The Challenge of Depth of Field in Macro or Close-up Photography

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Shallow depth of field (DOF) is one of the visual effects that many photographers seek in their everyday photographs. To accomplish this, there is the grail quest for lenses with larger and larger maximum apertures. In the world of macro and close-up photography, however, a shallow DOF shot can be the photographer’s nemesis. Large magnification macro lenses often have DOF distances that measure in the millimeters or less! This means that a photo of an insect or small creature might show the eyes in sharp focus, but nearly everything else is a blurry haze.

Depth-of-Field Basics

Before we dive in with macro DOF, let’s get the basics of DOF out of the way.

Depth of field is defined as the area in a projected image, forward and aft of the focal plane, which also appears to be in focus in the image.

Basically, the camera lens is focused at a single distance from the front of the lens and the human eye sees an area before and after that distance in sharp focus. That linear distance before and after the focus plane is the DOF.

The four primary factors that determine DOF are: lens aperture size, lens focal length, the subject-to-lens distance, and a concept known as circle of confusion (COC).

If you want to take a super-deep dive into DOF, please see my three-part series on the subject starting with this article. If you want to stay on this channel, keep on reading.

Without sufficient DOF, some of the watch face falls out of focus.

Factors Affecting Macro DOF

The four factors that affect DOF mentioned in the previous section also apply, of course, to macro photography—the math is constant regardless of what kind of photography you are doing. However, with macro photography we are getting into relatively large magnifications of a subject in the image—some macro lenses can project reproductions at life-size or greater.

My hair still hurts from when I wrote about circle of confusion half a decade ago, so I will just say here that one of the factors in the COC equation is “enlargement,” which is interchangeable with macro magnification and the lens’s reproduction ratio.

Therefore, you can say that the factors affecting DOF in macro photography are: aperture, focal length, subject-to-lens distance, and magnification (as part of COC).

If you want to see DOF numbers for your lens and camera kit, there are several macro DOF calculators online.

The result is that, in close-up or macro photography, you are dealing with very shallow DOF. How shallow? Well, using one of those online calculators, when I plug in my FUJIFILM XT-3 APS-C sensor with my Nikon AF Micro-NIKKOR 200mm f/4D IF-ED lens at its 1:1 minimum focus distance, my DOF is less than 1mm!

Let’s now look at ways we can extend the macro DOF and the pros and cons of different actions.

Shallow DOF can be artistic with macro shots, but, generally, you would want to show all of this ring in sharp focus.

Controlling Macro DOF: Aperture

One of the easiest ways to control your DOF in macro photography is to reduce the size of your aperture opening. The smaller the aperture, the greater the DOF. Easy. Right? Well, there are a couple of downsides to stopping down your aperture, and they are a reduction in light, and diffraction.

If you are creating macro photography in a controlled studio environment and using a tripod, the reduction in light from a tiny aperture opening is not a huge concern. Of course, you will be increasing digital noise because you are affecting the sensor’s signal-to-noise ratio (let’s skip over that rabbit hole for now). Generally speaking, the lack of light plays a larger factor if you are shooting handheld or in an already low-light situation where a slow shutter speed results in camera shake or a higher ISO gives you too much noise.

Another downside to stepping down your aperture is diffraction—a loss of image sharpness due to the light having to pass through a narrow aperture diaphragm opening. If you want to dive deeper into diffraction, read this article.

And a last downside of shooting through tiny apertures is sensor dust. As you work toward your smallest apertures, you will see sensor dust become more noticeable in the frame. While you can usually clean this up in post-processing, no one likes cleaning up dust on a photo (or anywhere else, for that matter). Ever.

In summary, stopping down to your smallest aperture settings might not be desirable.

As the 1:2 macro lens aperture gets narrowed, DOF increases. Notice how the f/32 image is subtly softer at the front of the ring than the middle aperture (f/5.6-11) images and notice how sensor dust starts to appear as the lens is stopped down. FUJIFILM X-T3 with Nikon Micro-NIKKOR 55mm f/2.8 lens

Controlling Macro DOF: Focal Length

Longer focal length macro lenses produce shallower DOF than shorter focal length lenses. But longer focal length macro lenses allow you to work at a greater distance from the subject while maintaining the same magnification. Proof can be found by looking at the minimum focus distance (where you get maximum magnification) specifications of these four Nikon Micro-NIKKOR lenses that all feature a 1:1 macro reproduction ratio:

Nikon AF Micro-NIKKOR 200mm f/4D IF-ED lens—1.6'

Nikon AF-S VR Micro-NIKKOR 105mm f/2.8G IF-ED lens—1.03'

Nikon AF-S Micro-NIKKOR 60mm f/2.8G ED lens—7.28"

Nikon AF-S DC Micro-NIKKOR 40mm f/2.8G lens—6.42"

There are times when the working distance to your macro subject matters, because the lens itself can throw shade on your subject and/or cause a tiny creature to suddenly get camera shy and hide from you.

In summary here, you can get shorter focal length macro lenses to get deeper DOF, but that is not always advantageous for other elements of macro photography.

Here we have a 200mm macro lens that has much narrower DOF than the 55mm lens shown above. Again, notice that sharpness drops off a bit with the narrow apertures, and sensor dust rears its ugly head. FUJIFILM X-T3 with Nikon AF Micro-NIKKOR 200mm f/4D IF-ED lens

Controlling Macro DOF: Subject-to-Lens Distance

Similar to the focal length issue, macro photographers searching for greater DOF run into practical limitations. Yes, you can increase the distance from your subject to get greater DOF, but then you are reducing the reproduction ratio, and that is likely counter to your goal of getting a close-up photograph of your subject.

A macro lens that does life-size (1:1) magnification only does that 1:1 reproduction at the minimum focus distance of the lens. Moving farther away to increase your DOF means you are no longer shooting a life-size image.

Backing away from this watch allowed fairly good DOF that encompassed the entire face and almost all of the case without stopping down dramatically. If we got closer to the watch, then we would lose this decent DOF.

Controlling Macro DOF: Reproduction Ratio

Again, aligned with the last two sections, there are practical considerations here, as well. When we purchase a dedicated macro lens with a 1:1 or 1:2 reproduction ratio, we generally intend to use the lens at its maximum magnification, which, unfortunately, sometimes gives us shallow DOF.

Yes, you can reduce your magnification by getting farther from the subject, but that is counter to most macro photographers’ goals.

A comparison of a 1:1 vs. 1:2 magnification ratio image shows a difference in the DOF with a constant aperture.

Controlling Macro DOF: Camera Angle

One way to change DOF virtually with a macro subject is the angle at which you photograph a subject. This technique does not alter the DOF math (we discussed the four factors above), but it does have a subtle effect on how the subject appears. If you photograph your subject at a right angle (or near a right angle) you will maximize your given DOF versus taking an image of a subject at an oblique angle.

While this also depends on the subject in question (you might not have the option to square up on your subject) you can easily visualize a photograph of a watch face or coin taken “head on” versus from an oblique angle—much more of the coin or watch will appear in focus for a given DOF.

This is an exaggerated example, but the crest on this ring is rendered more inside of the DOF when the camera is closer to perpendicular with the ring.

Controlling Macro DOF: Tilting

Similar in concept to the previous section, you can also use the tilting function of a tilt-shift lens (or use a tilt-shift adapter) to adjust the plane of focus mechanically to be more perpendicular to your subject. Many modern tilt-shift lenses have macro focusing capabilities.

Another exaggerated example of oblique versus right angle images showing a watch face.

Controlling Macro DOF: Focus Stacking

And last, but certainly not least, is the technique of digital focus stacking. Focus stacking involves taking multiple photographs of a single object while moving the focus plane through the object and then use post-processing software to combine and blend the images into a single frame that shows the subject in sharp focus from front to back.

Focus stacking is usually done in controlled studio environments, but you can also do it handheld, as I describe in this article.

For a tutorial on the surprisingly simple technique of focus stacking, check out this article. Some cameras also allow you to do this processing in-camera.

A cropped image showing focus stacking applied to the 1:2 macro shot of the ring reveals the subject in sharpness from front to back.

The Cards We Are Dealt

Macro photography is certainly one genre of photography where shallow DOF can be detrimental to the image. While there are some ways to help get deeper DOF in a close-up shot, many of the options have drawbacks. I would encourage you to try focus stacking if you haven’t done it yet, since it is relatively easy and fun, and the results can be amazing. If stacking isn’t an option, try to square up to your subject, use a smaller (but still sharp) aperture, and maybe give up some magnification to get deeper DOF when you need it.

Do you have any questions or techniques that I did not address? Drop us a line below in the Comments section!

2 Comments

Try the Olympus TG-6 or earlier versions, to automate Focus Stacking and Focus Bracketing, at a much cheaper cost than DSLR's or Mirrorless cameras and lenses.

Hey Josef,

Great tip! Yes, those Olympus "tough cameras" have incredible macro capabilities built it. I really need to pick one up!

Thanks for reading!

Best,

Todd

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