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Beyond Megapixels
TheTechLounge points to this "first of a three-part series of editorial articles examining current digital photography hardware, as well as the author's views of what is to come." It boils down to the excellent point that pixel count alone is not the way to evaluate digital camera capabilities.
Most people didn't care about resolution in the analog world. The fact that many people considered APS cameras to be better than 35mm is simple proof of this.
This seems analogous to consumer computer makers moving away from advertising GHz and MB.
It's what you (can) do with it that counts.
comes down to the lens. No matter how many billions of pixels you fit behind it, the lens is going to determine the first determining factor of the photo quality. It's certainly not the last (thus we move to 3 CCD systems etc. for better color reproduction) but the lens.. is always going to be the biggest factor.
I hate people
The biggest determining factor to me in buying a good digital camera is the optical zoom. With so much focus put on the number of megapixels and digital zoom (which, in my opinion, is better done in Photoshop anyways), the optical zoom is too often forgotten and hard to find in most "affordable" digital cameras. Without the optical zoom, one is limited to the same twelve-foot-away pictures that is great for people who only want to take pictures of friends and family standing in front of things, but is really useless if you want to get a good close up.
For example, this picture I took with my decent megapixel digital camera, my first time using it was a terrible disappointment because it was a great shot ruined just based on my not having the proper optical zoom capabilities.
(And my mistake in buying a camera that I thought would be top of the line, and stupidly didn't notice the difference between digital and optical zoom, this being my first move off of traditional cameras.)
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"We are Linux. Resistance is measured in Ohms."
When you're dealing with digital you quite simply need pixels. You need to decide what size pictures you intend to print or whatnot and get an MP count to match. You can't get a 1.0MP camera and do large prints of any quality.
Of course you also need picture quality. But it really doesn't matter how good the colors are if you're only getting a postage stamp image.
I have a 2.0 megapixel camera which I intend to replace eventually. Not because of the pixel count, but because of the image quality. I have a few pictures where a small branch got just a bit into the frame. The camera focused on that little branch and blurred the rest of the picture. There's no manual focus so all I can do is watch what's in the view carefully.
It also doesn't react intelligently to low light. Although with a bit of modification I can turn that into a feature as I can take time lapse photos to get good pictures in very low light.
As with all things, you need to pick the versions with the features you need.
Ben
Work Safe Porn
CCD size/quality
Quality of Glass
Then look at MP and other features (including price/battery life other doodads)
e.
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Check out this link. It details a bit on how the spirit rover only has a 1 megapixel camera on board, yet delivers IMAX quality images.
From the article: "NASA's Spirit Rover is providing a lesson to aspiring digital photographers: Spend your money on the lens, not the pixels. Anyone who has ever agonized over whether to buy a 3-megapixel or 4-megapixel digital camera might be surprised to learn that Spirit's stunningly detailed images of Mars are made with a 1-megapixel model, a palm-sized 9-ounce marvel that would be coveted in any geek's shirt pocket. Spirit's images are IMAX quality, mission managers say. "
It's not just for large prints, it's for creative freedom.
With a high megapixel camera I can take a picture of a statue from far away, get home and crap 3/4 of the picture out and still be left with a picture that's high quality enough for a print.
I have a 2 megapixel camera and it's good (not great) for 3x5 prints but I am not able to crop any of my picture or the quality loss is evident in prints.
If we can't use just one metric to identify the quality of a digicam, we'd have to do with something like a (megapixel,sensor size,optical zoom) triplet. Most of us already know to look for more than one feature while buying PC's. It would be nice if somebody well-versed in the mysteries of digital camera technology would standardize the set of features that I should be looking for as a consumer....
...electronics: Cheap ...optics: Expensive
Look at screens. Graphics cards have improved massively (electronics), screens (optics) used to be 1024x768 quite a while back, and typically aren't more than 1600x1200 now. The LCDs will hopefully change that though, since they're much more scalable (make more pixels) than a CRT (move beam faster).
Same with digital camera. The back-end is getting much cheaper, multi-MP CCDs and other electronics, but good optics in the lens is still damn expensive.
I read a piece recently about HDTV cameras. There were rumors that a certain camera would be sub-10.000$. The official comment basicly said "we can't tell you the real price yet, but you're smoking crack. the lens alone is in the 7-9.000$ range".
That being said, most digital cameras today should be just fine, if you don't try to take "impossible" pics. If the sun is saturating the CCD, it won't happen. If there's light casting ugly shadows, fill it in or you'll never get rid of them. There's a lot more bad photography than bad cameras...
Kjella
Live today, because you never know what tomorrow brings
The camera sitting at the extreme of the low megapixel, high quality spectrum is the Sigma SD10, which is the only camera to use Foveon's x3 sensors to capture three colors per pixel. This results in a very high quality image, even though the total pixel output is ~3.4 megapixels. I would like to see some of the other major players put out cameras with Foveon's tech. With competition, we might see further refinement of the design.
Here's a comprehensive review of Sigma's camera.
Having just purchased the new Nikon D70 digital SLR camera I can say that pixel count is definitely not what you should look at. At 6.1 megapixels, the D70 is relatively high but some of my friends derided me for not getting an 8 megapixel non-changeable lens camera. Trying to explain to them the benefit of having a real SLR body, the ablity to change lenses, manually adjust all settings etc. is a lost cause. Many people don't understand that although I spent twice as much for less resolution I can do things with this camera that they could never dream of with a traditional digital camera, regardless of resolution. Light sensitivity, signal to noise and optics all rank above resolution in my book. The ability to manually adjust all settings is right up there too.
:-)
Of course if you're just taking snapshots to send to grandma then forget everything I've just said
An 8 megapixel ccd behind a cheap lens is going to look worse than a 1 megapixel ccd behind a high quality lens. Look at the pictures of mars, they were taken using a 1mp camera.
Of course, the additional detail is nice. But to be really usable to blow images up (which is probably the only reason for going higher than 4-5mp), the following problems have to be solved.
1. Noise has to be reduced. Especially in dark pics. Less of a problem now, but still an issue. Of course, if you're taking a 8mp camera and printing out an 8x10, you probably won't be complaining. Zoom in to 300-400% and you will be easily able to see it (and all the stuck sensors, but that is another story).
2. The lens is good enough to resolve that detail.
No, your made in china $5 lens will not be good enough. There is a reason professional film cameras have "big ass lenses".
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I personally am waiting for a good Megavoxel camera. If you think pixels are good, imagine the images that can be rendered with voxels! It is incredible! ;)
I'd like a digital camera that responds as quickly as a film camera. I hate holding down the button and waiting for the camera to decide if it will take the picture or not. I want a digital camera that will take the picture when I press down the button not 1/2 to 3 seconds later.
I've hit Karma 50 and gotten a Score:5, Troll... I win!
One thing I hope future articles touch on is ergonomics. Unlike SLR's, which have had the same basic layout since the Exaktaflex, digital cameras are a hodgepodge of knobs, buttons and dials, laid out (apparently) at random at times. And the difference in features between cameras of the same pixel size can be stunning.
When people as me what's the best camera out there, I usually tell them find one that they find first easy to use, is a camera-brand (better glass), and has a decent image size. No amount of features will make up for a missed photo due to fumbling with a camera, and what's important to me (manual controls, accessory shoe, RAW/TIF, etc) may not be important to them."Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."
Even with good lenses and modern low noise sensors, digital cameras has a rather narrow exposure range as compared to classical photography. Shooting with negative film you can get something like twice the exposure range, compared to any ordinary digital camera (i.e. you will be able to see more details in both the dark and light areas of your photo)
I've done experiments with my 3MP camera, taking multiple shots from the same angle and layering them in photoshop. The enhanced resolution can be downright breathtaking, but the practice is only practical for still lifes and landscapes. What are you going to do with that 1MP camera when you want a high resolution image of janie's first smile?
The most important part of any camera is the lens. There are two main problems with lenses. Chromatic aberration causes colour fringing due to the focal length of the lens being different at different wavelengths. It can be corrected by using compound lenses {one positively-dispersing lens and one negatively-dispersing lens} or low-dispersivity materials. Spherical aberration causes distortion of the image due to the lens surface not being perfectly spherical, and thus the focal length varying over the surface. It can only be corrected by grinding lenses well.
A bad lens will produce a bad image regardless of the image sensor. Sometimes an image sensor will not have enough resolution to detect the distortion due to chromatic and spherical aberrations. But when the same manufacturer slaps a new sensor on last year's lens, the new sensor can pick up better on the aberration and the pictures end up looking lousy.
Another feature to bear in mind is hardware {optical} zoom. Don't buy a camera without it and don't reject a camera for not having software {digital} zoom -- your favourite graphics editor can do this for you.
Cheap image sensors are invariably noisy. Big pixels can hold more initial charge, therefore can accept more light in the course of an exposure. The sensor will only be saturated in really bright light, and the amount of charge remaining on the pixel {which is a measure of how much light didn't hit it} can be measured more accurately: one "unit" on the ubiquitous 0-255 scale represents many electrons. But more silicon costs more money. Small pixels don't have the same capacitance, so can't accept as much light before becoming saturated -- you have to run a shorter exposure. And the number of electrons per ADC count is smaller. The net result of having a higher density in the image sensor is that even in bright light, the resulting pictures will look a little bit as though they were taken in poor light. Of course, you can remove the noise by downsampling, but then you lose the benefit of the higher-res sensor.
And what's with the confusing term "digital SLR" ? As far as I can see, all digital cameras with LCD viewfinders are by definition SLRs, since the same lens is used for viewing and taking the picture.
Je fume. Tu fumes. Nous fûmes!
First of all, no one has mentioned DYNAMIC RANGE yet. This is the range between absolute black and absolute white. Whether you are using film or digital, this range is crushed compared to the human eye. Digital dynamic range tends to be worse than film, which is one reason film isn't going to go completely away any time soon.
Greater dynamic range will give you better details in your shadows and highlights. This is very important for the serious photog, although probably not important for snaps of your kid's Bar Mitzvah.
The other thing that matters is the actual size of the CCD. Manufacturers are using various technical tricks to squeeze out more pixels from the same size CCD, and the results are sometimes pretty bad. The worst problem I've seen was purple fringing in bright red objects that were backlit. Totally ruined an otherwise beautiful photograph.
The bigger the CCD the better.
It's not offtopic, dumbass. It's orthogonal.
Why not shoot in film and use a film scanner? I've got a 30 year old (Minolta X-700) camera that has been with me through a lot. The thing will not die and just keeps on going. I just have to change the battery once a year or so. I usually develop my photos at a grocery store. Ask to have it developed and cut only - no prints. It costs me 1.25 per roll and I have it in about 20 minutes. Later I scan them in myself, get 11 Megapixel images with 48 bit color, scanned 8 times to minimize noise. (They're about 62 Meg TIFF images) that I can print with up to 13x19 on my Epson 2000P printer. The best part is, in 5 years I'll buy the newest and greatest film scanner and I have the option to re-scan the images at 20 Megapixels or whatever. That's my solution at least. By the way, the scanner was only 500CAD ;-)
Foveon cameras have one three-color sensor per pixel, but for PR purposes, they, too, count R, G, and B as separate pixels. For example, the Sigma SD-10 mentioned in the article has an imager 2268 x 1512 pixels, but is listed as a "10.8 megapixel" camera. For Foveon units, divide by 3.
Foveon cameras, since the R, G, and B sensors are at the same place, don't generate color artifacts at black/white boundaries. This eliminates one of the main effects that makes "digital" look worse than film. Of course, if you compress to JPEG, you get color artifacts anyway, but that's a JPEG problem, not an imager problem.
The article is a bit misleading, and perhaps wrong. It exchanges one myth for another myth. Indeed megapixels alone do not define resolution. However, CCD size isn't the answer either!
The article fails to address the issue of optical resolution, i.e. lens quality and aperture. Does the number of pixels act as the resolution limiter, or does the quality or size of the lens limit resolution? Many consumer cameras use poor quality small lenses, but boast of large numbers of pixels. Since CCDs are cheap and good lenses aren't, why not over sample the image enough so the consumer thinks they're getting a superior image, and has to pay more for flash memory? The number of pixels can be irrelevant for a camera with a small or cheap lens. Larger aperture lenses will always resolve better, as is the case with all imaging optics anywhere in the spectrum between telescopes and microscopes. Cameras are no different.
The reason professional cameras are better is not just because the CCD is larger. A larger CCD demands a larger lens. That is the difference.
Furthermore, sensitivity and CCD size may not matter at all! The problem of noise for smaller pixels is only relevant when the camera is capturing lower intensity images. Brighter intensities overcome the noise. Larger aperture lenses also collect more light and resolve better, reducing noise and increasing contrast.
Well, it's fact. The larger the surface area of each cell, the better signal to noise ratio you will get. CMOS yields better quality than CCD, as well- although the margin has dropped as CCD sensors and the electronics behind them have improved faster(due to everyone and their grandmother working with CCDR sensors) than CMOS.
This phenomenon can be seen clearly in both the non-CMOS 14 megapixel Kodak 14n, or the Sony F828, which has a VERY tiny 8 megapixel CCD sensor. Both are horrendously noisy at their lowest ISO settings.
My Canon 10D has better noise characteristics at about 400 ISO than my Canon G1 had at 50 ISO, and 400 is about the limit I feel is appropriate for an 8x10. For images resized to 800x600 for, say, large images linked off a website, ISO 800 or 1600 still yields pretty decent images. The example he gives of buckets of water is flawed, since falling rain isn't *focused* like light is. Light entering a lens is just being focused on a smaller area. Sure the area is smaller, but it's also brighter.
Light is focused, but it's also made up of particles. Further, the smaller the sensor, the smaller the lens. The smaller the lens, the less light is gathered.
Smaller sensors also require much more precise optics and focusing systems(or smaller apertures, limiting light input even further). Tiny sensors are also very prone to flare.
Please help metamoderate.
1. Image quality will be determined by the combination of how many pixels you capture (megapixel count/resolution) and the size of those pixels (sensor size/photosite size), with the weight of the influence going to the photosite size. Thus, resolution being equal between two cameras, the camera with the larger sensor size will give you higher quality captures.
2. Garbage In, Garbage Out applies to cameras too. This should be obvious. Make sure your lens is able to capture all the data you want to feed to your sensor. If you have a full-frame, 24x36mm 11mp Canon 1Ds (the current professional favorite, myself included), you are wasting it's resolution by putting a cheap lens on it. I've noticed, in fact, that even the highest-quality lenses tend to be unable to deliver enough detail to this stunning sensor, so a cheapo lens is going to f*ck you.
3. For professional use, film is now dead. Game over. I've done the head-to-head comparisons. I own medium and large-format cameras. I own a high-end drumscanner. I own a large-format printer. I've compared the quality from my previous breadwinning equipment (medium format film scanned by drumscanner) to my current breadwinning equipment (full-frame digital Canon 1Ds) and the digital kicks film ass. That's why it's my current breadwinner.
Seriously, I had 4x6 foot prints made (notice I said FEET, not INCHES) from drum-scanned 6x7cm transparencies, and from 11mp Canon 1Ds captures, and my own lab couldn't tell the difference. Bye-bye film. And the $10,000 price tag was paid for in film/processing savings before I even got the credit card bill. (for more about how cost affects quality, see below, #5)
4. The best camera for you is all about what you intend to do with it. A camera is just a tool. Pick the right one for the job. Because of this, most professionals have, on average, more than 3 different camera systems. So, decide what you want the camera for, and the rest of the decisions about it's suitability get easy.
The most important factor is usually not sheer resolution and image quality. It's about usability of design and ease of handling. If it were all about resolution then most photographers would be using 8x10-inch view cameras. But we realize that a stunning, mega-high-resolution image is useless if the important moment we wanted to capture was missed due to slow camera operation.
That's why most pros use medium format or 35mm, and most ams use point'n'shoots.
So, pick a camera that feels good, is understandable to operate, and doesn't get in your way. After these criteria are satisfied THEN you look at resolution/sensor size.
5. The single most important equation for making better photographs is (forethought x volume of action). In other words, think about what you want to achieve with your images, then shoot as much as you can, and hone your results. This is really where digital capture shifts paradigms. Once you go digital, ANY digital, your visual experiments cost you nothing.
With film, every time you want to try something new, you are still paying for film and processing (even if you own your own darkroom). This means, effectively, that film and processing are an economic tax on your creative growth.
So, as long as you stay focused on what you want to achieve (rather then just shooting because you can), buying ANY decent digital camera will yield you better results then sticking with film, and it's use tax.
Class dismissed.
1. Almost all DSLR's have what is called a focal length multiplier - tends to be 1.3 or 1.5/1.6. This means that your "normal" 28mm lens ends up being a 42mm lens (for 1.5x focal length multiplier) - this has to do with the fact that the CCD chip is not "full-size". This is great for tele shots - i.e. your 300mm lens becomes 450mm ... but really sucks for wide-angle used - i.e. you need a 18mm lens to get a 28mm shot. All point-n-shoot digicams show the 35mm "equivelent", but in actual fact, that is NOT their focal length.
2. Related to the above is Depth of Field - especially with point-n-shoots, your DOF is much longer, so if you want to shoot a picture that is "tack-sharp" on the subject, but have a blurred foreground/background, that is more difficult - although on the other hand, you do have more DOF if you want that.
3. Another issue somewhat touched upon briefly is differences in the CCD size between point-n-shoot and DLSR's. With all else equal, the small the size of the imaging pixels, the more noise that can be present, and this tends to go up dramatically if ISO is turned up (first thing I do on a point-n-shoot is turn OFF the auto-ISO and force is to the lowest setting). I'm sure some will disagree, but I'd challange you to print, say a 10X15 print from one of the 8MP digicams compared to a DLSR, both shot in GOOD light (with lowest ISO). Yea, under photoshop, that DSLR shot is just super-silky smooth, but on the 10X15 print, I bet you'd be hard pressed to tell the difference. Having said that, crank up the ISO in your point-n-shoot to say, 800 (yes, even in the newest digicams), and it will look like CRAP - again, at outlined, because the sensor sizes are so darn small, whereas on the DSLR's, you can get away with this (and increase your shutter speed so you don't get motion blur) and the picture may be decent, especially with noise-reducting software/filters applied. From reading Part 1, THIS is the real emphasis of the article.
I've only scratched the surface here - the article talks about a lot of the above, but most of the Slashdotter's seem to have blown right by this stuff.
Hulkster
P.S. On those Mars pictures, YES, they were done with a 1MP digicam (with BIG sensors), but just about everything folks have seen is stiched togather, so you are (in some cases), seeing like an "effective" 50+MP shot - welll DUHHH it looks so good!
Flower shots from my folks Garden
All of these pictures were taken with my Canon-EOS10D, 420EX flash (used mainly for shadow fill), and Sigma 20mm 1:1.8 EX DG prime lens. The shots were taken hand-held in AP mode using F4.0-F16 depending on the conditions. This particular lens produces ultra sharp results at F4.0-F13 or so. The 10D (and 300D) use a 6 MPix low-noise CMOS sensor and you can see it in the above shots.
Insofar as all the discussion goes, from my point of view it all comes down to three things: Lens Quality, Sensor Quality, and Dynamic Range (of the exposure). SLR's like the 10D have gotten good enough that I don't use film any more. The lens quality is there (being an SLR and taking the same lens as the film EOS's), sensor quality is there, and while dynamic range still needs another 2-4 bits of resolution for my comfort it's still good enough for 99% of the shots I take. Film is dead, digital rendition at 11!
And I tend to agree with the few other obviously experienced comments (verses the bozo comments from people that don't know jack about taking photographs). You first need to know how to take a picture before you can take a good one. Then comes lens and sensor noise. A lens hood is important, and a good flash (articulated for bounce shots and also be sure to have a diffusor handy) is very important (even when you don't think you need it). For example, most of those flower shots I took were with flash+diffusor, even though it was a bright sunny day outside. The flash was used primarily to fill in some of the shadow (one way to correct for limited dynamic range but it also makes the shots look a lot better).
-Matt
Not to get too picky here, but the latest Noritsus and Fuju Frontiers are laser printers. Instead of exposing a selenium drum with an IR laser, they expose the photographic emulsion with red, green, and blue lasers. Some printers (e.g. ZBE Chromiras -- the best in the business) use LEDs, others (crappy ones) use CRTs, but most use lasers.
And not counting the cost of equipment, expect to pay $0.25 per sq. ft. for wet prints. It's going to be a lot more than 5 years before somebody has an inkjet process that can spit out 2000 4x6 archival prints in an hour for less than a nickel a piece.
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The only way in which a 300mm lens is remotely like a 450mm lens when used with the smaller physical sensor is that they would deliver the same field of view. The problem is, a given lens produces a image whose sharpness is a fixed physical size (like .01mm) in the focal plane. The smallest point feature is blurred to this size at the film or sensor.
As a reductio ad absurdum which illustrates the issue, imagine a standard 35mm telephoto lens with 300mm maximum focal length, used with an ultra-tiny CCD sensor exactly .02mm across. The field of view present in the image is in fact equivalent to having a 360,000mm=3km lens -- I can see the bright red metallic print hawking this on the lens packaging now. Think of the stunning shots you can take of shy and endangered wildlife in the next state over from the comfort of your own porch! Sadly, thanks to the limits of the lens optics, such an image would contain only 4 independent blobs of color (completely independent of the number of pixels in which those blobs are captured).
In reality, since the cost drivers for lens design is performance "off axis" or away from the optical center, coupling a high-performance 35mm lens with a smaller sensor is wasting this off-axis performance: the maximum field angle is going to be smaller! This may however allow you to use cheaper 35mm lenses which would suffer from unacceptable aberrations at large field angles with digital cameras, since you're only using the "center of the glass".