Digital Camera Tradeoffs, MegaPixel Secret, and "the Hunt"
Aug 07 '02
The Bottom Line You thought you knew what Mega-pixel means? Think again, or, before you buy, read this article.
Do you want a digital camera? Have a digital camera? Welcome to the club!
In this review I look into tradeoffs which one has to face when choosing a digital camera. I also talk about the “big secret” of the Mega-pixel. There are some tips on buying digital image equipment and using imaging software.
I have played with a few of these toys. Mind you, I am not a professional photographer, but I have enjoyed taking, making and playing with black-and-white and color pictures in both digital and old fashion film realms. I started making black and white photos when I was about ten years old. That makes me a devoted photography amateur for over 20 years.
First, I’ll suggest a few cameras I have played with, just in case you want to get your hands dirty ASAP. Then we will go into somewhat “philosophical” discussion about different tradeoffs of the digital photo world. I hope this will start you thinking before hunting for the camera, and then you can decide on what exactly you want. There will also be tips for the hunt, and home readings :-)
For the impatient reader
If you are looking for a digital camera, I’d suggest (that’s if you trust me) to consider the following models, depending on your preferences. For a couple of them I have reviews, listed on my profile page.
MP stands for Mega-Pixels. Keep in mind that the prices change, this just gives an idea of where the cameras stand relative to each other.
Toy cameras $40-$80 -- Aiptek Pencam 2 -- NOT for pictures...
Cheap, 1MP under $200 -- Fuji FinePix A101
Budget, 2MP, under $300 -- Fuji FinePix 2600
Decent, 3MP ~$600-$700 -- Olympus Camedia C3040 or Nikon CoolPix 995
Very compact -- Canon ELPH cameras
4MP ~$800 - Olympus Camedia C4040 or Canon Powershoot G2
Fast, 5MP ~$900 -- Nikon 5000
Lots of buttons :-) -- Minolta Dimage 7
Pictures straight to CD -- Sony MVC-CD300
Extreme (Pro) -- go and blow a few thousands on Pro level cameras, such as Nikon D100, Nikon D1X. But then you better know what you are doing, these are not quite point-and-shoot cameras...
Camera size and weight
Can I put that camera in my shirt pocket? This kind of question may arise when looking for a camera. there are small and compact cameras, and there are big and bulky, but packed with features. Here I’d like to offer two rules of thumb:
1) Small-light = portability. You can put it in your pocket or purse, you can take it anywhere. But pay attention! Is it sturdy enough to survive in your pocket?
2) Heavy = less jitter, sharper pictures. When the camera has more mass, it also has more inertia. This means that you are less likely to shake it when pressing shutter release button, and the camera stays where it is. Thus the pictures happen to be sharper. But still, the best choice is to use a tripod and remote switch for those “super-sharp” shoots.
Mega-pixels: Do you need them? (Cons)
Many people may think that the more mega-pixels you get the better. The truth is, it is a tradeoff. Yes, you can get better pictures with more pixels. But it is going to cost you. You need better (and clean ;-) optics, more memory, and a decent printer. And, if you really want to take advantage of the high resolution, then you should save the pictures in raw (usually TIFF) format, resulting in huge files. In some cases, one memory card is too small for a picture in this format, or barely fits one. Note, that 5-mega-pixel picture does not fit in 5 mega-bytes, but rather 15 megabytes, since every pixel is made up from 3 bytes (24 bits). That will barely fit on your 16MB memory card. Also, eventually you may find out that you are not using all these millions of pixels and could have gotten away with a smaller camera, and saved a hand or a leg in the process.
Mega-pixels: You might want them! (Pros)
However, if you occasionally find yourself of willing to make a big picture (or a poster), Then the high mega-pixels will start to matter to you. As a 3 mega-pixel camera Olympus C3040 seem to be a good compromise. If you want higher, I suggest Nikon 5000 as an excellent 5 mega pixel toy for under $1000. Anyway, check for the newest models.
Here is a table of how MPs usually scale to a nice quality picture sizes:
1MP -- 3”x 4”
2MP -- 8” x 10”
3MP -- 11” x 14”
5MP -- 16” x 20”
Mega-pixels: The dirty secret...
Here comes the “big secret”, which the digital camera marketers might not want to reveal, or even know themselves. A Mega-pixel is somewhat misleading measurement. For instance, let us consider a 4 mega-pixel camera. What this really means is that the digital camera has 4 million sensors (about 2000x2000 array) on the image detector array. However, not every pixel can assume “any” color. They are usually arranged in groups of four pixels (about 1000x1000 2x2 cells), where one pixel measures red intensity, one - blue, and two detects green intensity. Thus you in fact get an array of 1 million “any-color-pixels”.
Moreover, the colors (red-green-blue) are sampled at different locations, and then the real pixel color is interpolated relaying on the neighboring pixels. There are different ways and algorithms to do this, and every camera may have a different one. Thus different cameras may yield different, more or less realistic color pictures. This is one of the major deficiencies of the digital photography versus traditional, film-based one, where every pixel can be of “any” color (depending on film).
Due to the effect mentioned above it may make sense to go for the higher mega-pixel count, hoping that the granularity of the 2x2 cells will be finer and thus no image artifacts will be created. However, if you are taking a really fine grain, multi-color picture, you might get surprises due of the side effects of the different color pixel location and interpolation algorithms.
However, there are good news at the horizon. As all the technologies, digital photography is evolving, and there are next generation cameras being designed to sample all colors at every pixel. As an example you can read more about Foveon X3 technology and cameras here http://www.foveon.com/. And, if you are rich enough to buy one, why don’t you buy one for me, too :-)
The lens
Faster lens - lets more light energy to pass through the optics and hit the camera sensor array. This means better pictures at lower light conditions, such as days when the sun is behind the clouds, or indoors. Another advantage of such lens is for shooting action, where fast shutter speeds are essential, thus less light gets to the sensor over the time of the exposure.
For instance, Olympus C3040 has one of the fastest lenses (f/1.8) for digital cameras. If you want 4MP camera over 3MP, Olympus C4040 has the same lens as C3040.
High Zoom capabilities - it is great to get closer. But mind you, zooming in lets you capture less light, which may lead to lower quality images. More importantly, if you zoom, your camera becomes more susceptible to vibrations of your hand, when you press the shutter button. Less movement is needed to move image across the frame. Hence, tripod (and a remote switch) is highly recommended.
Macro mode – do you really need it? OK, you can shoot pictures of coins, flowers and bugs, but how often do you think you will do it? Unless you are a numismatist, jeweler or big time naturalist. Also, alternative is to use macro filters (1x,2x,4x...), that you can buy separately for about $30-$50, and combine according to your needs.
Smart Media vs. Compact Flash media vs. Memory Stick
Memory stick is a great and highly versatile memory media. However, it is also highly proprietary, which means, you will be stuck with mostly Sony products. I prefer to be flexible.
Compact Flash (CF) interface these days comes in quite high capacities, especially when you go for the IBM 1GB micro drive. However, the Smart Media (SM) thin cards seem to be slightly more compact, and have the interface contacts more reliable for multiple insertion operations. Also, the micro drive is a bit more power-hungry than the memory cards. There goes your camera battery life.
As for the interface to your computer -- most cameras provide a cable to USB or Serial port for picture transfers. However, I have found out that to have a designated CF/CM interface device permanently attached (through USB) to my computer is more convenient. This also saves camera batteries, and the need for the power adapter for the camera (unless you want to show pictures on TV, which some cameras allow). Such adapters can be purchased for about $15-$35.
Batteries
No free lunch here. You are going to have to buy them or recharge them quite often. In most cases it will be cheaper to use rechargeables, keeping another spare set in your pocket. Therefore a free charger and/or rechargeable batteries bundled with your camera is a bonus. You may need to buy an extra set, though.
Some cameras use proprietary rechargeable cells, such as some Sony and Nikon cameras. Pros: the cameras “know” what they are using, and they may have better efficiency, higher capacity. Cons: if all your rechargeables are gone while on a trip, you can not buy a set of regular batteries at the local drugstore and keep taking those “precious moments”. You need to recharge. Another hint here: see if you can get a car-adapter for the battery recharging unit.
Movies
Many cameras allow to record movies in Quicktime (MOV) or some other format. The length of a movie clip is determined by the amount of internal camera memory (not the media size). However, once one clip is finished and processed, you can shoot more clips until the media card is full. My 64Mb smart-media card allowed to store about 180 total seconds of video clips on Olympus C3040, each clip taking at most 75 seconds. Also, you can decrease the clip quality and fit more.
The movies are usually recorded at 15FPS. There might be no animation or antialiasing effects, rather the movie is constructed as a series of snap-shoots, which makes the result to appear somewhat jerky at this frame rate. Also, the cameras use data compression which leads to some artifacts in the frame images. For instance, shooting tall downtown buildings with many windows from a distance, the window pattern could be converted in a pattern producing diagonal lines rather than a grid. I have noticed effects like this on several occasions.
The movies may or may not include sound recording, however at fairly low quality.
I hope you get the picture, these are PHOTO cameras, not video. Therefore do not expect to buy one toy to cover both purposes and be overly happy.
There is life after the camera: The software
Most digital cameras are bundled with limited image editing and/or printing software. I usually find them insufficient or hard to use. Therefore I use tools from my own collection.
I can suggest that you search the Internet for public, "free" license image editing software, because there is such out there! My favorite is IrfanView (use www.google.com to find it). VERY nice and capable, both for single image and batch editing. Also my first choice for picture demos on the laptop screen.
MS Windows come with Paint (under Start -> Programs -> Accessories) -- this will allow you to do simple drawing and editing things, for example, putting a text onto an image. MS Office comes with more sophisticated image editing tool: Microsoft Photo Editor, which allows to sharpen or soften your image and to adjust brightness and contrast among a few other features.
You can also spend quite a bit of money and buy Photoshop - one of the most recognized image editing software product. But it is not cheap, And I have been able to do everything I need with other (free) software tools.
Some cameras are bundled with plug-ins for Photoshop. These are software add-ons which allow extra features to be added to Photoshop for image manipulation, improvement or storage. For instance, Nikon is bundled with Genuine Fractals - a Versaci favorite for image enlargements (you can find an article where he praised Nikon and the software).
As far as printing 4 or 6 or ... pictures per page, Many cameras (including A101) come with ArcSoft's PhotoPrinter software, which allows you to lay out several pictures on a page. Very simple to use and convenient software.
It takes some know-how: Read books first
Now that you have all the great possibilities that software post processing allow you, It is good to know what to do. A few “gotchas” here:
- Increasing the size by 100% in one step may give lesser quality results than in many small 1-5% increments. However, this technique can actually produces worse results with some resampling algorithms, other than “bi-cubic” interpolation used by the Photoshop. Try it both ways, and choose the best.
- Increasing sharpness is a one way street: be sure to keep a copy of the original image in case you want to revert to it. Well, usually software allows you undo option, but not if you have done it several times.
- Sharpening is the last improvement you should do on your picture, after all the other improvements such as resampling, red-eye and noise reduction, etc.
- Keep your originals! Often it might happen that you want to revert to the original, because the improvement did not work, or you want to frame the print differently.
How do you learn these things? From experience. Talking to people. Reading books and web information.
Let the hunt begin
A few questions you might want to ask yourself before going to the digital camera market:
What are you going to do with the camera? How often?
-- Why do you need one. Do you? Can you afford one? Should you?
What you want, what you need and what would be “nice to have”?
-- Sanity check between I want and I need.
What fits your decision: do your homework. Parameters, quality, reliability.
-- Write down what do you need to do your photography tasks. Low-res camera for fun? Hi-res macro mode for jewelry reproductions? High speed lens for low light conditions? High shutter speed for sports events? etc.
Shopping: retail stores vs. the Internet?
-- It is easier to return stuff to the retail store. It is usually cheaper to buy stuff on the Internet. Choose respectable retailers in either case.
Cheap shopping: avoid “Bite and switch”.
-- Some (Internet) stores advertise very low prices on camera. But then, before delivering the camera to you, they might press you into buying rather expensive accessories or “warranty” plans. Or sell you a “grey-market” camera, with no accessories, or “European” or “Japanese”, or some other model which may not be as usable in your own country, and will make warranty virtually nonexistent. Beware!
Homework: More info sources
Be sure to check out several reviews of the camera by different authors. At Epinions I strongly recommend reviews by Howard_Creech. They are not just informative and professional, but also fun to read.
Feel free to check out other websites, such as http://www.imaging-resource.com and www.DPreview.com which offer nice comparison charts and search tools by camera parameters. Another way is to go to a basic search engine on the Internet such as www.google.com and search for your chosen camera model. And talk to people, who know the stuff.
Conclusion:
Digital camera is often an expensive toy. But it can also be a good tool of skill.
It may promote laziness, for example “now I can take 1000 pictures and keep only 5 that are nice.” But you can also learn good skills of picture taking without being afraid to waste film (you’ll waste batteries though :-)
In any case, digital photography is a lot of fun. And beautiful things may get created.
Good Luck!
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Epinions.com ID:
elomage
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Member: Leo Selavo
Location: Pittsburgh, PA, USA
Reviews written: 15
Trusted by: 3 members
About Me:
Education and experience: graduate degree in computer science. Interests: computers, electronics, photography.
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