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04/28/2007 03:57:32 PM · #1 |
im doing a report for class on digital photography, and weather the info i have is correct, can i get some feedback? also its not done and i need to know what iso stands for, and a good definition for it.
here is what i have so far...
Think of a camera? Chances are it was a slim, sleek camera with a large LCD screen. That’s a good start, but to really get total control over photography, a digital SLR (Single Lens Reflex) camera will be needed. Some photographers will say film is better, but with increasing technology, digital is just as good and more versatile. In fact many companies such as Nikon and Canon are slowly discarding all of their film camera bodies. The age of technology has come, its time for an update.
Today, digital SLRs are affordable and user-friendly. Digital SLRs allow easy-to-use menus. Also, they allow for instant previews of every photograph taken, which time, and money is saving. Unlike digital point-and-shoot cameras digital SLRs have the option of using interchangeable lenses. For instance, a point-and-shoot can only shoot pictures at 35mm-50mm, but a digital SLR can shoot at any focal length as long as the lens attached is able to achieve that length.
Lenses are probably the most important piece of equipment to own. It is important to get a lens that fits the type of photography the consumer will be doing. It is also important to remember that lenses are what make a good picture, not the camera. There are many features to look for in a lens that will be important to the type of photography the user will be doing. The main features are focal length, glass quality, aperture, IS (image stabilization), and overall lens size.
Focal length is the range that the lens is able to achieve. It is also the main reason that a certain lens is sought after. Many photographers carry multiple lenses due to the different ranges they will need. There are five main categories of lenses: standard, telephoto, fixed, wide angle, and macro. Standard lenses usually cover from 18mm to 75mm and have a variety of options to choose from. Telephoto lenses are used to reach out to normally unachievable distances than that with a standard lens, they have the largest range of all the lenses but you will need more than one lens to cover the full range. Telephoto lenses cover from 70mm all the way to telescopic lengths. Fixed lenses tend to be the highest quality, however they are the highest priced. Fixed lenses only have one focal length, which means they can fit more features into it. Too, fixed lenses lack in versatility, making these lenses only really useful in the studio, or a controlled environment.
Macro and wide-angle lenses are their own breed of lens. Macro lenses feature the ability to focus on extremely small things at very short distances. Macro lenses have a large array of focal lengths anywhere from 10mm-135mm they can be very handy to own. Wide-angle lenses have the ability to capture an extremely large view of something that a normal lens would not be able to fit in its focal length, with focal lengths from 10-50mm it can be used as an all around lens for walking. They are usually small and convenient to have on the camera at all times.
Glass quality is the most important thing to look for in a lens. The quality of the glass itself inside the lens will determine the overall sharpness and quality of the image when a photograph is taken. However, like most things in photography, “you get what you pay for”. The highest end glass inside even the most basic lens will run the consumer over seven hundred dollars. Mostly professionals use these lenses, but it is not uncommon to see the average consumer carrying one around. Many companies for example, Canon have separated their “professional” lenses from their “consumer” lenses by marking them in some way. In Canon’s case their “L Glass” (professional quality) it is a simple yet dignified thin red stripe around the end of the lens.
When shopping for a lens, the consumer may hear the phrase “fast lens” from the sales representative. The phrase “fast lens” is referring mainly to the aperture. Aperture is like a diaphragm that limits the amount of light through the lens to get proper exposure. The lower the aperture number the more light it allows into the lens. More light into the lens means that a properly exposed photo can be achieved in low-light conditions. Like high quality glass, a low aperture will boost the price of a lens. As the lower the aperture number goes that means the lens manufacturer will have to make and fit smaller pieces into the lens.
Image stabilization and aperture go hand in hand when it comes to lenses. If a long exposure is needed at a large aperture, image stabilization will keep the image sharper because it counteracts minor shaking by the photographer or tripod. Image stabilization is not a magical feature, it cannot handle moderate to excessive vibrations. Image stabilization is not just for long exposures, as it is popular in many telephoto lenses. It is used in telephoto lenses mainly when it is zoomed into a large focal length due to that even the smallest vibration can cause an unsteady view. Lastly, image stabilization is used in action sports photography; it helps in focusing on the moving objects and creating “bokeh” or blur, behind it.
Many lenses are high quality, and many lenses are versatile, but it all depends on the intended use. The overall size factor will depend on what the consumer will be doing with it. Someone who hikes may not want to have a two foot long lens hanging around their neck while they are climbing, perhaps a telescoping lens that gets the same focal length as that lens just more compact. In this situation there will be compromise, for instance the aperture will get larger and the quality will be greatly affected. However the lens may still have image stabilization and other useful features. If the consumer is going to be doing professional photography, for say a career, it would be totally practical to carry around an excessively long lens. In the end, it is all user preference, and it may take a few tries to get it right.
The camera body, perhaps the most overrated piece of equipment a photographer can own. Granted one is required when using a DSLR but the most expensive one may not be better than the cheapest one. If a consumer is mainly taking family photographs, a less advanced body will usually cut it. There are 4 main things to look for in a camera body when in the market for a new body. They include photo resolution, LCD (liquid crystal display size) size, shutter speed, FPS (frames per second), along with other minor things.
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04/28/2007 04:20:05 PM · #2 |
The Acronym ISO stands for the International Standardizations Organization.
ISO, formerly called ASA, is a measure of the light sensitivity of the digital camera's sensor. In electronic terms it is called gain. The higher the ISO setting on a digital camera, the greater its sensitivity to light and and the higher the electronic gain. Also, the higher the ISO the greater the amount that the inherent noise of the sensor is magnified and recorded resulting in "noisier" images.
Message edited by author 2007-04-28 16:20:33.
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04/28/2007 04:24:26 PM · #3 |
I kind of skipped around while reading, but I would disagree with your last point about "four main things to look for".
Shutter speed is fairly uniform across all cameras. There really isn't much point in using that for comparisons. In SLR, you'll usually see a maximum speed of 1/4000 and a minimum speed of 30/1 in combination with bulb, which has no limitation at all.
LCD size is... not all that important, IMO. The increase in the size of LCDs on newer bodies isn't so much out of necessity, as it is the lowering cost of small, higher-resolution LCDs.
The four most important points (IMO) would be Comfort (a very personal choice), Versatility (does the camera have all of the features you need and/or want), Resolution (duh), and Lens Availability (a wonderful camera body with low availability of lenses isn't all that useful).
The last is largely a moot point with the larger manufacturers, unless you have special requirements. Certain lenses only available with certain models of camera, compatibility with 'legacy' lenses, etc. |
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04/28/2007 04:38:57 PM · #4 |
ISO = International Standards Organization
They publish standards.
Specifically related to photographic sensitivity is ISO 6:1993 - Photography -- Black-and-white pictorial still camera negative film/process systems -- Determination of ISO speed
and
ISO 2240:2003 - Photography -- Colour reversal camera films -- Determination of ISO speed
and
ISO 5800:1987 - Photography -- Colour negative films for still photography -- Determination of ISO speed
There are other standards related to the sensitivity of other photographic materials, but those are things like printing papers and aerial film.
You can purchase them from ISO, but that gets pricey. I purchased two ISO standards on measuring acoustic absorption of materials and they were nearly $50 each. If you have a university nearby, they often have the entire set as part of their collection and you can usually get a copy from them for free.
Message edited by author 2007-04-28 16:43:28. |
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04/28/2007 05:08:15 PM · #5 |
I disagree.
There are two main categorys of lenses, primes and zooms.
and some sub-categorys like;
(I'm refering to cameras with a x1.6 cropfactor and nothing else when I'm listing focal-lengths)
Wide-angles: 10-24mm
normals: 25-45
telephoto: 46->
And I wouldn't call primes studio-only lenses, there are great many photographers who work with primes, two of the reasons why I prefer primes for example are the size and the speed(larger aparture).
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