The two main types of shutters in all modern cameras are focal-plane shutters and leaf shutters. Focal-plane shutters are what you'll find in most DSLRs and mirrorless cameras on the market today. To learn more about focal-plane shutters, check out this excellent article written by Kevin Jordan. This article will dive into the more mysterious and lesser-known world of the leaf shutter; what it is, how it works, and why it matters.
What is a Leaf Shutter?
In the process of researching the topic of this article, it became apparent that a discussion of leaf shutters could indeed become quite complex. Not that the basic concept of a leaf shutter is overly complicated, but rather that there has been such variation in how the technology has been implemented over the years. The earliest leaf shutter designs, found on cameras such as the Kodak Brownie in the late-1800s to early-1900s, consisted of a single blade, or leaf. In some cases, the blade was actually shaped like a leaf. As cameras have evolved and technology has marched forward, the leaf shutter mechanism became more complex. More moving parts meant the possibility of things going wrong with the shutter increased. Reliability issues may have been a factor in why many camera manufacturers abandoned the leaf shutter in favor of the more popular focal-plane shutters.
How Does It Work?
To put it simply, the shutter mechanism in a camera is what dictates whether or not light is getting to the sensor (or film). If the shutter is open, then the sensor is being exposed to light for a set amount of time determined by the shutter speed. That light hitting the sensor is what makes an image. A leaf shutter utilizes a set of blades, or leaves, that open and close when the shutter button is actuated. The blades work similarly to the aperture blades in a lens, but the two should not be confused. Aperture controls the quantity of light getting through the lens and the depth of field, or how much of a scene is in focus, by changing the size of the opening through the lens. A leaf shutter, on the other hand, is either open or closed.
A leaf shutter consists of several metal blades that fit together in a circular arrangement and overlap in the center. When the shutter opens, each blade moves on a pivot point, opening the shutter from the center outward. As a leaf shutter opens, it is uncovering the aperture of the lens and allows light to reach the sensor. Since this type of shutter opens from the center out, light is continually falling on the center part of the camera's sensor from the time the shutter begins to open until it is closed.
One big difference between a leaf shutter and focal-plane shutter is the physical location of each. A focal-plane shutter is located right in front of the sensor, on the focal plane of the camera. A leaf shutter, however, is generally located directly behind the lens, or in some cases, inside the lens itself. Moving the leaf shutter closer to (or inside) the lens means that it has a smaller aperture to cover. Therefore, the blades can be smaller, lighter, and open and close faster.
Pros and Cons of Leaf Shutters
As with any gear, leaf shutters have their advantages and disadvantages. Let's take the “bad news first” approach and start with the disadvantages.
- Shutter Speed: Generally speaking, leaf shutter cameras are not capable of shutter speeds as fast as focal-plane shutter cameras. This is true in a traditional sense, as shutter speeds tended to cap out at 1/500 or perhaps 1/1,000 of a second. Some modern medium format cameras with lens shutter mechanisms are boasting shutter speeds up to 1/2,000 of a second. However, this is nowhere near the 1/8,000 of a second maximum shutter speed of many DSLR or mirrorless camera bodies.
- Cost: Leaf shutter cameras, and particularly leaf shutter lenses, are quite expensive compared to focal-plane shutters. Since each lens has a shutter inside, lens purchases can become very costly. Leaf shutter cameras and lenses are more complex and cost more to manufacture. Not only is that evident in the up-front cost, but will also hit the wallet much harder if gear repairs are necessary.
Not all is bad news, though. There are some very distinct and interesting advantages to using leaf shutters.
- Flash Synchronization: Flash sync speeds for focal-plane shutters are typically in the 1/180 to 1/250 of a second range. Leaf shutters, however, can virtually synchronize with flash all the way up the maximum shutter speed. That's a pretty cool feature that allows you to achieve shallow depth of field and kill ambient light, even in the bright sunlight. Focal-plane shutters can compensate by using high speed sync, but at a much higher cost in flash power output and decreased efficiency.
- Less Noisy: No, not as in less grain in the images, but rather, quieter operation. Leaf shutters are generally more compact and make less noise than focal-plane shutters.
- Distortion-Free: Focal-plane shutters suffer from “rolling shutter”, causing moving objects appear to lean in the image. Because leaf shutters open from the center outward, there is none of this distortion of moving objects.
What Does This All Mean?
Leaf shutters are somewhat of a specialty item found in very expensive medium format lenses. Manufacturers such as Hasselblad, Mamiya, and Phase One specialize in the camera bodies, digital backs, and lenses that comprise these systems. The new Hasselblad XD1 is a relatively “affordable” mirrorless version of the medium format camera with leaf shutter lenses. It's a beautiful camera and I'm sure would make amazing images, but the camera body alone will set you back upwards of $9,000! Then you have to start adding lenses into that equation.
Medium format certainly has its place in commercial and studio work. High-end portraiture shoots using off-camera flash in bright sun would definitely reap the benefits that a leaf shutter provides. Most of the rest of us who are shooting landscape and nature; street photography; sports; and the occasional portrait most likely wouldn't get as much benefit from using a leaf shutter. When the extra resolution is needed, we can turn to one of the megapixel monster DSLRs or even a medium format camera like the new Fuji GFX 50S to get our fix.
A somewhat intriguing and much more affordable way to get the leaf shutter experience would be with one of the Fuji X-series digital point-and-shoot cameras. The Fuji X10, X20, X30, X70, and the X100 models all have leaf shutters at much more affordable prices than medium format. The catch, of course, is that they all have fixed lenses with little or no zoom capabilities, and much smaller sensors. However, the Fuji X100 series of cameras are not your average point and shoot cameras, as evidenced by the amazing work of many professional photographers.
The Bottom Line
The bottom line is probably that leaf shutters are not going to make a major comeback and overtake the focal-plane shutter as the shutter mechanism of choice for most cameras. The high cost of manufacture and physical limitations just aren't likely to be a good selling point for most consumers. Although the benefits of a leaf shutter can be significant, the benefits are not going to be realized by the masses. Global shutters, on the other hand, may be a different story. But that's the subject of a different article.