F/stop or Focal Length?

Discussion in 'Nikon' started by jerry_curtis, Dec 3, 2011.

  1. I want to put a reversing ring on my D7000. In deciding what lens to use, what is more important, the maximum lens opening or the focal
  2. If you are using a reversing ring, I assume you want to take photos in the close-up (macro) range. Focal length would be my first consideration, as it will determine the working distance from the subject. I would not use a super-speed lens for that. Or am I misunderstanding your purpose?
  3. Maximum lens opening is largely irrelevant for this, assuming you have enough light to focus and compose with the darker lens. When you shoot, you'll want to stop down anyway for adequate DOF.
    The focal length determines your magnification/working distance. This is almost certainly the more important factor.
  4. What sort of reversing ring? Are you going to reverse the entire lens on the camera, or fit another lens in reverse on the front of the one fitted to the camera?
    If you're reversing the entire lens onto the camera you'll probably want to use a zoom. This sort of reversing doesn't work well with prime lenses using "unit focusing", since you'll only get one focusing distance and won't be able to vary it.
    Actually, I'd go for a set of extension tubes instead of a reversing ring option. You'll be able to use AF tubes with almost any lens regardless of filter size - and it won't put undue strain on a filter-thread that was never designed to take the weight of the entire lens.
  5. I'm not conscious of any particularly bad Nikons in this respect. In contrast, the F4 stands out and being almost devoid of "mirror slap" in my experience - you can hear the camera go off, but you feel almost nothing. This, of course, could be a result of the huge amount of inertia in The Beast, rather than a function of the shutter/mirror mech.
  6. I have no specific purpose in mind. I just want to give it a shot.
    The ring I am looking at costs $3.00, with free shipping, which is a bit less than extension tubes. I'm not doing this to earn a living, just to see how it works. I wondered about the plastic threads holding the lens in place, but people have been doing it for years. I'll just have to be careful. I have a Sigma 28-70mm lens that I'll use with it.
    Does shorter focal length give more magnification? I didn't realize a zoom would be better for this, but that's why I turned to you guys.
    Before I bought a reversing ring, I wanted to decide what lens to use so I would know what size ring to get. If necessary, I would have bought a used one on ebay.
  7. Shorter focal length gives more magnification, and less camera to subject distance.
  8. Jerry, usually you need a bit of extension between the camera and reversed lens. Extension tubes are fine for this.
    Just reversing and not adding any extension produces (usually) poor quality. Probably you will be disappointed without any additional extension.
    For best results: Try to adjust the extension of your reversed setup so that your focusing distance is about the same as the closest focusing distance of the normal setup with that lens. ( Focusing distance is from a subject to the sensor. ) With longer FL lenses this is, however, impractical.
    Reversing a G-type lens: it will stick to it's smallest aperture, that is difficult to control. Af-D or manual lenses are better/more flexible in reversed use.
  9. Thanks for you input. I have one or more "focusable" lenses.
    Would I be better off with a bellows, rather than extension tubes?
  10. Actually, there is some misinformation here. As having practiced a lot of macrophotography over the years, I have tried all sorts of methods. You can use a Nikon reversing ring (I highly suggest the all-metal BR-2) with any lens. It just so happens that you'll get pretty good macro results from a typical 50mm 1.8 lens from just about an old manual-focus camera. The only thing you need to make sure of is that the screw threads for the filter ring match the adapter. The BR-2 has typical 52mm threads -- you can use a step-up or step-down threaded adapter for any other size. A 35mm lens will give more magnification, and yes, less working distance. For static subjects, it's not a big deal.
    Extension tubes are a fairly cheap way to do macro work. The Kenko set has electronic contacts so that you can retain all AF functions of a lens. If you are using a manual camera, then that does not matter so much. But for future compatibilty's sake I would get the Kenko extension tubes for Nikon AF. A true macro lens works better than a normal lens, but let's say you want to shoot butterflies with a relatively cheap 135mm lens. You can do that with extension tubes.
    Bellows are really for extreme macro work, at 2 to 4x life-size, and without going into the use of them, let's just say that they really are specialty items. I do use them in my work, but rarely.
    Pick up a copy of John Shaw's Closeups in Nature to get a better feel for the techniques.
    Also, you can buy screw-on diopters from 1x to 10x that go in front of your lens -- the best are the Nikon 5T and 6T diopters (and of course, Nikon no longer makes them!). Cheaper diopters can be stacked for more magnification, too. Perhaps not always the best solution, but stopped down they are not bad, and you can pick them up fairly inexpensively. Make sure you get a set that has the same filter thread size as the lens you want to use.
  11. Wow! Lots of info in a small space. It's like you summarized the high points of a book on close-up photography. I'll save this for future reference.
  12. I confess that I have taught classes in macro photography... the method of image storage may have changed in 10 years, but the techniques haven't changed too much. Glad to be helpful.
  13. Mark. Please explain how a reversed prime lens can be variably focused when used on a BR-2 ring alone? The adapter fits on the filter thread of the lens - right? And the filter thread does not move in relation to the lens elements - correct? Therefore any lens which uses unit focusing (in other words, all of the lens moves forward on a helicoid to focus) will only be able to focus at one distance and one magnification. Not terribly versatile.
    A 50mm f/1.8 standard lens is such a unit-focusing lens. So, if fitted to a BR-2, rotating the helicoid will not alter the distance between the lens assembly and the camera body, but will simply push the helicoid out over the rear of the lens like an extensible lenshood. In other words there's no way to focus the lens apart from moving the whole camera in relation to the subject.
    A BR-2 or similar adapter is therefore best used with a bellows unit, with additional extension tubes, or with a lens that focuses by means of shifting elements - for example most zoom lenses, and the majority of current Micro-Nikkors. But then if you've already got a Micro-Nikkor, why would you want to experiment with a cheap reverse adapter?
  14. Joe:
    I did not mean to imply that you can use the helical to focus the 50mm lens. You have to MOVE THE CAMERA if you want to focus, which is why a copy stand is a good idea for such an application. It's not the best solution, which I thought I pointed out. As Jerry indicated, he wanted to do this "cheaply". I agree that the BR-2 is best used with a bellows. However, I have used as a quick and dirty way to get an image when I didn't have the proper macro lens with me. Here is a quick and dirty sample I just did for the purpose of illustrating what CAN be done with a simple setup - a D70s body, BR-2 ring, and a 1970s Ricoh M42 lens - 50mm 1.8. Please note that this carpenter ant is Camponotus gigas from Malaysia - it's an inch long.
  15. oops. here is the image...
  16. Sometimes you have to use a wrench for a hammer. In a perfect world we always have all the gear we need to get the picture, but sometimes we don't, and one needs to know what is possible.
  17. If you go the Nikon route with the reversing ring, be sure to use a BR-2A and not a BR-2. The BR-2 could damage your DSLR. See this link for details: http://support.nikonusa.com/app/answers/detail/a_id/4618/~/br2-and-br2a-inversion-rings

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