Digital Photography from 20,000 Feet
by Wesley Fink on September 25, 2006 12:05 AM EST- Posted in
- Digital Camera
Digital Challenges: What Needs to be Improved
Despite the huge leaps in digital technology in the past few years, there are still a few issues remaining. Most of the sensor makers and camera/lens manufacturers are working on these issues. You should keep them in mind when looking at digital SLRs, because they are the areas where development is needed.
Dynamic Range
Compared to film SLRs, digital SLRs still cannot match the dynamic range of film. Dynamic range is the difference between the brightest highlights and darkest shadow detail in an image. Most manufacturers are working very hard to provide improved dynamic range, but there is no consensus yet on what works or will work best to fix this problem. Solutions vary from the extra set of pixels designed just to capture highlight detail in the Fuji S3 PRO (for Nikon lenses), to the Bionz image processor in the new Sony A100 electronics, and the D-Lighting feature in the new Nikon D80 that can be used to improve shadow or highlight detail.
Most users are not really aware of this issue, and sensor and camera makers are not making a big deal about it unless they have a feature that improves this weakness. However, if you examine a high contrast image from film next to the digital image you will see highlights blowing out on the digital image and less shadow detail in the digital image. Digital has improved greatly in this area, and will no doubt continue to improve, but the dynamic range difference is still about 1.5 to 3 stops better with film than digital.
In shopping for a digital SLR you might pay attention to those that claim to address this issues and what they have done.
Dirt on the Sensor
One of the early problems identified by users of digital SLRs with interchangeable lenses was that the sensor could easily get dirty in the process of changing lenses. Unlike film cameras, where this issue went away with a film change, a dirty sensor will make all future photographs spotted with specks. This issue is particularly troublesome in digital cameras, because the sensor coatings are very delicate and the SLR needs to be returned to the manufacturer for cleaning dust from the sensor.
Most manufacturers have software tools to minimize this problem, mathematically "removing the spot and filling in with calculated pixels", but the first manufacturer to address it on the prevention end was Olympus with their wave filter. They provided a protective coating on the sensor and also used ultrasonic vibrations to clean the sensor on start-up to remove any dust that may have gotten through.
Sony also introduced a protective coating and start-up vibration feature to protect from and remove dust on their new 10.2 megapixel A100. Pentax and Samsung have apparently licensed the Sony system, as they have announced similar mechanisms on their new 10.2 Sony-sensor cameras. Even Canon, who denied for quite a while that there was a dust problem, is now providing the "EOS Integrated Cleaning System" on their new 10 megapixel Rebel XTi. The XTi uses special antistatic sensor coatings and an ultrasonic cleaner much like Olympus.
Auto White Balance
White Balance was not really discussed in this introductory guide, but digital cameras, unlike film, allow the user to set the color temperature or color balance of the sensor. With film you had to choose daylight (or flash), tungsten, Fluorescent, and other color balances when you selected film. In digital imaging you select the "color temperature" when you shoot. You can also leave the color temperature on Auto and let the camera choose - or be really fancy and measure color temperature (most SLRs have this capability) and set a Custom temperature.
Most users leave it on Auto, but we have yet to see a digital SLR that does a decent job with common indoor lamps and lights (tungsten) on the Auto setting. Almost all Auto settings seem to leave an orange cast in the images shot under indoor light. This can normally be corrected in images shot in RAW and some images shot as JPEG, but the easiest solution by far would be an Auto setting that really works. The best solution today is to move off the Auto White Balance setting to Tungsten (Indoor Light) when shooting indoors. Today's cameras do generally apply the correct temperature when the tungsten white balance is selected. Until this is fixed in the majority of Digital SLR cameras we plan to test the Auto setting under indoor lighting in our reviews.
Lens Confusion
This guide should help with confusion about lenses and lens factors, but the problem won't go away until camera and lens makers decide on a standard. Right now digital SLRs are still basically fed with 35mm lenses, even though the sensors are APS C and DX size and have a smaller image circle. It appeared for a while that the industry would settle on this APS C/DX size and eventually name lenses by their equivalent APS C/DX focal lengths once 35mm faded away. Now the outcome is less clear. Some now predict the SLR market will move to two tiers, with APS C/DX SLR cameras as mainstream and full-frame 35mm-size sensors at the Pro end. This certainly would maximize the existing 35mm lens line of the big camera manufacturers and still provide an upgrade path for advanced amateurs. This is the path that Canon appears to be following, but Nikon is still committed to the pro APS C/DX sensor size.
If you look closely at the new lenses Sony introduced you will see even more confusion. Sony does not make 35mm film SLR cameras, so there is no reason for them to introduce new lenses designed for 35mm just for the current Minolta film owners. Yet 2 of the 3 new Sony Carl Zeiss lenses are designed for a 35mm image circle. This leads observers to believe that Sony, one of the largest sensor manufacturers in the world, may be hedging their bets on a full-size 35mm sensor Sony SLR. It is also interesting that the major camera makers that have extensive lens lines seem to have slowed their introduction of lenses designed for APS C/DX sensor size. There is no crystal ball, but it will be interesting to see where the digital SLR industry goes in the near future.
The lens confusion and format confusion is likely to continue for a while, since none of the manufacturers except Olympus, with their all-new digital 4/3 system, have truly committed to a new sensor size. If Sony or Nikon introduce a new Pro full-size 35mm sensor in the near future, you can expect the industry to segment as Canon has now done with their 35mm sensor Pro EOS 1D Mark II and EOS 5D versus the rest of the Canon line whish uses an APS C sensor with a 1.6 lens factor.
Gaps in the Lens Lines
Perhaps because of the lens confusion, there are still gaping holes in the lens lines of the APS C/DX format digital SLR cameras. Due to the 1.5/1.6 lens factors the 35mm wide angles are pretty useless on a digital SLR. There is still a need for additional wide angle lenses that are wide angle on APS C/DX. The Sigma 10-20mm and Tamron 11-18mm help, but pickings form the majors are very slim. So are DT size lenses from the majors that address the need for fast fixed-focal-length wide-angles and fast normal lenses. Pentax recently introduced 21mm f3.2 and 40mm f2.8 pancake (flat) lenses for their digital line. Samsung recently announced they would introduce a 35mm F2.0 lens for their digital cameras. These three lenses will bring new options to digital photographers shooting with the Pentax KA mount.
Despite the huge leaps in digital technology in the past few years, there are still a few issues remaining. Most of the sensor makers and camera/lens manufacturers are working on these issues. You should keep them in mind when looking at digital SLRs, because they are the areas where development is needed.
Dynamic Range
Compared to film SLRs, digital SLRs still cannot match the dynamic range of film. Dynamic range is the difference between the brightest highlights and darkest shadow detail in an image. Most manufacturers are working very hard to provide improved dynamic range, but there is no consensus yet on what works or will work best to fix this problem. Solutions vary from the extra set of pixels designed just to capture highlight detail in the Fuji S3 PRO (for Nikon lenses), to the Bionz image processor in the new Sony A100 electronics, and the D-Lighting feature in the new Nikon D80 that can be used to improve shadow or highlight detail.
Most users are not really aware of this issue, and sensor and camera makers are not making a big deal about it unless they have a feature that improves this weakness. However, if you examine a high contrast image from film next to the digital image you will see highlights blowing out on the digital image and less shadow detail in the digital image. Digital has improved greatly in this area, and will no doubt continue to improve, but the dynamic range difference is still about 1.5 to 3 stops better with film than digital.
In shopping for a digital SLR you might pay attention to those that claim to address this issues and what they have done.
Dirt on the Sensor
One of the early problems identified by users of digital SLRs with interchangeable lenses was that the sensor could easily get dirty in the process of changing lenses. Unlike film cameras, where this issue went away with a film change, a dirty sensor will make all future photographs spotted with specks. This issue is particularly troublesome in digital cameras, because the sensor coatings are very delicate and the SLR needs to be returned to the manufacturer for cleaning dust from the sensor.
Most manufacturers have software tools to minimize this problem, mathematically "removing the spot and filling in with calculated pixels", but the first manufacturer to address it on the prevention end was Olympus with their wave filter. They provided a protective coating on the sensor and also used ultrasonic vibrations to clean the sensor on start-up to remove any dust that may have gotten through.
Sony also introduced a protective coating and start-up vibration feature to protect from and remove dust on their new 10.2 megapixel A100. Pentax and Samsung have apparently licensed the Sony system, as they have announced similar mechanisms on their new 10.2 Sony-sensor cameras. Even Canon, who denied for quite a while that there was a dust problem, is now providing the "EOS Integrated Cleaning System" on their new 10 megapixel Rebel XTi. The XTi uses special antistatic sensor coatings and an ultrasonic cleaner much like Olympus.
Auto White Balance
White Balance was not really discussed in this introductory guide, but digital cameras, unlike film, allow the user to set the color temperature or color balance of the sensor. With film you had to choose daylight (or flash), tungsten, Fluorescent, and other color balances when you selected film. In digital imaging you select the "color temperature" when you shoot. You can also leave the color temperature on Auto and let the camera choose - or be really fancy and measure color temperature (most SLRs have this capability) and set a Custom temperature.
Most users leave it on Auto, but we have yet to see a digital SLR that does a decent job with common indoor lamps and lights (tungsten) on the Auto setting. Almost all Auto settings seem to leave an orange cast in the images shot under indoor light. This can normally be corrected in images shot in RAW and some images shot as JPEG, but the easiest solution by far would be an Auto setting that really works. The best solution today is to move off the Auto White Balance setting to Tungsten (Indoor Light) when shooting indoors. Today's cameras do generally apply the correct temperature when the tungsten white balance is selected. Until this is fixed in the majority of Digital SLR cameras we plan to test the Auto setting under indoor lighting in our reviews.
Lens Confusion
This guide should help with confusion about lenses and lens factors, but the problem won't go away until camera and lens makers decide on a standard. Right now digital SLRs are still basically fed with 35mm lenses, even though the sensors are APS C and DX size and have a smaller image circle. It appeared for a while that the industry would settle on this APS C/DX size and eventually name lenses by their equivalent APS C/DX focal lengths once 35mm faded away. Now the outcome is less clear. Some now predict the SLR market will move to two tiers, with APS C/DX SLR cameras as mainstream and full-frame 35mm-size sensors at the Pro end. This certainly would maximize the existing 35mm lens line of the big camera manufacturers and still provide an upgrade path for advanced amateurs. This is the path that Canon appears to be following, but Nikon is still committed to the pro APS C/DX sensor size.
If you look closely at the new lenses Sony introduced you will see even more confusion. Sony does not make 35mm film SLR cameras, so there is no reason for them to introduce new lenses designed for 35mm just for the current Minolta film owners. Yet 2 of the 3 new Sony Carl Zeiss lenses are designed for a 35mm image circle. This leads observers to believe that Sony, one of the largest sensor manufacturers in the world, may be hedging their bets on a full-size 35mm sensor Sony SLR. It is also interesting that the major camera makers that have extensive lens lines seem to have slowed their introduction of lenses designed for APS C/DX sensor size. There is no crystal ball, but it will be interesting to see where the digital SLR industry goes in the near future.
The lens confusion and format confusion is likely to continue for a while, since none of the manufacturers except Olympus, with their all-new digital 4/3 system, have truly committed to a new sensor size. If Sony or Nikon introduce a new Pro full-size 35mm sensor in the near future, you can expect the industry to segment as Canon has now done with their 35mm sensor Pro EOS 1D Mark II and EOS 5D versus the rest of the Canon line whish uses an APS C sensor with a 1.6 lens factor.
Gaps in the Lens Lines
Perhaps because of the lens confusion, there are still gaping holes in the lens lines of the APS C/DX format digital SLR cameras. Due to the 1.5/1.6 lens factors the 35mm wide angles are pretty useless on a digital SLR. There is still a need for additional wide angle lenses that are wide angle on APS C/DX. The Sigma 10-20mm and Tamron 11-18mm help, but pickings form the majors are very slim. So are DT size lenses from the majors that address the need for fast fixed-focal-length wide-angles and fast normal lenses. Pentax recently introduced 21mm f3.2 and 40mm f2.8 pancake (flat) lenses for their digital line. Samsung recently announced they would introduce a 35mm F2.0 lens for their digital cameras. These three lenses will bring new options to digital photographers shooting with the Pentax KA mount.
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squiddy - Thursday, February 15, 2007 - link
I'm fairly versed in film and digital SLRs and have been shooting since the mid-80s. Nikon afficionado here but I did have a few Canon EOS film bodies back in the day. Currently use a D70s and soon hopefully a D200 in my bag.Anyway, as to sugestions for future reviews, the technical aspect tests are all well and good since numbers are always easy to quantify. The MP count, max resolution, test charts and etc do help people choose cameras after all. What I'd like to see more of are subjective reviews. How user-friendly is the camera? Are the menu's easy to navigate and the features easy to get to? How are the ergonomics and will my hand require a chiropractor after a long day of shooting? Is the camera balanced even when using a medium telephoto lens? How about accessories (flash kits, filters, battery grips, flash brackets, etc), are they useful for this camera or just gravy?
What made me write these additional questions is that I experienced it when I borrowed a Canon 350d for a friend's wedding. This was before my Nikon D70s and I absolutely loved/hated it. The pictures were great but required heavy menu navigation for white balance and iso settings. The camera was lighter than my old film Nikon so it wasn't tiring to carry all the time but the grip was awful. My pinky was sticking out under the body and a;; the weight was focused on the upper/rear quarter of my right palm. I'll tell you now, it hurts to use it for a long time. Especially with a 430ex flash. I then tried a friend's D50 and a D70 after that and it solidified my Nikon preference. Great ergonomics and the two dials give you much greater flexibility on the fly.
These reviews are probably aspects that the average consumer won't consider before purchasing and just focus on numbers but it greatly affects the usability of the camera in the long run.
Thanks guys and keep up the great work!
appu - Sunday, October 8, 2006 - link
I don't know if these have already been covered in the comments earlier. There are quite a few and I didn't read them all.1.) When talking about vibration reduction, you need to make sure you tell your readers that VR/IS *cannot* eliminate subject motion blur. It can only eliminate (to a degree) blur caused by handshake. I'm surprised you missed such an important point considering that you felt most AT readers are newbies at photography. It's all dandy to believe that VR gets you sharp images all the time. No, it doesn't. There are caveats and you might have mentioned them.
2.) The real benefit of SLR cameras is - more than anything else - the fact that the photographer sees what the lens sees. That's a major, major advantage of a SLR over point-and-shoots and rangefinders which exhibit parallax error by the nature of their design, especially if the subject is close to the lens/camera. Given this, you might have also mentioned that sensor-based stabilization techniques are a bit of a misfit (atleast that's what I tend to think) because having a stabilized sensor still *will not* give you a stabilized image in the viewfinder. However, lenses which have VR in-built *will* give you a stabilized image in your viewfinder - again going back to the "what you see is what you get" thing. Having stabilized sensors is good for the customers as they don't pay VR royalty on every lens they buy, but I don't see the point in seeing a shaky image in the viewfinder and somehow expecting something sharp (to what degree I may not know) in the final image. Maybe 99.9999% here (or anywhere) wouldn't agree with me on this point but I think it's worth a note.
3.) Not all kit lenses are dogs. The 18-70 DX I have for my Nikon D70 is a wonderfully sharp, contrasty lens (of course in available light situations) and after almost 2 years of shooting DSLRs I can safely admit that I've not "outgrown" this lens. It still manages to surprise me every once in a while and I don't see the need for an exotic f/2.8 zoom in this range as yet. Point I'm trying to make is - don't berate kit lenses. They are there for a reason, and as with any lens, there are certain advantages and certain disadvantages. As a photographer, it's important to understand what every bit of your equipment is good at and then maximize the technical potential of your images because of this understanding. Infact, building up on this point...
4.) I'll go so far as to say that, even with fixed focal length (prime) lenses, the so-called "sweet spot" in terms of image sharpness and contrast is usually achieved when the lens is stopped down by 1.5 to 2 stops from its maximum aperture. If you are always going to think in terms of how zoom lenses are "bad quality" compared to primes, I'd encourage you to start shooting 2 stops down on your primes (and thus lose all the speed advantage these primes offer). I think you get what I'm trying to say. Let's not get too hung up on trivialities like this because, and I repeat because, modern zooms, even the consumer zooms produce wonderful images in the hands of capable photographers. And then you have pro-grade zooms like the 70-200 f/2.8 VR from Nikon and Canon's 17-40 f/4L etc. Yes, they are costly, but so is a 300 f/2.8 VR Nikkor or a pro-grade ~100mm macro. The price differential is evident only when you start looking at wide-to-medium-tele or super-wide-to-normal fast zooms (28-70 f/2.8, 17-55 f/2.8) and even then the output from these lenses is well worth their cost and the walk-around convenience they present to photographers who prefer this range of focal lengths. So, not all zooms are "bad". Things have improved, just as they continuously do in the computer hardware business. Let's not get stuck in old notions based on old equipment manufactured using old processes.
Keep up the nice work!
appu - Sunday, October 8, 2006 - link
Ok, one last point -5.) In your second last page, you talk about "lens confusion" and how you'd like the industry to move to a standard naming of lenses. I don't understand what can be more standard than the focal length itself - a very physical property of a lens. A 35mm lens has a focal length of 35mm. Period. It doesn't depend on what format camera it's bolted on to. A 35mm lens is 35mm whether it's used on a 4x5 view camera or a 645 medium camera or a 35mm film camera or a digital equipped with an APS-C or.... you get the picture. In itself, the naming of the lens by its focal length (range, with zooms) is *not* confusing. What's confusing is what people make it out to be - quoting effective focal lengths for formats all and sundry, where as in reality, the measure everyone needs to be worried about is field-of-view. A 35mm lens will have different fields-of-view when used with different camera formats.
We don't need a standard for identifying lenses. We already have one - focal length (a physical property that doesn't change) and field-of-view (a very measurable metric). If anything, it's the "effective focal length" paradigm has to be done away with, IMHO.
appu - Sunday, October 8, 2006 - link
In the last line of the third from last paragraph - Nikon doesn't make a 11-18mm as far as I know. They do have a 12-24 f/4 DX and Sigma also has a 12-24 (I think a non-constant aperture) which can be used on full-frame cameras too, unlike the Nikon 12-24 DX. The 11-18mm is made by one (or both) of Tamron and Tokina I think.directed - Wednesday, September 27, 2006 - link
When reviewing DSLRs, I want to know how quickly they can autofocus in different lighting conditions. I want to know how good the autoexposure is in different situations. I want to know how the different flashes perform in different settings (not just the built in ones, but the ones you can buy for them). I want to know how accurate the color reproduction and contrast is. I want to know how good the jpg compression is (lets face it, few people will be using RAW). I want to know how long the batteries will last in different situations. I would also like there to be a comparison with other models in a similar price range as well as a comparison with the cheaper and more expensive models of the same manufacturer.Boy, looking at my post I sound demanding. LOL, I'm sure Anandtech is up to the challenge.
yyrkoon - Wednesday, November 1, 2006 - link
I dont know, I dont use AF for demanding lighting situations, I use the infinite Focus setting, and set the rest manually. That, and I think all 'prosumer' DSLRs have a fairly 'shitty' on cam flash, and alot of us would probably be more concerned with the hotshoe 'adapter'However, I will agree with battery life as an important factor, but to be honest I'm personally more concerned with how fast the camera is (FPS), and the media type used.
I see alot of stuff on dpreview.com like 'default <insert something relivent> setting is BAD' etc, but most of the these cameras can be manually adjusted away from default settings, so, IMHO, it's a moot point, and is pointless to really mention, learn how to use your camera ;)
You're not demanding, you just know what you want :)
yyrkoon - Wednesday, September 27, 2006 - link
Forget what all the nay sayers are saying guys, write you articles. I've been interrested in the Sony A100 for several months now, since the preview on dpreview.com. I also think you're right concerning the *mass* of information that dpreview gives off for thier camera reviews, most of it is un nessisary for all but the professionals, most of us just want to know things like, how many FPS does the camera achieve, how does it handle low light situations, how clean are the photos, etc.Carry on :)
silver - Wednesday, September 27, 2006 - link
Another good point. AT has always been about presenting good, practical information on the products that we use and in this context has always done a great job.The A100 certainly has my intrest as well but do note that most pro's do not need bells and whistles in their equipment. In fact most don't even want them available as it adds to both cost and complexity with almost no practical return in value.
Lord Midas - Wednesday, September 27, 2006 - link
Very good article Wesley. Thanks.Still a lot of this is still baffling at the moment but that should change when I get my Canon Rebel XTi 400D for Christmas.
What I would like to see in the reviews would also include the quality of the bundled lens (the Canon comes with the 18-55mm lens). As well as with a quality lens.
Will you also include reviews of lens:
For example you do the "Mid Range GPU Roundup - Summer 2006"
So you could do this with Normal, telephoto, etc lens.
So instead of reviewing one lens you can do a group test.
And I also think that a few standard photos for all the reviews would be good (indoor, outdoor, macro, etc) and a few random ones the the reviewer would think we would like.
Keep up the good work. Thanks.
mesonw - Tuesday, September 26, 2006 - link
Just wanted to add my 2p-worth. I feel I fit fairly well into the target audience you're aiming at. I'm very lacking when it comes to the technical details of cameras, digital or otherwise, yet I have a great desire to take good and interesting pictures.It's good for people to offer tips and ideas for your upcoming articles, but I don't see the point of the very knowledgeable and camera-savvy crowd out there making harsh criticisms simply because you're targetting people with less knowledge than them. Like they say, there are other sites to get in-depth information if they want it, so why berate AT for catering for others?
I for one look forward to your articles on the subject, because I know they will be well written, provide useful information and insights, and very likely make me a better amateur photographer.
Good work AT.