Results 1 to 8 of 8

Thread: wat does all the numbers mean?

  1. #1

    Default wat does all the numbers mean?

    i'm thinking of getting a dslr as i've been playing ard with s3pro, d70 and now got the chance to touch d200..been using s3pro n d70 with its kit lens 28-70mm b4 only. the d200 is with 70-300mm. other than these 3 models, all these while i've been using prosumers camera s5000 and s9500 only..

    i'm still quite confused by all the lenses zoom no. eg. 70-200mm, 80-200mm, 18-70mm etc etc..
    larger no. mean zoom len that can zoom further rite? how come 70-200 n 80-200 only 10mm difference but the price like so much different?
    and 18-55, 18-70, 18-105 they all got wat differences beside the prices? 17-55 n 18-55 any difference? seem like prices differ quite alot too if i rem correctly while browsing one of the thread..

    does small no. ie 17, 18mm means macro lens? or just wide angle? n how does a len get labelled as macro lens?

    sry these might be realli some noob questions but this has been bugging me for a long time and i dun dare to buy the dslr yet as i dun even know wat these type of lens means...

  2. #2
    Senior Member Galdor's Avatar
    Join Date
    Jul 2006
    Location
    Planet Gaia
    Posts
    9,544

    Default Re: wat does all the numbers mean?

    Well, let this newbie try to answer your questions.

    1) 70-200mm, 80-200mm, 18-70mm etc etc these are focal length. The bigger the numbers, the further you can zoom into.

    2) Focal does not really determines the price of a lens. Other factors include the coating of the lenses, the scarcity of the lens and the maximum aperture of the lens. (eg. a 70-210 f4.5-5.6 is less expensive than a 70-210 f4)

    3) A 17mm or 18mm is basically a wide angle lens. Macro lenses are dedicated lenses which allow you to go very close to your subject for magnification of 1:1 (eg. Tamron 90mm or Sigma 105mm). There are some zoom lenses with have the Macro feature too. Usually lenses with longer focal length will give your better bokeh.

    Hope I got it correct and have helped you in your queries.
    Last edited by Galdor; 10th February 2007 at 09:19 AM.
    Minolta. Konica Minolta. Sony

  3. #3
    Senior Member
    Join Date
    Nov 2004
    Location
    Changi
    Posts
    2,242

    Default Re: wat does all the numbers mean?

    and 18-55, 18-70, 18-105 they all got wat differences beside the prices? 17-55 n 18-55 any difference? seem like prices differ quite alot too if i rem correctly while browsing one of the thread..

    The difference in price could means that the quality of the lenses, i think the 17-55 you see is the f2.8 which is a fast lens compare to the 18-55 f4-5.6 that come with the kit. If its a IS or VR, its a image stabilitizer or Vibration reduction technology.

    This lens features Canon's latest optical Image Stabilizer technology, providing up to 3-stop compensation for image blur caused by camera shake and slow shutter speeds. This ensures clear, crisp images, even in dim light

    Same for Nikon, its vibration reduction technology has the same function.

  4. #4

    Default Re: wat does all the numbers mean?

    Quote Originally Posted by pg12 View Post
    i'm thinking of getting a dslr as i've been playing ard with s3pro, d70 and now got the chance to touch d200..been using s3pro n d70 with its kit lens 28-70mm b4 only. the d200 is with 70-300mm. other than these 3 models, all these while i've been using prosumers camera s5000 and s9500 only..

    i'm still quite confused by all the lenses zoom no. eg. 70-200mm, 80-200mm, 18-70mm etc etc..
    larger no. mean zoom len that can zoom further rite? how come 70-200 n 80-200 only 10mm difference but the price like so much different?
    and 18-55, 18-70, 18-105 they all got wat differences beside the prices? 17-55 n 18-55 any difference? seem like prices differ quite alot too if i rem correctly while browsing one of the thread..

    does small no. ie 17, 18mm means macro lens? or just wide angle? n how does a len get labelled as macro lens?

    sry these might be realli some noob questions but this has been bugging me for a long time and i dun dare to buy the dslr yet as i dun even know wat these type of lens means...
    Picture quality is not determined by focal length.

    Other factors to consider for lenses :
    1) External Build (tough or not)
    2) Lens elements, group and quality
    3) Maximum aperture possible at different focal length (this very much determines the fastest shutter speed you are able to obtain at a certain ISO. The bigger, the more versatility and more difficult to manufacture and therefore more expensive)
    4) Difficulty of manufacturing (wide angle and large aperture at long focal length are much more difficult to get better quality and therefore cost much more).
    5) Bokeh rendered (dependent on some of the above factors. Most people want a nice looking smooth bokeh which isolate the main subject very well.)
    6) Image stabiliser (yes or no.)
    7) brand (different brand has different quality and also different premium in their prices relative to competition.)

    Anything below 35mm is considered wide. But with sensor sizes smaller on most DSLRs, even 28mm isn't exactly wide because it has the same field of view as 28x1.5=42mm on a 1.5x crop factor DSLR. 17mm or 18mm is considered wide and not Macro. Macro is about the relative size of the physical image on the image sensor vis-a-vis the actual subject's physical size. For e.g. if a bee is 1cm in physical size and its physical image on the 23mm x 16mm APS size sensor on a DSLR is also 1cm (i.e. 10mm), there is a 1:1 magnification here and this is what macro lenses are capable of : shooting near enough to get a low magnification factor such as 1:1, 1:2 etc. The nearer you shoot from, the more details you get resolved by your lens and captured on your image sensor. If a lens is not macro capable, it is unable to get proper focus at short shooting distances to get a low magnification. (Go to the websites of the lens makers and you would see the differences in minimum shooting distances for macro and non-macro lenses).

    If you have low magnification such as 1:1 and you blow up the image from a APS size sensor to viewing sizes (such as 6" x4"), the 1cm bee will appear as about 6.7cm (or about 45.8x magnification in area) and thus a lot of details can be seen in the picture. If you had shot it with a normal lens and stand quite far away in order to get a proper focus, your magnification may be 1:10 and so your 1cm will be only 0.1cm (1mm) on your image sensor. This means that if you blow it up to 4R (6" x 4") picture viewing, your bee will only be 0.67 cm or 6.7mm. Although you can do a very tight crop on photo editing software and then blow it up so that the bee appears as 6.7cm on a 4R picture, you would have lost a lot of resolution and details because your lens have much less resolution of the bee from a further shooting distance and also less pixels on the image sensor capturing the bee and therefore less details have been captured on the image sensor.

    Just in case you might ask, the different focal lengths for different macro lenses are for different shooting distances to get the magnification wanted. Sometimes, you are unable (due to physical barriers) or, for fear of danger or scaring them, do not want to go so close to the subject (bees, ants, small animals etc.), you would need a longer focal length and shoot slightly further away but yet still able to get the magnification (such as 1:1) you want on your image sensor. To some people, true macro is only 1:1 while some others think up to may be 1:4 or even 1: 6 is still marco.

    It's always better to know more before jumping into buying or otherwise, you may end up with something which do not meet your expectation and needs.
    Last edited by Clockunder; 10th February 2007 at 10:39 AM.

  5. #5
    Member
    Join Date
    Dec 2006
    Location
    Tampines.Sg
    Posts
    126

    Default Re: wat does all the numbers mean?

    you would need something from 28mm till 300mm zooms (in 35mm film equivalent) for most of ur basic needs like taking group family/frens photo, holiday trips, portraits (with nice blurred background=bokeh) and some nice flowers.

    cant compare prices with zoom coverage the very same way cant compare prices of cars by number of wheels.

  6. #6

    Default Re: wat does all the numbers mean?

    so if wanna haf a better zoom lens, a 70-300 is better than a 80-200mm?
    how do u define a len whether it is fast or slow?

    my prosumer cam has a len of equivalent 28-300mm.. does that mean it can zoom as far as that 70-300mm len of a dslr?

  7. #7

    Default Re: wat does all the numbers mean?

    Quote Originally Posted by pg12 View Post
    so if wanna haf a better zoom lens, a 70-300 is better than a 80-200mm?
    how do u define a len whether it is fast or slow?

    my prosumer cam has a len of equivalent 28-300mm.. does that mean it can zoom as far as that 70-300mm len of a dslr?
    two types of fast

    -af fast
    -brightness... refers to the f-stop

  8. #8

    Default Re: wat does all the numbers mean?

    oh.. thx very much for all the comments. roughly haf some idea.. will posted some pics of a rugby match taken by d200 with 70-300mm soon later in the nite.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •