Panasonic G85 Shutter Type decisions 18 April 2018

On screen 5/8 of the G85 Rec Menu  The Shutter Type options are Auto, MSHTR (Mechanical focal plane shutter), EFC (Electronic first curtain) and ESHTR (Electronic shutter).

Up to and including the G7, M43 cameras used a spring loaded shutter mechanism which produced the highly unwelcome phenomenon of image degradation due to shutter shock with some lenses at some focal lengths with some shutter speeds. It is likely that the first shutter closure was the cause of the shock in these cameras.

But the GX85 and G85 have an electro-magnetic shutter mechanism which slows the speed of travel of the shutter blades towards the end of their travel so they do not bang against their stops. This greatly reduces the likelihood of shutter shock. It is also significantly quieter than the old spring loaded shutter.

The fastest speed available with MSHTR is 1/4000 sec. The fastest flash synch speed is 1/160 sec.

If you want a shutter speed up to 1/16000 sec, ESHTR is required. (see below)

So it is possible to use the MSHTR all the time with little risk of any problems with shutter shock. MSHTR is compatible with flash and gives the full range of slow shutter speeds.

For an even lower risk of shutter shock EFC can be selected. With this option exposure is commenced electronically and ended mechanically.

The fastest shutter speed is 1/2000 sec. All slow shutter speeds and flash are available.

There is less shutter sound and vibration with EFC than MSHTR.

It would be reasonable to use EFC for all general photography. The only disadvantage is the reduced top shutter speed.

ESHTR  The fully electronic shutter is silent (if beeps are switched off in the menu), has no moving parts and can never cause shutter shock.

This sounds great but there are many disadvantages:

* Shutter speeds slower than 1 second are not available.

* Flash synch is not available.

* Banding appears in pictures shot under some types of artificial light including fluorescent tubes.  With the G85 and a 50hz AC power supply there are 4 bands per frame.

This indicates an e-shutter scan time of 1/25 second. (4 divided by 50x2).

Some cameras such as the GH5 output 12 bit files with e-shutter but the penalty is an even slower scan time of 1/10 second.

* On the G85, file output drops from 12 bits to 10 bits. This leads to a marked increase in luminance and color noise in shadows especially if shadows have to be lifted in lightness.

* Rolling shutter effect with moving subjects or panning camera.

AUTO  This will use MSHTR most of the time and switch to ESHTR if a shutter speed faster than 1/4000 is required.

Which is best ?  Not ESHTR that’s for sure, unless silent operation is required. (turn off the beeps).

I use EFC routinely but I suspect MSHTR would be fine with most lenses.

Some lenses such as the Lumix 45-175mm and the Lumix 14-140mm have a reputation for being prone to shutter shock. I would carefully check for shutter shock with these lenses on the G85 before deciding to use MSHTR routinely.

Page 197 of the Operating Instructions for Advanced Features has a chart with further explanation about shutter options.