Getting started with macro photography.
In the last two preceding issues, we explored the unique ability of teleconverters to extend the capability of macro lens. And we see that it does the job well but not without compromise.To widen our options, let us look at some other ways to do the same job.
Use of extension tubes to add more magnification
The primary function (and application) of extension tubes in macro photography has been adequately discussed in our early issues (January 13, 2015, March 24, 2015, April 28, 2015) of this topic. So we will not repeat here (the mechanics and properties of extension tubes) what have already been discussed. The application to use it with a macro lens was mentioned--but was not explained. In this issue, we shall look at it closely.
Extension tubes (as we recall) work by providing the standard lens (normal to telephoto) with ability to focus up close to subject--where conventional lenses are not capable of. It provides the standard lens a capability to function just like a macro lens but without the ability to focus to infinity. When extension tube is attached to a macro lens, it does just the same as what standard lenses do. But there is more; it also provides the macro lens with additional magnifying power (on top of what the macro lens has). The strength of the added magnifying power is proportion to the length of the extension tube.
What does this mean?
To simplify, let us use the same example we used in our March 24, 2015 issue where we found that:
A 25mm extension tube has a magnification factor of .25(or 1/4 life size) if it is used with a 100mm standard medium telephoto lens.
From what is given above, it appears that if we attach the 25mm extension tube to a 105mm macro lens, the effective magnification at closest focus will be 1.24:1.
From the example above, we see that the longer the extension tube you put in (say, 68mm the total length of three tubes stack together), the higher the magnification ratio you get from your macro lens and extension tube together. And remember that with extension tube, there are no added optical anomalies (I am referring to usual optical aberrations inherent with lens structure) being inserted into the image path. But then again as already mentioned, the trade-off is the shrink (or reduction) of your working distance and of course, the lost focus to infinity while the extension tube is attached to your lens.
In actual shooting, 1.24:1 magnification is already a huge advantage considering that the cost of the gadget you add (extension tube) is very minimal. However, if the reader asks: Which is better to use, the extension tube or the teleconverter? That will depend on the preference of the user. But there is a saying that "we do not compare apples to oranges." Both options have their own advantage and disadvantages.
Use the teleconverter and extension tube together
This option probably originated from creative macro photographers who crave for more and more magnification from their present gears. I am not aware of gear manufacturer that endorses this solution. But it cannot be disputed that this technique is really worth the additional effort. This author has not tried this personally but accounts from other macro enthusiasts have proven its effectiveness. This is how it works (see illustration photo).
Caution: This option is where the integrity of your chosen gears really matters. Low quality extension tubes or tele-extender could break or give way to the weight of extended macro lens. Safety of your macro lens must not be compromised.
As earlier stated, this author has not tried this personally. The reader is encouraged to try and send photos to this column. For more details of this technique, you can try this link: http://www.the-digital-picture.com/News/News-Post.aspx?News=14731.
(More in our next issue)
For comments and suggestions and contributions, please call at 5278121 local 407 or email at firstname.lastname@example.org.
Depending on the ability of the photographer, the technique of putting together your macro gears will produce spectacular results: (C) Teleconverter to camera body; (B) then assemble and stack together three extension tubes; and (A) attach macro lens.