March 12, 2012

Canon vs Nikon

Canon VERSUS Nikon
Canon vs. Nikon

The overwhelming majority of DSLR astrophotographers use Canon cameras and, to a lesser extent, Nikon cameras. This is not to say that other manufacturers don't make some DSLR cameras that might be useable for long-exposure deep-sky astrophotography, it's just that examples are hard to find, so it's difficult to know which cameras to recommend. Therefore, we will stick to Canon and Nikon cameras in this overview.

DSLR Development
Early first generation DSLR cameras where high noise. These cameras did not perform very well for long-exposure deep-sky astrophotography.
Second generation cameras were real breakthroughs in terms of noise. They had relatively large pixels with a good signal-to-noise ratio. This is when astrophotography with DSLR cameras really became popular.
Later cameras were more evolutionary than revolutionary. Pixels got smaller so more could be crammed onto the same size chips, but new technologies, such as microlenses, kept the signal-to-noise ratios pretty good. The later models of Canon cameras also do not suffer from amp glow, a red glow on the edges of the screen from the camera's electronics in long exposures. The latest models of Nikons have also improved amp glow.
The very latest generation of cameras, such as the Canon 50D, 40D 450D, 1D Mark III, and Nikon D3, D3X, and D300, are now adding live-view focus, dust reduction, and higher bit depths. Overall, for astrophotography, purely in terms of signal-to-noise ratios, the latest cameras are not much better than second generation cameras, and in fact may be just a little bit worse because of the smaller pixels. Nikon's D3 and Canon's 1D Mark III are an exception to this because they have larger pixels and produce excellent signal-to-noise ratios, but these are very expensive cameras.
For a long while, Canon was pretty far ahead of Nikon in terms of digital camera noise and high ISO performance. Camera noise is one of the most critical considerations in terms of quality for long-exposures for deep-sky astrophotography. Using the latest generations of Sony sensors, Nikon seems to have caught up to Canon, but for the most part, Canon cameras still have lower read noise than Nikons.

Today's Cameras
For casual astrophotography with stock cameras, as well as normal daytime photography, both Canon and Nikon offer some excellent cameras that are also very reasonably priced.
For serious astrophotographers who intend to try to extract the maximum amount of data out of their cameras, Canon today offers cameras that are easier to use and that produce true raw data for image calibration.
If you already have a Nikon system and Nikon lenses, then you will probably want to go with a Nikon DSLR for astrophotography. If you don't have a lot of money already invested in Nikon, then I would recommend going with Canon.
Here is a timeline of camera models from Canon and Nikon and the dates of their release:

Canon EOS DSLR Cameras (Date Announced)

  • 550D (Digital Rebel T2i) (Feb 2010)
  • 1D Mark IV (Oct 2009)
  • 7D (Sept 2009)
  • 500D (Digital Rebel T1i) (March 2009)
  • 5D Mark II (Sept 2008)
  • 50D (Aug 2008)
  • 1000D (Digital Rebel XS) (June 2008)
  • 450D (Digital Rebel XSi) (Jan 2008)
  • 40D (Aug 2007)
  • 1Ds Mark III (Aug 2007)
  • 1D Mark III (Feb 2007)
  • 400D (Digital Rebel XTi) (Aug 2006)
  • 30D (Feb 2006)
  • 5D (Aug 2005)
  • 1D Mark II N (Aug 2005)
  • 20Da (June 2005)
  • 350D (Digital Rebel XT) (Feb 2005)
  • 1Ds Mark II (Sept 2004)
  • 20D (Aug 2004)
  • 1D Mark II (Jan 2004)
  • 300D (Digital Rebel) (Aug 2003)
  • 10D (Feb 2003)
  • 1Ds (Sept 2002)
  • D60 (Feb 2002)
  • 1D (Sept 2001)
  • D30 (May 2000)
Canon's professional series is designated by the single digit nomenclature, e.g. "1D".
Canon's prosumer series is designated by double digit nomenclature, e.g. "40D".
Canon's entry-level series is designated by triple digit nomenclature, e.g. "450D".
The 1000D is a new entry-level model.
The 550D is the entry-level version of the prosumer 7D model.
The 500D is the entry-level version of the prosumer 50D model.
The 450D is the entry-level version of the prosumer 40D model.
The 400D is the entry-level version of the prosumer 30D model.
The 350D is the entry-level version of the prosumer 20D model.
The 300D is the entry-level version of the prosumer 10D model.

Nikon DSLR Cameras (Date Announced)

  • D3S (Oct 2009)
  • D300s (July 2009)
  • D3000 (July 2009)
  • D5000 (April 2009)
  • D3X (Dec 2008)
  • D90 (Aug 2008)
  • D700 (July 2008)
  • D60 (Jan 2008)
  • D300 (Aug 2007)
  • D3 (Aug 2007)
  • D40x (March 2007)
  • D40 (Nov 2006)
  • D80 (Aug 2006)
  • D2Xs (June 2006)
  • D200 (Nov 2005)
  • D50 (April 2005)
  • D70s (April 2005)
  • D2Hs (Feb 2005)
  • D2X (Sept 2004)
  • D70 (Jan 2004)
  • D2H (July 2003)
  • D100 (Feb 2002)
  • D1H (Feb 2001)
  • D1X (Feb 2001)
  • D1 (July 1999)
Nikon's professional series is designated by the single digit nomenclature, e.g. "D3".
Nikon's prosumer series is designated by triple digit nomenclature, e.g. "D300".
Nikon's entry-level series is designated by double digit nomenclature, e.g. "D60".

Camera Comparison Chart
Here is a camera comparison chart that lists the following camera features and specifications that are of interest to astrophotographers for every D series DSLR camera produced by Canon and Nikon:
  • Camera Model
  • Pixel Pitch
  • Pixel Array
  • Sensor Size in millimeters
  • Number of pixels
  • Bit Depth
  • Crop Factor
  • Sensor Type
  • Memory Card Type
  • Dust Reduction
  • Live View
  • Computer Connection
  • Announced
  • Availability
  • Price

Considerations for Long-Exposure Deep-Sky Astrophotography
Listed below are some things to consider when choosing between a Nikon and Canon DSLR camera for long-exposure deep-sky astrophotography. The list is not meant to be exhaustive as things change very rapidly in the world of DSLRs.

  1. Canon recognizes that astrophotography is a specific use of their cameras and has produced the Canon 20Da, a camera that is specifically designed for astrophotography. Although this model has been discontinued, it can still be found used.
  2. Canon provides excellent documentation on their equipment, such as detailed technical documents like the EOS 400D white paperEOS 1D Mark III white paperEOS 350D white paper, and this white paper on full-frame Canon CMOS sensors.
  3. More support for Canon cameras is available from third party software vendors, such as Images Plus and Nebulosity. Although these vendors are beginning to implement more extensive support for Nikon DSLRs, Canons are usually supported first because so many more people are using Canons for astrophotography.
  4. Canon EOS Digital SLR cameras can only use EF auto-focus lenses. When Canon designed their EOS system, they completely redesigned the lens mount. Canon's previous FD lens system for film SLR manual focus cameras are not made for EOS bodies. The lens flange to focal plane distance for the FD series is 42mm. The lens flange to focal plane distance on the EOS series is 44mm.You can get a simple mechanical adapter that will mount FD lenses on EOS bodies, but they will not focus at infinity. You can also get a more complex optical adapter that has lens elements that will allow focusing of FD lenses at infinity on EOS bodies, but the Canon version is no longer manufactured and is difficult to find and very expensive when available. The Canon optical adapter also had a 1.26x multiplier factor which made the focal length of the lenses longer and also slower by that factor. As with the use of any multiplier or converter, optical quality also suffered somewhat. Third party manufacturers also make optical converters, but their optical quality is very poor.
  5. Because of the shorter lens flange to focal plane distance on Canon EOS bodies, other manufacturer's lenses (indeed, such as Nikon) can be used on Canon DSLR bodies with inexpensive adapters, such as this one from Fotodiox for $28. Note that the lenses must be used in stop-down metering mode and auto-focus doesn't work, but these are not a necessity for astrophotography anyway. Many other brands of lenses can be used with Fotodiox adapters on Canon DSLR cameras.
  6. Canon has a plug on the camera body for a hard-wired remote shutter release to allow use of the TC-80N3, a very handy and useful timer remote control.Out of the box, this timer remote control has a proprietary Canon N3 plug on the end of the cord that will only fit the high end Canon EOS DSLR cameras such as the 1D series and the 40D, 30D, 20D. However, it can very easily be adapted to work with the Canon EOS consumer DSLR cameras such as the 300D, 350D and 400D. All you have to do is cut the plug off and replace it with a mini stereo plug. It is just three wires involved and is simple to do.
    While the Canon TC-80N3 remote is expensive at $130, it allows you to completely automate the image acquisition portion of an astrophotography session because it is also an intervalometer which allows shooting numerous frames at a particular exposure with a pre-determined amount of time between exposures.
    Much less expensive Chinese clones of remote release interval timers are also becoming available. Go to Ebay and search for "Aputure Timer Remote" or "Timer Remote Control" by DSLRBaby.
  7. The latest generation of Canon cameras, such as the 50D,40D, 500D, 450D, 5D Mark II 1D Mark III can be controlled through a single USB cable. Even long bulb exposures (exposures longer than 30 seconds) can be controlled with this single cable.


  1. Because of the relatively long flange-to-focal-plane distance on the Nikon cameras, few lenses from other manufacturers can be used because they will not reach infinity focus with an adapter.
  2. You must use an infrared remote with some of the Nikon cameras such as the D40x, D40, D50 and D70. They do not have a plug for a hard-wired remote shutter release at all. This can be quite inconvenient. The Nikon infra-red, while inexpensive at $17, only has one button that triggers the shutter on the camera once, and must be used from in front of the camera where the IR sensor is located.The latest Nikon Digital cameras, such as the D300, D3, D80 and D200 do have a hard-wired release plug. Nikon offers the MC-36 Multi-Function Remote for $130 with the proprietary Nikon plug for the high-end Nikon cameras such as the D300, D3, D100, D200 D1 and D2 series. It is very similar to the Canon TC-80N3.
    There are much less expensive Chinese clones of the Nikon MC-36 also available. Go to Ebay and search for "Aputure Timer Remote" or DSLRBaby "Remote Timer Control".
  3. If you already have a significant investment in Nikon Lenses you can save money by going with a Nikon DSLR and not having to replace all of your lenses. Many photographers have been loyal Nikon users for years. For these photographers, sticking with Nikon may save them a lot of money if they would have to replace an extensive collection of lenses. Just about every Nikon F series lens ever made will work on the latest DSLR bodies (with a couple of exceptions). Unlike Canon, Nikon did not change their lens mount when they went to autofocus lenses. Not all functions, such as autofocus will work on all of the Nikon DSLR bodies however.
  4. Some Nikon entry-level cameras, such as the D60, D40 and D40x, will only autofocus with AF-S and AF-I Nikkor lenses. These cameras do not have an autofocus motor built into the camera body. They require an autofocus motor in the lens. Other lenses can be used on these bodies, but you will have to focus manually. This is not really a problem if you are shooting through a telescope however.
  5. Nikons must use an inconvenient "mode 3" work around to acquire true raw files from the Nikon DLSR cameras, documented on Christian Buil's web page. This appears to be true even for Nikon's latest top-of-the-line D3 camera as documented here.Nikon apparently applies a mathematical median blurring filter to their images (in addition to the low-pass filter in front of the sensor) after the in-camera dark frame subtraction for built in noise-reduction. This occurs even before the raw image is written to the file. To work around this and get a true raw file, it is necessary to physically turn the camera off during the in-camera dark frame acquisition. This is called the "mode-3" workaround. This work-around will make it difficult to automate the acquisition of multiple light frames which is the usual method of imaging with a DSLR for a dim astrophoto subject. Or, you can just live with this extra blurring from the median filter.
  6. Nikon is also apparently truncating low-level signal during the digital-to-analog conversion performed by the electronics. See Christian Buil's Nikon D3 analysis. Emil Martinec reports that Nikon is doing the same thing to the D300. This is probably not really be a serious concern since most of this low level signal may be noise.
  7. Nikon raw NEF files are not truly lossless in the Nikon D70. See Christian Buil's D70 vs 10D comparison page and also the discussion on Fazal Majid's weblog. Again, this is probably not a serious problem since the compression scheme seems to be very efficiently applied. Newer models offer user selectable options for lossy compressed, lossless compressed, and uncompressed raw NEF files.
  8. Nikon's latest generation of cameras, such as the D3 and D300 can also be controlled with a single USB2 cable. However, Nikon software will still not allow bulb exposures (exposures longer than 30 seconds). A separate bulb cable with a proprietary Nikon plug must be used in addition to the USB2 cable to automate an astrophotography imaging session.

Honestly, today's camera models from both Nikon and Canon are very low-noise, the most important thing for long-exposure deep-sky astrophotography. If you get a camera model with Live View, you won't go wrong.
Nowadays, the quality of images produces with current generation DSLR models is more dependant on the skill of the astrophotographer than on the camera.

Astrophotography Examples - Canon DSLR Cameras

Astrophotography Examples - Nikon DSLR Cameras

Red Sensitivity and Long-wavelength Filters
Normally the CMOS and CCD chips used in DSLR cameras are sensitive to red light. Most DSLRs however, are designed with a built-in, low-pass, long-wavelength cutoff filter in front of the sensor. The low-pass characteristics of the filter are designed to prevent moire. The long-wavelength filtration is designed to improve color reproduction and make it more like our human visual perception.
The problem is that the long-wavelength filtration also filters out most of the light at 656.5nm, the wavelength of hydrogen-alpha. This is the red light of emission nebulae. Filtering out most of this light is a problem for astrophotography if you want to take pictures of these red nebulae, which are some of the largest and most beautiful objects in the night sky.
Canon was the only manufacturer to make a DSLR camera body specifically for astrophotography with improved hydrogen-alpha sensitivity, the EOS 20Da. Canon however, has discontinued production of this camera as of the spring of 2006.
It is possible to modify other DSLR cameras for astrophotography of emission nebulae by removing the low-pass, long-wavelength filter. This, of course, invalidates the warranty and runs the risk of ruining the camera if not done correctly. However astrophotographers have successfully removed the filters in both Nikon and Canon cameras and produced excellent images of objects with emission wavelengths. Gary Honis provides instructions if you want to do it yourself.
Additionally, third-party vendors such as Gary Honis and Hap Griffin offer modified cameras with these filters removed and various replacement filter options.
* WARNING: Modifying your camera VOIDS the manufacturer's warranty. Any modifications are undertaken at your own rise and the author is not responsible for any damages that may be incurred.

Canon Rebel T1i vs Nikon D5000: Entry-Level DSLR Battlemodo

Nikon and Canon—eternally locked in battle—do each other good by keeping product quality neck and neck. But in the newest entry-level DSLR shootout, if there has to be a winner, it's Canon's Rebel T1i.
I'm not trying to be all namby pamby, like "Oh, you're each so special in your own ways, it's so hard to choose!" but I can't stress enough how solid both the Nikon D5000 and the Canon Rebel T1i are. For the price—$850 for the D5000, $900 for the T1i, both including beginner-level 18-55mm lenses—either one will work fine, whether you're a beginner looking to learn about photography, or a veteran with investment in a few lenses but not enough cash for a step-up Nikon D90 or D700, or a Canon 5D Mark II. (I highlighted their spec differenceshere.)
In fact, the differences between the D5000 and the T1i tend to be more about button layout and interface design than picture-taking ability. If you basically know what you're doing, you can take essentially the same picture with either camera, except in certain situations mentioned below.

Like I said, there are differences in interface. Unlike fancier DSLRs, both have single dials on the right-hand side, and both have just one large full-color LCD screen for managing settings, setting up shots and reviewing them later. The Canon's is a little bigger with a lot more resolution, which makes a big benefit when you're shooting video or focusing in Live View, but is otherwise irrelevant.
In interface design, however, the better design goes to Nikon. As you can see below, the organization of information on the screen is much more palatable and less arbitrary. Nikon users who are used to having the second LCD screen up top for basic info—plus specialized buttons—can quickly learn a new behavior, getting all information on the big LCD, using the "i" info button for making most quick setting tweaks.
The Canon interface is similar to previous Rebels, and is pretty durn fugly, and the extra buttons only help in some cases where they are clearly labeled. (And even when the buttons are clearly labeled, there are some hidden functions—hitting the ISO button while shooting video will lock the auto exposure, for instance.)
Automatic Modes

I tested each camera both in full-manual mode and on some of the automatic modes. I've heard from a lot of uppity photographers who don't like people discussing auto shooting, perhaps as a way of trumpeting their own apparently stellar knowledge of the workings of photography. But it's important to remember that these sub-$1000 cameras are aimed at untrained entry-level shooters, and many of those people tell me that they almost always leave it in auto.
In this case, Nikon has six auto modes, plus a SCENE setting with like 14 different options, in each case including a photo. The Canon is shy on this point, with just five presets. The scene modes are helpful to newbies who can't translate what they see into camera settings. Still, anyone who buys a camera like this should do so with the intent to learn manual settings, and may benefit more from just taking 100 shots in each setting, like I do, changing settings all along.
What I did find is that even in semi-automatic modes, the Canon and Nikon were more different than better. For instance, when I set the White Balance on Cloudy, both got the white more or less right, but the Canon tended to look more pink, while the Nikon was more green, as you can see:
Canon Rebel T1i vs Nikon D5000: Entry-Level DSLR Battlemodo
ISO Noise

Everybody bitches about how more megapixels don't matter and that optics determine picture quality more than anything, and they're right. But sensors still matter, especially when shooting in low light—which you do by jacking up the ISO. As you can see below, while both cameras handle relatively noise-free shooting at ISO 800, they both start to get noisy by 1600, and at 3200 they are both noisier still. But the Canon is less noisy in this case.
Canon Rebel T1i vs Nikon D5000: Entry-Level DSLR Battlemodo
It stands to point out that I shot this with both cameras on the default "normal" aka "basic" noise-reduction settings. Both cameras let you jack up noise reduction more, or take it off entirely, but in each case, you probably have to consult the manual to learn how, hence me testing on the default settings.
Live View

Live View was last year's ace in the hole, something first championed by Sony and Olympus, which Canon then took and ran with, followed, only recently, by Nikon. Now everybody's got it, and it's okay, but it's not great, and it's certainly not the preferred shooting mode for either of these cameras.
The problem is, when you have a live picture on your LCD, the typical auto-focus mechanism doesn't work, because the mirror inside the camera is lifted up, exposing the optical sensor.
Canon and Nikon have different ways of handling this. Canon says "screw it" and drops the mirror for a split second, letting the camera use its normal AF sensor and getting a nice tight focus.
The Nikon, from what I've seen in my testing, can't do this. Instead it uses secondary auto-focus techniques that are annoyingly slow. The fact that the Nikon has a flip-out "vari-angle" LCD to make Live View more useful is actually silly—by having to wait for the damn thing to autofocus, and by not guaranteeing as good an autofocus, you lose any advantage you'd have by watching this happening in the LCD. I think the mirror-drop technique used by Canon and the vari-angle LCD would be a good combination, however, and my guess is, Nikon is exploring this even now.

This year's killer upgrade is video, specifically, high-definition video. The Nikon D5000 has 720p at 24 frames per second; Canon's T1i shoots 1080p at up to 20fps. The question is, will you use it?
I said it before and I'll say it again: Shooting higher-res video with larger sensors and big honkin' lenses is awesome. They wide-aspect shots have a cinematic quality, and make better use of light in the room for a more natural feel.
BUT—yes, big ole "but"—the fact that autofocus is pretty borked when you're shooting videos means you get naturally lit cinematically scoped blurry videos, unless you and your subject remain perfectly still.
Like with standard Live View, Nikon and Canon take different approaches. Nikon says "no AF during shooting whatsoever," meaning you focus first, then hit record, then, if you have to, start manually refocusing as your toddler, cat or ginormous model rocket starts to make its move. Having lived with the D90 for a while, I want to say I got good at manually focusing, but I did not.
As is the case with Canon's 5D Mark II, the T1i does let you autofocus during shooting, but it's not the nice instant refocus you get while shooting stills. It's the wiggy servo-noisy zoom-zoom-zoom-zoom kind of contrast-based AF that takes too long. So while you're shooting, you not only see the auto re-focusing in action, but you hear it too.
While Canon's noisy AF is by far the better option of the two for shooting videos, Canon does something in the T1i that might piss off serious photographers: It disables shutter, aperture and ISO controls for video shooting. It's full auto, unlike the Nikon D5000, which, like the D90, gives you a certain degree of camera control while shooting video. While the Nikon lets you choose your ISO for instance, the Canon actually varies ISO settings along with auto exposure every time your video's lighting changes dramatically. I personally don't miss it—and in my experience, Canon does a slightly better job of getting automatic settings like WB right, and is a more trustworthy camcorder maker in general—but you might miss the control.
One overlooked benefit to the Canon is that you can take still shots while shooting video, without interrupting the video itself. You just get a momentary freezeframe, and the recording continues. On the Nikon, when you shoot video, you can take a still pic, but the video recording stops when you do.
In the End

So, why did I pick the Canon by a nose? Mainly the video and the better Live View focus technique, as well as the slightly better high-ISO performance. When I chatted with NYT's David Pogue about his rave review of Panasonic's Lumix GH1—a far better camcorder than either of these because of its quiet lens and full-fledged autofocus—he told me that this kind of half-baked AF makes the video on these cameras a mere "parlor stunt." I reprint his comment because I agree with him for the most part.
Still, as someone who enjoyed the Nikon D90 video mode, half-baked as it is, I look forward to extended testing of the T1i, shooting video whenever I can. Because in the YouTube era, we're not looking to go remake Dr. Zhivago. I for one just want something to record a quick vid of my kid doing something hilarious (which her mom won't let me post on Giz). What I find is that the best video camera is the one built into the still camera I already use. And that's why, parlor stunt or not, DSLR video is going to be important from here on out. Here's hoping both Nikon and Canon keep working to make them better.

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