focusing Teleconverter. Besides having superb optics this teleconverter has a helicoid which works as an extension tube and allows close focusing for macro photography. With some lenses this allows 1:1 magnification. The drawback being slight loss of image quality and 2 f-stops of speed. Prices range from $8-$120 depending on condition and lens mount. For the Pentax KA mount I got one for around $50. Try B&H Photo, their prices are cheaper than what they go for typically on eBay.
As a teleconverter (manual focus only) it allows me to take shots I couldn't otherwise get with my 18-55mm kit lens:
And in the macro mode I can get 1x or better magnification instead of about 1/3x. Wide open performance on the kit lens isn't very good and the teleconverter makes this very obvious. Solution, don't shoot wide open whenever possible:
While not really a cult lens, the
Super-Multi-Coated MACRO-TAKUMAR 1:4/50 again has superb optics. Any of the 100mm Pentax macro lenses are more "cultish" and they're prices run about twice what the 50mm go for. With a screw mount adapter these can be used with most DSLRs. The drawback is you have to use stop-down manual metering. With the lens stopped down the viewfinder can get very dim making focusing difficult or even impossible. Anybody who used pre-auto aperture SLRs from the 60s is familiar with the process. Other drawbacks is most of the macro lenses from this era only do 1x magnification with an extension tube and were slow with max f-stops 3.5-4.
The crown jewel of my cult lenses is the much coveted
Kiron 105mm f2.8 Macro lens. Legendary for it's optical quality and build this is considered one of the best macro lenses ever manufactured. Revolutionary in its time for its fast (f2.8) speed, optical performance and 1x magnification without need of an extension tube or lens. Being able to focus to infinity this makes a good telephoto lens. It is also outstanding as a portrait lens. I got lucky and picked up the dental version (Lester A. Dine branded) with macro ring-light in the PKA mount for just under $200. This is usable with all metering modes on my Pentax DSLR. The cult status of this lens has pushed the average price of the lens alone to the $350-450 range. Unless you're a lens collector at those prices you're better off getting a modern lens for your DSLR. While the optics are superb they aren't much better than modern lenses plus depending on your camera you won't get auto aperture and image stabilization/shake reduction.
Many of these are just test shots, checking different lighting sources. Some are handheld, others on a tripod.
With the 2x teleconverter I can get 2x magnification. The helicoid is not very sturdy and the lens (all metal and glass) is too heavy to use the macro extension mode.
The last "cult" toy is the
Minolta Auto-Bellows III. With a glassless adapter I can now use this with the Pentax body. With adapters I can use enlarger lenses as macro lenses so I have plenty of low cost options. I have posted a few test shots before but haven't taken any further shots. Setting up can be tedious.