I think you're trying to grasp too many variables at the same time. First choose a camera type to meet your needs. Smaller camera classes such as ultra-compact and compact will have smaller sensors. DSLR are larger and will have larger sensors..
Within each class of camera size there will be some variety of pixel count. For an 8x10 or 12 inch print 6MP will serve you well..
After you've decided on what sort of camera you want decide on what focal length range of lenses you need to get the photo's you're interested in. With ultra-compacts and compacts the lenses are fixed to the camera and cover a popular range for many but not all people and situations. If you go the DSLR route you can change lenses and choose lenses that meet general or more specific needs..
What is your objective? What sort of photo's are you after? How much equipment do you want to carry?..
Yes you might be true, I may be trying to grasp too many things & get some technical knowledge out of it..
Basically I am trying to gather technical knowledge of the specifications that camera vendor's present and how to interpret those specifications to choose a camera for me when I buy one for me. I am just a starter and not trying to become a pro, and want to know for my personal knowledge as-well because if I don't understand the specifications and how they effect I can't buy good camera and without knowing my camera can't do good photography too..
I don't want to carry much equipment but only a little & can hang one around my neck rather in my pocket. Rest will depend on my clarifications if I buy a prosumer or DSLR...
What I was able to get from one of the articles if understoodcorrectly is that smaller the sensor size, higher the zoom I couldget.
No. "Zoom" is just a ratio between two numbers the maximum focal length of a lens, and the minimum focal length of a lens..
A given focal length will give different magnifications and fields of view depending on sensor size. So a Canon S2 IS superzoom, with it's zoom lens set to 6mm, may offer roughly the same field of view as a 35mm SLR using a 36mm lens, or a Nikon DSLR using a 24mm lens. (I say roughly because the S2 IS takes photos that are TV-shaped, while the other two cameras take pictures that are 4x6-shaped.).
Also are all those lenses with various mm-ranges defined keeping 35mmfilm/sensor size or is it something else?.
You'll usually see (D)SLR lenses advertised using their absolute focal lengths and point-and-shoot zooms advertised using "35mm-equivalent" focal lengths. (But on the barrels of point-and-shoot lenses, you'll see absolute focal lengths in tiny print.).
"35mm-equivalent" length is convenient because.
(a) many people are accustomed to what absolute focal lengths mean on 35mm cameras..
(b) there are many different sensor sizes for P&Ss and DSLRs, so direct comparison of absolute focal lengths often is not meaningful. Even for DSLRs, there are crop factors of 1.0 (35mm-sized full frame), 1.3 (Canon), 1.5 (Nikon), 1.6 (Canon), and 2.0 (Olympus Four-Thirds system)..
But note that you can only define it with respect to a (lens, sensor) combination. Move a lens from a Canon Digital Rebel XTi to a Canon EOS 5D, and while the lens does not change, the pictures you get at a specific setting do...
The marketing trick is the words can have different meanings depending on which class of camera you're talking about..
For instance in the ultra-compact, compact, prosumer range lenses tend to be rated in terms of zoome range. Ex: 3x or maybe 10x zoom. This tells you nothing about the end points of the zoom range, only the difference between the two. If they do specify the focal length range of the lens it's typicaly in terms of 35mm film (analog) camera equivalent. It's very important to realize that focal length of a lens is a property of the lens itself. The lens does not change based on the size of the sensor behind it..
In the DSLR world lenses are typically specified in their true focal length (not converted to 35mm film equivalent)..
A prosumer type camera has the advantage of convenience, the disadvantage of less range of possibilities. The DSLR is less convenient and requires more work of the photographer to produce a good image, but has increased possibilities..
I continue to assert, decide what sort of photo's you're trying to take first. Then decide on the equipment to meet that need. Since you are a beginner spend as little as possible on equipment and learn by experience. With that experience you will better understand. Many people see the need for a compact/prosumer in some circumstances and a DSLR in others. You won't go wrong as long as you don't go equipment happy and buy gear as a shortcut to gaining experience with the gear you have..
Chances are you should start with a midpriced compact or prosumer and gain experience. If you decide to move up to a DSLR the original camera will still be of value...
Let me put differently. suppose I have two cameras both 10x zoom but with different sensor sizes & let zoom be my only priority. At this point what will be the effect on how far I will be able to zoom..
Will this be [ 10x + small sensor = 10x + large sensor = same zoom range ] or will it be.
[ 10x + small sensor !=(not equals) 10x + large sensor = different zoom range ]..
Will this also have effect on Angle of view or it depends from camera to camera..
Since DSLR's too come with different sensor sizes. Attaching same lens to different sensor sized DSLR might have similar effect as above. Please correct me if I am wrong..
After this is cleared I think ill ask on 35mm equivalence topic..
Also please don't ask what kind of photography I am after, as I myself don't know that, but as a consumer of a product I believe I should know what these specifications mean to choose a right product later on apart from my interest in photography.==========..
The larger the sensor the larger the lens..
A small sensor of 1/2.5" will need a smaller lens than that of a larger sensor of 1/1.8". Look at the difference between Panasonic FZ8 and Panasonic FZ50.The larger the zoom the larger the lens.Look at the normal 4x lens and at 12 x lens or Canon A570 and Canon S5.The higher the speed the larger the lens..
It's more obvious in dSLR world where the f/2.8 lens are much larger and heavier than usual f/3.5-f/5.6 lens.VictorBucuresti, Romaniahttp://s106.photobucket.com/albums/m268/victor_petcu/http://picasaweb.google.com/teodor.nitica/..
Thanks you gave good examples.
A small sensor of 1/2.5" will need a smaller lens than that of a larger sensor of 1/1.8". Look at the difference between Panasonic FZ8 and Panasonic FZ50..
So should I consider that D40 will zoom more than 450D, since 450D has bigger sensor if same lens is used with both of them.
Also these have 35mm equiv values such as for Panasonic FZ8(1/2.5") it is 36-432mm and for Panasonic FZ50(1/1.8") it is 35 - 420 mm. What effect does these have on the zoom, since these are different values and zoom range specified is same 12x. If not on zoom what other thing does they effect============..
If they do specify the focal length range of the lens it's typicaly in terms of 35mm film (analog) camera equivalent. It's very important to realize that focal length of a lens is a property of the lens itself. The lens does not change based on the size of the sensor behind it..
What I was able to get from a article on net is that if sensor size decreases the focal length required decreases if angle of view remains same. So that means if for small sensor if I use a lens with particular focal length with small sized sensor it will have zoomed and if large sensor is used zoom will be lesser. am I right. Since DSLR's too come with different size sensors it would have same effect with them too.=============..
Let me put differently. suppose I have two cameras both 10x zoom butwith different sensor sizes & let zoom be my only priority. At thispoint what will be the effect on how far I will be able to zoom..
This is what I was trying to get at with respect to the marketing trick. 4x or 10x or 12x tells you the ratio between the wide angle and telephoto focal length of the lens on a compact fixed lens camera. It tells you nothing about the absolute values of the focal length..
DSLR lenses are typically specified in terms of absolute focal length. For instance 18mm to 200mm (slightly over 11x). Specified in this way you can judge the wide angle effect, the telephoto effect, and the range between the two. Specified only as 11x you don't know where the the endpoints of the focal length are..
To simply explain this you may see both compacts and DSLR lenses converted to "35mm (film) equivanlent" focal length. While this allows you to compare lenses in terms of field of view it ignores other factors such as the depth of field in focus (front to back area in focus) at a given focal length and f/stop. 35mm equivalent is a simple answer to complex question that will lead to improper conclusions..
If you don't know what you wish to photograph get a midgrade compact or prosumer and learn. If you need to move to a DSLR you will recognize it and better know what you need. The compact will and DSLR will complement each other if you find you need a DSLR..
If you find photography a casual thing the compact/prosumer will probably be all you need. If you find it an interesting hobby and are willing to spend the time and money you will probably want at least one of each. Therefore start with the compact/prosumer and learn. It's less expensive this way...