Of all the cameras I saw at the recent PMA tradeshow, the most impressive was Leica’s M8.

It’s the first digital camera from Leica that’s built from the ground up to resemble the famous M-series 35mm rangefinder cameras. The M-series cameras are renowned for their small size, precise engineering, and razor-sharp lenses. They’re ideal for street photography. Henri Cartier-Bresson used a Leica with a 50mm lens throughout his career.

The M8 doesn’t come cheap. The body would set you back roughly $5,500, while the 50mm f/1.4 Summilux-M manual focus lens would add another $3,000 to the tab.

What happens when it becomes out-of-date? Would you have to trade up to a newer, more expensive model? I spoke with Christian Erhardt, Leica’s director of marketing, about this. He said Leica will offer hardware upgrades for a flat-rate of 1,200 euros. Leica picks up the camera at your home or business, sends it to the factory in Germany, replaces or adds new parts, and delivers it back to your door. The two-year warranty starts over again after each upgrade.

I asked if an upgrade might someday replace the 10.3-megapixel sensor with an improved sensor? Erhardt didn’t answer directly, but he did say that potentially any part could be replaced. There are no plans for an M9.

Is the Leica M8 and 50mm f/1.4 lens worth $8,500? If you want the best quality photos in the smallest possible configuration — and can afford the high price tag — you won’t find a better camera for discreet street photography.

If price isn’t an issue, you might consider opting for the Leica 50mm f/1.0 Noctilux-M manual focus lens. The lens is about $5,500, but you’ll be able to capture incredible photos from the light of a single candle. An F/1.0 lens sees the world approximately the same as a human eye in terms of illumination and perspective.

I had a chance to play around with the camera at the booth. Though the focusing system takes some getting used to, the M8 is clearly a big step up from other digital cameras. It really does have the remarkable feel of a Leica 35mm rangefinder.