Nikon F Long Roll Backs


F250

Note: if you've already read the F250 entry on the motors page, you can skip over this rehash.

This motor completely replaces your standard Nikon F's back, and includes a pressure plate. On the front of the motor is the coaxial power connector; the back holds three dials: from right to left, they are the "countdown" selector, S/L/C collar and firing button, and firing rate knob.

The "countdown" selector is most useful for bursts of specific numbers of frames (set the number by pressing in on the selector and turning it clockwise), or for automatically stopping the motor at the end of a roll (again, set the appropriate number of frames). Unfortunately, the F250 does not integrate the "Orange Dot" position of the MD-1/2 and MD-4, which allows an indefinite number of pictures to be taken.

The S/L/C (standing for Single, Lock, and Continuous) collar surrounds the motorised shutter release button. Turn the collar so that the dot appears next to the appropriate setting, and press the release button to take a picture and wind the camera on to the next frame. You will want to be sure to hold the button down long enough for the shutter to completely cycle, or else the mirror will remain locked up from the previous exposure. Any speed (except "T") may be used in single-shot mode, although it might be more convenient to leave the motor in continuous mode -- it is quite easy to remove your finger in time to avoid taking two shots in a row, plus you have the option of sequence photography, if you so desire. While the thought of blasting film through your camera may be impressive and certainly will make you sound like a pro, I find motor drive most useful for keeping the camera pressed firmly to my cheek, without taking it away to wind on the film (I am left-eyed, so the lever inevitably pokes me in the right eye). I also find it useful for power-rewind when it is cold out, and I have gloves on and do not wish to unfurl the tiny rewind knob that Nikon gives to us. As the S/L/C selector on the Cord Pack overrides the one on the back, Nikon recommends that you leave that S/L/C collar in "L" when using the Cord Pack.

The firing rate control is fairly self-explanatory. Because the F has a mechanical shutter and does not communicate well with the motor drive, you need such a device to set the delay between firing the shutter and winding the film on (otherwise I suspect that you could probably do violent harm to the shutter-timing gears). The F3 has an infinitely more logical system -- you set the shutter speed, don't worry about when the film will wind on, as the camera and motor will chatter away happily to each other about this. On the other hand, you can't set the MD-4 to fire at a specific framing rate without purchasing the accessory MK-1. I find that the benefit afforded by knowing the framing rate is outweighed by the inconvenience of figuring out the appropriate shutter speeds to use.

The F250 uses its own special cassettes, can only be used with the Cord Pack, and has its own set of loading and attaching procedures. In a frontal view of the F250 (i.e. with the three knobs facing away from you), note that the film chamber on the same side as the power connector is smaller than the other side; the smaller side will be referred to as the supply-side, and the larger side will be the take-up-side (please, no cheesy economics jokes).

Unlike the F36, the F250 does not have the keyed lock/unlock on its bottom plate. It actually attaches over the strap eyelets. The top of the F250 is dominated by two large, knurled knobs at either end; there is one slider just inboard of each knob, which goes over the strap eyelets. The very right edge (i.e. the take-up side) of the F250 also has a back-plate lock on it. To fit the F250 to the F, assuming camera and motor are synchronised:

  1. turn both knurled knobs so that "open" lines up with the white index dot towards the back of the camera (i.e. turn the supply-side knob clockwise, and the take-up-side knob counter-clockwise)
  2. slide each slider outwards, uncovering the grooves into which the camera's eyelets will go
  3. fit the camera (without standard back) to the motor and back
  4. slide the sliders back inwards, locking the camera's eyelets in place
  5. raise the back-plate lock on the take-up-side chamber and remove the back-plate

Now you are ready to load the MZ-1 cassette with 33 feet (10m) of film. On the other hand, you can use your camera as a massive F36 -- you need to remove the camera (reverse steps 3-4 above and load the cassette [can't use Nikon's reloadable cassette] normally) and then fit the camera to the F250 again. For those of you with MZ-1's, this is how you load one:

  1. open the cassette:
    1. press the silver button under the "J" in "Japan"
    2. rotate the shell relative to the top plate until the openings in the two halves line up
    3. separate the two halves
  2. go into the darkroom
  3. trim leader of bulk film to form a "tongue" appox. 30mm long and 20mm wide (1.2 in. long and 0.8 in. wide)
  4. put the tongue into one of the two slots on the spool inside the MZ-1
  5. wind about 10m (33ft) onto the spool, with the emulsion side on the inside (using the winder, if available):
    1. put the bulk-film supply on the film drum spindle, with the film coming over the axis, not under.
    2. put the MZ-1's spindle on the winding spool
    3. trim leader, if necessary, and thread film into the MZ-1's spindle, taking care to pass over the sprockets and passing film over the axis of the MZ-1's spindle
    4. swing the film pressure lever over the film
    5. pull and turn the exposure-frame dial to set the total number of frames to be wound
    6. wind (at appox. 2-3 frames/sec) until you reach the preset, which will cause the winding to stop
    7. cut the film approximately halfway between spools
  6. place loaded spool into "top half" of MZ-1 with film protruding (to the right, if "top half" is held so that "Nikon" and "Japan" are facing up)
  7. close the cassette:
    1. slide "bottom half" over "top half"
    2. turn "top half" clockwise until you hear two clicks, meaning that the catch has fallen into place
  8. leave the darkroom

Hey, we're not through the woods, yet. You still need to put the loaded cassette into the supply chamber, which requires a bit of care:

  1. pull out the supply-knob (on the bottom of the chamber)
  2. align the small tab on the cassette with the corresponding notch in the chamber
  3. align the two silver buttons with the recess at the chamber's top
  4. align the white (or red) dot near the base of the cassette with the corresponding white line on the chamber's floor

Now that all that's been done, you have to pull out some film (about 400mm or 16 in.) from the supply spool, cut the leader to shape, and thread it onto the take-up cassette as outlined above. Again, note that the emulsion side should be in. After sliding the take-up cassette back into the F250, as outlined above, take up any slack in the film with the supply-knob. Make sure that the sprocket teeth of the camera engage appropriate holes on the film. Whew! I'll tell you this much: I don't think that the whole business of bulk-loading film and fiddling with the MZ-1's has much changed, even today with the F5. Finally, replace the back plate and turn the two top knurled knobs to "close" (which locks the eyelet holders in place and somewhat perversely opens both MZ-1's.

You may confirm that the camera and motor are winding the film correctly by making sure that the supply knob is turning as you expose film. Because you lose so much film to being the leader, you need to make five complete "blank" exposures before getting to the unexposed portion of the film. Similarly, when taking the completed 10m roll out, you will need to make five "blank" exposures before removing the back.

Nikon made plenty of exciting accessories for the F250, but the one that you really need is the Cord Pack (or the MA-1) to supply power. It attaches just the same as to the F36, through the coaxial connector on the motor's front. Strangely enough, F250's are often cheaper than F36's, probably because of their limited usefulness to modern users (much easier to perform time-lapse photography with an integrated intervalometer, autoexposure, and autofocus -- ergo the F4/MF-24) and amazing bulkiness. On the other hand, you might be able to accomplish reportage more efficiently by not having to stop and reload so often, although the F250 only holds the equivalent of seven rolls of regular film, and whatever you save in not reloading so often, you probably lose again in weight/bulk, handling, loss of portability, inefficient reloading, and unwieldy processing. So perhaps the F250 is best for the budding F collector who wants to obtain a reasonably rare item at a decent price.


F Index | F2 Index | Next: Backs: Large Format Backs