Question related to Macro Lenses

Discussion in 'Open Discussion' started by roundball, Jun 13, 2014.

  1. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    Question related to Macro Lenses

    From what I’ve read, my understanding of a couple of things is as follows:
    1) Dedicated Macro lenses have greater degree and range of sharpness due to their design.
    (IE: you turn and turn and turn the focusing collar forever)
    2) Longer focal length Macro lenses (ie: 200mm compared to 100mm) allow for a greater working distance from the subject;

    One thing I’ve noticed about trying to get close-ups at the Arboretum is that a lot of the things I want to shoot are a few / several feet away in ‘beds’ that we’re not supposed to walk in.

    Since I already have an excellent / very sharp Canon FD 80-200 / 4.0-‘L’ lens…plus 25 & 50 FD Extension Tubes…would using an extension tube with an already very sharp 200mm ‘L’ lens produce results similar to a dedicated 200mm Macro lens?

    Planning to test the above combo myself this weekend…but also thought I’d toss it out here to see what some might know about the situation…and while theory is good, I’m hoping there would also be some input from someone with actual first-hand experience...thanks
  2. michelb

    michelb TalkEmount Veteran

    Oct 27, 2013
    Greater Montreal area in Quebec, Canada
    Michel Brien
    Macro lenses are optimized for short range focus and for flat field ( stamps and the like). Corners of flat objects should be as close to sharp as they can be with curved lenses the way they are designed ( this is why there is no wide aperture macro lenses since the curved lenses would be close to impossible to correct for corner sharpness). They are also usually designed to be used at smaller apertures with little diffraction (F16 normally before diffraction steals some sharpness)

    The challenge with macro photography is that as you increase magnification, camera shake ( i don't think your Super Steady Shot stabilizer will work with your Canon Zoom since it would bean adapted lens on a NEX/ILCE ) and subject movement becomes a major issue. Using a long tele will give similar challenges or increase them as you increase magnification too. So a very fast shutter speed will be in order along with a small aperture to increase DOF and anything below F11 on a zoom will probably bring diffraction stealing you of sharpness. Using flash ( not the built-in if any but rather a full sized one with maybe a reflector to increase the lighting surface ) may destroy some of the atmosphere in your pictures but may be the only way around these shutter speed/aperture challenges unless you are ready to really boost ISO and live with the grain/noise.

    Using tubes on your Zoom can provide reasonably good results but only testing will give you an idea. Center sharpness should be OK but corners on somewhat flat subjects may be an issue.

    I personally would test around the house with objects at distances i am expecting to see at the arboretum since the issue with tubes is that your focusing range will now be limited to whatever the tube you have on allows. Your focusing limits with the 50 tube could well be limited to 2-3 feet only with a magnification ratio you may not like for the subjects you are looking at.

    The other thing with tubes ( applicable to regular focusing lenses as opposed to Internal focusing ) is that your maximum magnification is approx your focal length divided by your tube extension. A 50mm lens with a 50mm tube can go approx 1:1 at the infinity setting ( this is actually increasing as you focus towards minimum focus but is still pretty limited. Your 200mm lens with a 50mm tube will give you approx a 1:4 ratio which is what some standard zooms can achieve. If your lens is internal focusing, it probably changes focal length as you focus ( mostly getting shorter mm) and then the tube effect may be limited to less than that.

    Test before you go. This will save you a lot of frustration when on site and may even let you leave some unnecessary equipment home

    If you think of taking pictures through glass, a polarizing filter may be a good idea to bring along.

    You don't mention the camera you intend to use ????
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  3. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    Here is the lens extension calculator I use:

    Lenses beyond 135mm need lots of extension tubes to work as a macro. 50mm of extension will take minimum focusing distance from 1.5m to 60cm and bring magnification to 0.5 with a 135mm lens. I will try this when time permits, may be next spring. My problem is exactly same as Roundball's, photographing plants in arboretum.

    Macro lenses are basically three things, much longer helicoid to allow close focus, flat field and no geometric distortion for copy work. Quite many lenses are optically very good too.

    The old macro lenses are not really optimized for any shooting distance. They work by moving the whole optical block and when you do that image circle will be larger. That basically means that you lose resolution in the center but the center will be much larger. With normal shooting distances corners may be soft as with any lens.

    With plants you don't need flat field, good resolution and preferably good contrast are needed. Apertures have to be pretty small too or DOF will be very small.

    I plan to use tripod and focus stacking for plant photos. My summer vacation starts in two weeks and there were bunch of trilliums not flowering two weeks ago so I hope to see some of them flowering them. There will be roses and very probably mushrooms (I planted them two months ago and the are older plantations outside too).
  4. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    Good stuff so far.
    Unless things change over time, I suspect my interest in Macro will continue to basically be nature / wildlife related.
    I suspect benefits of precise flat field and the possibility of soft corners would not be a high priority for me, and probably not an issue at all.
    I invariably clean up / trim / crop edges some anyway so original corners would not even be present in nature / wildlife shots.

    The main interest is seeing what options I might have to increase macro working distance without investing in a longer dedicated macro lens.
    I was hopeful that some existing Canon FD lenses like 135/2.8, 200/2.8, and that 80-200/4.0-L zooms could give me more reach than the excellent 100/4.0 Macro I just picked up, and with similar macro results if I used extension tubes. If not I may have to bite the bullet, flip some assets, and get a 200 macro.

    Rain has finally stopped here and not a drop showing in the 7 day today I'll set up a pot of Petunias 10' feet away, snap a couple with the 100 macro, then without changing any physical relationships, experiment with 25 & 50 FD tubes using a few different lenses like those I mentioned above, and compare the results.
  5. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    NEX-7...they have brought back to life my entire inventory of good Canon FD lenses from the '80s...retired now and fully re-engaged in the hobby
  6. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    By calculating:
    200mm lens at 3 m will provide magnification of 0.08. That means that subject that is 300 mm in width will fit in frame.
    At 1 m the same lens will have magnification of 0.38 and subject width on 63 mm.

    If closest focusing distance is 2 metres you will need 75mm of extension to get to 90 cm focusing distance.

    Definitely worth trying. I will try 135mm some day, maybe my Nikon 180mm/2.8 ED too. (If Jupiter 37A 135mm/3.5 would work I would be happy. Seems a working idea,
  7. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    Well, more lessons learned...just ran some vary rudimentary tests, and found that adding an extension tube to normal lens does indeed influence the close-focusing working distance a little...really leveraging the investment in an on-hand normal lens.

    BUT..."unlike my existing 50 and 100mm actual macro lenses which also work as normal 50 and 100mm soon as an extension tube is added to a regular 135, 200, 70-150, 80-200...they no longer function as normal lenses...they only seem to function in the macro world of close focus.
    For example, the Canon FD 200/2.8 with a 50FD tube has a focus range of about 1.5' -2.5'...big improvement over its normal close focus distance of 4'.
    But nothing else outside of the small range will come into focus, severely limiting having the lens on a camera, compared to having a true dedicated macro lens on a camera.

    So its good to know the investment in an existing normal prime or zoom can be made "macro-ish" by simply adding an extension tube...I was disappointed at the overall limitations the use of a tube on a normal lens brings along with it.
    Wouldn't matter in any kind of fixed studio, but out and about with nature / wildlife subjects, I like the flexibility of both macro capability & normal lens capability in my hands that a true dedicated macro lens at an Arboretum (or a woods walk) mainly looking for macro shots, a bird lands on a bush 10' time to start fumbling around changing lenses as it'll be gone in seconds, etc.
    Based on what I just went through, a dedicated macro lens would get the bird, an extension tube on a regular lens would not.