Making Peace With APS-C

March 19, 2010

It’s shocking to realize it was only six years ago when the first digital SLRs costing under $1000 arrived.

The original Canon Digital Rebel (300D) and Nikon D70 were the first to smash that psychologically-important price barrier. These 6-megapixel pioneers effectively launched the amateur DSLR market we know today.

Sub-$1000 DSLRs

New for 2004: DSLRs for Regular People

But one argument that raged at the time—and which has never completely gone away—was about the “crop format” APS-C sensor size. (The name derives from a doomed film system; but now just means a sensor of about 23 x 15 mm.)

Was APS-C just a temporary, transitional phase? Would DSLRs eventually “grow up,” and return to the 24 x 36 mm dimensions of 135 format?

This was a significant question, at a time when virtually all available lenses were holdovers from manufacturers’ 35mm film-camera systems.

The smaller APS-C sensor meant that every lens got a (frequently-unwanted) increase in its effective focal length. Furthermore, an APS-C sensor only uses about 65% of the film-lens image circle. Why pay extra for larger, heavier, costlier—and possibly dimmer—lenses than you need?

Also, after switching lens focal lengths to get an equivalent angle of view, the APS-C camera will give deeper depth of field at a given distance and aperture. (The difference is a bit over one f/stop’s worth.)

But a more basic question was simply: Do APS-C sensors compromise image quality?

Well, sensor technology (and camera design) have gone through a few generations since 2004.

Microlenses and “fill factors” improved, so that even higher-pixel-count sensors improved sensitivity. (For one illustration, notice how Kodak practically doubled the quantum efficiency of their medium-format sensors between a 2007 sensor and the current one selected for the Pentax 645D.)

Today’s class-leading APS-C models can shoot with decent quality even at ISO 1600. And the typical APS-C 12 megapixel resolution is quite sufficient for any reasonable print size; exceeding what most 35mm film shooters ever achieved.

So it’s clear that APS-C has indeed reached the point of sufficiency for a the great majority of amateur photographers.

Still, Canon and Nikon did eventually introduce DLSRs with “full frame” 24 x 36 mm sensors. They were followed by Sony, then Leica. In part, this reflects the needs of professional shooters, whose investments in full-frame lenses can be enormous.

And for a few rare users, files of over 20 megapixels are sometimes needed. In those cases, a full-frame sensor maintains the large pixel size essential for good performance in noise and dynamic range.

But these are not inexpensive cameras.

So the question has never completely gone away: Is APS-C “the answer” for consumer DSLRs? Or will full-frame sensors eventually trickle down to the affordable end of the market?

Canon Full-Frame Sensor

Canon Full-Frame Sensor

I have mentioned before an interesting Canon PDF Whitepaper which discusses the economics of manufacturing full-frame sensors (start reading at pg. 11).

It’s not simply the 2.5x larger area of the sensor to consider; it’s that unavoidable chip flaws drastically reduce yields as areas get larger. Canon’s discussion concludes,

[…] a full-frame sensor costs not three or four times, but ten, twenty or more times as much as an APS-C sensor.

However, since that 2006 document was written, I have been curious whether the situation has changed.

More recently I found a blog post from 2008 which sheds more light on the subject. (Chipworks is an interesting company, whose business is tearing down and minutely analyzing semiconductor products.)

Note that one cost challenge for full-frame sensors is the rarity of chip fabs who can produce masks of the needed size in one piece. “Stitching” together smaller masks adds to the complexity and cost of producing full-frame sensors—Chipworks was doubtful that the yield of usable full-frame parts was even 50%.

Thus, Chipwork’s best estimate was that a single full-frame sensor costs a camera manufacturer $300 to $400! (This compares to $70-80 for an APS-C sensor.)

And that’s the wholesale cost. What full-frame adds to the price the consumer pays must be higher still.

Thus, it seems unlikely the price of a full-frame DSLR will ever drop under $1000 (that magic number again)—at least, not anytime soon.

And actually, APS-C pretty darned decent.

So let’s embrace APS-C. That means it’s time to reject overweight, overpriced lenses that were designed for the older, larger format. We need to demand sensible, native lens options.

It would have been nice if APS-C had somehow acquired a snappier, less geeky name—maybe that’s still possible?

But it seems time to declare: It’s the standard.

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7 Responses to “Making Peace With APS-C”

  1. Quido Says:

    These articles are heaven-sent. Petavoxel, you are my favorite photo tech blog (together with 1001nc for daily news).
    Thank you!

    Too bad the K-x doesn’t have the focus point indication in the viewfinder, I think it would be the most acceptable APS-C camera for you and me – coupled with a pancake ( http://www.flickr.com/photos/johnmflores/4242966137/ + http://www.radiantlite.com/wp-content/uploads/2009/08/pentax-km-k2000-with-40mm-f2.8-pancake-lens-300×262.jpg ).
    I shoot with a D40 + 35/1.8 combo, which is much deeper than these.
    My dream camera would be a D40 with D3000’s AF module and D3s’s sensor cut in half (= ca. 6mpx), with video and audio gain control. If available, I’d sacrifice the depth for a vari-angle display.
    Would the readers of this blog be the only people who’d buy it? 🙂
    Greetings from Prague

    • petavoxel Says:

      Thanks—and greetings back to Prague! (My stats show steady traffic referred from technet.idnes.cz, and I appreciate all the visits.)

      I do think most of the “easy” improvements to sensor technology have been found; perhaps now we are reaching a plateau in performance. If that shifts competition to other areas—like handling and size—it could be a welcome development.

    • Quido Says:

      One more thought: since Pentax now has a sweetheart relationship with Kodak as evidenced by the price (of the sensor in) the 645D, I can’t help but stretch my imagination to a possible 35mm product.
      Maybe it wouldn’t be so difficult for Pentax to obtain the Leica M9 chip, too, put it into a 35mm body and do what they’re good at – make it a lot smaller/less ugly than e.g. the 5D.
      Yes, in my post above I lied, my dream camera would be a digital Nikon F made by Pentax :))

      • petavoxel Says:

        Ah, but you’ll notice the M9 has no video mode at all; and only can shoot 2 frames per second. It’s unfortunately one downside of that (otherwise lovely) CCD sensor…

  2. Huggs Says:

    With my budget, I accept APS-C with wide open arms & wallet. 😀


  3. […] Armwaving assertions that “costs of semiconductors always fall” are easy; but there remain real reasons why a full 24×36 sensor will always carry a premium price. And there are large up-front costs […]

  4. Miserere Says:

    What can I say? I wholeheartedly agree! People get really hung up on Fool Frame, and I suspect their pictures would suck even more if they went FF because they’d have more out-of-focus images due to the reduced DoF.

    Today’s APS-C sensors offer better IQ and higher usable ISOs than cameras costing $5,000 a few years ago. Within 2 years we’ll have good ISO 25,600 from $500 APS-C DSLRs, at which point I’ll have to ask why do you need the 1-stop improvement in ISO performance FF gives you if you need to pay 4-5 times more for it? I already ask that question now, and except for wedding photographers, nobody can answer it to my satisfaction.

    I’m happy with APS-C, smaller cameras, smaller and lighter lenses, and cheaper prices overall. I will not be fooled by Fool Frame.

    PS: However, if Pentax shoehorned the Leica M9 Kodak sensor into an LX body, I might just have to sell my car to buy that camera. But an APS-C sensor from Sony would do just as well…and there’d be no need to sell anyone’s car 🙂


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