The limitation comes from the lens resolution. There's a point where more megapixels simply becomes a burden without bringing any perceivable benefit at all. I personally believe with 35mm, it is probably around 20 megapixels. Of course, there is not a clear cut off line, but a gradual approximation.
With 35mm full frame, the first critical point of megapixel arrives at 4M. I will show you why below. Before reaching that point, any increase of number of megapixel resulting a quite strict one-to-one increase of resolution. For example, 2M quite literally has twice as much much resolution as 1M. After that, this will start to degrade. For the matter of better communication, consider a coefficient called ratio between the perceivable resolution increase and the pixel number increase. This ratio is practically 1/1 before the number of pixels is 4M, but starts to fall off gradually after that. My estimate is that it would fall to less than 0.5 when the number of pixels reaches 10M, and probably less than 0.1 at 20M. I'm pretty certain that this ratio approaches 0 by 40M. What that means is that after 10M, the perceivable resolution increase one receives from every 1M increase of megapixels is less than .5M, and after 20M, the perceived resolution increase for every 1M is less than .1M. As a practical matter, after 20M, the more megapixels simply become "the Emperor's new cloth" which really is not there to be seen. It just makes some people happy. And I'm talking about full frame 35mm. For APS sensors, the number is even smaller.
All that is because the inherent limitation of the lens resolution. Take 35mm full frame. I'll use approximation to simplify the explanation. Suppose there are N columns (or rows) of photosites for every 1mm. The total number of pixels of a full frame 35mm sensor is then (Nx36)x(Nx24), which is roughly 1000N^2 (pixels). Now, good 35mm lenses usually have excellent MTF at 30 line pairs per millimeter. Especially at the center of the frame, a good 35mm lens can have 80% or above MTF at 30 line pairs per millimeter. So it is reasonable to take 30 line pairs per millimeter as a baseline. A sensor that matches this resolution would have N=2x30 (two photosites for each line pair), and correspondingly the total number of pixels of 1000xN^2 = 1000x60^2, which is approximately 4M (or slightly less). This tells you two sides of the story. First, on a 35mm full frame sensor, before the number of pixels reaches 4M, most lenses have enough resolving power to take full advantage of the more pixels. Second, when the number of pixels goes beyond 4M, most lenses will not be able to fully take advantage of the increase of the pixels.
That of course doesn't mean that after 4M, the increase of the pixel numbers will have no benefit at all. They still do, but will not have the full benefit due to the lens resolution limitation.
For example, suppose you have a lens that has an MTF value of 50% (or MTF50) at 50 line pairs/mm (meaning that at this resolution, the lens delivers a perceivable contrast of only 50% of the full contrast, i.e., losing 50% of contrast). A sensor that matches this resolution would have N=2x50=100, and correspondingly a total number of pixels of 1000xN^2 = 1000x100^2 = 10M. That means, with this lens, a 10M sensor is able to represent each line pair with two columns/rows of photosites, but with a loss of 50% of contrast at such resolution. It could be said that at this level, you are only getting 50% of the perceivable resolution out of the increased number of pixels.
Now, those who are familiar with lens tests will tell you that a 35mm lens with an MFT50 at 50 line pairs/mm is a very good lens. For 35mm full frame, this is about 1200 lp/picture height.
With a 20M sensor, you need a lens that has an MTF50 with 70 lp/mm or an equivalent of 1700 lp/picture height for full frame. This is already surpassing the optimal resolution (center of the frame with a stopped down aperture) of even the best prime lenses. And we are talking about MTF with a 50% loss of contrast here.
Overall, even with a full frame, going from 10M to 20M has less than 50% increase in perceivable resolved pixels even with the best lenses. You're certainly not doubling the resolved pixels there. Of course, even an increase of 50% can be important for some people who (1) actually need a greater resolution; and (2) actually have possession to the top lenses and use them. On the other hand, with the same technology, going from 10M to 20M will lose at least one full stop of the ISO performance. I have no problem with people's preferences. I just have a problem with people making choices without the necessary information and understanding.
Still, one could make a rational (albeit discounted) argument for 20M for a full frame sensor. But beyond that, it certainly looks like an Emperor's new clothes to me, unless they suddenly come up with drastically better optics, which is extremely unlikely.
Besides, unless you want to make prints larger than 30 inches, you really don't benefit from more than 20M anyway even if you had a lens that could resolve more. And you're not getting those large files as a freebie. They impose a heavy tax on your computer system.
Friday, January 23, 2009
Understanding Resolution - Do You Need More Pixels?
Monday, June 9, 2008
A Digital Still Camera Able to Shoot Video That’s Ready for YouTube
By J. D. BIERSDORFER
Published:
YouTube is turning up everywhere — even on digital still cameras. Casio’s new 8.1-megapixel Exilim Zoom EX-Z80, like a few other recent cameras, features a YouTube capture mode that shoots movie clips in the site’s recommended format and resolution, and comes with software to upload the videos easily to the Web.
The camera, which sells for about $200, records video in the H.264 standard, which also makes the mini-movies compatible for iPod viewing. As a still camera, the EX-Z80 has a 3X optical zoom and a face-detection feature to help improve the focus and exposure of people in a photo. There is also a self-portrait mode that automatically snaps the picture when your face is fully within the frame.
The Exilim EX-Z80 (exilim.casio.com) comes in six colors — green, blue, black, silver and two shades of pink — and has a 2.6-inch L.C.D. screen. The camera incorporates image-stabilization technology and comes with a motion-detecting Auto Shutter feature that snaps the picture as soon as the subject settles down and holds still.
J. D. BIERSDORFER
Thursday, June 5, 2008
How You Win Photography Contests Online
These days, with the advancements in technology, more and more people are buying cameras. It’s very easy to own one because of the improvements in ease of use and maintenance. We don’t have to buy rolls of film just to use a camera. It’s also easier to take great pictures, because we can preview the image that’s going to be taken and if it’s not up to standard, it can be deleted in just a press of a button. No film is wasted, and the photos come out as we want them.
It’s normal practice to bring a camera everyday, especially those that are compact and lightweight. This is so that every important moment is captured and thus, preserved throughout time. With this in mind, more and more people are getting interested in photography and enjoying it. Even non-professional photographers can take very good pictures, and there shouldn’t be any surprise if there are more people who join photography contests, whether it’s for the prize, the recognition, or just for fun.
If you’re one of the many people who enjoy photography, and someday you hope to enter and win a contest, here are some photography contest tips and advice:
- Follow all the rules of the contest
There is always a different set of rules for every contest, and you should be aware of them first and foremost. Familiarize yourself with them and follow them to the letter. You might not understand why some rules are there, but don’t assume you can just disregard them. They are there for a reason. It’s better to follow the rules rather than have your work returned to you because you did not follow the rules.
- Research on past entries
Researching on past winning entries will help you learn more about the contest that you want to join and its standards. If you know more about the standards and the judges’ basis for a good photograph, you’ll have a better edge against the other contestants. You also might get inspired from studying the past entries.
- Study the categories
There are different categories in every contest, and you must consider the requirements of each category before submitting an entry under the category that you’ve chosen. Your photograph should be focused on the category’s topic. Many entries get disqualified for not following the requirements, and it’s sad because the photographer may be talented, but the entry is not even seen by the judges because of a technicality. For example, there are categories that might require your picture to have a few items at the background of the photograph’s main focus. One missing item may hurt your chances in the contest.
- Consider your work with a critical eye
You might have a photograph that you’re really fond of. You might even consider it as your best, because of its meaning to you. Remember, your contest entry will be judged by many different people who are strangers to you. They don’t know the story and circumstances behind your favorite work, and they don’t care. They are also given a set of guidelines in choosing entries, and each of them has unique standards. If you want a good chance of winning, better submit photographs that are good on all technical factors. For your entry to stand out, your subject should be doing some actions. A subject that is doing something is more noticeable and has more depth compared to a subject that is on a pose.
- Send only your best work
There are contests that allow multiple entries, and if you plan on submitting more than one entry per category, it’s better to submit just a few of your best work, rather than submit a lot of entries that include a few decent, but lackluster, photographs. This is to protect how the judges think of your best photograph. If you include a few second-rate photographs, chances are the judges’ opinion on those photographs might dampen their opinion on your best entry. Instead of your best photograph standing out, it might get buried under the mediocre ones.
It’s easier now to take pictures, and it’s even easier to prepare for a contest if you only study how. Apply these photography contest tips and advice, and improve your chances of winning a photography contest.
Tuesday, June 3, 2008
The Best Time To Choose A Wide Angle Lens
First things first, the best time for a wide angle lens is to be used is when you are planning to take a beautiful shot of a landscape.
Another important aspect of landscape photography is the selection of the appropriate light as well as the perfect location of the landscape shot. As much as possible, and depending on what it is being shot, the selection of the appropriate day to catch that landscape picture perfect landscape view is everything.
Lights, location and action
When the location has finally been chosen for the wide angle lens shot, try to notice the light effects visible on the area that you plan to shoot in over a whole twenty four hour day. This ensures that you know how the lights play over the range of mountain, sand or seas. This also helps you plan just how it is you are to go about taking that shot, when and how.
When you finally know, it is therefore time to be a little bit creative. You may include elements in your picture’s foreground in order to have an additional scale and depth to your pictures. Also, feel free to look around from other points in the area where you think the shot could just as well be taken. This may add a little bit of interest to the final picture. Also consider taking a variety of levels and positions.
Time is always of the essence
Believe it or not, in order to avoid any shadows that may appear harsh on the picture, the best time to shoot is early during the morning as well as late in the golden afternoon.
During this time, take your camera out and set it up using a tripod. Then, take a reading of any area of the shot using a light-meter. Once the appropriate measurements have been taken, adjust the speed of the shutter and the aperture.
After all these, all you need to do is to press the release button and take a beautiful picture.
Make use of natural effects
If there are any natural creations occupying your shot, try to use a backlight or side lighting that provides the leaves, – for example – grass, water or smoke an appearance that these seem to be translucent, almost ethereal.
Pictures of a beautiful sunset are best taken just when the sun has gently touched the horizon and immediately a maximum of five – count them - five short minutes just after the sun has finally set.
It is best that you use or position yourself to a geographically high point.
A filtered polarizer may also be used in order to heighten the sky’s color or tone, thus delivering a picture befitting a postcard.
A wide angle lens helps a lot in increasing the picture’s scope.
Do not forget to relax. This prevents the camera from unnecessarily shaking and helping you focus on the subject more than anything else.
Supply yourself with much needed supplies
Since landscape photos are usually taken far from the city and well into the country, it is best that you pack up a host of equipments that enables you to take pictures even during temporary obstacles. A flashlight always comes in handy, bottled water is another (to keep the photographer replenished and not thirsty), as well as a lot of extra rolls of film. This is one equipment that photographers generally can't do without.
Basically, a wide angle lens has a focal length that measures less than forty millimeters. Be aware as well as be wary that the length of the lens changes how an image is seen.
All in all, determining the best lens to use for a particular shot requires a lot of patience, skill and practice. The art of mastering landscape photography doesn't have to be difficult. And the best lens to use for such kind of photography is a wide-angle lens. Getting that that shot right takes not only skill but the strength, stamina and endurance to get to where the location of the landscape is and the energy – upon reaching that location – to get the job done. And when that moment arrives, the job has only just begun.
Saturday, May 31, 2008
Starting A Photography Business
You can start a photography business with only a few bucks, or possibly nothing at all if you already have the right camera equipment. You can even start your business in the comforts of your own home.
You can probably find a small space in your house or a room dedicated for your business. That will serve as your “office” space.
With the advent of digital SLR (single-lens reflex) cameras, you don't even need a dark room to develop the pictures you have taken. All you need is a personal computer with above average specifications and photo editing software such as Adobe Photoshop.
If you want to make your hobby a business, you should not only have your basic camera unit but the additional equipment as well. Of course, you would want your pictures to stand out and be more appealing to potential clients. You would need different zoom lenses and camera filters to make your shots clear, sharp and even have some special effects.
Starting with a few of them will do, then just gradually increase them as your business progresses. You don't even have to make this a full time business right away, especially if you don't have a client base yet. Doing this part time would be sufficient enough while in the start up stage.
Even if you only do this on your free time, make sure you are still dedicated and serious. You won't be able to get enough clients to sustain yourself if you don’t take this business seriously.
Since you are going to make this engrossing hobby a business, there will be some legality that you need to take care of. First, you need to have your business registered and have a name and logo to be able to operate legally. Once registered, you can issue receipts and file taxes for your business.
Also, it would be good to write a business plan. Having one will help you identify your goal for your business and keep focused with this goal. This way, you will know if the business that you start up is worth all your time and effort.
With your business plan, you can also define the different strategies that you can do to make your business more profitable. You can change the business plan from time to time as needed. Having a business plan will surely help your business increase earnings, as well as help you to find ways in financing your business.
Your business plan should include your business’ objectives. This is important because it will help you stay in focus on how you want your business to turn out in the long run. It should also include a marketing plan, how you intend to advertise and market your services to get customers. Also, the price you intend to charge on your services should be included. You may want to change this as your business grows.
With regard to marketing your services, who else can help you better than your relatives and friends. At first, you may want to volunteer your services for free for birthdays and other occasions of your relatives and close friends. For sure, once they have seen your good shots, they will recommend you to their own circle of friends and colleagues.
And it will go on and on until you realize that you are now having difficulty arranging your schedule because of so many appointments. Of course, doing some marketing and advertising techniques would help. You can probably give away flyers or brochures to your neighbors. Or maybe post an ad in your local newspaper.
There are many ways to gain clients. Many people now consider photographs as a very important part in special occasions. Companies also rely on good photos to market their products.
Starting a photography business may be easy to do but it should be taken seriously. For anyone who wants to make serious money, dedication is important. You should also be responsible for all your actions. After all, wouldn’t it be nice to earn decent income with something you love doing?
Thursday, May 29, 2008
The World Of Modern Photography
After the invention of the camera and the growth in popularity of photography, it is only natural that mass production as well as dissemination of photo prints will follow. Because of photography, personal as well as public history, time, and the perception of man himself has notably changed. The idea of privacy became altered as more and more well known public figures and that of the common man were recorded. Photographs became the unchallenged proof of any experience, event, and even a state of being.
Photography as an art
Certifying photography as an art form was a hard thing to undertake during its early stages. It was challenged by artists as well as critics and focused on both the chemical and mechanical facets of photography. They considered photography as a craft and nothing more.
Taking away the restrictions
When musuems and art schools finally opened up themselves to photography, the resulting trend was carried up to the present. Photographers began to set themselves free from the strict impositions made by the norms of the straight aesthetic mode as well as the documentary modes as forms of expressing their individuality. By the 1960's photography became a major force in visual arts. This art form has been combined with other types of expression including computer imaging as well as mixed media.
Practical applications of photography
Photography has many practical applications. It has evolved to become a vital tool used in diverse fields like education, medicine, military activities, and commerce. Science has greatly benefited from photography, including aerial mapping of areas, geology, surveying, archeology, meterology, and anthropology just to name a few.
The digital age
With the onset of the 21st century, images can be manipulated and altered in so many ways with the help of digital imaging and computer utilizing techniques. Digital photography started a change in photographic techniques and its nature. The conventional method of photography involved the passing of light into a lens then to an emulsifying agent or digital photography, where color filters as well as sensors are used to create an image. There are two kinds of techniques used in digital photography. The first one involves the use of 3 layers of filters. Each one only allows one color like green, another red, and the last one, blue.
These are some of the notable things with regards to modern photography. Photography has been present for more than a hundred years and yet more and more innovations are taking place. Looking at it, one can surmise that more things are yet to come in the world of modern photography.
Tuesday, May 27, 2008
Aerial Photography
Origins
Aerial photography is formally defined as photograph taking from an overhead viewpoint by using cameras that are mounted on an airborne tool such as a balloon, an aircraft, a kite, a skydiver and other similar tools. The art of aerial photography was first developed by Nadar, a French airman back in 1858. During the Second World War, aerial photography found a niche in military operations. Aerial photographs were used in spying and in the assessment of the battle ground. These photographs provided updated and realistic impressions of the topography and current situation in a certain area.
Uses of Aerial Photographs
There are many conceived and actual uses for pictures which are taken from above. Aerial photographs are actually used in the construction of topographic maps, in cartography, planning land use, archeology, production of movies, espionage, environmental studies, commercial advertising and in other fields.
The use of technology has also crawled into the field of aerial photography. Advances in radio technology has allowed for the use of aircraft models which are controlled by radio in the conduct of low-altitude photography. This is mainly used in advertising for the real estate business. This is because manned aircrafts are not allowed to fly low altitudes in populated locations. This task can be done by these radio-controlled aircraft models and they do the job very well.
Public Domain
Aerial photographs are considered public domain, because the pictures are taken from aerial views which are considered public places.
There are many ways to view aerial photographs on-line. One of the most popular ones is the Google Earth by Google. Google Earth provides satellite imagery as well as aerial photos of the planet. You can actually use the service to be able to search for different places in a certain area such as parks, restaurants, schools and hotels. It can also be used to be able to track down the best routes for reaching a certain location. You can also view the aerial photographs in different angles by tilting and rotating them.
These are some basic things about aerial photography. If you are interested in learning more about this topic, you can browse through some basic materials at the local library or use the Internet to get more information about it. Technorati Profile
