Tuesday, November 5, 2013

what do numbers on 35 mm nikon camera lens mean?

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Rico


I am confused by what all the numbers mean on a 35 mm nikon camera lens .. for example . .Nikon mount 28-75 2.8 tamron lens .. what do all the numbers mean and what is the difference .. this is very confusing .. thank you


Answer
OK I'll break it down for you, and I'll try to explain everything
So lets hold up our imaginary lens, the Nikon Mount 28-75 2.8 made by Tamron:

Nikon Mount: the technical name for this is called the "F-Mount" and has been in use by Nikon for many years, so you can get great deals on used older lenses

28-75: That is the "focal range" of the lens (in terms of millimeters). It is telling you how wide the pictures can be (28 mm in this case) and how zoomed in they can be (75 mm). Of course, that means that, on this particular lens, you can take pictures anywhere between 28 and 75 mm.

2.8: that is called the "Æ-stop". This part is a little counter-intuitive, but the smaller the number, the bigger the aperture hole is. The aperture hole is what controls light amount of light entering the camera. So a little Æ'ing math:
Æ2.8 will let in more light than Æ4, and Æ4 will let in more light than Æ5.6

However, there is a catch: the smaller the Æ-stop is, the amount of the picture that will be in focus drops off quickly. So on a picture shot at Æ2.8, there will be a very Shallow Depth of Field
[example: http://en.wikipedia.org/wiki/File:Shallow_Depth_of_Field_with_Bokeh.jpg ]
On the flipside, a picture shot at Æ32 will have a much bigger Depth of Field [example: http://en.wikipedia.org/wiki/File:Jonquil_flowers_at_f32.jpg ] <-- that is the 28-75 tamron lens, but on a canon instead.

Tamron: the lens maker.

Hope that helps a little bit :)

Why do my glasses look like a fish eye?




Tyler


I barely ever wear my glasses because I can't stand this. I don't know what kind of glasses I have or anything. I usually wear contacts. When I put them on for the first time, I tripped down the stairs (lol). My contacts seem normal, but it looks like I'm looking through a fish eye camera lens with my glasses.


Answer
BK is right. If you wear your glasses often enough your brain will learn how to deal with the strange distortion. Even glasses of moderate strength will initially give a noticeably different perspective until the visual processing centre of the brain becomes accustomed to them. Contacts give less distortion because they sit directly on the eyes.




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