How can Sigma make sure the FFF is the best success it can be? Locked

Full frame standard lens: 50mm 4/3 standard lens 25mm

Full frame wide angle: 24mm 4/3 wide angle 12mm

Full frame tele: 100mm 4/3 tele lens 50mm

First thing to note is that 4/3 has never had anything to do with full frame. In no point in the history of 4/3 has any vendor made a full frame format lens to work on a m4/3 body (ignoring adapted lenses). This means that there is no justification at all for calling 4/3 a crop of full frame 135 format. It never has been, it never will be. You also can't use L mount lenses on 4/3 (ignoring adapted lenses) and you can't use 4/3 lenses or m4/3 lenses on L mount. No connection despite Pany's involvement in both, and therefore no justification for calling 4/3 a crop of full frame.

It is true that 4/3 is smaller than 35mm/135/fullframe. But smaller cannot be called a crop unless the same camera bodies and lens systems can use both sensor sizes and they can't.

Full frame is a format and system in its own right as is 4/3. Neither has anything to do with other and neither is a positive or negative crop of the other. They are entirely independent with their own unique focal lengths and depth of field characteristics. Just keep them separate in your mind and you'll be fine. Insist in translating 4/3 into 35mm terms and you will get in a muddle about something.

A typical example of this would be to start calling a 25mm f/2 4/3 lens a 50mm f/4 lens. You see this all the time on forums and it's wrong. And f/2 lens is an f/2 lens it can never be accurately described as an f/4 lens.

When people attempt this, what they are trying to do is generate a 35mm format equivalence for the depth of field differences between the format sizes. But in doing so they ignore the primary reason for calling a lens f/2, which is the amount of light it lets in.

And no one doing the equivalence dance ever bothers to do it properly and say something like:

"A 4/3 25mm f/2 lens, has the same angle of view as a 50mm f/2 lens on full frame, the same bright f/2 aperture, but the depth of field it has is similar to that exhibited by a 50mm f/4 lens on full frame. If a 4/3 sensor has the same pixel count as a full frame sensor, it will have a reduced signal to noise ratio, and noise will be more visible (assuming same generation sensor tech)".

Nobody ever bothers to properly spell out all the meaning of equivalence, they just stumble along with some half-assed jumbled up mess.

Just learn the characteristics of the formats you use and stop converting everything into full frame terms. It's an archaic practice.