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What Is Mirror Lock Up & Electronic First Curtain Shutter?

February 16th 2017 1:14 PM

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, one who often shoots from a tripod, (even if you have recently switched to a mirror-LESS camera) then you need to watch this video and read the article below!

What Is Mirror Lock Up And How / When To Use It

The History Of Mirror Lock Up

Regular readers will know that I do love history/trivia about camera gear and the way things work, so I’ll start by explaining mirror lock-up as it was originally designed. The feature that has been around since the days of professional film 35mm and medium format cameras.

Nikon D750, Nikon 50mm f/1.8 AIS, 1/6 sec @ f/11 & ISO 100,
Slik 614 CF Tripod, 2-sec exposure delay mode

The basic idea of mirror lock-up is to protect your images from the mechanical shake that is caused by a mirror. In traditional mirror lock-up mode, when you click the shutter release, only the mirror goes up at first. You wait a few seconds for the moment to be right, (say you’re waiting for waves to crash on rocks at the beach) and then you click the shutter release again, at which point time the shutter itself actually opens and closes.

Now obviously, touching the camera’s shutter release button is a source of camera shake itself, so you must either use a cable release (wired or wireless) or one of the more modern adaptations of Mirror Lock-Up which we’ll explain in a second.

The end result, one way or another, is that you’ve eliminated all mechanical shakes that are caused by the mirror. The only mechanical movement left is the shutter itself.

Nowadays, however, with such high-resolution sensors, the “shutter itself” can still be a problem that creates mechanical shake, as some mirrorless shooters have discovered. This is why I said that understanding “MLU” (and mechanical shake in general) is still necessary for all tripod-using photographers who want maximum sharpness at any and every shutter speed or focal length.

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.)

Note: 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

The Cutting Edge Of Mirror Lock-Up: 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.

[REWIND: How Different Cameras Perform With The Same Lens | Crop Vs. Full Frame]

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.) Good luck! If you have any questions about particular features or how to customize a particular camera, please comment below!

Take care and happy (shake-free) clicking,
-Matt-

Matthew Saville is a full-time wedding photographer at Lin & Jirsa Photography, and a senior editor & writer at SLR Lounge.

Follow his personal wilderness adventures: Astro-Landscapes.com

See some of his latest wedding photography featured on: LinandJirsa.com

Comments [3]

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  1. Colin Woods

    Matthew, how do you program your Fn button to do Exposure Delay? When I go to Custom Settings there are a whole load of things that I can do with the various buttons, but Exposure Delay is not on the list. I’m on the D750.

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    • Matthew Saville

      Hi Colin!

      My apologies for never getting around to publishing videos about how I customize Nikon, Canon, and Sony camera bodies, I’ve been meaning to do it forever!

      On the D750 specifically, here’s the procedure:
      Start with the Custom Settings Menu, (the pencil icon)
      …then Controls, (f)
      …then (f*2) Assign Fn Button
      …then “Press + Command Dials
      …then “DLY” Exposure Delay Mode

      With this custom function enabled, hold down the Fn button  and whether you are looking at the top LCD, through the viewfinder, or in Live View, a menu will show up that allows you to choose options of OFF, 1, 2, and 3. Simply turn the rear command dial to select what you want.  I find that 1 second is enough for certain “easy” conditions where camera shake is only a minor issue, at say decently fast shutter speeds like 1/30 or 1/60, however I often use 2 sec or 3 sec exposure delay if I am down around 1/2 or 1-4 sec.

      I wish the D750 had electronic first curtain shutter, but alas, Nikon determined that feature to be too professional and only let the D810 have it. Oh well, I do just fine without it on most days.

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  2. David Dotson

    Love the articles!

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