Is This A Good Lens????

Discussion in 'Digital Photography' started by SolracSelbor, Mar 1, 2008.

  1. SolracSelbor macrumors 6502

    Joined:
    Nov 26, 2007
    #1
    This lens seems pretty nice. Anyone have experience with it or lenses similar to them?
    [​IMG]
    http://www.pentaxslr.com/lenses/lens_18_250
    Lens mount:

    - PENTAX KAF2 mount
    Lens construction:

    - 16 elements in 13 groups
    Angle of view:

    - 76° - 6.5° (when used with PENTAX Digital SLR camera body)
    Diaphragm control:

    - Fully automatic
    Number of aperture blades:

    - 7
    Minimum aperture:

    - f/22-45
    Metering system:

    - TTL open-aperture metering
    Minimum focusing distance:

    - 1.48 in (0.45m)
    Filter diameter:

    - 62mm
    Maximum magnification:

    - 0.28X
    Maximum diameter:

    - 3.0 inches (75mm)
    Maximum length:

    - 3.4 inches (85.5mm)
    Weight (w/o hood):

    - 16.0 oz. (455g)
    Hood:

    - PH-RBB 62mm
     
  2. -hh macrumors 68020

    -hh

    Joined:
    Jul 17, 2001
    Location:
    NJ Highlands, Earth
    #2
    Maximum aperture?

    Ah...there it is: f/3.5 -to f/6.3


    Naturally, it depends on what you plan to use the lens for, and at f/6.3 at the telephoto end, this is about the slowest you'll find, as most consumer autofocus systems stop before f/8, and recommend no worse than f/5.6 As such, I'd expect the lens to become quite slow and "seeky" at focusing under less-than-bright conditions, so I'd read through some online reviews to see if the reviewer found any issues there.

    Thus said, I think that it has some promise to be a decent 'walk around' lens, probably not unlike the Canon EF 28-135mm IS for film (and today, full frame), or Tamron 28-200, plus some more range overall. In any event, particularly when you're in the realm of a 10:1 zoom range, I'd read the reviews to see where the optical compromises are, specifically the amount of pincushioning when wide versus the lens going soft at tele.


    Glad to see it comes with a hood, but do watch out for the lens/hood combination probably shadowing any built-in strobe when wide.


    -hh

    PS: check to see if the hood can be reversed & mounted on the lens backwards for storage.
     
  3. balofagus macrumors regular

    Joined:
    Jan 11, 2006
    Location:
    Ontario, Canada
    #3
    The Pentax and this Tamron are the same lens in different bodies. The only changes are a Pentax housing, name and addition of SMC. Quality starts dropping as you zoom (which is to be expected). The hood is reversible for storage. I haven't used it, but I think it could make an all right general walkaround. Look up some reviews; reviews for the Tamron will apply too.
     
  4. SLC Flyfishing Suspended

    SLC Flyfishing

    Joined:
    Nov 19, 2007
    Location:
    Portland, OR
    #4
    Most at Pentaxforums.com are plenty happy with this lens. Just curious, are you considering this for the efficiency of having all that range on one lens? If not, I'd probably reccomend getting the Tamron 70-200 f/2.8 when it comes out, having a fast constant aperture would be really handy, especially at the tele end where fast shutter speeds are handy to combat the shake that even the Pentax SR system can't completely eliminate. You can't get 1/250th in anything but the middle of the day at f/6.3 or whatever the max aperture was on the 18-250 at the tele end.

    But like I said, if you're OK with all the compromises, that lens has people raving at the Pentax forums.

    SLC
     

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