The new Canon G7 X

By Kevin Purcell

In the usual Photokina binge of "really interesting stuff" I think the Canon G7 X rather got lost. It's in a different category of compact to the excellent Panasonic LX100 or the tiny Panasonic GM5. It's also missing the EVF which will turn off some people.

Thom Hogan has a nice summary of the camera:

What we get in the US$700 Canon G7 X is the Sony 20mp 1" BSI sensor coupled with a 24–100mm (equivalent) ƒ/1.8–2.8 lens, a 1m dot touchscreen, a built in ND filter, 1080P/60 video and some other PowerShot stuff.

I can see the elevator pitch for this product: The G7 X is an S90 with a bigger sensor and a faster lens.

I'd add the following thoughts about Canon G7 X:

1. It's the same size as the S90/S95/S100/S110/S120 "enthusiast" Powershot series. That's small, perhaps as small as you'd want a camera to be. It is thicker though at the lens, like the Sony RX100. (The lens size limits the camera size for larger sensor compacts.) It might fit in a not-too-tight jeans back pocket like my Canon S95 and my Ricoh GRD4 do. I feel this is one real definition of "compact camera." A useful one too as I often take one of those two cameras when I'm not in "photographer mode," just stuck in my back or front pocket waiting for an opportunity.

2. It has a longer and faster lens than the RX100 but still fits in the same space. They might have let some other design parameters go, perhaps distortion or chromatic aberration (all fixable in software...to some extent) or Canon has better optical chops than Sony does. This is a nice move.

3. It isn't called an S series Powershot anymore but a G series with an extra X. I think that implies that there won't be a G12 equivalent in this range. That would be a shame for those who like the "knobs" UI and an EVF. Perhaps Canon think that might compete too strongly with the "too big and too slow" G1X and its not-so-great APS-C sensor.

4. Are Canon really using the Sony 20Mpx type 1-inch BSI sensor that everyone else, including the Sony RX100 III and the Panasonic FZ1000 are using? They're being tight-lipped about it and not mentioning it in their press releases, but both Thom and dpreview have been told that it's a non-Canon BSI sensor.

This is perhaps an admission that to compete in this product area, Canon has to use a rival's CMOS sensor rather than develop its own. In the S series the S90/S95 used a rather good Sony CCD sensor and then switched to a Canon CMOS sensor for the S100/S110/S120. Now they've switched back to Sony.

To continue this line of thought, it's interesting to compare the latest Canon APS-C compact with the Sony RX100 III as a proxy for the sensor in the G7 X. You can get a rough idea of the relative performance of the sensors from the DxOmark comparison for these cameras.

Click on the Measurements tab for a more detailed comparison. Too few people do this, I think. DxOmark provides more information than single numbers often referenced in Internet forums. Especially the Tonal Range measurement that nobody pays attention to but that I think is the best way to judge a sensor. In this case you can see the two cameras have identical tonal performance. But the Sony wins on dynamic range, especially below ISO 400.

You get more technical details on sensor performance at sensorgen.info for the G1X and the RX100 III.

The Sensorgen numbers are sensor engineering parameters reverse engineered from DxOmark sensor measurements by curve fitting. They're quite accurate when compared to sensors whose specifications have been made public.

The G1X sensor limitations are in quantum efficiency (what fraction of photons hitting the sensor contribute to the image) and analogue to digital converter read noise (a problem that Sony, and others, solved some time ago). Back-side illumination is one contribution to improved QE in the Sony sensor.

The smaller type 1-inch Sony sensor equals or outperforms (in dynamic range) the bigger Canon type 1.5-inch sensor. That's got to be a worry for Canon as it's a trend across all of the sensors Canon manufactures.

Kevin

Current cameras mentioned in this post:

Canon G7 X (pre-order)

Panasonic LX100 (pre-order)

Panasonic GM5 (pre-order)

Canon S120

Sony RX100M III

Panasonic FZ1000

Canon G1X Mark II

TOP reader Kevin Purcell is the only Scouse street photographer in Seattle with a Ph.D. His first camera was a Diana that used Kodak 120 film. He owns too many cameras and still hasn't found the "best" one. He is interested in everything. His "workprints" are on Flickr.

©2014 by Kevin Purcell, all rights reserved

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