The 15-45 switch.

Jayson A wrote:

nnowak wrote:

Jayson A wrote:

nnowak wrote:

Jayson A wrote:

why do lenses with the EF adapter require the lens cap when turning the camera off, but native lenses don’t?

What???

Every time I turn my camera off with an EF or EF-S lens on, it says "Keep the Lens Cap On after Camera is Off", but native lenses don't say that. The camera just shuts off normally. I thought the sensor is aways exposed whether you have the camera off or on since there's no mirror covering it. So why is it important to keep the lens cap on when an EF or EF-S lens is attached vs a native EF-M lens?

Never noticed that before.

My guess it is due to the difference in aperture mechanisms. The EF-M lenses stop down to the smallest aperture when powered down. EF and EF-S lenses are wide open when powered off.

Apparently Canon must be seeing a rash of people starting their mirrorless cameras on fire by mounting giant telephoto lenses and leaving the camera pointed at the sun while sitting on the dash of their car in Arizona in July.

Correct me if I'm wrong, but wouldn't stopping down create a smaller pin of light if your camera is facing the sun, causing more damage than a large amount of light evenly spread over the whole sensor?

I just don't see how stopping down is safer than wide open.

Stopping down 6 stops reduces the power by a factor of 64. That makes a huge difference if the lens is focussed at infinity. As it will probably be, by Sod's Law, or if you have the Retract lens on power off menu option enabled.

If you have managed to leave the lens at minimum focus, opening up 6 stops increases the size of the bokeh circle from a point source by a multiple of 8, so it increases its area by a multiple of 64. It also increases the power by a factor of 64. That means the intensity of the light within the bokeh circle from a point source should in theory be constant. In practice, the Sun isn't a point source, and the bokeh circle isn't a uniform brightness, so there's definitely an advantage to stopping down.