If you put any faith in DxO Mark scores (and I do understand their limitations), today’s best $500 DSLRs make better images than all of the sub-$4000 cameras sold until 2008. Largely that’s thanks to some good recent APS-C sensors from Sony.

So I’m not sympathetic towards certain Pentax users, who bleat that they can’t make adequate photographs—not until the company delivers a DSLR with a 24×36 mm sensor. (With pre-Photokina Pentax rumors swirling, the issue is once again a hot topic for discussion.)

Full-Frame Pentax?

Full-Frame Pentax?

Yes, many long-time Pentaxians do have investments in full-frame “FA” lenses, ones that could cover the format.

But keep in mind, over the history of photography there have many camera mounts which died out entirely—obsoleting numerous fine lenses. How about Contax/Yashica mount? Minolta MD, or Canon FD? (Or even earlier systems, such as Exakta or the superb Zeiss Contarex?)

By contrast, any Pentax lens made since 1983 can at least be used on a modern DSLR—metering automatically, and with the benefit of built-in shake reduction. So the handwringing that some great lenses have been “orphaned” by Pentax can get a bit exaggerated.

Some point out hopefully that not long ago, Pentax introduced new telephoto lenses bearing the FA designation. Ergo, full-frame is coming!

But truthfully, no decent lens design even breaks a sweat in covering an image circle much smaller than its focal length. With a telephoto, full-frame coverage is basically “free”—so why not go ahead and use the FA labeling? It allowed Pentax to finesse the format question for a while longer; and maybe even sold a couple of extra lenses to Pentax film-body users.

I do agree with the complaint that the viewfinders of most consumer DSLRs are puny and unsatisfying. The view through the eyepiece of a full-frame body is noticeably more generous.

However, the electronic viewfinder of an Olympus E-P2 neatly solves this problem too—at a price savings of about $1400 over today’s cheapest full-frame DSLR. And the EVIL wave is only gathering momentum.

The perpetual cry from full-frame enthusiasts is that Moore’s Law will eventually slash 24x36mm sensor pricing. To me, this seems like a wishful misunderstanding of the facts.

The shrinking of circuit sizes which permits faster processors and denser memory chips is irrelevant to sensor design—the overall chip dimensions are fixed, and the circuitry features are already as small as they need to be.

Also, figuring the costs of CMOS chip production is not entirely straightforward. It costs money to research and develop significant new improvements over prior sensor generations; it’s expensive to create the photolithography masks for all the circuit layers. Then, remember that all these overhead costs must be recouped over only two, perhaps three years of sales. After that, your sensor will be eclipsed by later and even whizzier designs.

Thus, there is more to a sensor price than just the production-line cost; it also depends on the chip quantities sold. And full-frame DSLRs have never been huge sellers.

If APS-C sensors prove entirely satisfactory for 95% of typical photographs (counting both enthusiasts and professionals), a vicious circle results. With no mass-market camera using a full-frame sensor, volumes stay low, prices high. But with sensor prices high, it’s hard to create an appealing camera at a mass-market price point.

Furthermore, let’s consider the few users who would actually benefit from greater sensor area.

For the few who find 12 megapixels inadequate, nudging the number up to 24 Mp is not the dramatic difference you might imagine. To double your linear resolution, you must quadruple the number of pixels. Resolution-hounds would do better to look to medium format cameras, with sensors 40 Mp and up—which conveniently, seem to be dropping towards the $10,000 mark with the release of Pentax’s 645D.

The last full-frame holdouts are those who need extreme high-ISO potential. There’s no doubt that the 12Mp full-frame Nikon D3s makes an astounding showing here, with high-ISO performance that’s a solid 2 f/stops better than any APS-C camera. This is a legitimate advantage of class-leading 24×36 mm sensors.

Yet aside from bragging rights, we have to ask how many great photographs truly require ISO 6,400 and above. ISO 1600 already lets us shoot f/1.7 at 1/30th of a second under some pretty gloomy lighting—like the illumination a computer screen casts in a darkened room.

A day may come when sensor technology has fully matured, and every possible sensitivity tweak has been found. At that point, a particular sensor generation might hang around for a decade or more. So might those long production runs permit much lower unit costs for a full-frame sensor? There will still be a full-frame surcharge simply from the greater surface area and lower chip yields.

But who knows, perhaps it’s possible? By then we may have 40 Mp, 24×36 mm chips that are our new new “medium format.”

Samsung’s new “enthusiast” compact, the TL500 (or EX1 outside the US) was announced at the PMA show in February; but as of this writing, it’s not yet available from the usual mainstream sources. However, reviews are starting to filter out: Both Luminous Landscape and now Photography Blog have given it very positive ratings. (DP Review has a sample gallery posted, which suggests they’ll be posting their own full rundown soon.)

Samsung TL500 (EX1)

Stout Little Fellow

As with any small-sensor compact, there’s still some image-quality compromises. The active area of the TL500′s sensor measures about 7.5 x 5.6 mm, so ISO 800 still shows obvious noise.

However this new Samsung is beginning to look like one of the better options in the “serious compact” segment. (Street prices will start out about $400, presumably to drift downwards from there—that’s higher than a Canon S90, but well below Ricoh and Leica levels.)

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DxO Mark Relaunch

June 22, 2010

As of 22 June 2010, the DxO Mark website has been redesigned and greatly expanded—now adding tests of lens/sensor combinations.

There’s certainly an enormous amount of new information there to chew over, although presented in a somewhat bewildering format.

Unfortunately one side effect of the change is that it has broken all of the links my articles included to their sensor comparisons.

Sorry about that. I may try to fix a few of them as I have time.

Photokina 2010

June 6, 2010

I’m puzzled why there is so much buzz recently about cameras & whatnot which might be introduced “at Photokina.”

Has everyone forgotten that it’s more than three months away?

On Pentaxian discussion boards, one dispute that absolutely refuses to die is whether Pentax will (or should) introduce a “full frame,” 24x36mm sensor DSLR.

The pleading for 24×36 often comes from those who might have already invested heavily in earlier FA lenses—meaning, ones originally designed to cover the old 135 film format.

I understand the emotion here—it’s quite true that an APS-C sensor wastes some of the capabilities of those lenses. And let’s take it as given that Pentax’s engineers would be fully capable of producing an excellent 24×36 camera.

But does Pentax “owe” its existing customers such a model?

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BSI: No Panacea

May 21, 2010

In a few earlier posts I have mentioned the new generation of Sony sensors boasting “back-side illumination,” and marketed as Exmor-R (as distinct from Sony’s conventional sensors, just branded Exmor).

Back-side illumination (BSI in the industry jargon) is a tricky and costly chip-fabrication technique, where after depositing all the wiring traces on a silicon wafer, the substrate is flipped over and almost entirely thinned away. This leaves the wiring on the underside of the light-sensitive photodiodes (as Sony describes here), so these unobstructed pixels will theoretically collect more light.

BSI is promoted as one of the technological breakthroughs which might help save image quality, even as manufacturers race to cram more megapixels into tiny sensor areas. In fact, the IMX050CQK actually scaled back its pixel count to 10 Mp, compared to the 12 and 14 that have been becoming increasingly common in the point & shoot market.

Sony BSI Sensor

A Whizzy Small Sensor is Still A Small Sensor

Sony introduced the chip in its own first models in the fall of 2009, for example in the WX1. But clearly Sony found it advantageous to spread the sensor development costs over a larger production run, and apparently they’ve aggressively marketed the chip to other camera makers as well. Pretty much any 10 Mp camera sold this year advertising a backside-illuminated sensor uses it. It seems particularly popular in today’s nutty “Ultra Zoom” market segment.

So I was interested to read the review just posted by Jeff Keller of Nikon’s P100 ultrazoom camera, which uses this chip. See his conclusions here.

As reviews of these new BSI-based cameras filter out, the word seems to be that they do offer decent image quality—but hardly anything revolutionary. If their high-ISO images look smooth, it seems to be partly thanks to noise reduction processing, which can destroy detail and add unnatural, crayon-like artifacts.

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A Nameless EVIL

May 13, 2010

The introduction of Sony’s NEX-3 and NEX-5 has once again thrown a weird anomaly into sharp relief.

Even 20 Months after the introduction of the Panasonic G1, there is still no universally-agreed-upon term for this new class of cameras.

The defining aspects of the genre are a largish sensor size (as compared to typical compacts) plus interchangeable lenses. Yet by omitting any reflex viewfinder, and instead streaming a live digital image from the sensor, the body size can be reduced from the bulk of conventional DSLRs.

Dictionary-Evil

Name that Evil

Now, the most widely-known term (and the one I use) is “EVIL,”  meaning “electronic viewfinder, interchangeable lens.”

A few pedants object that the Olympus E-P1 does not have a “viewfinder” in the sense of something you hold up to your eyeball (nor do the Sony NEX models, so far). But you can slightly revise the phrase to be “electronic viewing” instead, if this bothers you.

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