One of the first decent comparisons of two of the most popular mid-priced D-SLR models can be found on the dPreview website at this URL:http://forums.dpreview.com/forums/readflat.asp?forum=1021&thread=17071974
This comparison was done over about a week's time by Raxel,and it has a number of observations and some good posts by contributors other than the OP. The OP is a Nikon D200 owner who borrowed a colleague's 5D,and so there might be a few familiarity issues handicapping the 5D's performance, but then again, the way the test shooting was done in RAW mode and Capture 1 and Nikon Capture being used as the raw conversion software means that the D200 and the 5D were both shot in raw mode and the files used for comparison purposes were made using top-quality,professionally-capable software applications.
The conclusions are pretty obvious and not at all surprising to me: the 5D is clearly a better HIGH-ISO camera than the Nikon is, by around 1.5 stops I would say, and perhaps as much as 2 stops,depending on how one looks at things. But clearly, and I mean CLEARLY, the Canon is resolving small details AND showing less noise than the D200 is at the higher ISO's of 1600 and 3200. Even if noise reduction were to be run on HIGH-ISO D200 files, I do not think there is ANY way the D200 files could be noise-reduced and still maintain the same amount of fine detail and shadow detail as the Canon 5D can produce. Larger pixels, with a coarser pixel pitch are also LESS-demanding of lens optical performance than very small pixels are. Larger pixel sensors, like the full-frame sensor in the 5D, are also probably a bit more forgiving of diffraction than are small,tightly-packed sensors like the sensor in say, the Nikon D2x,so for those who want or need to shoot at smallish f/stops, the 5D is probably a pretty good choice as far as a higher-rez D-SLR option is concerned. Being forcefully limited to using small f/stops is a frequent fact of life in synchro-sunlight outdoor fill-flash type work. And by small f/stops I mean stops like f/11 to f/16.
The MOST obvious and probably the most important difference is the increased angular view of a full-frame Canon sensor as opposed to the narrow-angle 1.6x EOS 20D or the 1.5 (think closer to 1.55x or higher!) Nikon and FujiFilm D-SLR sensors. Full-frame versus APS-C sensor size arguments are many, but the fact remains that cropped-sensor cameras dramatically CHANGE the way the vast majority of 35mm lenses actually function.And the FACT is that the smallish, APS-C type sensors limit shallow depth of field photography options where one wants to really throw the backdrop well and truly out of focus with many of today's lenses. Let's face it--topday's TOP LENSES are typically lenses with a maximum aperture value of f/2.8. Or physically smaller, like f/4 for example. There is about a 1.5 f/stop depth of field penalty with crop-sensor cameras like a D2x or 20D whenever one wishes to LIMIT depth of field by using wider aperture settings.A lot of today's newbies are unaware of how radically the 1.5x to 1.6x FOV factor affects their photography,since many of them never shot 35mm film,and most of them have never shot 120 rollfilm or 4x5 sheet film.
In actual practice, getting shallow depth of field can be achieved by going to a lens with a very wide maximum aperture,such as going from an f/2.8 lens to an f/1.8 model and shooting wide-open or nearly wide-open, or by going to an f/2 lens or an f/1.4 lens,if and when such focal length lenses are possible to buy.Dramatically increasing focal length is another way to get shallow depth of field when using a crop-sensor camera. The fact is however, that the vast majority of TODAY'S Nikon lenses top out at f/2.8 on pro-grade lenses, and much,much smaller like f/4.5 to a dismal f/5.6 on many consumer-level zoom lenses. A 55-200mm consumer zoom that maxes out at f/5.6 at the long end is NOT a recipe for shallow depth of field looks,or for achieving really outstanding foreground/background separation and "Pop!".
The Nikon DX lens marketing campaign's idea of providing Nikon users with a small handful of Dx or cropped-sensor-optimized lenses has been far from adequate if what one wishes to do is to capture pictures with sharp foreground subjects and maximally blurred background renderings.The "smaller and lighter" line of BS about the DX lenses from Nikon is a hilarious no-show--the Dx zooms are large,and heavy. The tremendous impact of a 1.5x or a 1.55x or a 1.6x FOV narrowing cannot be underestimated in terms of its impact on how we now must use our lenses. The 1.5 to 1.6x sensor cameras forcefully impact the way each and every single lens "sees" the world; the 1.5-1.6x FOV narrowing changes the way prime lenses work, and especially the 200,300,and 400 prime lenses, and also the 35,50,and 85 and 105 and 135mm primes. Zoom lenses are not immune either, with the 70-200 2.8 lenses being nice and all, but also TOO LONG at the short end in many outdoor situations. Formerly extremely useful lenses like the 28-70 and 35-70 2.8 models have been made, well, a lot LESS useful for coverage in the sense of "angular field of view".
Speaking of "angular field of view" and lens lengths, I am now going to introduce a point here most modern shooters are
entirely,entirely unfamiliar with, and that is the discussion of "what IS 'normal', anyhow?"According to what I have learned over the past 30+ years,on full-frame 35mm ameras like the Leica and Contax rangefinders of the 1930's and later,the 28mm focal length is the TRUE "normal lens", while a 50mm lens is considered as functioning as a "short telephoto" lens. Re-read that if you need to. And let's not forget the huge field of view difference between a 28mm and a 35mm lens when capturing on 24mm x 36mm media. Going back to the olden days of 35mm photography, the 28mm was considered the TRUE "normal lens"--not the later idea that a "normal lens is roughly as long as the diagonal measurement of the film negative" concept. NO, under the earlier 35mm paradigm, the "normal lens" was considered to be a focal length which produced an approximation of the way normal human vision "sees" the world.
And so,again,to recap,if a 28mm lens is the true "normal lens" of 24x36 format, then the 50mm is actually a "short telephoto" lens, and a lens of 70 to 75mm is actually a "moderate telephoto" while the 135mm is a true "telephoto" lens. If you've shot enough 35mm film using the 28mm,35mm,and 50mm lens lengths, you know what a 28-70mm lens on full-frame means. On a 1.5x or 1.6x crop-sensor camera a 28-70mm lens is an entirely different animal.
Now, the most-important and the most difficult thing to get one's head around is the idea that a 28mm lens is the "normal" lens, the lens length that works much like human vision does, and that the 35mm length lens is more selective or narrower-angled than human vision, and that a 50mm lens is a lens length that actually functions as a short telephoto, and that a 75mm lens or an 85mm is actually a fairly long-ish and a decidedly telephoto lens length. At actual close-range shooting,that is at distances of under 20 feet or less, a 28mm is the NORMAL view lens, a 35mm lens is more-selective, and a 50mm lens is in fact a tele-angle of view lens which encompasses a very narrow angle of view.
Consider that in many situations the shooting distance is less than 20 feet, and so when a 50mm lens is mounted on the camera, the resulting pictures will be somewhat selective, and the pictures sure as HELL will not cover a "wide angle of view" in any sense of the word. If fact, as distances of 5 feet, a 50mm lens is a frickin' telephoto lens. A 50mm lens is _selective_ when shot at very short distances, such as under 10 feet. At a distance of 5 feet, you damned sure will be glad you have a 28mm lens on a 35mm-sized capture camera if you hope to convey a feeling of setting,or a feeling of "place"in the scenes you are capturing.
On 24x36mm capture media, a 35mm focal length lens encompasses an angle of view about one foot wide for each foot of camera-to-subject distance. IE, at 10 feet back, a 35mm lens has a left-to-right frame width of,roughly, 10 feet. SO, WHEN WE LOOK AT THE REAL WORLD and taking photographs using a 24x36mm capture camera, a 50mm lens offers the user a selective angle of view.
The idea of a "normal lens" being a 58 to 50mm lens may result from the focal lengths needed to provide 1:1 finder eye/off-eye vision on early 35mm SLR cameras. If one has a 35mm camera with a viewfinder image magification which allows the shooter to look through the camera and through his "off eye" with a feeling of 1:1 magnification through the camera's finder and through the "off-eye, the benefit is the ability( honable with practice) to look and to SEE through the camera with BOTH EYES OPEN ! Herbert Keppler did a column on this subject years ago,and as I recollect, it was the pairing of the 58mm Nikkor and the early Nikon F magnifcation which was 1:1 optimized only when a 58mm lens was mounted on the body. Later cameras had viewfinder magnification levels that were a smidge higher, and a 50mm lens became considered "normal". Perhaps the earliest optimization of a single lens length to a particular camera was with the Exaktas and their 58mm lenses,coupled with fairly LOW-magnifcation viewfinder systems, and the 50mm-as-Normal came later, well after Exakta's heydey and around the period when Nikon became THE preeminent 35mm SLR maker in the period of 1959 to 1962. Anyway, the notion of a lens length approximately the diagonal of the film format means the 35mm film format would need around a 43mm length for its normal lens. And so if that is true, then why would a 50mm lens be considered "normal"? In the sense of the angle of view used for normal,everyday scene photography, a 50mm lens is a selective-angle-of-view tool which is longer than the diagonal of the format by a noticeable margin; again, the concept of the 50mm lens as the "normal" lens length is a somewhat "new" concept in 35mm photography--the early masters of 35mm or "miniature camera" photography would tell you that their #1 lens was the 28mm lens.
You've simply GOT to understand that in the context of taking photographs at distances of under 20 feet on 24x36mm film, a 28mm lens does not capture an_especially_ wide angle of view,nor an especially selective angle of view, but ratheron full-frame 35mm a 28mm lens sees with an angle of view that can be said to be approximately what your brian THINKS your eye SEES. That is the best way I can describe how the 28mm lens functions of 24x36mm capture media. 28mm is NORMAL. To go wider-than-normal you go to the 24mm, and then to go wider still, you go to 20mm,and then you go to 17mm for TRUE wide-angle. That is my world view of 24x36mm photography.
Interestingly, leafing through a Canon full-system lens brouchure a couple years ago, I noticed that Canon includes its 50mm lenses in the "telephoto" category. Seriously. Now that many of us are shooting to 1.5x or 1.6x or crop-sensor D-SLR's, the idea that a 50mm lens is a telephoto lens makes sense. A 50mm on 1.5x or 1.6x has a nice,semi-selective angle of view at close shooting distances. A 50mm lens, like an AF 1.8 model makes a nice lens for portrait-range photos of people,and does great work at recording sports,news,or wedding scenes at indoor distances,either with or without electronic flash assistance. Focusing is usually quite good with a 50mm lens. Viewfinder magnification and focal length combine to usually make the viewfinder image through a 50mm a crisp,clear,bright,excellent experience with "most" 1.5x to 1.6x D-SLR camera bodies. In simple terms, on a crop-sensor D-SLR like a D70 or a 20D or an S3 or a D2x, a 50mm lens is,in many ways, a short,telephoto lens. Not a normal lens, but really, a narow-angle lens, a lens which constricts the picture's area quite a bit when shooting at 20 feet or closer. The closer one gets with a 50mm lens, the more-restricted is the area of the picture,and the shallower the DOF band at any given aperture. Set to a three-foot focusing distance and stopped down to f/8, a 50mm lens does not have overly deep depth of field,and the background will be rendered OUT-of focus, as a telephoto lens will do. The entire area of the in-focus image will be small.Ergo, a 50mm lens on 1.5-1.6x is a telephoto.
The good,and the bad, of these 1.5x sensor cameras comes when the reality of f/2.8 maximum aperture is paired with the smaller-than-35mm sensors. The shallowest depth of field always goes to the closest focusing distance, the widest aperture value,the longest focal length,and the largest film format size with "typical,real-world lenses". In comparing the shallow depth of field type of photography that many people like, the smaller-sensor cameras give inherently deeper (greater) depth of field. More distance appears to be in acceptably sharp focus as film format size goes down in relation to lens lengths. The inclusion of the full-frame Canon EOS 5D and the APS-C-sensored Nikon D200 in the title of this piece has apractical iumplication that many advanced amateurs and hobbyists can relate to. Namely, for many amateurs, their longest and their BEST lens is a 300mm f/4 telephoto. Using a 300mm f/4 telephoto lens wide-open ,backgrounds will appear to be MORE IN-FOCUS with the cropped-sensor camera than with a 24x36mm camera. In searching for the shallowest depth of field, with a 300mm f/4 lens, the larger-format capture device will show LESS depth of field than the smaller-format capture device.
When Kodak wanted to invent the perfect snapshot camera, their engineers realized that what they needed to do was to make the film format REALLY,REALLY small! And thus was born the Disc format, with absolutely TINY negatives, much smaller than even 110 format negatives! By approaching the problem from the back end, Kodak engineers realized that by making a camera that used a really,REALLY tiny negative, they could create an entire film format that brought with it almost INFINITE depth of field with a fixed-focus lens. The Disc format allowed you to shoot from about a foot away,to the moon, with no need to focus a lens. Ever! This is similar to the extensive DOF that small-senor consumer digicams have; using a teeny-tiny sensor makes consumer digicams exceptional, AMAZING macro-range tools; it is very easy to make macro-range photographs that are IMPOSSIBLE (literally,impossible) to make in single-shot capture mode with ANYTHING other than a small-sensor camera. Fact. If you do not understand why that is so, well, the answer is out there on the world wide web.
With crop-sensor D-SLR cameras using the 35mm lenses we all have, there's a sort of plus/minus that happens from the marriage of a new,smaller capture format with the lenses we've had for many years. When trying to throw backgrounds really out of focus, the 300mm f/4 lens can not really do that task all that well at longer,outdoor ranges of say, 100 to 150 feet. At typical outdoor sports ranges, a 300mm focal length lens set wide-open to f/4 will show a background that is still QUITE in-focus,and in many cases, quite distracting.Even at f/2.8 at outdoor ranges, a 200mm zoom set to 2.8 on a 1.5-1.6x camera will show a lot of the background in-focus enough that the background will be clearly rendered enough to draw a lot of emphasis away from a foreground subject that's at 150 feet. On crop-sensor cameras, deliberately out of focus backgrounds demand fairly long focal lengths, like 300 to 400mm, and wide apertures.Getting really wildly, totally "blown out" backgrounds on crop-sensor cameras is more difficult than on larger-capture cameras or on 35mm full-frame SLR cameras.
One of the most-distressing areas with the crop-sensor D-SLRs is that today's longer lenses are very slow,in terms of maximum aperture. Like the 50-500mm Sigma, with its pokey f/6.3 maximum aperture at 500mm. or the Nikkor 80400 VR,with its pokey f/5.6 maximum aperture. The consumer 70-300mm lenses from Nikon and Canon offer very slow, f/5.6 max apertures. Nikon makes a 400/2.8, but nothing else in 400mm except for what can be had with a zoom lens or a zoom+ teleconverter lashup.When shooting sports or natural-world scenes,under many situations very long focal length lenses and wide apertures are BOTH needed to create the shallow depth of field that brings with it the feeling of foreground/background "Pop!" or separation,especially at outdoor field sports distances,using the lenses that MOST of us own. if a person owns a 100-400 Canon or a 80-400 Nikon lens, his telephoto lens tops out at f/5.6 at 400mm. When using a smaller-format consumer digicams like a Nikon CoolPix or a Sony 828, the large aperture opening of f/4 brings with it very DEEP depth of field; like with the Disc format cameras, consumer digicams offer basically NO shallow depth of field options. Using a crop-frame D-SLR, a wide-angle lens set to f/8 provides nice,relatively deep depth of field, but NOT even CLOSE to as much will be in focus as when a small-sensored $500 Sony or Canon pocket digicam is used to focus at one foot. The smaller the sensor, the MORE is in focus at real-world f/stops. The larger the sensor, the less will be in focus with real-world lenses at real-world f/stops. With the consumer-speed lenses that are so plentiful today, shallow depth of field photography on crop-sensor digital SLR is very difficult to pull off many times.
At times, I actually kind of LIKE the increased depth of field that a DX-sized camera provides me. To me, having the DOF benefit of 1.5 stops on the DX-format cameras means I get that extra little bit of safety margin, that extra bit of foreground and background focus zone depth, which can cover for all sorts of screw-ups,both human and mechanical. I myself prefer to use longer lenses than many people do,and so to me, shrinking my sensor down means that, at f/4, I get MORE in focus. More room for error, more depth of field band to encompass people and their bodies, shoulders, heads, and so on. Oftentimes I enjoy the depth of field benefits of a crop-sensor camera.
But there are times when I would like to be able to create shallower depth of field images, images where the camera and lens combination offers me the LEAST in focus, at the real-world apertures most lenses offer me.Considering that I own a set of Nikon AF lenses, I really,really wish I had a full-frame Nikon F-mount camera available to me. A body that would use my established Nikon lens kit, in the same manner in which Nikon designed almost its entire lens lineup to be used. Where an 85mm is an 85mm lens. Where a 300mm offers pretty shallow DOF at the normal f/stops of f/4 and f/5.6. When trying for foregound/background isolation or "pop!", the fact of the matter is that in outdoor sports shooting,the vast majority of today's zoom lenses are so slow that depth of field at 200 and even 300mm is gonna be fairly DEEP. With the 70-300 Nikkor consumer lenses offering f/5.6 maximum up to 300mm in most lenses, long focal length photography with truly well blown out backgrounds demands a 300mm f/2.8 lens,or a LONGER lens than 300mm.Both which spell pain in the ass. If the depth of field advantage/disadvantage is 1.5 stops, consider that for shallow depth of field effects, a 300mm f/4 telephoto prime lens on a full-frame D-SLR will give you MORE "separation" than a 300mm f/2.8 lens will on a 1.5-1.6x camera.
Another big PITA is that 300mm lenses,typically the most-expensive lenses most people own, and some of the finest-quality lenses made, have angles of view on crop-sensor bodies that make them simply too damned narrow-angled for many shooting situations. And there really is NO OTHER LENS available to take the place of a 300mm lens. The 400mm lens has on 1.5-1.6x become a very,very narow angfle of view lens, so narrow-angle that it is very difficult to use in many situations.ANd,as with the 300mm prime lens length, the 400mm prime lens legnth has basically NO OTHER offering that comes close to what a 400 is or what it "does".While the DX-designed Nikkor zoom lenses like the 12-24 DX and the 17-55 DX are being made, there has ben basically NO MOVEMENT by Nikon to rectify the fucked-up mess that the 70-200 and 80-200 and 300 and 400 lengths have become under 1.55x. The wide-angle DX area has been conquered quite nicely by Nikon, and the 10.5mm fisheye's low price and surprisingly high optical quality and beauty of image are commendable. But in the telphoto end of the lens game, Nikon's really got its thumb up its ass. The failure is to design a NEW LENS that incorporates the idea of what a danged small-sensor camera brings; we need a NEW zoom lens with a FASTER-aperture than f/2.8, like f/2, and with a shorter bottom end than 70 or 80mm. A 40mm to 50mm short end, at f/2 or faster, and a top end of 250mm-300mm with an f/2.8 ,or FASTER, maximum aperture would be wonderful. Hell, even a 50-135mm f/2 AFS lens with AF-S focusing would be a godsend.
Nikon has NOT really addressed the problem of what their tele-length zoom lenses have,in effect, become when shooting to 1.55x sensors. The wide-to-tele zooms have become useless lenses under 1.55x sensor cameras. 28-70? What an albatross. The 17-55 is a substitute, but not REALLY anywhere near the same thing as 28-70 on full-frame.The 70-200,while nice and all on 1.55x, is still too LONG on the 70mm end when the action is close, and the depth of field at the 200mm setting is still noticeably deeper at the lens's optimal aperture than if it were used on a full-frame camera. The 85mm 1.4 lens suffers a lot on a crop-sensor camera, and its character "changes" quite a bit on the small-sensor cameras.
Let's face it...prime lenses and the way the actually "work" differs a great deal depending on whether a full-frame or a cropped-frame body is being used. Where we have to stand in relation to our subjects, how much apparent magnification our lenses give, and how shallow we can go on the depth of field,all these things change,markedly, when the camera and the lens follow the 35mm SLR-type model as closely as it was developed. Right now, only the wide-angle lens area of the cropped-frame issue has been acceptably solved. And, no matter what, there are always some physical/optical constraints which are applied to our photogreaphy based upon the size of our film format, and the available lenses. Full-frame 35mm-type cameras behave differently than cropped-frame models do, with the REAL lenses available to us,at the real-world f/stops we are forced to shoot at.
If you can grasp the idea of the 1930's and 40's that the 28mm lens is the TRUE "normal view" lens for a 24x36mm format camera, then you can understand why I am so torqued off with what the 35-70 and 28-70 Nikkor lenses have become under this Dx-only party line that Nikon has been pushing.And why I am so annoyed at Nikon's failures to really well and truly address the mid- to tele focal length zoom lenses for professional use. Nikon has some real "missing lengths" in its lens lineup. In situations where the 28-70 would be considered a no-brainer, a super-useful tool, on 1.5x that lens is now a PITA. Same with the 70-200, which is now frequrently on assignment found to be too long at
70mm, and ironically NOT long enough at 200mm to provide foregound/background separation at apertures like f/4.5 to 5.6. On the small-sensored cameras, one really needs 300mm of focal length to get a large degree of foregound/background out of focus relationship at apertures like f/5.6.
For many types of sports photography, subduing backgrounds that are 200-500 feet away on subjects which are 100-150 feet distant requires, absolutely, at the VERY least a 300mm focal length, or better yet a 400mm lens with a WIDE aperture.The problem with this is that there are damned few lens choices between 200 and 300mm and between 300mm and 400mm in length.The 300mm f/2.8 lens has had its actual utility dramatically cut back on 1.5x-1.6x sensor bodies. The 300 has become too narrow-angle for a prime lens on 1.55x. It's as simple as that. Nikon desperately needs a 100-300mm f/4 or f/3.5 or f/2.8 zoom lens,and it'd be a a HELL of a lot better if it were a 60mm-300 of the same range of maximum apertures. But,as I see it, Nikon will soon be offering some type of full frame offering which will once again, restore the superb Nikon prime lenses to their former utility in the field and in the studio.