My friend Rob bought one of these. He said "I own the first autofocus medium-format SLR." I replied "You mean the first medium-format SLR for wimps, don't you?"
Let me air my prejudices first. I like the 6x6 format and used a Rollei 6008 system for many years. I love being able to defer horizontal/vertical decisions until I'm editing my photos on a light table. I take my best-composed pictures looking down into a waist-level view finder. For me one of the great joys of medium format is that you can take square pictures. Also, if you're going to suffer with the weight of medium-format lenses, then you should at least put film underneath as much of their image circle as possible, something that only a square format does.
The 645N is about the size and weight of a Nikon F4, which is pretty good considering that it produces a 6x4.5cm image (actually 41.5x56mm versus a Nikon's 24x36mm frame). The standard lens is a 75/2.8. Pentax cheaps out and doesn't give you a lens hood. What's worse, the optional lens hood does not bayonet around the outside of the lens as with a Rollei, Hasselblad, or top-quality 35mm camera lens. It screws into the 58mm filter thread. Speaking of screw-in filters, that's also what you get with Pentax lenses, not the delicious bayonet-mount filters of a 'Blad or Rollei.
The manual focus ring on the lens is rather too narrow for comfort. There is a somewhat-difficult-to-operate switch to kick the lens into autofocus mode.
Depth of field preview is accomplished by pulling a lever towards your hand. It is in exactly the right place; the best feature of the camera. Unfortunately, the shutter speed dial is too far away from the shutter release; it is tough to adjust shutter speed and then get back to take another picture.
The viewfinder eye relief is just barely enough for me with my eyeglasses. The LCD displays of aperture, shutter speed, and under/over exposure are clear and will be very familiar to people who've used modern 35mm SLRs. I was able to figure out the entire camera including autobracketing without the manual.
The exposure and metering system are identical to that on my old Rollei 6008. You set your aperture and shutter speed and you're in metered manual mode. You move the shutter speed dial to A and you're in aperture-priority autoexposure mode. You move the aperture ring on the lens to A and you're in program autoexposure mode. You move the shutter speed dial to 1/60th and you're in shutter-priority autoexposure mode. I wish all cameras worked this way and we were freed from the mode dials and switches that clutter most 35mm SLRs.
Compared to my Canon EOS system, the AF is absurdly slow and noisy. It also hunts much more and is incapable of achieving focus on targets that a modern EOS body would catch in 0.1 seconds. Rather than license the USM motor system from Canon, lens focusing helicals are driven from a screwdriver-style blade inside the body.
If you try to manually touch up focus while the lens is in AF mode, you're treated to a sickening grinding sound.
The whole AF experience with this camera reminds me of my Nikon 8008 back in 1989, just before I turned off AF for good.
The viewfinder only shows about 92% of image area, similar to a 35mm SLR. But medium-format chromes aren't usually mounted and negs aren't sent to 1-hour labs so I think a lot of folks will be in for compositional surprises.
There is no mirror lock-up as far as I can tell. This will limit the camera's utility for macro and critical telephoto landscape work.
It is rather painful to adjust the ISO speed for the meter. I can't figure out why the Pentax can't read the bar codes that Fuji is putting on its 120 film these days. The Fuji "P&S-style" 120 cameras can. Then the 645N could set the ISO automatically for you.
No Polaroid back is available for the Pentax 645N, mostly because there are no interchangeable film backs for the camera. You can't leave the camera on a tripod and get chromes and negs by changing film backs the way you would with a 'Blad, Bronica, Mamiya, whatever.
The 645N imprints exposure data, metering mode and compensation employed, even lens focal length. All of this goes onto the film but outside the image area.
If you're used to the latest Canon and Nikon gear, the Pentax 645N will seem like a half-baked effort. If the Canon EOS or Nikon F5 engineers made a camera like this, they'd put in USM lenses, full-time manual focus, ability to shift AF to a button other than the shutter release, etc. But technical innovation comes slowly to the medium format market. Witness the fact that this AF SLR arrives more than a decade after the first 35mm AF SLR systems. So don't hold your breath for a 6x6 Canon EOS. If you want a medium-format SLR that autofocuses and that you can hand to your friend for a few shots and have the pictures turn out, this is your only option.
The price? With a lens, filter, hood, shipping, etc., you're going to be spending close to $3000. The Hasselblad kits are actually cheaper but you'll get reamed when you want to buy more lenses whereas Pentax 645 lenses tend to be reasonably priced.
[December 1998 update: Contax (Kyocera) has introduced a 645 AF slr that is rather similar to the Pentax. The good news is that each lens incorporates a Canon EOS-style ultrasonic motor. The bad news is that the prices seem to be three times Pentax prices. I wish I could say that Rob and I have critically tested the Pentax against the Rollei. But instead I finished writing my book and he did the 45th anniversary cover of Playboy Magazine. Then Rob got a Sinar X and Nikkor 210 ED macro lens and the image quality is so breathtaking that it makes a 645 chrome look like an APS point-and-shoot.]
Stay tuned. Rob and I are going to stage a carefully controlled comparison between his 645N toy and a Rollei 6003/Zeiss 80 combo. We will post the results.