Lenses in general

[cowasaki]

I have a Nikon AF-S 18-200mm f/3.5-5.6 VR2 DX ED IF lens which I bought when I bought my D200 about 18 months ago. Now this lens clearly goes from 18mm right up to 200mm and is f3.5 @ the 18mm end again rising to f5.6 at the 200mm end. I understand all this and can use the lens.

Now I also have 3 prime lenses a 50mm f/1.8, a 85mm f/2 and a 105mm f2.8. I bought the 105mm specifically to use as a macro lens and I bought the 50mm because it was dirt cheap (about £50) and everyone had been raving on about it.

I really like the 50mm as I can get really good small dof shots and the same with the 85mm (although I miss the AF).

I have been looking at my next lens and was going to get the new 35mm but I plan to get a FF camera later in the year so not now sure.....

Now getting to the point of my post.....

I see a lens that is say 17-55 and costs about twice what my 18-200 cost. The speed of the lens at that relevant zoom is only f/0.7 different.... Not a massive amount, what other differences are there? How does the quality actually change when you move up from a mid range lens like mine to something 'better'. With the laws of diminishing returns is there much difference?

This is a serious question because I do not know where to go with my next purchase and I don't, for example, want to buy a lens that is not going to give me any better quality or range. I do not have the money to get everything I want but I would like a longer zoom, a wider angle and another quick prime (around 28-35mm ish). I have seen some 10-20mm lenses which look like a good next step. I am about to start a photography degree so will be looking at several difference genres. This purchase is not going to be for a few months but I would like to know how much money I will need to find.

 

[Martyn...]

The Nikkor 17-55 f2.8 is a constant f2.8 throughout its range, the 18-200 minimum aperture changes throughout its range.

The Nikkor f2.8 zooms are a level above the 18-200, both optically and in build quality.

If you are considering the D700 the Nikkor 17-55 is a DX lens so is not ideal for your future D700, however it is a stunning lens for your current cropped sensor camera.

Options to consider, the older Nikkor 20-35mm f2.8 zoom, which was replaced by the 17-35mm f2.8 zoom (which now fetches silly money used), the 20-35 should be no more than £400.

Another really good older Nikkor is the 35 - 70 AF D f2.8, these should be well under £300 used, these were replaced by the 28-70, then the 24-70.

If you want a 35mm prime, I have the 35mm AF D f2, and think it is a great lens, there are a few that do not, but most like it.

 

[Woodsy]

^^^ All very good points. I used to have the 17-55, and it was a frankly brilliant lens. As said above, the constant aperture is very usefull, and the optical and build quality is far superior imho.

I believe that spending the premium on good glass is money well spent.

 

[Flash In The Pan]

There's a huge difference in both and build quality between the 18-200 and 17-55, which accounts for the huge difference in price, however optically the 17-50 Tamron isn't a great deal far behind the 17-55, so it might be worth having a look at that if you're on a budget.

 

[OutLore]

Although you say it's only 0.7 faster than the 18-200, that's only at 18mm

At 55mm, the 18-200 has a max aperture of f4.8, 1.5 stops worse.

 

[puddleduck]

I see a lens that is say 17-55 and costs about twice what my 18-200 cost. The speed of the lens at that relevant zoom is only f/0.7 different.... Not a massive amount, what other differences are there? How does the quality actually change when you move up from a mid range lens like mine to something 'better'. With the laws of diminishing returns is there much difference?

Both the Tamron 17-50 and Nikkor 17-55 are significantly better than the 18-200 VR in the overlapping range.

For example (no exaggeration) my Tamron 17-50 @ 50mm wide open has better corner sharper than a Nikkor 18-200 @ 50mm stopped down to f/8. Ditto for the Nikkor.

This isn't really a surprise - the Tamron is about 2 stops faster at f/2.8 and covers less range.

I've never been a fan off the 18-200 VR, I'll be honest. You don't have to look far (or spend as much) to get much better performance.