Avid photographers with an expensive macro lens may use it for years and years, never taking a single macro photograph…
Macro Lenses are Just Close-up Lenses
None of the photos in this blog post, taken with the Sony FE 90mm macro lens, are macro photos. Experienced photographers trying to take a macro photograph with a macro lens will likely end up never taking a true macro photograph. Lenses advertised as macro should really be referred to as close-up lenses, in my opinion.
The major brands of macro lenses, Canon, Nikon, Sony and Sigma, advertise their lenses as a macro lens having a 1:1 ratio. The problem is that all of these lenses only take a macro photograph at their very closest focusing distance. For my Sony 90mm macro lens, that is 11 inches. Photographers do not typically set the focus to the minimum then move the camera back and forth to focus the scene. The photographer’s goal is to take a good, artistic photo, not to compose a photo at exactly the minimum focus distance. Nobody viewing the finished photograph would know the difference anyway.
Photographers typically use either manual or auto focus. The other option is to use neither and move the camera to and fro. When using manual focus, the photographer will twist the focus ring back and forth and stop where the subject is in focus. Focusing at any distance other than 11 inches with my Sony 90mm macro will not achieve the 1:1 ratio required for a macro photograph. To achieve the macro photo, the photographer would need to set the lens to 11 inches then move the camera forward and backward to frame and focus their subject. This is not the way photographers generally work.
In Macro Photography, Millimeters Count
This second in a series of macro photography articles assumes the reader has read or knows all that was discussed in my first article, My Journey into Macro Photography . A macro photograph is one which captures a scene on the camera sensor in life size or greater. Therefore, a 35mm camera sensor needs to capture 35mm or less of a scene to be a macro photo. A metric ruler can illustrate this best.
In the photo above we are seeing 35mm of the ruler captured on a 35mm sensor. Since 35mm of the ruler is captured on the 35mm sensor, we have the required 1:1 macro ratio. This macro photo can only be achieved when the camera sensor is exactly 11 inches from the subject. In the chart below I calculate the magnification ratios when focusing the camera 12 inches from the subject instead of the 11 required for a macro photograph, then at 13, 14 and finally 15 inches. I stopped. Even I get bored with this after a while.
If a photographer misses the minimum focus distance by just one inch, the resulting photo is nowhere near a macro photo. In a brief discussion about my macro photography observations with a very talented fellow photographer, we will call him Dan to protect his identity, it turns out even other photographers do not care much about these ratios and macro photography facts. What is driving me at this point is just curiosity and the realization that I was never able to clearly learn the definition of macro photography through my photography clubs and explanations from other professional photographers. Most photographers do not know about magnification ratios…. and apparently do not care. So… we move on.
Food for Thought
My local camera club has a different photo assignment each month. September’s assignment was to create a series of photographs. Pick a subject and do many photos of the same subject, a series. There are some very successful photographers who do this as their niche. One famous New York photographer, Arne Svenson, has done a series with sock monkeys, stray cats and even his unsuspecting neighbors inside their own Manhattan condo. My choice was food, more specifically vegetables, all taken with the Sony 90mm macro lens.
None of these vegetable photographs qualify as a macro photos. I’m spending time learning about using flash vs. constant illumination and how to better diffuse bright lights.
Extension Tubes, the Least Expensive Answer
Extension tubes are simply spacers between the lens and the camera sensor and have no glass inside. These rings move the camera lens further from the sensor. They are literally an empty tube, just like the bellows shown in my previous article. B&H Photo in New York City is happy to sell these to you for less than $10, as soon as they get resupplied from China. B&H Extension Rings They are on back order as are so many of the macro supplies I’ve needed. More expensive versions have electronic connections, as seen below, but these are not recommended nor needed. Electronic communication through the lens is not needed in macro photography, since manual focusing is often preferred. So the less expensive tubes are often best.
How Much Magnification Can Extension Tubes Provide?
The good news is I won’t show you more photos of blue rulers, at least not in this post… The bad news is I have another chart. Small extension tubes like this get you into the realm of macro photography, but do not provide much magnification. Combining two extension rings, 10mm plus the 16mm, does not achieve even a doubling of the image or a 2:1 ratio.
The working distance is the space between the subject and the front of the lens. These extension tubes provided about 4 1/2 inches, which is very good. A bigger working distance makes the task of lighting your subject easier and 4 1/2 inches of working space is plenty of space to work within. Of course, more and more extension tubes could be stacked for greater magnification.
Finally, a Macro Photo
For a peek behind the curtain and my personal macro photography progress, here is a photo of a common housefly taken last weekend. This fly had the misfortune of finding its way into our home. I’m learning that the single biggest challenge in macro photography is keeping dust away. This applies to both the camera and to the bug and the resulting photo.