September 28, 2022

Sony Full Frame Mirrorless Camera

I find the Sony A7 series nomenclature endlessly confusing, and I'll bet you do also. So here we go trying to sort it out.

Once upon a time there was an A7 and an A7R. The A7 was more affordable, and the A7R had the crazy high resolution sensor. Since those simple days, Mark III and Mark IV versions of each of those has been introduced, and probably by the time you are reading this, mark V will have come along.

BSI sensors

First, a diversion. The latest Sony full frame cameras all have a BSI (Back side illuminated) sensor. This does not mean that some kind of light illuminates the sensor from the back. What it does mean is that what used to be the back of a sensor is now the front, and that is the light gathering array. This puts the "wiring" in the back where it belongs so it is not blocking light, so you get a more sensitive sensor. The language is kind of silly. The front of the sensor is indeed illuminated (as it always has been), but the structure of the sensor now makes the front side contain the light sensitive elements (which used to be in the back).

A7 IV

This is more affordable (compared to the A7R). The A7 IV has a 33 megapixel BSI sensor and sells for $2500. The A7 III had 24 megapixels.

A7R IVa

This is the full frame flagship. It has a 61 megapixel BSI sensor and sells for $3500. The A7R III had 42 megapixels. I don't know what the "a" is all about.

A7C

Here "C" is for compact. This is a 24 megapixel camera for $1800 in a rangefinder style body. It weighs 509 grams (compare to 503 grams for the A6600). Find a good light lens to pair with this and you would have a very light full frame rig that would compare the the APS-C lineup.

A7S III

This is a 12 megapixel (yes, 12 megapixel) camera for $3500. This camera is all about video, along with low light sensitivity. Don't ask me why these go together, but I am probably missing something since I don't do video.

A1

This is the no-holds barred professional camera, selling for $6500. It has a 50 megapixel sensor. As is typical for a professional camera, it doesn't necessarily have the highest pixel count and balances other things (like shooting speed in particular) against resolution.
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Tom's Digital Photography Info / tom@mmto.org