Why is zoom avoided in large sensor compacts?

"You can't have your cake and eat it (too)". 1. Large Sensor 2. Compact 3. Wide aperture 4. Focal length range. Having all of the list is of course at the limits of the technology today. The models you mentioned are very close, and impressive at that! Especially the part around a "compact" size AND a large focal length range; those two points are very competing.

You could get something like the Canon PowerShot SX510 HS if you really must have a superzoom, but then of course you give up the larger sensor and the larger maximum aperture. You could look into micro four thirds and add lenses to get the lengths you need, but it will not compare the to Sony RX100 in size.

Simple, because the lens is proportional to the sensor. The larger, the sensor, the bigger the area it needs to project. This means that longer lenses would be, well, bigger and therefore the camera too would get bigger.

The cameras you mention is a great example but take a look at the Sony RX10. It uses the sensor of the RX100 II and puts it behind a 24-200mm F/2.8 lens. It is no longer compact but is probably, in my opinion, the camera a lot of people are looking for, maybe not at that price.

As you zoom exists in a relatively compact factor but they get long roughly in proportion to sensor size. Even look at Micro Four-Thirds lenses, all the ones less than 3cm in length have 42mm or less focal-length. To reach 200mm at least, they are all 10cm long or more.

Basically for two reasons:

• A larger sensor means a larger lens. If you want the same image quality from the lens, the size difference of the lens is directly proportional to the size difference of the sensor.

• A larger sensor is used for more demanding photo situations, so it puts a higher demand on the image quality of the lens. Putting a large sensor behind a low quality lens would simply make for an unbalanced camera that could not deliver image quality that corresponds to the price.