Do you need a 180mm macro lens or will a 60mm do? What's the difference when both can deliver 1:1 magnification?
We’ve all seen them. That amazing close up of some insect in National Geographic, or a close-up of some mascara-covered eye for Estee Lauder, or a shot of a Voigtlander 12/5.6 Heliar for Adorama…..huh? Welcome to the world of Macro Photography. The above sentence encompasses the range of what macro photography is: the art of photographing things up close.
Please note I said up close, not very small. While the classic macro shot may be of an aphid on a flower stamen, the everyday truth is far more mundane. Product shots of shampoo bottles, cameras and jewelry are far more common in the professional environment. Knowing this, why are there such things as Macro lenses, and why are there different focal length macro lenses?
There's close, and then there's Macro
Most zooms today are capable of close focus of some sort. An example would be the Canon 24-105/4 L IS, available from Adorama, with a close focus of .45m (1.5ft). Does this make it a true macro lens? In short the answer is “No.” A macro lens is simply a lens that is designed to provide optimal performance at its closest focus. When a lens designer sits down at a drafting board and begins to create a lens, all the math for that lens presumes it is set at infinity focus. In the case of a macro lens, the reverse is true. Macro lenses are designed to provide the maximum resolution and sharpness and least distortion the closer you focus. They are specialist lenses designed for a very specific function.
Another hallmark of a macro lens is magnification. The vast majority of macro lenses designed for 35mm photography are capable of “1:1” magnification. So what does that mean? All Macro lenses have a magnification factor usually represented as “X:Y”, where X= the number of millimeters on the actual sensor (or film) the image detail occupies and Y=the number of millimeters of actual detail being shot. A 1:1, therefore, is what is called life-size: A 1mm detail takes up 1mm of space on the film or sensor. Now while that doesn’t sound like much, it is actually quite a difficult thing to achieve from the engineering standpoint.
It also means that no matter which macro lens you use, the final image size on a sensor will be identical, whether you use a Canon 60/2.8, Nikon 60mm f/2.8G AF-S Micro, or Sony 50mm f/2.8 shorter forcal length lenses, or longer lenses such as the Canon 180/3.5 L, Nikon 200mm f/4D ED-IF AF Micro, or Sigma 150mm f/2.8 EX DG APO macro, available from Adorama, at their closest focus you will only ever achieve 1:1 magnification. To achieve larger than life size, say 5:1, you need to use extension tubes or bellows.
What the Focal Length is Going On Here?
So, why invest in a 180/3.5 lens if it will only achieve the same level of magnification at closest focus as a 60/2.8? The simple answer is distance from the subject. When shooting a diamond ring, for example, it is far easier to do creative lighting when you are two feet from the subject (as you would be with a 180/3.5) versus the nine inches you would have with a 60/2.8 at the same 1:1 magnification.
To achieve higher magnifications one must use extension tubes such as the Pro Optic Auto Extension Tube Set (exclusive at Adorama) or a bellows system such as the Novoflex Automatic 6" Macro Bellows. In addition a macro focusing rail such as the Adorama Budget Macro Focusing Rail is very useful. Another option for Canon shooter is the 65/2.8 MP-E, a very specialized lens that starts at 1:1 and climbs up to an amazing 5:1 (5 times life size) at its closest focus.
But all this is academic without some examples, so let’s start off with what many folks would consider a “macro” shot:
Here is a tulip. Now let us take a closer look...
This is a 1:1 life size macro shot. At 1:1 we see a lot more detail than in the previous shot. What happens when you use extension tubes, bellows, or in this case a Canon MP-E 65/2.8?
Wow! This is a 5:1 shot (5x Life Size) of one of the anthers of the tulip showing the individual grains of pollen. At this level of magnification, a tripod, focusing rail, and of course a cable release are a must along with a macro light like the Canon MR-14EX used here.
All of the above shots demonstrate the value of a shorter focal length macro. You can easily transport it, and its size makes it easily handy in tight spaces. The MP-E also has the benefit of having for the equivalent of built in extension tubes. This allows quick adaptation in the field when doing this type of technical/scientific macro work. Here is an example of the levels of magnification that this lens is capable of:
Canon MP-E 65/2.8 Macro Lens Magnification Examples
The only issue here with the shorter lengths is distance to subject. For the 5x sample the front of the lens was mere millimeters from the subject. When shooting in a commercial environment, this would be unacceptable. That close to a subject, one could not use creative lighting that would present the subject in an appealing manner. In those situations a longer focal length buys one distance from the subject. Distance to allow flexibility in lighting
Here is a commercial shot, one of many I do for Adorama:
This is a shot of the Adorama Soft Release, at near 1:1 shot with a Canon EF 100/2.8 macro lens. Unlike the shots with the MP-E which were all lit by ringlight, here we have more subtle lighting, with shadows that give depth and a bit of life to the image. The additional distance from the subject allows for this. Below: a shot of the lighting setup I used to shoot the above.
The Adorama Macro Product Studio. 5 Dynalight heads, three softboxes, and three 2000w/s Powerpacks
Hopefully this gives you all a better understanding of what a macro lens truly is, and of course the various situations where one would use a specific macro lens, and when. Please feel free to ask questions below and I’ll answer them as quickly as possible.