How to choose a macro lens – Photography Course

This article is part of the online digital photography course

Picking a lens is always a sort of taboo for those who lack of practice.

Is it short focal better than a long one?

It’s important to say that besides the technical and practical aspect, the financial one is fundamental too.

For example, talking about Nikon cameras, the difference between a 60” and a 105 is 300 euros, with a starting price of 500 euros for the 60, while between a 60 and a 200micro it’s almost 1000 euros and it’s obvious that the investment is getting higher and it must be taken into serious consideration.

But which are the differences between the focals?

Mainly there aren’t big differences, both the optics allow reproduction ratios of 1:1 and the same extension on the depth of field.

The prospective (field angle) and the minimum distance of focusing are the main difference but the elements that we’re going to frame will have the same extension of the focused areas.

To better understand the matter I took a caliber and I put it at 45 degrees from the focal plane of the camera, this inclined position allows me to simulate a hypothetical depth visible on the millimeterical scale of the measuring instrument.

Let’s see the examples.

If you notice any difference in the reproduction ratio between the three lens it’s because all of them at minimum working distance actually reproduce from 1:1 to 1.09:1




The pictures in the example above, show how between the three focals at the same aperture set value and at the same reproduction ratio, the depth of field has the same extension.

Then why should we chose a longer focal, more expensive and less manageable, if with a 60 we get the same result?

The solution is both simple and complicated.

Let’s start first of all to understand which are our photographic needs and with that I mean to understand the kind of framing that we like doing, contextualized subjects, subjects shot including their natural environment or artistic or didactic details.

Mainly, the highest amount of our shots are almost never at reproduction ratios that we could define macro (by macro we consider those reproduction ratios that go from 1:2 to 10:1), instead we do a Close Up, in other words we reproduce our subjects with a ratio of 1:2 or lower.

If for example we frame a butterfly and we want to put it in the frame operating a graceful composition, we’ll actually notice that our distance of shooting and the value displayed on the helical focusing, no matter which focal are we using, is far from what we’d define a Macro ratio.

What actually influences the shooting is the field angle or better it’s prospective that will give a more or less blurred background.

The example I’m showing is the same of another article I wrote, in which you can see how the same framing with different focals keeps the same reproduction ratio contextualizing the subject to obtain a quite pleasant result.

In all the four examples the butterfly was framed at the same reproduction ratio but what changes is the working distance, closer for the 60 while with 200 the distance is bigger.
A bigger distance for a long focal, if on one hand allows to use this particular practice to extend the depth of field, it’s also true that it forces us to close more the aperture because the prospectic angle or the field angle won’t have enough perspective needed for the same parameters of a short focal.

Using a long macro focal demands the help of a good tripod and a solid head, but with a short focal you can frame freehand relatively small subjects using the prospective to include in the frame particular details important for a document we are interested in to file, for studies on the habitat of the subject.

1 comment:

Mircea said...

Good review!!!!!