At f2.8, optically, is the 50mm f1.8 AF-S any better than the 50mm f1.4 D?

Discussion in 'Nikon' started by wade_thompson, Sep 25, 2011.

  1. Thinking of upgrading for the focus improvement to the AF-S, but was wondering if anyone had an opinion at f2.8 if the 50mm f1.8 AF-S is any better optically than the 50mm f1.4 D?
     
  2. ShunCheung

    ShunCheung Administrator

    I suggest you buy the f1.4 version only if you are planning to use it at f1.4 quite a bit. The two 50mm AF-S are decent lenses from Nikon, but they are not among Nikon's best.
     
  3. I'd go for the Sigma 50mm f1.4.
    Kent in SD
     
  4. The Sigma is a nice lens, but Wade is asking specifically about optical performance at f/2.8. If you look at the various sites that do test results (Photozone has the same tests run on the three lenses using a D3X) the Nikons do a lot better in resolution and CA at 2.8. And the Sigma is a $500 lens, more than twice as much as the 1.8G.
    I've hardly used the Sigma lens but have experience on the two Nikons at issue and to me they seem equal when stopped down a bit. I give an edge to the 1.8G because the 1.4D's bokeh has a more geometric quality due to the aperture blade design. But both the Nikon lenses will deliver an excellent image.
     
  5. ShunCheung

    ShunCheung Administrator

    It happens that I captured the attached image this morning with the 50mm/f1.8 AF-S on my D700. I stopped down to f2.5, not exactly f2.8 but quite close. I think sharpness is just fine. The details on the girl's hair, sweater, etc. are excellent. Therefore, IMO, it is not worthwhile to research any minute difference among different 50mm lenses.
    The Sigma 50mm/f1.4 is a $500 lens, even more expensive than the Nikon 50mm/f1.4 AF-S. Therefore, if the Sigma is not "better," something is very wrong. It is also a much bigger lens with a larger front element that requires a 77mm filter. At $220, I think the Nikon 50mm/f1.8 AF-S is just fine from my point of view. Both Nikon's 50mm AF-S lenses, 1.4 and 1.8, use 58mm filters.
    It is well known that AF speed on the Nikon 50mm/f1.4 AF-S is on the slow side. It is also a little slow on the f1.8 but I never had both lenses at the same time to compare. However, e.g. my 60mm/f2.8 AF-S macro clearly has faster AF than the 50mm/f1.8 AF-S.
    00ZNog-401439584.jpg
     
  6. thanks Shun, that's very good information.
    I already own the f1.4D and I was thinking of trading for the f1.8 AF-S for focus speed and focusing noise reduction alone and was wanting to see if there was another bump in bokeh and/or sharpness at f2.8 which is where I shoot 80% of my portraits.
    thanks to all.
     
  7. It's only a slow to medium speed AF. The AFS 50mm lenses appear to be optimized for accuracy instead of speed.
    (Accuracy gives me nothing to complain about, and speed - I wouldn't want to use it for sports, but that's not what a
    50mm is for anyway.) The only advantages I can see are noise and bokeh, unless your current setup is not focusing
    accurately enough for you.
     
  8. ShunCheung

    ShunCheung Administrator

    I think even the AF speed on the 50mm/f1.4 AF-S is prefectly fine; it is certainly not fast, but few will use it for sports anyway. For its intended applications, it is ok. My impression is that AF on the f1.8 version is slightly faster; it takes about half a second to AF from close up to infinity. But without both lenses sitting side by side, it is difficult to judge.
    Here is another sample captured @ wide open f1.8 on a DX body: D7000. It gives you an idea how the background is rendered. ISO 800 affects the quality somewhat, though, but that is not a lens issue. Looking back, I should have used ISO 400 and 1/125 sec.
    00ZNth-401529684.jpg
     
  9. pge

    pge

    It is also worth noting that the AF-S is easier to hold than the -D, being a small lens, having nothing spinning in your hand when you are AF'ing is nice. Not Wade's question, but still it is something that I noticed when I made the switch from my pre-d to the g.
     
  10. Shun is always very knowledgeable, answers accurately and very helpful. His comments are worth considering.
    Regarding autofocus speed Wade is concerned which he thinks shud be better with faster AFS lens, Theoretically it is correct . I saw AF test on a website, (for which I forgot name/link). that site has shown w examples that all lenses faster than 2.8 will not Auto focus accurately.
    Thus we have to rethink for accuracy of AF faster lenses and I fully agree that F1.4 shud be purchased if it is really used at its max aperture.
     
  11. "all lenses faster than 2.8 will not Auto focus accurately" My fast lenses must be defective as they always focus accurately.
     
  12. pge

    pge

    and in fact the lens at issue in this post, the 1.8g, is faster than 2.8 and considered a great focuser by many, which has also been my experience with it. However I do not dispute that using an aperture larger than 2.8 does make focusing more challenging.
     
  13. Taking a shot with very short depth of field, close up or at large aperture or whatever, is a focusing challenge because you have to nail just the right spot and any focus flaws will be visible. If your lens goes to 1.4 but you're using it at 2.8, it won't be more difficult to get the right focus than if your lens were a 2.8 lens. In low light it's easier on the AF system because the lens lets in more light while the AF is operating, before the lens is stopped down to take the shot.
     
  14. There's a well done test on the net somewhere that I've viewed several times comparing the 1.4 and 1.8 at various apertures. In a nut shell the 1.8 doesn't fully match the 1.4 (afd) until F4. It doesn't do bad mind you but the 1.4 is a bit better at f2 and F2.8
     

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