When you actually use a Nikon F4, you pretty much learn that everything anyone has ever said about it on the internet is complete baloney. I will offer my own observations about the camera here:
Ergonomics. The F4 is very well laid out, with the F3's left side (rewind crank, ISO dial) and its own right side (analog shutter speed dial, exposure compensation dial, mode selector lever, shutter release and concentric drive selector). It is a very good setup for people who like dials rather than thumbwheels. Every single setting is visible and accessible by looking down. The MB-21's grip surface provides more of a pinky-rest than the F3's MD-4 does. The F4 is Nikon's best ergonomic design; it sits well in the hand and feels... solid.
Finder. Wow. I never thought a camera could best the F3's finder for brightness and clarity, much less an AF camera. I was wrong. The DP-20 finder with its B screen is a bit brighter than the red-dot F3 screen, although the groundglass is a lot finer, meaning that you really have to watch what you are doing when manual-focusing (the electronic RF is helpful when you get stumped - and believe you me, it is more often than with the F3). A J screen is a better choice for extended MF action. The built-in diopter correction is fantastic.
–If you are planning to use largely manual-focus lenses, plan to buy a J or a K screen to use with those. Note that it is pretty tough to use AF with these screens, since their focusing aids do not show the AF brackets.
–The Nikon E (grid) screen effectively creates a crosshairs in the center of the focusing brackets - which makes it really easy to aim the AF system.
Although the LCDs aren't that easy to read in ambient light, the F4 has a wonderful frameline illuminator (whose switch is oddly in the same place as the F3's self-timer), which even lights up the ADR on the lens. Who knows what effect this has on battery life, although it does turn off after 16 seconds when the meter does. The F4 has clear readouts, but it shares the F3HP's need to shift your eye up and down to see them. There is plenty of eye relief for the image itself.
Metering. In terms of metering patterns, you can switch between centerweighted, spot or Matrix metering, using a switch on the DP-20. The metering pattern is shown on the bottom LCD in the finder. Notably, you can use Matrix metering with all manner of Nikon lenses. Of course, you have to use stop-down metering with pre-AI lenses. The only camera to share this ability was the FA.
In terms of metering modes, you get manual, aperture-priority, shutter-priority, program and program-high with AF lenses. With AIs lenses, you only get manual and aperture-priority. This is something of a step down from the N2000/N2020, FG and FA, all of which could deliver programmed operation from AIs lenses (the FA did lose this when you used AI'd lenses and lost hi-program with AI lenses).
– AI lenses in general have a metering cutout on the aperture ring. Theoretically, this is capable of telling the camera what aperture the lens is set to.
–Original AI lenses have an absolute aperture lug that was unused in early AI bodies but later read by cameras designed for AI lenses and programmed operation (N2000/N2020/FA/FG). Retrofitted ("AI'd") lenses lack this. This is the feature that allows the camera to generate those annoying "FEE" messages in shutter priority or programmed modes when the lens is not set to f/11 or smaller.
–AI-s lenses also have a coupling that indicates the focal length of the lens (over 135mm/under 135mm). This is read in P Dual mode by the N2000 and N2020 and in P mode by the FA and F4.
–AI-s lenses also have a small scalloped cutout in the face of the mount which tells cameras with open-loop exposure systems (all cameras but the FA, which corrects exposures after the lens stops down but before the mirror flips up) that the aperture lever travel is linear. The FA, N2000, N2020 and F4 are capable of reading this. On the FA, if this cutout is not detected (i.e., if the lens is an AI and not AI-s lens), the camera corrects exposure by its closed-loop system.
See compatibility chart here. The ability to read the absolute aperture lug is absent from the F4 and later cameras, which use the lens CPU to obtain the same information. What's odd about this situation is that most AF lenses have that absolute aperture lug, focal length trigger and linearity indicator anyway, notwithstanding the CPU. Only with the G series did these things begin to disappear. So why does the F4 rely on a CPU instead of the absolute aperture lug? In a professional camera, the mechanical couplings may have been a weak link.
Fill-flash metering in P mode with a TTL flash and Matrix metering simply does not miss. The high 1/250 second maximum synch speed does not hurt in this connection. TTL operation in A mode is almost as good — not quite as easy to do balanced fill, but it works well.
Motor drive. I was really surprised at the F4s configuration - it basically leaves the F3 wheels up in a ditch. Not only does it have the CH setting (similar to the MD-4's C) but it also has CL (a much lower speed in which something is still happening at all times) and CS, which is a "silent" mode involving pulsing the advance motor. Although revisionists would say that it is not as silent as modern cameras, the important thing is that it does not make a high-pitched whine.
–The MB-20 (F4) is the small battery grip. It holds 4 AA batteries. It makes the camera about the size of an N90. It is somewhat difficult to find this grip in the U.S., since the F4 was normally sold with the MB-21.
–The MB-21 (F4s) is the more substantial 6-battery grip. It has a built-in vertical release, battery check button, a socket for normal cable release, and a terminal for one of the Nikon remote release cables.
–The MB-23 (F4e) is even bigger than the MB-21, and it adds the capability of using a Nicad power pack.
The rewind is interesting; if you hit the R1 lever, you can rewind manually; if you choose R1 and R2, the motor will rewind the film and stop as soon as the film is completely rewound (unlike the MD-4, which lacked this nicety without an auto-stop back). The F4 can be reprogrammed to leave the leader out in power rewind mode, but you can always either (a) use manual rewind or (b) stop the rewinding at the right time. The exposure counter actually counts backward during rewind.
Autofocus. A lot of people complain about the autofocus system on the F4. I tend to think that they are crybabies. When you shoot for Sports Illustrated, then raw AF speed makes a difference - so spend the money on an F5. These are my considerations.
–Speed. When you compare the N2020 to the F4 (both share the same AF system), the F4 is about four times as fast in focusing. Under normal lighting conditions, the F4 actually no slower than an N90. In situations where both "hunt," the F4 is actually a lot faster. The difference is basically that the F4 makes up for in sheer torque for what it does not have in processing power. There is no problem with focusing even first generation non-IF zooms.
–Sensitivity, I have been able to use AF in any situation where there is enough light to see. The key is contrast - AF systems need contrast, just like your eyes do, to focus. I have observed that the F4 can focus in any situation in which a human could focus on an E screen and a lot in which the human eye would be stumped (EV4 is where I find manual focus really breaks down; the camera can work at EV-1). All AF systems, like all MF systems, require an intelligent choice of something to focus on. Nothing focuses on blank walls except $60 AF point and shoots...
–Accuracy. For all of the hype about AF speeds coming up in the last 15 years, there has been very little to indicate that AF accurary has increased - at all.
One added bonus with the F4 is the ability to use the TC-16A teleconverter, which basically adds IF capability to many Nikkor manual focus lenses. The converter contains its own focusing mechanism, and it multiplies the aperture and focal length by 1.6.
Bottom-line. There is a reason why the F4 is still a really expensive camera, even used. It's a great platform, even if you don't really need AF to do what you want to do.
