Cristiano on Tech/Life

Together with my acquisition of a D80 came the time to get a nice prime lens. I had been looking at the Sigma 30mm F1.4 for a while, but at a whooping £234 it is way more pricey than some of the alternatives. I therefore decided to go for the Nikkor 50mm F1.8 prime. The lens has a bit longer focal length than the Sigma, which (on my D80 with a crop factor of 1.5) makes it a nice portrait lens (~75mm). It has the added “bonus” of not having a build-in focus motor, which makes it cheaper and lighter (and unusable on my D40).

The Lenses

The lens comes in two “versions”. The first version, labeled the Nikkor AF 50mm F1.8 was made first released in 1986. It is easily recognizable by the large pushpin on the side.

The pushpin locks the aperture ring into place. On most modern cameras you will want to keep the aperture ring into the highest aperture number (F22) so it’s a bit big for such a useless function. The rest of the lens feels pretty solid, dare I say heavy.

The second lens that’s a interesting alternative to the Sigma is the Nikkor AF-D 50mm F1.8. Notice the little added “D” that was added tot he previous model. By specification the new lens (launched in 2002 and replacing the previous model) is exactly the same. The most noticeable cosmetic changes are the loss of the push pin and a more plastic (and lighter) casing.

Technically there’s one more important difference between the lens with and without the “D”, except for the fact that the earlier version has only one layer of coating. Which brings us to the showdown.

The Showdown

So what is the real-life difference between the two lenses? First off there’s a price difference of about £15 depending on where you get it. This doesn’t sound like much, but as the modern model goes for about £80 this sums up to about 18%. For a student or amateur on a budget the non-D version is therefore an interesting option.

In performance though, the lenses seem to be very, very different. I like most of Ken Rockwell’s articles on lenses, but in this case he seems to be rather wrong labeling the D functionality as a “almost meaningless feature”. To understand the difference between the single coated and multi-coated (D) lens you have to understand that lenses with large apertures quickly suffer from lens flares. Coating on a lens can help prevent the lens flares to some level and this makes a lot of difference.

Here is a photo I took with the single coated lens.

As you can see in the left bottom corner there’s a big lens flare. It’s not that much of a problem in this photo but it also shows up as a more annoying and larger flare in normal conditions (I couldn’t find any of the worst photos because I deleted them already). 

The modern multi-coated lens still has this issue sometimes but not as large and intrusive as the single-coated version. It is for me at least the reason to get rid of the non-D version and get myself a D version. Even with a hood on the older version still generates massive lens flares and discoloration from time to time. A good example is this photo I took of Reinier:

Conclusion

It seems that the AF-D lens performs much better under low light conditions with consideration to lens flares. Yes, the older version can be found about £15 less but it’s definitely not worth the trouble of lens flares and lack of build quality.