Saturday, 25 October 2008

AFS Micro Nikkor 60mm f/2.8

I rented a Nikkor 60mm f/2.8 over a weekend so that I could compare its performance with my Nikkor 50mm f/1.8. The results can be found here.

dibyendumajumdar's Nikkor 60mm f/2.8 AFS versus 50mm f/1.8 photosetdibyendumajumdar's Nikkor 60mm f/2.8 AFS versus 50mm f/1.8 photoset

I wanted to find out whether the 60mm could be used as a replacement for a standard 50mm lens for general photography. The answer seems to be a 'yes', if you are happy to give up 2 stops of speed. My tests are not scientific, but they seem to indicate that the micro nikkor has the edge over the 50mm lens at comparable aperture stops. What do you think?

I also hope to try out the Sigma 70mm f/2.8, which according to some review sites, is the sharpest lens in the Sigma line-up.

Tuesday, 21 October 2008

My dream lens

My dream lens is one that is reasonably fast (f/2 at least), has exemplary sharpness right from the maximum aperture, is affordable, and has a camera that delivers great image quality up to ISO 1600. Not much to ask for but alas, there is not such a lens in the market.

Only Leica lenses seem designed to work well right from the maximum aperture. An illustration of this can be found at this comparison of the Nikon Millennium S3's 50/1.4 versus Summilux ASPH 50/1.4. Okay, this is not a fair test, as the Nikkor is a remake of a very old design, but I am pretty sure that the current SLR standard lenses from most brands, including Nikon, do not match the Leica's performance at f/1.4.

But the Leica is way too expensive. And doesn't have a camera that can exploit the quality of the lens.

Inconsistent exposure with Nikon D80

Recently I shot some test pictures with my Nikon D80 and a Nikkor 50mm f/1.8 lens. To my surprise, there appeared to be an inconsistency in exposure. I shot exactly the same scene at f/1.8 and at f/2.8. The exposure at f/1.8 seemed perfect, but the shots at f/2.8 were over exposed.

The test photographs can be seen at my Flickr Photostream.

Ken Rockwell discusses the D80's propensity for over exposure. Searching on Google reveals many others have faced similar problems.

Tuesday, 7 October 2008

High anticipated 50mm f/1.4 Nikon Lens

The recently announced 50mm f/1.4 AFS Nikkor was much anticipated for several reasons:
  • The existing 50mm Nikkor will not autofocus with the newer range for low-budget Nikon SLRs.
  • The 50mm f/1.4 design hasn't changed in two decades, and as with most lenses that were designed more than 20 years ago, the design was looking slightly outdated.
Still, I had almost given up hope that Nikon would introduce such a lens. Nikon's policy in recent years has been to focus on Zoom lenses. No doubt their lens sales indicate this is where the market demand is. What many people who criticize Nikon for not releasing exotic primes don't realize is that for many years now, Nikon's lens production seems driven by "what sells". During the film era, Nikon had a range of "prestige" lenses, which looked great on paper, but few could afford to buy. Ever since Nikon lost ground to Canon in the professional market in the 1990s, and its profitability plunged, Nikon changed its strategy. No more indulgences, all lenses must sell (and presumably make a profit). If you are a lens designer working at Nikon, it must be very hard to get any exotic lens design past the marketing guys.

How many people buy the 50mm lens anymore? It would be interesting to see some statistics. I am sure that the majority of the 5 million Nikkors sold in the last year were mostly zoom (kit) lenses.

I want a good 50mm lens that performs well under low light conditions. It is no good having an f/1.4 lens that performs well at f/5.6 but poorly at f/1.4. I am not talking of sharpness alone. At f/1.4, most lenses handle point sources of light very badly due to coma aberration. I haven't tested the old 50mm Nikkor AF-D, but I know that even the Zeiss ZF 50mm f/1.4 doesn't handle coma very well at f/1.4.

I remember that one of Leica's main selling points was that its lenses were designed to perform well at their maximum apertures. I still remember that in a brochure they had provided comparisons of a night scene shot with the Summilux-R 50mm f/1.4 and an unspecified competitor lens.

The introduction of the Sigma 50mm f/1.4 lens was interesting because of the special attention Sigma had paid to the correction of coma aberration. Sigma claim that even at maximum aperture, this lens is very well corrected. Surprisingly, the two tests published so far (DPreview and Photozone), do not test this aspect of the performance. This goes to show that most testers do not test a lens for its primary design goals, they just apply a simplistic yard stick to judge a lens, regardless of the especial characteristics of each lens.

With the new AFS Nikkor f/1.4, Nikon are also claiming good correction of coma, but it is not clear whether this is at maximum aperture. Surprisingly, Nikon have not used an aspherical lens element in the design (they used an aspherical lens element in the famous 58mm f/1.2 Noct-Nikkor and in the 28mm f/1.4 Nikkor to correct coma). I think this has something to do with preserving a good bokeh. This is probably the same reason why the 85mm f/1.4 Nikkor doesn't have an aspherical lens element. Cost probably is no longer an issue, as aspherical lens manufacturing has improved considerably, but I could be wrong.

The lens is much smaller in size compared to the Sigma. It remains to be seen whether its maximum aperture performance is better than the Sigma. I would expect the bokeh to be better, but coma correction to be worse.