Shutter settings on EOS 90D: Mechanical vs Electronic

[Ramsden]

Hello from Yorkshire Uk,

Apologies if this sounds like a dumb question - but - while furthering my knowledge of this great camera and all it has to offer, I came across this section in the EOS 90D for dummies book. Basically I can choose between: Mechanical, Electronic 1st Curtain or Electronic shutter settings. For some reason Electronic only works in the One Shot mode - but apart from that, the book doesn't explain the operational differences.

 I like the cluncky sound of the Mechanical, and the Electronic would be good for bird spotting - but one shot limits its use.

So help please - are these major operational differences that I should make use of?

Thanks as ever

Ramsden

 

[p4pictures · Accepted solution]

The choice of shutter mode is only possible hen using Live View mode on the EOS 90D. 

Mechanical is much like the normal - viewfinder - style, so the first shutter curtain uncovers the sensor at the start of the exposure and the second curtain closes over the sensor at the end of the exposure. However the process of taking the photo is close the first curtain - it was open to allow live view - then start the exposure then close the second curtain. This makes the most noise due to the two operations of the shutter curtains, but it does produce images with the best looking bokeh when shooting with the lens at maximum aperture - eg f/1.8 or whatever small number your lens can do.

Electronic first curtain uses the electronics to start the exposure since the first curtain has already uncovered the sensor to allow live view to operate. At the end of the exposure the second curtain covers the sensor to end the exposure. This is a good compromise for most situations and shortens the time between the shutter being pressed and the photo being taken. 

Electronic - with purely electronic start and end of the exposure the camera does not move the shutter curtains for quieter, almost silent, results. However since the sensor is scanned sequentially it is possible that moving objects in the frame are captured in a distorted way. Also bokeh is not the smoothest. As you have found, your EOS 90D cannot be set for high speed drive with electronic. 

In the main for birds you are likely to be some distance away from the subject, so using electronic first curtain is probably the best option. 

[Ramsden · Accepted solution]

Thanks again Brian. That is really helpful. I can't believe that its taken me nearly 2 years to 'stumble' across this option. 

Just for clarification, is the default Electronic 1st Curtain for the view finder mode?

Plus: is this  common amongst a wider range of cameras? ( just out of interest)

Ramsden