Close-Up Lens Recommendations For A Nikon D80?

All the pieces finally arrived today, and almost everything fits together. However, the Confirm- Nikon-to-M42 adapter is going to be a problem. It fits fine when I go straight to the camera. But in order to get the clearance that will let me rotate the camera on the bellows, I need to add an extension tube to the setup first. When I add that, then the chip on the adapter hangs on the chip inside the tube, so it doesn't sit square and I can't get a lockdown. Fortunately I also bought an adapter without a chip, so I can get started with the setup.

For lenses I have three 75mm (a Rode El Omicron, an El Nikkor, and an Apo-Rodagon) and a 105mm El Nikkor. I also have three micro objectives (2 10x and a 4x) and I'm working on a conversion that will allow a dedicated bellows for micro.

As I work to learn these tools I want to turn attention to lighting. I must confess I feel like I am now back at Photo 101, especially in the matter of lighting. I hope that in a few days I will be ready for a critique and some corrective tips, but at the moment lighting is hit or miss. I have two large lamps with 5000K bulbs in them, but no snoots or diffusers.

Is it better to put the diffusers on the lamps or to mount a diffuser board on the lens stack? If the latter, I'm not sure how to do that. Either way, I think I'm in the market for some translucent ridged plastic. Anyone got any recommendations?

Rather than using translucent rigid plastic, I highly recommend Canson Opalux diffusion paper. It's cheap and easy to work with.

It holds its shape nicely without a frame up to a fairly large size. The configuration you see in the Example-2 system is exactly what I use. In the case shown, the Opalux is stuck to the lens with double-stick tape. But some lenses don't have a flat area to stick to, so you can attach the Opalux using a filter adapter or other accessory that threads onto the lens.

I have very few trade secrets. Lighting is obviously a critical aspect of coin photography but everyone does it differently. I've shown several times on various forums exactly how I do it, but I don't think anyone actually does it the same way. I'm sure you'll find your own way to use the Opalux! It's a nice material with good properties for making diffusers.