lens - is the Nikon 35mm f/1.8 worth it after i have the kit lenses?

I have a Nikon DX (D5100) camera with the two most basic kit lenses: 18-55mm f/3.5-5.6 VR and 55-200mm f/4-5.6 VR. These two lenses cover lots of scenarios, but I'm starting to believe there is more that awaits me. I'm only a hobbyist, so I'm not sure what exactly :). First of all, I don't want to spend a lot of $. So I started checking out the cheap 35mm f/1.8 prime lens. Reviews say that, with the same exposure settings, the image quality of this lens is superior to mine. However, I started doing the math and got confused.

First of all, the advertisement says that VR effectively gives me +3 f-stops. Am I correct in assuming that the +3 f-stop advantage of VR means that eg. a 1/30s exposure will be as stable as one with 1/240s without VR, and it doesn't change anything else? But I guess it has its limits, so I doubt that it can make anything below 1/30s stable.

So let's compare my lens with the prime lens. Let's say that I set my wide zoom lens to 35mm, max aperture is around f/4.5, VR is off, and let's say that this is too slow for me because it's too dark for example. I can turn on VR, I get +3 f-stops. The 35mm prime lens is f/1.8, which is 2.666 f-stops away from f/4.5. It's not that better, or is it?

I know that advertisements can exaggerate, but I trust Nikon that VR is not totally useless at least. So if my math is correct, then the prime lens is not all that better exposure-wise (except for the supposed image quality). What do you think VR actually gives me and what does the bigger aperture prime lens give me?

Answer

But I guess it has its limits, so I doubt that it can make anything below 1/30s stable.

I think that is not correct and you can go below 1/30s. This depends on focal length of course.

What will the 35mm f/1.8 give you:

• Shallow Depth of Field: It will give you nice background blur if you want it. However, a 50mm f/1.8 with the same framing of an object will give better blurred background (because DoF depends on focus distance, too).


• 2 stops of more light coming in. This allows faster shutter speeds, so you can freeze motion more easily. However, if your subject moves you still have to focus and that doesn't change between these lenses (more or less).


• Prime lenses are generally of better optical quality. This is also true for the 35mm compared to the 18-55 that you have.

Ask yourself, what you want to use it for. It is great for upper-body portraits. Night street photography, and many other things but certainly not for all things.