"Electronic" Shutter

Nikon's acronym and icon specialists for the loss. 

I'm seeing a lot of confusion lately about shutter type (Update: including my wording. I've clarified a couple of sections, below). The Z9 doesn't help this in any way, as it further confuses something people were already confused about.

What am I talking about? Nikon's use of the letter E in Shutter Type (Custom Setting #D5 on my Z6 II, your mileage may vary ;~). Here's what tends to cause some of the confusion: the icon for Electronic First Curtain Shutter (EFCS) is an E, and some lenses remove Mechanical (M) as a choice, leaving only Auto (A icon) and Electronic First Curtain (E icon). People start to panic when they can't set Mechanical shutter, and the E icon makes them think that they're in "electronic" shutter mode, and they've heard stories about how that is "slow" on the current Z cameras and can cause artifacts on motion.

We really have four shutter possibilities with the current Z's (all but the Z9, which introduces a new, faster variation of #4):

  1. Auto (A icon) — This is the new default with current firmware on most of the cameras, and with this option set the camera will use EFCS (see #3) up to 1/250, and mechanical shutter (see #2) beyond. 
  2. Mechanical (M) — The old default: the camera always uses the mechanical shutter at the beginning and end of every image.
  3. Electronic First Curtain (E) — The camera does not perform a shutter action at the begging of a photo, it just turns on the image sensor to collect data (this is done via a rolling shutter effect), but at the end of the exposure the mechanical shutter is used to stop the data collection. The one drawback to EFCS is that it is limited to a top shutter speed of 1/2000.
  4. Silent Photography (SL) — When this is set to On, the camera does not use a mechanical shutter for anything. 

#1-3 are set with a Custom Setting (in the D's, setting number varies with camera). #4 is set with the PHOTO SHOOTING menu. It's only #4 that causes really bad motion artifacts or bad banding with frequency lighting, and how much of a problem that is depends a bit on the camera, as they all have different image sensor transfer rates. It's generally safest to use #1 or #3 for your photography, because #2 can cause shutter slap issues at lower shutter speeds. (The Z9 changes this, as it's silent photography all electronic shutter is just as fast as the mechanical shutter. For all other models, #4 can generate visible issues in your images.)

Here's where the dilemma comes into play: a number of Z-mount lenses don't allow Mechanical (M). If you were previously set to #3, all you see is the grayed out E and you might think that you're in some kind of "all electronic" shutter mode (you're not, you're in EFCS). All three DX lenses lock you out of changing Shutter Type to Mechanical. The upcoming 100-400mm lens does it, too. Indeed, many of the lenses with built-in VR do this. I believe the reason for this has to do with the timing interaction of the VR mechanism and the image sensor. But in no case is this "all electronic" as some people are complaining. Again, there is the limitation of 1/2000 shutter speed to worry about, though, if you set EFCS.

On the other hand, using Silent Photography is absolutely something you should avoid with fast moving objects or some frequency-based lighting, as the sensor refresh time may not be fast enough to avoid motion artifacts. (Again, the Z9 will be an exception to this.)

Is EFCS perfect? No. Which is why Auto is the preferred setting for Shutter Type if you can set it. The biggest issue I see with EFCS has to do with mid-range out-of-focus areas with VR active at fast shutter speeds. Unlike the mechanical shutter, which would have first and ending shutter mechanisms that perfectly mirror each other, EFCS is a rolling shutter at the front end and the mechanical shutter at the other end is a different timing, so sometimes we see what people call "nervous bokeh." 

At some point I'll need to add an item to the lens database on this site about whether the lens supports Mechanical shutter or not.

Bottom line: Set Auto for CSM #D5 (or D4 on some cameras). It's what we asked for, Nikon added it, and it's the default on all the Z's now. Also, don't confuse EFCS with Silent Photography. 

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