The whole crop-sensor versus full frame sensor thing never quite made sense to me, ’til I saw the difference between a 50mm lens on a crop camera versus the exact same lens on a full frame sensor. If this whole thing already made perfect sense to you, feel free to skip this post. For those of you to whom the whole thing makes about as much sense as Finnegan’s Wake — in Swahili — read on.
Sensors come in several sizes, from the thumbnail-sized sensors in your average point-and-shoot to the 120mm sensors in medium-format cameras. If we’re taking a 35mm film frame as our point of reference (also the size of the sensor in a “full frame” camera), any sensor smaller than 35mm is going to have a crop/multiplier factor when used with 35mm lenses. You’ll recall that some time back we talked about the difference between digital and optical zoom, where digital zoom essentially crops the image captured by a sensor at its native resolution; the crop factor introduced by a smaller sensor does the same thing, minus the software trickery.
Here’s why it didn’t exactly make sense to me. Lenses have different fields of view at different focal lengths. A fisheye lens (say, 8mm) can give you a 180 degree angle of view. A 50mm lens, sometimes called a “normal” lens, closely approximates your natural field of vision. A much longer lens, like a 300mm lens, gives a much tighter field of view (around 8 degrees).* You’d think (or I thought, at least) that regardless of the size of the sensor, the photo would be the same because the lens’s field of view at a given focal length would be the same in any case, so a lens racked out to 300mm would have the same FOV whether you used it on a full-frame sensor, a crop sensor, or a point-and-shoot.
Only it isn’t quite. So how’s this crop thing work? By way of analogy, think of it like this. Let’s say you’ve got a slide projector that’s ten feet from a three foot wide screen. The image fills the screen with no problems. The projector is your lens; the image coming out of the projector is the “image circle”; the screen is your sensor. When you’re using a crop sensor, you’re not moving the projector relative to the screen; it’s simply changing the area covered by the projected image. So if you put a two foot wide screen in front of the projector, you’re going to notice that a much smaller part of the image is visible on the screen (with some of the image spilling over to the area beyond it). A DX lens has a smaller image circle (in essence, focusing the “projector’s” beam more tightly), so it’s going to fill a smaller “screen” (sensor) easily enough, but it’s going to come up short on anything larger.
This is also, incidentally, why a lens that exhibits light falloff or softness in the edges and/or corners on a FF camera generally looks better on a crop camera. Most lenses — at least once you stop them down a bit — are going to be reasonably sharp in the center. The part that’s sharp is the part that’s being projected onto the smaller sensor, whereas a larger sensor’s going to also incorporate the dodgy bits from the perimeter of the frame.
Therein lies a lesson. Some people — and I was one of them — purchase full frame lenses when they have a crop sensor camera just in case we decide at some point to jump to a full frame camera. When you’re reading reviews of lenses, therefore, one of the things to pay attention to is who’s using the lens as they review it. It’s not unheard of for a lens to get rave reviews from DX/crop users only for the FF people to point out flaws in the lens’s image quality. If you have no plans to switch formats, you may not have much to worry about (though other issues, like lens flare, coma and color fringing will typically manifest no matter what body you’re using). But if you’re going to be switching at some point, pay attention to those flaws. You may be willing to put up with them, but at the very least, go in with eyes open.
Oh, and about the images accompanying this post: the camera wasn’t moved relative to the bookcase (it was on a tripod). I’m also using the same lens (a 50mm 1.8) in both shots. The only change is that the first shot was taken in the camera’s full-frame mode, while the other uses its crop mode. So on full frame, the 50mm looks… well, like a 50mm looks. In crop mode, it acts more like a 75mm.
If I haven’t been as clear on this as I’ve tried to be, feel free to sound off with your questions (or better examples) in the comments section below. We’ll be revisiting this topic (albeit from a different angle) soon.**
For years now, no camera discussion forum has been worth its salt if it hasn’t included a thread or two speculating about how neat it’d be if someone would stick a full-frame sensor into a crop-sensor body and slap an affordable price tag on it. Rumors have come and gone and come again, but now we’ve got the real deal with the Nikon D600, which was announced barely three weeks ago, and has actually been available in stores since its September 18 release date (if you’re even a casual Nikonian, you know this is nothing to take for granted). Read below for the results of real-world use (read: no test charts or silly photos of brick walls) from a real live photographer.
The D600’s $2,100.00 price tag isn’t exactly pocket change, but as full-frame cameras go, it’s enough to put this Nikon in the “affordable” category, relatively speaking. The price is held down by a few things; it doesn’t have the D800’s 36MP sensor or control surfaces, or a huge buffer, or the D4’s frame rate. Its body largely carries over from the D7000, from the remarkably similar design, measurements and weight to the use of titanium only for the back and sides. With all that being said, this isn’t a no-frills camera; there’s an awful lot of capability packed into a comparatively small package. Read on to find out more.
Sensor: If you’re the kind of person who obsesses over lab tests, the DXOMark score for the D600 is 94 (third only to the Nikon D800 and D800E, which came in at 95 and 96; more on that here). If, on the other hand, you’re concerned more with the resultant photos… Look, the thing’s got 24.3 megapixels. You can, in other words, crop like an overzealous barber and still get good shots out of this puppy. There are caveats, of course. Higher-megapixel sensors have a tendency to show the flaws of the lenses put in front of them (or of the photographer behind them), not to mention that the file sizes are much larger. Color depth is very good, and the dynamic range is… well, it’s a good reason to give this camera a close look if you hadn’t already.
Ergonomics and Controls: this is, naturally, highly subjective; one thing I’ve always liked about Nikon is that they feel right in your hands, and the D600 is no exception. There are plenty of knobs and buttons, which makes a huge difference when it comes to changing settings quickly (if it has, or can be assigned, a knob or button, that’s one less thing you’ve got to hunt for in a menu). Some of the buttons do double duty, controlling different functions depending on how you’re using the camera at the time; in other words, the buttons that control ISO and white balance will control your ability to zoom in and out on an image during playback. Some people see this as a major drawback… I’m not one of them. Like anything else, you adapt. The D600 is further helped by the inclusion of user-customizable menus, as well as two banks’ worth of user settings on the mode dial, which can be useful if you’re making lots of wholesale changes to your settings for certain situations. So if, for example, you’re doing product photography strictly for the web, you can dial in smaller file sizes, different color and ISO settings, et cetera, and recall them on the dial rather than having to set everything manually each time you want to shoot that way. As an added bonus, both halves of the mode dial now lock, so you don’t have to worry about accidentally changing from Aperture Priority to Manual when you take the camera out of your bag.
ISO: Native ISO spans 100-6400, with a “Low” setting of 50 and a “HI2” of 25,600 ISO. I was fully prepared to write off the HI modes altogether; on the D7000, 6400 was useable, but just barely, and by Hi2, it was as noisy as a bar band. Even without noise reduction, you can get useable prints up to 6400. Noise is very well handled in the upper ranges. The pleasant surprise here is in the reaches beyond 6400. It’s still noisy in the Hi modes, and there’s still loss of detail, but it’s held down much better on this camera than on the D7000. What’s more, even where there’s grain, it looks (up to 6400) like film grain. I’m not seeing the kind of luminance noise with the 600 that I’ve noticed with nearly every other camera I’ve tried – even in RAW, or in JPG with noise reduction turned off.
Metering: I’m finding the metering on this camera to be a tad more reliable than on the D7000. Left to its own devices (at least in matrix metering, which I tend to use most often), the 7000 had a tendency to slightly overexpose. The D600 blows fewer highlights in Matrix metering than the D7000, and also has visibly improved dynamic range (the inclusion of in-camera HDR is a nice touch, but I haven’t used it nearly enough – or used dedicated HDR programs like Photomatix at all – to be able to say exactly how well it does HDR).
Autofocus: 39 focus points with 11 cross-type sensors. While I don’t have the fancy gear of the folks at Popular Photography or DP Review, I will say that the AF is noticeably faster in low light, even with my finicky, screw-drive 105 f/2.8D mounted to the camera. The one thing that may pose an issue for you, depending on what you shoot and how, is the grouping of those AF sensors. It’s essentially the same grouping as on the 7000, and in the same amount of space. In other words, what gave you pretty generous coverage on a DX sensor instead gives you a relatively tight grouping toward the center of an FX sensor. If you’re used to shooting with a single sensor point (or coming from a camera like the D60, which has only three evenly-spaced focus points on a single horizontal plane), this doesn’t present a huge issue.
Battery: The D600 uses the same EN-EL15 that’s used in the D7000 and D800. It’s CIPA rated for 900-1050 shots. I haven’t shot quite that many frames (yet) with this camera, but my experience using the same battery in the D7000 bears this out. Other factors (overuse of the burst mode, lots of chimping, using the onboard flash, cold weather) can, of course, lead to your results varying.
Finder: 100% coverage, .71x magnification. It’s big and bright, with the option to overlay grid lines, plus a frame that shows the DX coverage area if you’re using a DX lens, or if you set the camera to shoot in crop mode using an FX lens. Unlike previous and other current Nikon FX cameras, the 600 carries over the square viewfinder found on the DX line (not that I mind; it means not having to buy another eye cup for the finder).
Lenses: You can use practically anything with a Nikon F mount on this camera, including DX lenses, from your old AI-S lenses, to the more recent 2.8D screw drive AF lenses (the drive’s built in, as it was on the 7000) to the newest VR G lenses. If you’re weighing the move from a dedicated DX camera to FF but have hesitated ‘til now because you needed the additional magnification provided by the crop sensor (and/or didn’t want to lose too much resolution), you’ll be happy to know that this shoots at a respectable 10 megapixels in crop mode, so you can still use that 70-300 like a 450mm at the long end if you need to.
Video: I’m a stills guy. I can count on my fingers and toes how many videos I’ve shot with any cameras I’ve used that had the capability, and would only need one hand for the number of those videos I’ve actually kept. I bring this up by way of suggesting you take this section with a grain of salt. Video quality was, to my eyes, pretty darned good in daylight, but not so much in lower light. The edge still goes to Canon (or Sony) on video performance, though Nikon’s improved significantly since they introduced SLR video with the D90. Audio’s spotty, but then again, I didn’t expect much from the audio to begin with; nearly any non-video camera that relies on a built-in condenser mic has poor sound quality, and picks up every whirr, click, and hum from the camera’s and lens’ guts. If you’re serious about DSLR video, get a shotgun mic. But then, if you’re serious about DSLR video, you already knew that.
Extras: A strap, which is the usual cheap, garish and and uncomfortable nylon Nikon strap; if you haven’t already, I’d suggest buying something more comfy (like the Crumpler Crumpler Industry Disgrace***), especially since your neck’s going to feel like hamburger if you’ve got anything larger than a 50mm on the camera for any length of time. There’s also a USB cable, the little thingy that protects your hot shoe, that other little doohickey*that you’re supposed to put over the viewfinder if you’re not going to be shooting at eye level, another slab o’ plastic that covers the rear LCD, instruction manuals in English and Spanish (which you probably won’t read, choosing instead to ask on the NikonRumors forum, you scallywag), one EN-EL15 battery (with charger) and a body cap.
Pros include excellent dynamic range, very good high ISO performance and color depth, good ergonomics, plenty of manual controls and buttons, quick buffering, and all the perks that go with shooting full-frame packed into a body with the form factor of the prosumer D7000. Cons** include a tightly-grouped 39-point AF system, slightly slower burst rate, and 1/200 flash sync.
Is this the camera you need? Well, that all depends. As with any other camera, a lot has to do with expectations. My last camera, traded in toward this one, was a D7000. That wasn’t an easy choice to make; the 7000 was an excellent camera, and if I had to do it over again, I’d buy another without hesitation. I heard gripes about the 7000 (notably, hot pixels, and sometimes gimpy AF, especially in low light). I didn’t have the same hot pixels that some early adopters had (one of the benefits of waiting), and given that I was coming to the 7000 from a point-and-shoot that could be poky in broad daylight, I found the 7000 a joy to use. If you’re stepping up to the 600 from an older generation of the D series (say, anything from a D40 to about a D80), this camera is a quantum leap.
Build quality is identical to the D7000, and the frame rate in burst is half-a-frame slower. If those things are deal breakers for you, plunk down the extra $900.00 for a D800 for the added build quality (and 36MP) and a more evenly-distributed 51 point AF. Or, for just (just?) an additional $3,800.00, you can get 10 frames per second, 51 point AF, and the build quality (not to mention concomitant weight) of a freakin’ tank with a D4.
I could easily sum up the D600 in two words: Holy shit. I’m a bit given to profanity as it is, but this camera had me cursing like a sailor on shore leave. Over and over again, it’s performed better than I expected: quick AF, jaw-dropping performance at high ISOs, the ability to crop with impunity, the lovely bokeh that’s the reason you buy fast lenses to begin with, and superb image quality.
If you’re on the fence because you’ve got a D90, D7000, or D300, all I can tell you is, put this puppy through its paces. Its controls are very close to those of the 7000 (with a couple of minor variations), and its dimensions and weight are so close that you won’t feel the difference in your hands. If you’re looking for the successor to the D700, this could well be that camera (keeping the caveats above in mind). If you’re looking for a backup body for your D800… well, that all depends. In terms of image quality, the D600 gives the D800 a run for its money, but the controls on both are very different, so unless your other camera’s a D7000, that could prove to be frustrating. With all that said, here’s the bottom line: if the compromises that come with this camera are the kind that you can live with (for me, they were) then this is a damn good camera for the price.
**Whether some of these things are “cons,” of course, depend on your needs and expectations.
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A note on the photos: The file sizes on the original photos, as you’d expect on a camera with a 24MP sensor, are enormous. The photos above have, therefore, been cropped and downsampled. The only one that’s had any processing applied beyond in-camera noise reduction (set at Normal) is the flower photo above.