Site Sponsors
Results 1 to 7 of 7

Thread: So on the Auto Focus....

  1. #1
    Senior Member
    Join Date
    Dec 2010
    Posts
    2,115
    Post Thanks / Like

    So on the K-5 Auto Focus....

    Ok, so I tried it this morning in daylight (cloudy) and noticed that:

    - it's pretty fast and good
    - yes, the size of the area seems big. If there is anything more detailed than the point you are focusing, it will back focus
    - colors with Chroma/slide under cloudy WB seem to work rather well. No red magentas though still some "happy reds" on car lights, I notice at least can selectively be brought down. Still not quite a fan but better.

    So the question then is- how to take a shot of something that is smaller. I guess the AF system is just not built that way. So either it assumes you are using a telephoto lens and by virtue of the shorter DOF it may pick whatever seems most in focus when you point (say a bird with a telephoto) or if you have a wider lens, then you have to come closer or point to a similar distance region.

    Or use live view
    Or use manual focusing.

    - Raist

    PS: Need to now try this theory in harsh light / low light like last night.
    Last edited by raist3d; 18th December 2010 at 11:33. Reason: more precise title.

  2. #2
    Senior Member
    Join Date
    Dec 2010
    Posts
    2,115
    Post Thanks / Like

    Re: So on the Auto Focus....

    Someone mentioned in DPreview that a French Magazine went on an expedition, testing the K-5 in the real world and also noticed that somehow the K-5 got in focus some hard to get subjects while missing some others that one would expect to "just get." Kind of similar the experience I am describing.

    Anyway, just need to corroborate what I first wrote.

  3. #3
    Super Duper
    Senior Member

    Join Date
    Dec 2007
    Location
    Germany
    Posts
    3,623
    Post Thanks / Like

    Re: So on the Auto Focus....

    I took some images with the K5 in dim and "medium-dim" light today (x-mas) and the AF is not good. I would say 70-80% front focus (even though I had fintuned my lenses some days ago.
    So yes, I agree that either in Dim light/ and or mixed light something is NOT good.

    The camera feels great but the results from the M9 and A900 were much better focused ;( ;( ;(

    Either Pentax improves this or the camera is not reliably usable in dim light for me.

  4. #4
    Super Duper
    Senior Member

    Join Date
    Dec 2007
    Location
    Germany
    Posts
    3,623
    Post Thanks / Like

    Re: So on the Auto Focus....

    Now I took the same scene in natural daylight, and the AF seems better.
    So I start to believe what I have read somewhere else that it could be a problem with artificial light or certain color temperature. However it could be also just a problem of low light.
    Anyways - the somewhat no so bright viewfinder (and smaller than a ff camera) makes it specially in those conditions also unpossible to check with the eyes if the focus is correct or not.
    So right now the K5 for me is not a reliable choice for artificial/ available light photography. I hope a lot that this can be improved in the future. Its not about some shots being off, its about most shots being off (in my case frontfocused).

  5. #5
    Member
    Join Date
    Jan 2010
    Posts
    178
    Post Thanks / Like
    Images
    3

    Re: So on the Auto Focus....

    Here is the AF under artificial light thread: http://forums.dpreview.com/forums/re...ssage=37284828

    Pentax, you need to sort this stuff out! I am tired of my E-620

  6. #6
    Workshop Member ptomsu's Avatar
    Join Date
    Nov 2007
    Location
    Austria, close to Vienna
    Posts
    3,867
    Post Thanks / Like

    Re: So on the Auto Focus....

    Same with my K5 - did some shots at ISO 6400 (very dim light) and all are front focused.

    Will try to calibrate the 18-55 in good light, but so far in good light I did not see and focus problems wit that lens

    I hate it ....

  7. #7
    Workshop Member ptomsu's Avatar
    Join Date
    Nov 2007
    Location
    Austria, close to Vienna
    Posts
    3,867
    Post Thanks / Like

    Re: So on the Auto Focus....

    Played around with AF Tuning and finally I ended up calibrating both my 18-55 and DA70 to -6 (Back Focus), which seems to be the optimal value for them.

    This also showed (what of course should be expected) that the DA70 is the far more sharper and better lens of the 2 (WRT IQ).

    Was surprised that both lenses needed the same AF calibration, so I suspect the AF calibration is needed because of the AF in the camera.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •