Variable magnification / telescopic extension tubes?

Discussion in 'Accessories' started by piggsy, May 25, 2015.

  1. piggsy

    piggsy Mu-43 All-Pro

    Does anyone make one of these, or something that can be used as one of these, for MFT?

    I'm thinking of something similar to -

    * the Telescopic Auto Tube 65–116 for Olympus OM -

    http://www.alanwood.net/photography/olympus/telescopic-auto-tube.html

    which with the right lens (the 135?) designed to be used with it, still allows infinity focus, and has a tripod mount on it ( :inlove: ), and doesn't need a stage/some delicate leather bellows, or

    * the Vivitar 2x Macro Focusing Teleconverter -

    http://www.pentaxforums.com/userreviews/vivitar-2x-macro-focusing-teleconvertor.html

    which has glass in it and is a really neat toy, acting as a 2x teleconverter on any lens while retracted and still leaving you with the ability to focus to infinity, and by turning the ring you can change magnification smoothly from 1:20 to 1:1 on a standard 50mm (different lenses more/less).

    What happened to these as, well, as a thing? From using the Vivitar one I can only guess they were too awesome to live?
     
    • Informative Informative x 1
  2. zensu

    zensu Mu-43 All-Pro Subscribing Member

    Aug 8, 2012
    Alabama USA
    Bobby
    I don't recall these two specific products but I do recall there was a third party telescoping extension tube way back before all the electronic components appeared in modern lenses (the 80's). These electronic free tubes were very expensive for the time period and I honestly don't recall any reviews in the photography magazines (pre-internet). Your ability to even find these two is surprising. Keep up your search and please post your results here.
    Bobby
     
  3. piggsy

    piggsy Mu-43 All-Pro

    I don't have the Oly one - there are currently 3 on keh -

    https://www.keh.com/239664/olympus-manual-focus-ext-tube-65-116-auto

    and keh also have a few of the compatible lenses (135 f4.5, 80 f4, 38 f2.8) for not insane prices. Don't recall the 20mm being at all cheap when I last saw it on ebay, though, and IIRC it's well past 1:1 magnification at the lowest on that tube - link says 5.8 to 8.3:1.

    I do have the vivitar 2xMFTC one though, which is pretty common, pretty cheap (apparently expensive when it came out) and pretty great. Tried it today on my freshly repaired Vivitar S1 90 2.5 today, and the 135 2.8 Close Focus, both of which have enough resolution on them to begin with to make it worthwhile.

    Viv S1 90 2.5 - just a couple of flashless daylight shots, wide open, done as straight out of camera style shots via oly viewer 3. Not at absolute maximum magnification here - couldn't do more because the wind picked up and the light disappeared and then it started spitting rain pretty much as soon as I started :( -

    p5260215thhwupw.

    p5260224thulup8.

    earlier samples of it on the 135 2.8 CF -

    https://www.mu-43.com/threads/14026/#post-774141
     
    • Like Like x 1
    • Informative Informative x 1
  4. Petrochemist

    Petrochemist Mu-43 Top Veteran

    824
    Mar 21, 2013
    N Essex, UK
    Mike
    I have a M42 adapter with a built in Helicoid extension tube which sounds like what you're refering to. My set are marginally to long for infinity focus with the lenses I've tried so far - they might be OK with long focal lengths as my measurements make them only 0.1mm too long! I have seen other sets that claim to give infinity focus & might even end up getting some if I can't skim a touch of my current set.
     
  5. piggsy

    piggsy Mu-43 All-Pro

    There's a manual scan here -

    http://mailch.blogspot.co.uk/2012/08/the-users-review-vivitar-2x-macro.html

    of what the 2xMFTC does - different example lenses with their min/max magnification at closest/infinity focus at max on the tube are listed on the last page. I've also tried it on the E.Zuiko OM 200mm F4 and the results are ... uh, not fantastic. The main issue I think being that the lens (or my single coated copy anyway) doesn't really get going sharpness/aberration control wise until about F8 to begin with, and adding another 2 stops (plus loss from extending the tube all the way) from the converter, plus the m43 crop doubling the length/effective aperture again, and you have something that really struggles to hit usable shutter speeds hand held :D

    Some wide open samples of it here -

    http://forum.mflenses.com/olympus-om-e-zuiko-200mm-f4-t71079.html#1436956
     
  6. PacNWMike

    PacNWMike Mu-43 Hall of Famer

    Dec 5, 2014
    Salish Sea
    I have both of those. Didn't ever use the Viv macro focus 2X much and never on digital so can't comment. I remember that it gave decent results but not up to the Oly macros. However I really like the 65-116. I have the 135 and 80 macros which both give smooooth bokeh. Also have the Close-up Lens 80mm Macro f=170mm for use on the 80. The 135 will stop down to f45 which gives a pretty deep DOF at the expense of diffraction. Still it's useful if you don't want to stack. I'll see if I can dig up some examples. ...
     
  7. Petrochemist

    Petrochemist Mu-43 Top Veteran

    824
    Mar 21, 2013
    N Essex, UK
    Mike
    When I tried the links before my stupid work PC had issues (now I can read them)
    I have 2x macro focusing teleconverter and a 3x 'clubman' version too. Not yet tried either on µ4/3 but I have used both on APSC. These were designed to be used with the then standard 50mm primes & work reasonably well at least if you bear in mind the usual limitations of teleconverters.

    The 'auto tube' looks like a fairly standard helicoid extension tube, though one of the longer models available. In the past these were fairly rare but chinese manufacturers are now making generic ones in a range of different screw fits (I've seen M42, M52 & M65 models in multiple length options). Normally they won't give infinity focus, for that you either need to use a suitable focal length bellows lens (which has no focusing control itself) or you need on built into an adapter where it's short length is no more than the difference in flange distances for the mounts concerned.

    IMO hand held macro at any significant magnification is going to need added light however you get your magnification.
     
  8. piggsy

    piggsy Mu-43 All-Pro

    Of course of course, just, I had real trouble getting light on subjects with the 135mm 2.8 CF with the 2xMFTC, let alone taking on an even longer MFD and extra stops on the 200 F4 :D. Start running into stuff like 1/250 RC sync being uncomfortably close to the minimum shutter you can get away with too.

    I mean - ideally - there would be some kind of MFT native thing that was

    * able to restore infinity focus, adjusted for its own size while retracted - whatever the minimum optics are required for that to cover a given reasonable range of base lens focal lengths

    * able to telescope and extend to decrease mfd/increase magnification by a lot

    * had a tripod foot on it :D

    For me the Oly Telescopic Auto Tube starts off a bit too extreme in terms of minimum tube distance and costs you infinity on all but one lens (that then only goes to 0.45x at maximum extension anyway), and the Vivitar teleconverts to something that is a bit extreme on longer lenses (and loses 2 stops before you even start extending it). Something in between, smaller, able to be mounted closer to the center of mass between the body and lens if needed, less extreme TC, more range in the telescopic extension tube part - that would be perfect. I mean, I would buy one.
     
    Last edited: May 28, 2015
  9. Bytesmiths

    Bytesmiths Mu-43 Top Veteran

    Any lens that focuses to infinity without an extension is not going to be able to focus to infinity with an extension. the OM Zuiko 135/4.5 macro is the only lens I know that is designed to focus to infinity with the TET. It's a lot of fun, and focuses to near 1:1 with the TET.

    I'm in the process of converting my Olympus Telescoping Extension Tube to MFT. I'm waiting on some 62mm —> MFT reversing rings to arrive from China. Then, I'll grind off the threaded part, remove the OM mount from the TET, put some short nails in the remaining holes to mark the back of the reversing ring, drill holes, then screw it down in place of the OM mount.

    But getting the reversing rings from China is slow! I got some 58mm ones, but they won't cover the original screw holes in the TET, and I didn't feel like putting new holes in it.

    I'm currently using the TET with a standard OM —> MFT adapter. The main reason I want to mount it direct is to not have such a high magnification on the short end. (And also, less wobble.)
     
  10. Petrochemist

    Petrochemist Mu-43 Top Veteran

    824
    Mar 21, 2013
    N Essex, UK
    Mike
    When the extension is additional to the lenses designed registration pretty much all, but perhaps not quite all. Very long focal length lenses are often designed to focus 'beyond infinity' and these are less effected by extension tubes, so something like a 600mm lens on a short extension tube might still focus all the way to infinity.

    When lenses are being adapted then the adapter can include a variable length extension (helicoid) such that at it's shortest the lens is held at it's registration distance, performing as it was designed to. With a twist of the adapter helicoid the adapter extends giving extra close focusing capabilities. A couple of the adapters I have now are of this design, the first I got (mentioned two years ago up thread) is marginally too long at it's shortest- My micrometer suggests the error is only 0.1mm - so that many wider lenses don't quite reach infinity. The more recent version is a MFT to EOS model which does focus to infinity with any of the lenses I've tried it on.

    The macro focusing teleconverters Piggsy mentioned are a similar item where the TC's length at minimum allows it to focus to infinity, while also allowing a helicoid extension to be added. The helicoid here increasing the distance between the lens & the TC optics.
     
    Last edited: Jun 16, 2017
    • Informative Informative x 1
  11. Bytesmiths

    Bytesmiths Mu-43 Top Veteran

    I'm getting ready to play with such a thing. The 35mm end will be considerably too long for infinity (normally, ~33.5mm), but the shorter helicoids had a way shorter long end, and I wanted it primarily for macro.

    The M42 end will just slip inside a 62mm —> Micro 4/3rds reversing ring, with the 62mm threads ground off on a belt sander. Then you just pop the screws out, drill matching holes in the modified reversing ring, and screw it down.

    This particular one is an M42 —> M52. I think if I were to do it over, I'd go with M42 on both ends, but I was worried about having enough diameter to stick an OM mount on the lens end. Looks like I have the opposite problem; the M52 screw holes will be on the edge of the OM mount, so I'll have to drill and thread new holes.
     
    Last edited: Jun 16, 2017
  12. Petrochemist

    Petrochemist Mu-43 Top Veteran

    824
    Mar 21, 2013
    N Essex, UK
    Mike
    There are some combined C-mount/short M42 adapters around that would be an easier way to mount your helicoid. They give the M42 thread pretty much flush to the cameras flange.

    The one I use is (I think) Canon EOS EF lens to Olympus PEN Micro 4/3 mount adapter Macro Focusing Helicoid | eBay Yes it's much shorter at it's longest, but with wider lenses still get to reasonable magnifications. Perhaps I should try one of the longer models sometime to give some options with more working distance :)
     
    • Agree Agree x 1
  13. Bytesmiths

    Bytesmiths Mu-43 Top Veteran

  14. Petrochemist

    Petrochemist Mu-43 Top Veteran

    824
    Mar 21, 2013
    N Essex, UK
    Mike
    I doubt they make them for OM or T2, but the EOS one can be taken to either. I use mine for an OM 28mm (in both forward & reversed orientations).