Significance of DX Lenses?

Discussion in 'Lens Lust' started by kja6, Jul 23, 2008.

  1. kja6

    kja6

    93
    Feb 22, 2008
    Vancouver, Canada
    Assumption (to make answering my question easier): Nikkor 17-55mm f/2.8 DX and Nikkor 17-35mm f/2.8 non-DX lenses are exactly the same in quality, optics, etc. - disregard the loss of 20mm of zoom, as I only care about shooting at the wider end of the zoom.

    Are there any huge advantages to using the DX lens instead of the non-DX lens, described above, on my D2X? I read something about the image hitting the sensor more perpendicularly if a DX lens was used on a cropped body?

    I'm thinking ahead, into the future, about 900 years for when I might become a full-time FX shooter. If so, then the 17-55mm f/2.8 will be wasted. So, if the 17-35mm f/2.8 will do just as well on my D2X (keeping in mind I only care about the wider end of the zoom (they'll both be 17mm x 1.5 = 25.5mm on my D2X)), and that there aren't great advantages to using DX lenses, it might be safer for me to get that just in case I do convert to FX completely.
     
  2. cotdt

    cotdt

    Jul 14, 2007
    Bay Area, USA
    DX lenses have a smaller image circle which allow for greater optical correction, and so they tend to be sharper wide open. But this is an "all else equal" thing, and is not neccesarily true regarding all lenses.
     
  3. kja6

    kja6

    93
    Feb 22, 2008
    Vancouver, Canada
    Hmm.. thanks for the info, cotdt.
     
  4. Steinar

    Steinar

    Aug 16, 2007
    Denmark
    I have shot with the 17-35 lens, but never with the 17-55, so what I write here is from what I have read from others, but I think I have read it so many times, that it maybe might help you.

    The 17-55 lens is sharp allready from f 2.8 but more prone to flare/ghosting than the 17-35.

    The 17-35 lens is sharp from about f 5.6 and about here or maybe lower it is really, really sharp.

    So therefore many says, that the 17-35 is very good for landscapes.

    ---

    The Nikon 14-24 is sharper, but can not use a filter.

    The Tokina 11-16 could maybe also be an option for you. Cheaper than all the others.
     
  5. kja6

    kja6

    93
    Feb 22, 2008
    Vancouver, Canada
    Thanks, Steinar.

    I'm aware of the two lens' optical (in)capabilities, but was wondering if there was anything else aside from that, as in any downsides because a lens is a non-DX instead of a DX, on a DX body... more immediate flaws.

    Thanks for the suggestions, but Nikkor only for me :)
     
  6. Steinar

    Steinar

    Aug 16, 2007
    Denmark
    Hi Kevin

    Sorry, I misunderstood you.

    Thank you for your respons.

    I understand your "Nikon-feelings" - the Tokina 11-16 is the only non-Nikon lens I have among about 9 Nikon lenses.
     
  7. the hood on the 17-35 is cut shorter than it needs to be for use on a DX camera.
     
  8. dan1son

    dan1son

    Sep 24, 2007
    Austin
    Since the DX lens is designed for a smaller sensor they only guarantee consistent light on a smaller area in the back of the camera. That could manifest itself as bad edge performance, blocked light from hoods, blocked light from internal parts, etc. So essentially they can be quite useless on an FX body (when using the sensor in FX mode).

    Those two specific lenses will have varying characteristics. You'll have to let someone else familiarize you with those. But just because both lenses are Nikon F/2.8 lenses that in no way means they're the same optical or will have the same performance, DX or not.
     
  9. mchung

    mchung

    99
    Sep 17, 2007
    Vancouver, Canada
    If you've already investigated the lens IQ differences then I won't get into them. For landscapes (i.e. stopped down), I can barely tell the two lenses apart, and if I were going to give one an edge for corner sharpness and CA control it would be the 17-35. So if landscapes are going to be your main usage, I have no qualms with the 17-35 as a future-proof lens and a lens that compares quite favourably to the 14-24 when stopped down.

    Personally, I've moved on to the 14-24 and 24-70. The 17-35 is still decent on both DX and FX, but by no means gives me the phenomenal IQ of these lenses. I also do people photography and I'm not as pleased with the 17-35 in that sort of situation, but keep in mind I am picky about skin tones. The 17-35 contrasty rendition, while not awful by any means, I feel is more favourable to landscapes. The 17-55 would be my preferred choice on DX for my PJ/event work, no question, as I need the range primarily.

    Yes, digital lenses in general are designed to have more perpendicularity of the light rays hitting the sensor. It's on FX where you really need this retrofocal / telecentric design of the lens or you will get significant corner light fall-off. The 17-35 was designed with digital in mind back in the D1 days so that's not an issue with it though the more recent lenses do improve on the fall-off.

    Note that the 17-55 is also usable on FX as well. It's just at the wider angles where it vignettes significantly on FX. I believe around 25 (?)mm it starts to have full coverage on FX.

    Martin
     
  10. pforsell

    pforsell

    Jan 15, 2008
    Hi Kevin,
    the 17-55 has better boke than the 17-35 and it is cheaper. These are the only positive things that come to mind.

    On the other hand the DX lens suffers from significant field curvature adding the problems of the already soft corners, has strong distortions and tendency for ghosts (bright spots) and flaring (severe loss of contrast) with light sources in the image.

    I was going through the same questions about a year ago, borrowed both lenses, shot loads of test images, and bought the 17-35.
     
  11. Julien

    Julien

    Jul 28, 2006
    Paris, France
    Hum I'm surprised on one jumped on that one ( or I didn't read all the answers correctly ) : the wide end on the 17-55 on your D2X will be just that , 17mm whereas the wide end of the 17-35 will be as you said 25.5 ( because it's not a DX lens ). So if you're only interested in the wider end than the answer is pretty simple …
     
  12. RedTownCats

    RedTownCats

    314
    Jun 23, 2007
    UK
    Sorry, don't understand that. :confused:

    17mm is 17mm, DX/FX doesn't change that.
     
  13. cotdt

    cotdt

    Jul 14, 2007
    Bay Area, USA
    yes but the 17mm on the 17-55, on put on an FX camera will vignette. The 17mm on the 17-35 will cover the whole frame.
     
  14. RedTownCats

    RedTownCats

    314
    Jun 23, 2007
    UK
    Sure, but the focal length remains the same. A 35mm DX lens has the same focal length as a 35mm FX lens; however, as you rightly point out a DX lens may not cover a full frame sensor at some or all of the focal lengths in its stated (zoom) range.
     
    Last edited by a moderator: Jul 24, 2008
  15. the advantage of using an FX lens on a DX body is sharper corners.

    Look at the 70-200 2.8 VR on an FX body, it vignettes quite badly, and corner performance isn't fantastic. However, on a DX body, the sensor is smaller than the bad bits. So the this lens is generally better on a DX than an FX.
     
  16. I'm surprised that nobody's mentioned that the 17-55 actually does cover FX from about 26mm-55mm. And apparently, it performs very well in that range, even on FX.
     
  17. Woah!

    17mm is 17mm is 17mm on both lenses.
     
  18. 17mm is 17mm. I think what you're getting confused with is the crop factor. 17mm will have the same field of view as a 25.5mm on a full frame camera. Regardless of whether it's 17mm DX lens or 17mm FX lens, it will still have the same field of view.
     
  19. guys, the original question is regarding the use of the 17-35 range on each lens on a DX body only, and if the DX design has any advantage over the non-DX design.

    so far it has been suggested that ....

    the 17-55 has better bokeh
    the 17-35 is sharper stopped down
    the 17-55 is sharper wide open
    the 17-35 is more flare resistant
    the 17-55 has the correct hood for DX

    the question is not about focal lengths and FX usage at all.

    personally, if the extra zoom on the DX lens really is of no importance, I recommend the 17-35. getting ultra sharp shots wide open is novelty to me, very difficult to take advantage of in the field, and often easy to work around when you don't have it. I would value the flare resistance as much as any other parameter. But i would also recommend to think twice about that. My brother tried my 17-35 on his DX camera and did say that its a very awkward zoom range.
     
  20. Steinar

    Steinar

    Aug 16, 2007
    Denmark
    Two of my best lenses - 35-70 f/2.8 and 70-200 VR are prone to flare/ghosting.

    I can work around it .... at least at some level, but I would be happy if I do not have to do that, and it is not always possibly, so I agree:

    I also value the flare/ghosting resistance very much and it will be one of the things I will look for, when I buy new lenses.