G7 hoopla

Another thing I missed from the photography world is the release of the Canon G7.

Canon Powershot G7 rear view

The spec sheet is very impressive for a compact camera:

  • 10 megapixel 1/2″ sensor
  • 6x zoom (though a slow f/4.8 at max zoom)
  • Image stabilization
  • ISO 1600 with a super-high ISO 3200 scene mode
  • hot shoe for external flash
  • $550 retail

Not on the spec-sheet, but appreciated nonetheless are a nice control layout and an optical viewfinder.

From the its non-budget-but-very-reasonable price, its complex control layout, it’s overpowering spec sheet, and it’s not-exactly-svelte-like size, you’d think this camera would be ideal as a second camera for enthusiasts. But no, because the dang major thing missing is RAW file support. Which many people speculated was to protect entry level dSLR sales.

Now I read today that this is because the high photosite density makes the superfine JPEG indistinguishable from the RAW shot:

Smaller pixels means it’s harder to distinguish the signal from the incoming light from the random electronic noise in the sensor, said Chuck Westfall, Canon’s director of media and customer relations.

“The net result is that even if the G7 offered raw image capture…there would be no discernible improvement in image quality compared to…superfine JPEG mode,” Westfall said.

What a load of bullshit.

[An explanation why, after the jump.]

A careful parse

First, there is no lie in the above statements.

  • It is true that the G7 at 10 megapixels has a smaller photosite than the 7.1 megapixel G6.
  • It is true that smaller pixels mean signal-to-noise is worse.
  • It is true that there is no discernible image improvement between a superfine JPEG and a RAW shot on the G7

That doesn’t excuse all the deliberate deceptions leading to a bald-face lie.

A more careful parse

To the first point, ask yourself how much smaller is a G7 photosite from a G6 one (the sensor size is the same). Because we are comparing a linear dimension to an area, the megapixel has to quadruple for the photosite to halve in size. This means the G7 photosite is actually only 15% smaller than the G6 one. A JPEG is an 8-bit image; most RAW images are 12 bits (close to 11 bits of usable dynamic range). Each bit of difference means the photosite has to be half the size! We’re talking about a fraction of a bit lost dynamic range. And all of a sudden, it’s too crappy to do 12-bit RAW?

To the second point, while the smaller photosite means much larger signal-to-noise, the comparison with a dSLR is not apt since the sensor is 9 times bigger and therefore thus has has 3 bits worth (23) better signal-to-noise than a compact camera.

Here is the thing though. This better signal-to-noise is why your dSLR goes up to ISO 1600 or ISO 3200. In other words, if signal-to-noise in the G7 is so bad, then Canon should have seen them reduce the max ISO from ISO 400 down to ISO 360. Instead, they did the opposite: upping it to a dSLR 1600 and 3200!

Hmm, Chuck, are you telling me that ISO 800, 1600 and 3200 were just added for marketing and I’d get a more usable picture drawing a impression of the scene with a set of crayons?

To the third point, there is no discernible image improvement between a fine JPEG and a RAW in any image in any camera, not just this one. That’s because my monitor has a dynamic range of only 8 bits, paper even fewer. That doesn’t mean that the extra 4 bits of dynamic range couldn’t be a huge boon to a photographer editing the image in Photoshop. That doesn’t mean that it wouldn’t help greatly to have the original un-demosaiced RAW image to do my own processing because, quite-frankly, I don’t must care for Canon’s overly contrasty in-camera RAW processing that loves to blow out reds in order to reduce the color noise in tests.

Imagine it is a bright day, and you’re taking a shot and a pocket camera is the only thing you have around. You set the camera to it’s lowest ISO because it is so bright and take the shot. Are you honestly going to tell me that there isn’t more than 8 bits of dynamic range in the sensor?

Yes, a journalist doesn’t give a damn. JPEG’s small size and easy of use is more than good enough for him.

But you aren’t selling it to him. You’re selling it to me, an enthusiast, an amateur. And since we do photography “for the love of it”, we can afford the time to process our RAW images to get the look we want (and make up for some of our behind-the-lens deficiencies).

That’s why I own a Panasonic LX1—not the best noise performer (heh), but it has great controls and shoots RAW.

And that’s why you’re getting all this flack from Canon amateurs who know the only reason you removed RAW support in the G7 is to segment the market. They love photographing with their Canons, and hate the blatant market segmentation. They’re mad as hell and not going to take it anymore.

So you do your damage control. And I’ll sit on the sidelines as these passionate people call you on it and say “Chuck Westfall, you’re a fucking apologist for a deliberately crippled product.”

10 thoughts on “G7 hoopla

  1. In the latest issue of Photo Techniques, there is an article “Measuring Digital Dynamic Range” by Timothy Edberg.

    You’ll have to pick up this magazine to get to the meat of the article. The relevant part here is he Timothy measures the dynamic range of the Canon Powershot G6, which has RAW capability. At the lowest ISO 50, the measured usable dynamic range is 10 f-stops for RAW, and 7 2/3 for JPEG. At ISO 400, he gets 5 2/3 f-stops for JPEG. (Smaller sensors have a larger drop off of usable DR at higher ISO.)

    As I explained above, there is almost no difference due to the increase megapixel between the G6 and G7. I think the conclusions show two things:

    1) RAW has more usable dynamic range than the best JPEG at the lowest ISO in the G7
    2) One can speculate how almost worthless the signal-noise is at the high ISOs: 1600 and 3200 on the G7.

    Meaning that the inclusion of high ISO in the G7 is pure marketing. The exclusion of RAW in the G7 is pure business (selling more dSLRs).

  2. This week’s Gary’s Parries besides agreeing with the basic premise of this article points ut that the G-series was previously “discontinued” and that another feature that got dropped from the G5 was the flip-out/twist LCD.

  3. I could not agree more with this article. I actually bought this camera, and took it back after finding out it didn’t support RAW… What is the point, since you can get the PANASONIC for less with all of the features…

  4. Actually, I think the G9 does. And I’ve been telling people that it is an excellent camera. The reviews, too, bear this out.

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