Sizing a Sensor: No Easy Way

Sensor size is important in pocket cameras, but figuring out that size among various products is baffling.

Comments: 42

  1. Exactly what is needed-a way to move forward now that the myth of megapixels has widely been debunked. Knowing the true sensor size will truly give the ability to compare apples to apples

  2. David,

    I greatly enjoy your reviews. In this case, due to the confusing sensor sizes and feature implementation, why didn't you reference the prior large sensor cameras you have tried. For example, in the Spring you loved the SONY NEX. Where does the SONY fit against these reviewed cameras. Happy holidays.

    Dennis

  3. For the purposes of this column--pants-pocket cameras--those ILCs (interchangeable-lens compacts) really aren't any better than SLRs.

  4. While I agree the convention is clunky, I don't really agree with your point about the relationship to 'old TV' sizes. As long as it's consistent, whether the actual sensor is that dimension in inches isn't really important. Only the relative relationship of one sensor to another is relevant. It's a bit like gun calibers: they don't all reflect actual diameters in fractions of an inch. That said, coming up with a better index of some kind would definitely be more convenient.

  5. David, I don't think so.

    First, once the pixel is more than 3 microns or so on a side, it's the light-gathering power of the lens (said more simplistically, how big the lens looks, when you look into it) that matters.

    Whether the lens forms an image a half-inch on a side, or something Hasselblad-sized, the incoming light - for the same lens - is the same.

    If anything, an overly large sensor in too-short a camera can cause image planarity issues.

    Second, the "SLR" blurring - to which you refer as virtue - is simply because lenses with more light-gathering power (more expensive cameras tend to have lenses with more light-gathering power) have a shallower depth of field. Not to complicate things, but a lens with a lot of light-gathering power can be ratcheted down to gather less light, and increase the depth of field - so there is a flexibility.

    As far as how many megapixels is too many, that depends.

    If you store your pictures as-is, anything more than 4 megapixels doesn't help - unless you're blowing your pictures up to poster size. Displaying them on a 50" TV doesn't count - the native resolution of the TV screen is about 2 megapixels.

    If you crop your pictures, having 16 megapixels is a hoot. That holiday group shot of two dozen relatives can be cropped to a single face or a couple, with great detail.

    Which brings me back to the lens. If the quality of the lens (distortion,aberration) is suspect, the (mega)pixels are - again - wasted.

    And, if you do want to crop your pictures later on, dump them out of your camera onto a (large) disk drive - without compressing them. That is, output raw image data, not JPEG images compressed by the camera.

    So, here's what I'd suggest - and if you're willing to dumpster-dive (i.e. manufacturer refurbished), you can find these for less than $100:

    > Get at least a 5X optical zoom. Indirectly, aside from the versatility, it generally means a higher-quality lens

    > Image stabilization. This can matter as much as the lens or the sensor, for casual photographers getting great shots.

    > Get at least a 10 megapixel sensor. Not because you need all of it - but because the price of these has been driven to commodity levels.

    > Get a rechargeable battery system - and a spare battery.

    > Get, at least, a 16 Gb memory card. If your camera uses a common standard (e.g. SD), these can be had for as low as $20.

    > Burst mode (several shots, in rapid sequence) is useful, if you take sports or racing pictures - or your holiday pics have lots of young children in them.

    > Red-eye elimination and some other image enhancements can save manual photoshopping, and some otherwise great pictures.

    Final piece of advice: pictures of people look better, if taken from a distance, at higher magnification. That's where the image stabilization really helps.

  6. Thanks for calling out the industry for their shortcomings. There are so many cameras and specs to deal with, and very hard to know which camera will work for you personally. I just purchased the Nikon P7000, and it is not a brick as you claim, especially when I compare it to my D300 and D90. How about a column on using the iPad with cameras? Just starting to do that as a way to lighten up. Happy Holidays!

  7. Hi David:
    Once upon a time, in 2006, Sony released the DSC-W100, a pocket camera with a 1/1.8" sensor, and a year later, the DSC-W200, with a 1/1.7" sensor - light years (in digital camera time) before the three cameras you tout. They took great pictures. Too bad Sony doesn't make cameras with sensors that size anymore.

  8. David!!!! You are the very last person I would ever expect to fail to make the distinction between perpetrated and perpetuated. I am sooo disillusioned!!

    Please tell the world that you didn't really mean it

    Carol Guthrie

  9. Well, I wrote about "a shady scheme that’s being perpetuated by the world’s camera companies."

    PERPETUATE: "To make (something, typically an undesirable situation or an unfounded belief) continue indefinitely"

    PERPETRATE: "To carry out or commit (a harmful, illegal, or immoral action)"

    So actually, I think either one works in this context. But thanks for caring!

  10. From slideshow - "The Canon PowerShot S95 favors rich, saturated colors; Canon’s studies show that Americans prefer photos that “pop” this way."

    I've heard this finding before, American preference for photos that "pop". But I've always wondered (I'm American) what other generalizations Canon or other manufacturers may have gleaned for other countries. Do Nordic nations prefer low contrast, "bleak" photos, and maybe Japan likes even "poppier" shots? Do the manufacturers tune their cameras differently for different countries? Anyone have any insight?

  11. I remember Canon telling me that Asians prefer real-life colors, even if they're drab. Americans almost universally admire photos with more saturation.

    It must work. Canon went from having missed the digital camera boat entirely to becoming the #1 camera company!

  12. It's the relative size which matters when comparing two (or more) similar cameras, not the absolute size. So while I agree that a simpler, more straightforward measurement - the same as DLSRs use - would be better, knowing that one pocket camera has twice the sensor size than another is the important information.

    In fact, the really important fact is the combination of pixel size and number of pixels. It's actually pixel size which determines the light sensitivity; using sensor size merely allows you to compare two 10 megapixel cameras to guess at their relative pixel size. That's why a 10 megapixel DSLR is so much more sensitive to light than a 10 megapixel pocket camera - the pixels are much bigger. And that's why the Canon S95 has only a 10 MP sensor when the technology exists to cram more pixels on a small chip. So ideally, camera manufacturers would advertise pixel size and pixel count. The size of the sensor, which is determined by these two, would be an interesting but irrelevant fact (unless you're the engineer charged with actually designing the camera and lens).

    The f-stop advertised is actually more misleading. The Canon S95 (which I love, by the way) is only f/2 at it's widest setting, and it rapidly drops down to a much smaller aperture as you zoom. The same is true for the other large-aperture cameras. And since many pictures are taken at something other than the widest setting, the user rarely gets the advantage of the f/2.

  13. "The LX5 is a bigger, heavier camera, too. And it has a detachable lens cap, which you’ll lose." Having been shooting with (D)SLR's for 30 years as well as owning the LX5 for the past several months, I can safely say I have never lost a lens cap. Assuming everyone will is lose theirs is presumptuous of you, David.

  14. I also looked at the 3 models mentioned in your article when I was shopping for a camera.

    Judged on taking still photos, I found it hard to pick a winner out of the 3.

    However, looking at video recording capabilities, I think this is where the 3 models differ significantly.

    I wanted to be able to shoot HD videos and be able to zoom during videos. The Sony records in HD videos but does not allow zooming. The Samsung allows zooming during video recording but can only shoot in 640x480 VGA clips. The Panasonic model is the only 1 that allows zooming during video recording as well as shooting videos in HD format.

    This is why I ended up buying the Panasonic LX5.

  15. The difference in light-gathering ability between an f/1.8 lens and an f/2 lens is ~1/3 of a stop, which I think stops short of incredible. Under most circumstances, 1/3 of an f-stop is negligible.

  16. I used "incredible" to refer to the difference between the f/1.8 lens on the Samsung and the typical pocket cameras, f/4.0 and so on.

  17. What kind of view finder do these cameras have? LCD only is useless in bright sun. It is just point and hope.

  18. Actually, LCD in sunlight has come a long way! Technology has marched on, and these cameras are very good in sunlight. As noted, though, you can attach an eyepiece viewfinder to the Panasonic, if you feel like popping $200!

  19. The fractions-with-inches measure is unbelievably confusing as well as usually wrong, and the "diagonal" doesn't tell you the area of the sensor. Kudos to those manufacturers who just tell the sensor size in millimeters (like 24 x 18 mm) - and where can we get that for all the pocket cameras?

  20. Great insight into the pocket camera metrics, David. Too bad you didn't write this about a month ago before I bought several lesser pocket cameras as presents :-(

  21. Here's an easy link to check actual sensor sizes for point & shooters based on the ratio system of catagorizing:
    http://www.dpreview.com...
    The entire dpreview.com website is a wealth of information on all things digital in the camera world.

  22. Sensor size isn't the right metric - it's pixel density. If a sensor is 10% larger, it won't have better image quality if it has 20% more pixels (all other things being equal).

    The expert camera site dpreview.com understands the importance of pixel density, and lists that stat on its camera specification index pages, even above the lens size. For example, the Canon S95 and G12 sensors both have 23 MP/cm², while their lower image quality pocketables are 35 MP/cm², and the super zoom SX30-IS buys the zoom range with a 50 MP/cm² sensor.

  23. Yes, that's right. Pixel density really is the metric we care about.

    I considered bringing that up in the column, but it was getting WAYYY too technical--and in general, a big sensor MEANS better pixel density, so I left it at that. :)

  24. The Panasonic LX5 comes with a small cord that you use to attach the lens cap to the body (as did its predecessor the LX3).

    You won't lose the lens cap.

  25. Good comments all. Here is one that's not been mentioned yet so far as I can tell: Look at the images in the slide show closely and you will see one of the major drawbacks of small-sensor cameras: digital "noise" in the darker tones and blues. This is caused by pixel-packing camera marketing: too many pixels into a limited sensor size. Consumers have been tricked into thinking that more megapixels means better images. Not so. Do you really need more 14MP in a compact camera? No. The fewer the pixels in these cameras the cleaner the image will be. Megapixel size really only relates to how large a print you can make while maintaining good image quality or the ability to crop a small area from a larger scene while maintaining decent image quality.

  26. Could someone comment on the view finder in these cameras? I don't know the right terms, but am distracted by inner frame lines in the view finder. I'm looking for "true" sight without a delay between seeing and getting the shot. Thank you for thoughts.

  27. David,
    Good article on an important point in digital cameras which has been grossly overlooked in the popular media. People do need help. Living in a heavily tourist traveled area [North Beach section of San Francisco near Fishermen's Wharf] I have come to believe that cell phones are the most common or heavily used "cameras" in this country.

    There is another, perhaps, easier way to compare sensor size among pocket cameras. Most manufacturers give the 35mm film equivalent focal lengths for their cameras. The higher the ratio of the actual focal length to its 35mm film equivalent, the larger the sensor. For example with my pocket camera Leica's X1 [yes it readily fits in my coat pocket and yes it extremely pricey] has a 24mm lens that is the 35mm film equivalent of a 36mm lens: a .67 ratio. Some people use the inverse [35 equivalent to actual focal length] calling it an aspect ratio where clearly lower is better. For zoom lens, this ratio is constant at all focal lengths.

  28. A few Micro Four-Thirds cameras, like my Olympus Pen E-PL1, are somewhat pocketable (with a pancake lens, it fits in my pants pocket) and they have a much larger sensor size than these 3 cameras. I also love that the E-PL1 has a built in flash, image stabilization, and a dust reduction system.

  29. My Nikon S8100 is now my "on the road" camera. It takes photos that rival my Canon xsi and fits into my shirt pocket. Incredibly small and wonderfully useful tool. The full HD movies look great, too. You should check this one out, David.

  30. David,

    Thanks for your insights and for guiding me to the S95. I'd add one feature to your discussions: The viewfinder.

    I can use a screen to frame a shot when I have to, but my extended arms are unstable, and I feel disconnected from my surroundings as I focus on the little screen. When I view the scene through a viewfinder, I'm steady, part of the action, with my eyes naturally focused on the scene. When the viewfinder provides me information (shutter speed, ISO, etc), I've got creative control on top of it.

    I'm sorry to see so many camera makers drop the viewfinders and I'd add that feature as another basic advantage of the SLR.

    Chris

  31. David,

    I will look forward to a review of the upcoming Fuji X-100. A camera with an AP-C sensor in a very cool retro and pocketable(?) form. It may not have a zoom, but all the other specs look great.

  32. Hello again. Thanks for your article several weeks ago tauting the Canon S95, I have bought it and used it on the recent musical tour (Irish Christmas) that I work as musical director. It's a great opportunity to take advantage of live stage shots without the annoying flash. I like the camera and have gotten some really good pix.
    THe problem for me is the flash: the pix taken of people using the flash look bad, washed out, overlit.
    Which brings me to my peeve/suggestion. Why are all flashes the same unalterable intensity? How many times would a 25% flash be more useful and natural than 100%? ANd I know about partially blocking the flash but that is unreliable and awkward. In this age of alternative light sources, low voltage and led, lcd lighting, why can't the user define the AMOUNT of light necessary in any given shot?
    HAPPY HAPPY
    BUGSY



  33. David: As always, we appreciate your attempt to shine light where it is needed (pun intended) even if the readers/commenters disagree somewhat.

    Here is another area that needs work in describing camera features: the width of field or magnification factor of the lens.

    Now, I go back to the early 1960s and 35mm film cameras were always my main tools. So, I very clearly understand the difference between a 24mm and a 28mm lens in "35mm equivalents." Or between an 85mm and a 135mm, without the use of a calculator. It has just become instinctual for me. And with time, I have become quite adept in thinking about focal length on my Nikon DSLR--just add half again as much to the mm setting. Thus, at 18mm: 18+9=27mm or 55mm: 55+28=83mm. (Nikon has a 1.5x factor, Canon a 1.6x)

    But how many others know this easily? And as there are fewer and fewer users who EVER used a 35mm film camera, this method of description will become even less useful !

    I have thought about the value using angle of view (40 degrees across for a 50mm "35mm equivalent") or using the magnification factor above or below some normal lens (a 21mm lens is .5x compared to a 50mm or a 100mm is 2x compared to a 50mm, all in "35mm equivalents"). But I know that sensors are not all proportioned the same, and what after all is "normal?" And to complicate the matter, there are (more or less) full-frame sensors being used, but only in very expensive cameras.

    Could you give it some thought, or do have others good suggestions? Another job for the Camera and Imaging Products Association. Let's be able to compare oranges and oranges, please.

    Thanks for all you do.

  34. Thanks for your excellent reviews! I bought a Canon S90 last year as a result of your review, and I love it. This year, the S95 is even better, but my S90 is too nice to replace--so far. I just received my copy of your book Magic for Dummies, and I look forward to "entertaining" people with what I learn--and being entertained by the book too, which looks very enjoyable. Best wishes, Tom

  35. Although my old -but larger-Canon G2 has served me very well over the years, in anticipation of a trip to Paris last month, I was debating on whether or not to buy a new small pocket camera. The convenience of a pocket sized camera was a big factor but I hadn't seen many photos from the smaller cameras that impressed me enough to make the investment. Then I read your review of the Canon S95 and was convinced that I should buy it. All I can say is I LOVE this camera. I was able to take beautifully clear and bright photos even without a flash-a necessity in most museums. Even in the very low light of the Pantheon's catacombs my pictures came out clearer than I could see with my naked eyes! Neither of my two friends' small cameras came close to the quality of my pics. I now make a habit of keeping this in my pocketbook everyday--just in case I see a good picture begging to be taken. So glad I read your review and the timing was perfect.

  36. Hi all,

    One of the most affordable, low pixel density camera is the Fujifilm FinePix S200EXR: 25 MP/cm^2; 12 MP, 14X zoom for about $350. The down side is that it takes regular (not HD) videos.

    Aloke

  37. Better but you're still flashing in your video. The point of a fast lens is to use available light.

  38. Pogue,
    I enjoy your writings, but you wimped out on this one.

    It was much more of a description of the cameras versus a review or comparison between them.

    Which one is the best? Or are they about equally matched?
    How about image quality comparison between the three? You devoted one sentence to the image quality of the Canon, but said nothing of the Panasonic and had one sentence about the Samsung except the TL500's white balance problem. How do they compare in landscape photos? Bright light photos? Low light photos? Portrait photos?
    What are the strengths and weaknesses of these cameras?
    I'm in the market to buy one of these three cameras and I didn't learn anything from this piece that helps me towards making a decision.

  39. I have the Olympus Pen - E1 ILC camera, as mentioned as a comparison here. Unless my fifty-six year old eyes have been deceiving me, I believe it takes more crisper, natural, and quality shots in all light, and in many ways is better than my Canon XSi DSLR! Therefore, I'm sure that it is better than the three reviewed cameras in this article.

  40. Terrific stuff David - as always, exposing (sorry) the truth behind the blurred (sorry) industry line...keep it coming!

  41. David-- I couldn't agree more with your praise of the Canon S95. I have its immediate ancestor, the S90 (partly as a result of your positive comments on it a year or two ago) and use it constantly. The one problem I had with it was holding it securely. Then I discovered a custom grip that fits on the right front & solves the problem neatly. It's made by a guy named Richard Franiec (www.kleptography.com/rf/), and I believe he now makes a similar gadget for the S95. Full disclosure: my only connection with Mr. Franiec is that I am a very satisfied customer.

  42. David:

    I'm no expert in this area, but from what I understand (outside of macro photography) these pocket sized cameras with smaller than DSLR sized sensors cannot get a shallow depth of field effect even with an f/1.8 lens (contrary to what you said regarding the Samsung).

    Take for instance the new Voightlander Nokton f/0.95 lens for the Micro 4/3rds camera system. I am told that since the Micro 4/3rds sensor is exactly half the size of the a full frame (35mm sized) sensor, the super fast Nokton at f/.95 (on a Micro 4/3rds) has the same Depth of Field blurring as a f/1.8 lens on a full framed sensor camera.

    Since these small sensor cameras have at best an f/1.8 lens, they are severely limited in the shallowness of Depth of Field, unless some genius finds a way to make something impossibly fast like an f/0.32 lens. Being that the fastest lens ever built was the Zeiss 50mm f/0.7 , I doubt such a thing could exist.

    I think that in the future people with small cameras with a desire for shallow depth of field will have to rely in in camera software to create that "Bokeh" effect.

    You have nonetheless have written an excellent and important article.

    Levent