How to Use Mirror Lock Up & Electronic First Curtain Shutter

Mirror lock up is an SLR camera feature that has been around for many years, yet you may have never used it before. If you’re a serious landscape or still photographer, however, Mirror Lock-Up can help you  yield even sharper images by eliminating the subtle movement in your camera caused by the mirror action.

The Mechanics Of The Camera Mirror

There is a mirror inside of every DSLR. When we look through the View Finder on our camera, we are actually seeing the reflection of what the mirror is seeing through the lens attached to the camera. When we press the shutter button on the camera, the mirror flips up. When the mirror flips up, the actual shutter is underneath and will open to expose the image to what the lens sees.

The process of the mirror flipping up and down creates a little bit of vibration inside the camera. This vibration does not really matter when we are shooting handheld bracketed sequences because it does not make a difference in comparison to the motion shake caused by your hands, which is much greater. However, when you are shooting with your camera on a tripod, the movement of the mirror will slightly reduce the sharpness of the image. Because of this, we want to use the Mirror Lock-Up feature on our cameras whenever we are shooting on a tripod.

Using The Mirror Lock-Up Feature

We recommend that you only enable the Mirror Lock-Up feature when you are using a tripod. When you have your camera on a tripod, enable the Mirror Lock-Up feature to lock the mirror in the “up” position so that the only thing moving inside of the camera is the shutter. This means that there will not be any vibration since the mirror will not flip up/down while the shutter opens to expose the sensor underneath.

The Mirror Lock-Up feature is great when you are shooting landscape images because this feature ensures that there is not any additional vibration introduced by the mirror as it flips up and down. The Mirror Lock-Up feature is also handy in bracketed sequences as well. Simply set your camera on the tripod and enable both the Mirror Lock-Up feature and the Auto Exposure Bracketing (AEB) feature. Your camera will then consecutively take the shots specified in your AEB with the mirror flipped up, prior to exposing the sensor with each shot.

Enabling The Mirror Lock-Up Feature

Each camera will be different, so consult your camera’s manual or go online to know how to enable the Mirror Lock-Up Feature.

On a Canon 5D Mark III, use the dial to scroll down to “Mirror lockup” and push the “Set” button on your camera to select “Mirror lockup.” As you can see below, the Mirror Lock-Up feature is turned off right now.

After you have selected “Mirror lockup,” spin the dial down to “Enable” and push the “Set” button again.

As you can see below, the Mirror Lock-Up feature is now enabled.

Each camera functions differently when simultaneously using the AEB and Mirror Lock-Up features. For example, if the AEB and Mirror Lock-Up features are both enabled on a Canon 5D Mark III but the HDR mode is turned off, you will need to manually depress the shutter button with each image in the bracketed sequence. This eliminates the reason to even use the feature since we would be introducing motion by touching the camera with each shot in our bracketed sequence.

However, with the HDR mode turned on in the Canon 5D Mark III and the Mirror Lock-Up feature enabled, you will be able to take consecutive shots with just one press of the shutter. If you find that you need to manually press the shutter button multiple times to shoot your bracketed sequence, then use a shutter release. Either way, using the Mirror Lock-Up feature in your camera will yield slightly sharper results when you have your camera on a tripod.

The New Mirror Lock-Up: Exposure Delay Mode

Exposure Delay Mode, as it is called on most Nikon bodies, is a modern adaptation of MLU. (On many Nikon shooting mode dials, “old school” mirror lock-up is called M-up, by the way. Exposure delay mode is, in fact, a different function than this.)

What “exposure delay mode” does is, it combines mirror lock-up and a self-timer. You click the shutter once, the mirror goes up, and the camera waits one, or two or three seconds, then opens the shutter.

This is the best of both worlds for most shooting situations where timing is not that critical. (And where shutter-shake is not a concern.)

On Canon, and other cameras, similar options are now often built into the traditional 2-sec timer, so do check your camera manual to see if your camera has this function. Also note that on newer Nikons, exposure delay mode is NOT the same as the traditional self-timer, so don’t get those two Nikon options confused!

Anyway, on each Nikon body I’ve owned since the D800, I’ve programmed the FN button to bring up the exposure delay mode options, so all I have to do is hold down the FN button and turn my command dial for 1, 2, or 3-second exposure delay. As a landscape photographer, I use this function religiously! I only use the old M-up mode when I actually need to time a moment perfectly, which is very, very rare.

The Shutter-Shake Danger Zone

The real danger zone is within a few shutter speeds of the ½ second shutter speed mark, depending on factors such as how light (or heavy) your tripod is, how well-balanced your lens is, what focal length you’re shooting, plus of course whether or not there is wind. Can I just take a moment to say how much I hate wind when I am backpacking with my ultralight tripods?

Nikon D800e, Tokina 11-16mm @ 16mm, 1/3 sec @ f/16 & ISO 100
Slik 614 CF Tripod, 3-sec exposure delay mode

If you’re shooting at 1/2, 1/4, or 1/8 sec shutter speed, or anywhere thereabouts, you’re going to need to eliminate all possible mechanical shake!

Mirror Lock-up or Exposure Delay Mode can really help in this regard, however, beware: If it is even the least bit windy, and/or if your tripod is flimsy, you may still be totally outta luck! In this case, you have a couple options: try changing your ISO so that you can get out of the shutter danger zone, or throw on an ND filter and go the other direction- aim for a 10+ second exposure! A super-long exposure, in all but the worst wind or drooping-tripod conditions, will yield equally sharp images.

Nikon D750, Nikon 70-200mm f/2.8 @ 110mm, 1/4 sec @ f/11 & ISO 100
Slik 700DX tripod, 3-sec exposure delay mode

Electronic First Curtain Shutter

I hope the mirrorless camera shooters haven’t dozed off yet, because any camera that uses a mechanical shutter is still at risk of a mechanical shake which can reduce fine image detail, especially on a high-megapixel camera.

This was particularly “deadly” on the original Sony A7R; in fact it was so bad that at almost all shutter speeds it was nearly impossible to get a sharp photo when using longer telephoto focal lengths. The ultra-lightweight mirrorless body was just too light, relative to the mechanical “clunk!” of the camera’s shutter. Sony has since greatly improved the shutter dampening in the A7R II, and also beefed up the camera in general.

Here’s the exciting part, for all you high-resolution pixel-peepers out there: in addition to shutter dampening, cameras have started offering what’s called electronic first curtain shutter. Essentially it is MLU for your shutter!

When using electronic first curtain shutter, both your mirror (if your camera has one) and shutter are open. If you have a DSLR, this means your camera is in live view. However, the exposure does not begin just yet. The actual “exposing” is started electronically, (usually using a timer delay or remote trigger) which results in absolutely zero mechanical shake whatsoever. By the way, the exposure still ends mechanically with the shutter closing; I guess this is not a factor in blurry images, for whatever reason.

Therefore if you shoot on a current-generation mirrorless camera or DSLR, and you want the absolute best sharpness possible, you’re going to want to try and find “Electronic first curtain shutter” in your camera settings and give it a try, especially if you have a thirty, forty or fifty megapixel camera and if you use a super sharp lens.

Unfortunately, these features are implemented in rather different ways on Canon, Nikon and Sony, so I’ll have to cop-out and just say, “read your camera manual!”

As a general rule, on Sony cameras it is simply one of the menu items organized with all the other shutter-related menu options, while on Canon and Nikon DSLRs it is an option either in Live View and/or in the same shutter or exposure related customization settings.

If you’re a serious landscape photographer, or any sort of still-life shooter who uses a tripod and wishes to capture the utmost level of detail possible, then I highly recommend delving into the mirror lock-up and electronic first-curtain shutter features on your camera. (And getting a wireless  remote as well as a solid tripod, if necessary.)