advice on picking a cheap lens for a macro project (note: 50x+ magnification reached)

Discussion in 'Adapted Lenses' started by julienrl, Aug 8, 2010.

  1. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    I want to make macros out of old manual lenses by making tubes etc. My problem is I am not sure if I should for for an old prime 135mm fro 15$ or a 80-200 with a 2x extender accessory for 25-30$ (still negociating).

    I don't have much money to spend on this project and when I offered 15 for the second lens he said he wanted closer to 30. Would it be worth the extra bt of money for an insane zoom 200 x 2 on mu43 + the extension + the 2x adapter, making it an incredibly close up lens (probably technically a microscope at this point :p) or should I just stick with a prime with the reasoning that primes will be sharper? (sharpness is important here since I will be loosing so much of it with the tube)

    Thanks
     
  2. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    For one thing, you're better off using wider lenses if you're going for higher magnification. The macro magnification ratios are inversely proportional to the lens focal length when using extension tubes, so you need fewer tubes with a wider lens. For example, a 50mm tube with a 25mm lens would give you 2:1 magnification, whereas the same 50mm tube with a 200mm lens only gives you 1:4 magnification. The same logic applies to reversing lenses - wider lenses achieve higher magnifications reversed than tele lenses.

    Your best bet if you want to stay on the cheap is to either reverse one of your existing lenses (a cheap reversing adapter/ring is all you need), or to find a cheap 35-50mm lens and reverse it either using rings or tubes. In general terms, yes a prime would be sharped than a zoom, but it depends on the brand and on the lens. I suspect there isn't much difference in lenses in your price range, so don't worry about it too much. Just expect to deal with some aberrations, etc. in your photos.
     
    • Like Like x 2
  3. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    oh wow, thank you! does reversing really work that well??

    I am making my own tube, so tube length are not an issue since I am using PVC tubing that I will sand to make it mat.

    So if I already have a 50mm, if I put a 10 cm custom tube, how I will be able to get right up there on it? So there would be zero advantage to having a lens that already has a long focal length?

    Thanks for the help!
     
  4. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Yes, it does, but the image quality obviously depends on the lens quality. Some lenses are better than others, and reversing brings its own issues like really close working distance.

    I'm not sure what that means. Can you rephrase your question?

    Long focal length works against you in macro when reversing or using tubes. The only advantage you get is having a longer working distance, which may or may not be important to you.
     
    • Like Like x 2
  5. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    So if I get longer working distances, but it zooms in... if I have a 100mm and a 50mm. if I put the 100mm on a 100mm tube and the 50mm on a 50mm tube, I should get 1x on both, but how close\far will I have to be with each respective lens to get that 1x magnification?

    Thank you
     
  6. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Different lenses have different working distances (close focus distances), so I can't give you exact numbers. Figure in general the working distance on a 100mm lens would be about twice as long as that for a 50mm lens. The other advantage of the 50mm lens with a 50mm tube is significantly reduced loss of light vs. the longer lens with longer tubes (not to mention easier to carry). With the 100mm lens at the end of 100mm of tubes you'd have to provide much more lighting, or increase your ISO, in order to get good exposure. Moreover, the farther you get from the sensor, the more distortion you introduce (unless you use macro/tele converters with built-in correcting lenses), so that also works against using the 100m lens at the end of 100mm of tubes.
     
    • Like Like x 2
  7. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    Thank you for all this information. This just cut the time sensitivity issue, I will abandon the negotiations for the 135mm and 80-200mm and stick with my minolta 50mm. I do not mind getting close in.

    When they say that at 50mm tube on a 50mm lens you get 1x, is that the max? or can I just go closer?
     
  8. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    You can add as many tubes as you want to get even higher magnifications, but as I wrote above there's diminishing returns in doing so. You lose light and you introduce distortions the more tubes you add. The nice thing about using the lens reversed is you avoid the loss of light due to the tubes. You can get roughly 1:1 with a reversed 50mm lens. There's a reverse adapter available for MFT cameras off eBay for pretty cheap, and it fits 52mm filter threads which is pretty common for 50mm lenses. It might fit yours so you can try it.
     
  9. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    interesting, and if I add a tube on a reversed lens, will I get higher than 1:1 magnification?
    Ideally I would like to get 3x or more (and I would be willing to suffer the loss of light for this kind of magnification)
     
  10. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    can tubes be added to a reversed lens?
     
  11. tam

    tam Mu-43 Regular

    107
    Apr 12, 2010
    Not sure if this will help, but here's a set of test pics from a nikon 50/2 mounted with a £3 reversing ring on my G1:

    macro-testing - a set on Flickr

    For scale the giraffe's about 2" tall, and the keyboard etc. are closeups on a nokia N900 phone. Pink thing's the nose of a knitted mouse. Nose is 7mm across, i just measured it.
     
    • Like Like x 2
  12. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    nice! thanks. If you get a chance to try tubes + reverse, let me know :p
     
  13. tam

    tam Mu-43 Regular

    107
    Apr 12, 2010
    I don't have any tubes I'm afraid, I just thought it'd give you some idea what to expect with your 50.

    Having said that, assuming it's an adapted lens you can just hold it in position reversed on your adapter then tape it in place, gives you a rough and ready idea. It's what I did before I got the adapter ring. I guess I could fashion a tube out of something (but then you could too!)
     
  14. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    ya, I bought extra caps and will be making tubes :) I was just eager to see the result since I have to wait a few weeks to get the caps from china lol :p
     
  15. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    so I got my reverser and I am immensely disappointed... maybe I just don't know how to use a reversed lens? My reversed pentax f2 50mm seems to give me about the same field of view as my regular panny 20mm... Help?

    Thanks
     
  16. Porky4

    Porky4 Mu-43 Regular

    32
    Apr 4, 2010
    Staffordshire, UK
    Hello,

    I've just seen this thread, so haven't had chance to reply earlier. Yes, you are correct about reversing a 50mm lens, I found no appreciable difference when I reversed two or three of the 50mm lenses I have. I think what has been said about reversing the 50mm is true for full frame cameras and (less so) APS-C sensors, but it's just not true on a m4/3 sensor. Extension tubes do work OK with the 50mm. I went up to about 110mm extension with one of mine, but Chromatic Aberation was starting to raise its ugly head.

    I notice your signature shows you have a 14-42 kit lens. That lens set on 14mm will give you a magnification of about 2.4:1, with good quality. The only problem with that lens is it will be stuck at it's fully open aperture setting which will give a very small DOF, unless there is some way with the E-PL1 of setting a smaller aperture and removing the lens with it still set. I know you are supposed to be able to do this with a Panny G1, not sure about the Olympus.

    Hope that helps,

    Paul :cool:
     
  17. Brian S

    Brian S Mu-43 Top Veteran Charter Member

    714
    Apr 11, 2009
    Reversing the lens does not offer much of an advantage for a normal or telephoto lens. It works best with retro-focus wide-angle lenses when used on a bellows or series of extension tubes. The "Nikon/Nikkormat Handbook of Photography" by Cooper and Abbott included a write-up on the Nikkor lenses and their use with a reversing ring. Some normals had improved optical performance when reversed for close-up work, but it was the retro-focus 24/2.8 and other wide-angle lenses that increase magnification when reversed.
     
  18. julienrl

    julienrl Mu-43 Regular

    100
    Jul 28, 2010
    Ottawa, Ontario
    thank you. The most readily available manual lenses I see are 28mm, what kind of ratio would that give me?
     
  19. Porky4

    Porky4 Mu-43 Regular

    32
    Apr 4, 2010
    Staffordshire, UK
    I'm not sure, to be honest. It's certainly going to be better than 1:1, but I don't know actually what it will be. I determined the magnification of my reversed Panasonic 14-45 at 14mm by photographing something that I knew the size of (a steel rule with millimetre markings) and comparing that to the sensor width. This is what I took:

    [​IMG]

    There may well be a formula for determining the magnification of a reversed lens on m4/3, but I don't know of one.

    Paul :cool:

    PS. The Canon FD 28mm F2.8 is a very sharp lens and is available for peanuts on eBay.
     
  20. JoepLX3

    JoepLX3 Mu-43 Top Veteran

    509
    Jun 13, 2010
    Japan
    Somebody has a link to a site with "Marco's for Dummies"-info?
    - Step-by-step explanation, preferably including some of the math and examples