Tuesday, February 16, 2010

Why a 50mm and not my kit lens that came with my camera?

         With the little time I have been taking my photography seriously I have discovered the importance of fast glass, as they call it in the business.  What that means is the speed your lens will allow light to pass through to make and exposure on your sensor. How can you tell if you have fast glass? Every lens will give you its specifications on the side for example with the D90 outfit you receive a kit lens. This lens tells you what is its max aperture is and the zoom distance on the side in gold lettering.
AF-S NIKKOR 18-105mm 1:3.5-5.6G ED

         This means the lens has Auto focus (AF), has a zoom distance from 18mm all the way to 105mm, and the max aperture when fully zoomed out as wide as it can go at 18mm will be  3.5 and when fully zoomed in will be 5.6. You might ask why does it change when you are zoomed in? If you notice when you do zoom in on your subject the lens becomes physically longer in shape. Thus the light must travel all the way from the front of the glass to the back making it harder to get as much light in at one time. In the case of the 18-105 having  the lowest you can get the aperture to 3.5 means this lens will really only be effective in good light such as outdoors or in a very bright room. The lens comes with VR (vibration reduction) built in. Using this function on the lens you will find that images that might have become blurry from a slight hand shake or movement of your body will be accounted for inside the lens and the camera will actually let the element almost float inside the lens to help make the image as clear and sharp as it can be. This will help in low light situation but is defiantly not a fix all. For taking low light photography you are not going to get the outcome you had wanted from this lens. You can use it and might get one or two images that you like but for the most part you will have to jack up your ISO very high causing your images to become very grainy. ISO is very important for low light shooting and really can make or break an image if used correctly. But that is a post for another time.
                So what lens will work well in low light that will not cost me an arm and a leg?
      This is a question I get asked all the time. Especially by people who have just had babies or are just interested in taking pictures indoors but still have bright color full images. There actually is such a lens out there that works like a dream and will not hurt your bank account that much. It’s the Nikon 50mm 1.8 or 50mm 1.4. As we have already learned those numbers tell us the max aperture the lens can achieve. I own the 50mm 1.8 so I will talk on that model. 

       The 1.4 is just as good if not a little better but the lens is almost double the price of the 1.8. This is because of the jump from 1.8 to 1.4 that allows you to get just that little bit more light in thus giving you a faster shutter speed. No this lens is known as a Prime lens. This means that it is a fixed focal length at 50mm. So unlike the 18-105 we cover earlier you will not be able to zoom in and out. The lens stays at its length forcing you to do the moving. So the main reason for this lens being such a great tool for new parents or event photos is that mat aperture is so low. The trade off for having sure a low aperture number is the incredibly shallow depth of field you get at those numbers.  What I mean by that is that at aperture 1.8 if you were lets say focusing on a subject face for a portrait you might get the nose and their eyes and rest of their head would be blurred out. This is really something you have to practice and play around with till you feel comfortable you are getting all you want out of your images.  A good way to discover for yourself how your camera will do with this lens is to mount it on your body and turn your Nikon onto A mode (aperture priority) as you spin the command dial up and down increasing and then decreasing your aperture watch your shutter speed increasing and decreasing. In the end it really comes down to what you are looking for. This lens at just over $100 is a steal and I think a MUST for anyone interested in really getting the most out of their cameras.

 A couple weeks ago at my nephew pictured here on the right had his birthday dinner at a local Mexican restaurant. This was a perfect place to let the 50mm do it think. Take a close look at the images to see the beautiful blur and sharp focus parts in each image. All I am doing to playing around with my aperture finding the best one for each image…… 


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