Sunday, January 26, 2014

Macro or Micro?

As I look deeper into my ‘macro’ experimentation, it is clear that I need to learn a new way of looking at my equipment; for instance ‘normal’ depth of field and apertures cannot be estimated by using the standard equations or Apps. When you are within a few centimeters of your subject, you need to account for things that can be ignored if your subject is meters away.
It is also clear that my current experiments are ‘beyond macro’, as macro is usually defined as 1:1 magnifications, ie 1mm on the image plane (the sensor) is actually 1mm. What I am experimenting with are magnifications greater than unity, ie in the micro-photography zone.

Most lens manufacturers tell you what your base lens is capable of, for instance my 50mm F/1.8 only gives a native magnification of a x0.15, and adding extension tubes would ‘only’ take this maximum magnification to .39x and .68x for 12mm and 25mm tubes respectively. Which is why, of course, I need to use bellows and/or to use a reversed 50mm lens, say, to get above a magnification of unity.

Before I spend more time in the micro world, ie magnifications of greater than unity, I thought I would remind myself what a 1:1 magnification lens could do for me, ie what could I get out of my 100mm F/2.8L?

The set up was simple, my 5DMkIII, my 100mm F/2.8L set at F/16, an off camera flash and my Promote Remote. Why my Promote Remote, because I could set the 100mm F/2.8L to auto focus mode and use the Promote to automatically carry out linear focus steps. In the image below, ‘Dying Days’, I simply focused on the front of the tulip and, using Promote Remote, moved the focused to the back of the tulip, and told Promote how many slices I wanted (20 in this case); and pushed the start button. Promote then did the rest, ie drove the lens to the start and took 20 images from the front to the back of the tulip, with no intervention from me.

Once ingested into Lightroom, I exported the bracket set to Helicon Focus for focus stacking, and reimported it back into LR to 'finish off'. Although the composition is not brilliant, and the flash settings could have been tweaked a bit, the focus stacking worked really well. Thus, if I can stay in the macro world, ie 1:1 magnifications, I have a very easy process to capture as many focus slices as I need, ie using my Promote Remote (or my Cam Ranger).

The challenge is going to be when I move into the micro world, where the depth of fields are going to be smaller than with my 100mm macro lens and my current equipment is all manual, eg the camera-bellows-lens system has to be handraulically driven to change focus, and the (flash) lighting, because my lens will be closer, is going to need some thinking.

Bottom line: if your subject is of a similar size, or larger than your camera sensor, then normal or macro techniques will get you what your want. However, if the subject is, say, just a few plus millimeters, ie, say, a tenth of your DSLR sensor, then you will need to consider other techniques to nudge you into the micro capture world of magnifications of x2-x4 plus, say. Which is where I will be going next.

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