Focusing rail for macro photographing

Discussion in 'Nature' started by anders_stavland, Apr 14, 2011.

  1. I have recently seen a focusing rail named Accura.
    I just wonder if anyone have experience with this focusing rail.
    How does this Accura focusing rail compares to more well known brand as Novoflex focusing rail and Minolta focusing rail.
    Thanks in advance.
  2. stemked

    stemked Moderator

    Hi Anders.
    I have used an older Novoflex and Pentax Macro Slider III. Both of them were 2-d units. I googled the Accura and it looks like a 3-D version. Since I haven't used the Accura I can only speculate some of this. Both the Pentax and Novoflex use a worm gear to move the camera very accurate very smooth, I don't think the Accura does. The Pentax lock up very easily. My Novoflex is pretty light weight, the Pentax was large enough to handle a 6X7. I would think a 3-D version would be a pain to hike with because it is bulky.
    Sorry, not very helpful.
  3. Anders, I've used a lot of rails, but I'm sorry, the Accura isn't among them.
    Douglas, I've never seen a worm gear Novoflex or Pentax. All the current Novoflex rails use rack and pinion gears, as does the only Pentax rail I've ever used, and the Nikon and Oly rails, and the old Accura rails that I've seen pictures of. As far as I know, the only worm gear focusing rails currently on the market are RRS (the king of worms) and Manfrotto. The surprisingly respectable Velbon is a rack and pinion, as is the whole Novoflex line, and the generic Chinese rails that you see branded everything from Adorama to Kirk.
    You've also added one to the dimensions. Most rails are 1 axis, with a few 2 axis "crossed" rails. The Velbon is a surprisingly compact 2 axis rail, not much bigger than most 1 axis units in its class.
  4. stemked

    stemked Moderator

    Hi Joseph.
    I stand corrected in every thing you noted. Gotta stop doing this late at night.
  5. Thanks for your replies. Joseph, You mentioned that you have tried several rails. Which do you recommend?
    Now I am just wondering if I could try to buy a used one. I think that a well manufactured rail is still very useful even if it is a used product. The two brands I considering buying is a Minolta rail or a used and older Novoflex mini Castel than the current one, and a bigger Novoflex rail back from the nineties. Are any of the above mentioned rails amont them You could recomment
  6. Douglas, I might have made the same mistake, if I hadn't written 2 chapters on the care and feeding of focus rails for my upcoming book on macro photography.
    Anders, I recommend different rails depending on what people are shooting. The reason I made such an issue of the difference between worm-screw and rack-and-pinion rails is that they each have different strong points.
    • Rack and pinion rails generally have the best compromise between how much the rail moves in response to knob movements, they can crank over a large range, 10s of mm, quickly when you want to locate the subject, but still move in fractional mm increments suitable for high magnification or focus stacking work. The control placement is convenient, with the knobs on the side. But their smoothness is a downfall when you have to point the camera up or down more than about 20-30 degrees. Pointing downward is especially dangerous, as soon as you release a friction lock, they want to send the camera and lens crashing into your subject. You learn how to work the rail with 2 hands.
    • Worm screw rails are slower, but more precise. A turn of the knob produces a very small rail movement, so they're good for the very highest magnifications, but you can spend a minute or two cranking the rail to the subject position, if you set things up 20mm off. Worm screws are "slip neutral", you can point them straight up or down, 90 degrees, and they will stay put, and not respond to anything other than knob motion. The knobs come out the end of the rail, so they're always under something or poking something. But they can be worked one handed, even when pointed straight down.
    Buying used rails is tricky. If the gears are in bad shape, they jam or jump. On a rack and pinion, the rack (the big, long gear) is often visible, and a quick look with a magnifier will verify the condition of the teeth. The pinion (the small, round gear) is typically hidden. On a worm screw, the worm is easy to see, rotate it so you get to see all sides, but the slider is hidden.
    Most "dovetail" rails (Novoflex mid and large rails, that Minolta, the Accura, my Nikon, etc.) have plastic "friction blocks" that sit between metal of the rail and the truck (the part that moves). If those are worn, the rail will be wobbly, and there's usually no way to get replacements from the manufacturer. I've shimmed friction blocks before, but it's not easy. Other rails use rods, and those are usually metal-to-metal, but the design makes them very immune to wear.
    Personally, I don't like the Novoflex Mini. It's a double rail, essentially something cobbled together from parts they use for their small bellows, 4 rods, 2 through the lower truck, 2 through the upper, and those tend to twist enough to make it wobbly. A big older Novoflex would definitely be worth looking at, just inspect it carefully and mount a camera to make sure it's not wobbly, they're known for not aging well.
    Is the Minolta a III? That's a curious bird, large and strong enough, but a little awkward to use close to the subject, you'll typically find yourself with the camera at the end of the rail closest to you and most of the camera body and lens projecting along the length of the rail. This is actually useful, because you can add a post and a rest to the rail to provide additional support to the lens, if you like to tinker. Again watch out for the condition of the friction blocks.
    I highly recommend the Velbon mag slider. It's an underrated (who takes Velbon seriously?) little gem of a rail with 2 thick rods, and a heavy cast truck that moves precisely. It comes as a 2 axis rail, with a second rail set for lateral motion: I dismount that and just use the long rail. That's the magnesium Velbon, there's an older non-magnesium model that's pretty wobbly, thinner rods and not as good a truck.

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