Sigma SA Mount

Started 2 months ago | Discussions thread
Jeffry7 Regular Member • Posts: 241
Re: Sigma SA Mount

dmccoy wrote:

Jeffry7 wrote:

Sigma is part of the L-Mount alliance along with Panasonic and Leica. The three have agreed to make cameras and lenses that conform to that standard.

I am guessing that besides the advantage of the alliance, Sigma moved away from the SA Mount because of the flange distance. The SA mount has a DSLR style flange distance and the whole industry is moving to mirrorless.

There is already an adapter for SA Mount lenses to L-Mount bodies. I plan to get one when the time comes so I can continue to use my SA lenses.

I've heard mention of the flange distance change. I assume it refers to the distance from the mount plane to the sensor plane. What changes with mirrorless and what is driving it?

With a DSLR you have a movable mirror. The mirror reflects light up into the viewfinder. When you press the shutter the mirror swings out of the way.

The lens has to be far enough from the sensor to allow for this swinging mirror.

Mirrorless cameras are mechanically simpler. Also how many shots per second you can take is related to how fast you can move the mirror in a DSLR.

In a mirrorless camera, the viewfinder is now electronic and read directly off of the sensor.

I think their are two drivers. The first is that mirrorless cameras are simpler to make. There are just fewer moving parts. Second taking out the mirror allows for short flange distance lenses. I think there is debate about if shorter flange distance lenses are better, but what is certain is that lens makers have more options with a shorter flange distance.

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