Is phase detection that good?

Discussion in 'Sony Alpha E-Mount Cameras' started by alaios, Jul 13, 2013.

  1. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    Hi all,
    yesterday I was reading a book for my nex-f3. If I understood right nex-f3 does not have phase detection and it can get it through the LA-EA2 adapter (by also using the appropriate series A lens).

    1)Does it really pay off to have phase detection and invest money for such an expensive adapter or go for the simplest LA-EA1
    2) Any comments how slower the LA-EA1 autofocus is compared to the camera's version?
    3) What do you think about what the above says regarding less light 30% for the autofocus to work
    4) How better is the autofocus (what you feel) with LA-EA1 and LA-EA2?

    I would like to thank you in advance for your help
    Regards
    Alex
     
  2. NickCyprus

    NickCyprus Super Moderator

    Oct 11, 2012
    Cyprus
    Nick
  3. Electric Shepherd

    Electric Shepherd TalkEmount Regular

    103
    May 12, 2012
    Leicestershire, U.K.
    Ben
    As usual, it depends. If you're considering shooting moving fast moving targets such as sports, wildlife etc, then phase detection will make your life much, much easier with a far greater success rate.

    I've tried shooting sports with my Nex and it really struggles compared to my Nikon D300. Maybe not entirely fair, but the AF speed of the contrast detection AF on the Nex is dismal in comparison. So if rapid AF is required then the LA-EA2 and A mount lenses could be your way forward. If not, and you're mostly a landscape or portrait shooter, then I really wouldn't worry about it.

    As regards 30% less light, that applies to all SLT equipped devices including Sony's "SLR" range. Some light is reflected off the mirror to the AF module and so there is less to hit the sensor. A bit of a trade off but not probably all that significant in the real world.
     
  4. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    NickCyprus: This A mount lens is quite cheap
    Electric Shepher: How much you needed that in sports? Is manual focus really too tough for real action?
     
  5. Electric Shepherd

    Electric Shepherd TalkEmount Regular

    103
    May 12, 2012
    Leicestershire, U.K.
    Ben
    Well people managed using MF for shooting sport with for decades of course, but I think it's a skill that's hard to manage. Since I have the right tools for the job, I've stuck with AF all the way.

    Partly it depends on the sport of course. In a track event say, the runners are taking a predictable path that's easy to track or you could prefocus on a point that you know they will be at. Sports with more random movement such as football or tennis will be much more of a challenge, even more so as you'll typically be using a large aperture resulting in a narrow depth of field and less forgiveness of missed focus.
     
  6. Electric Shepherd

    Electric Shepherd TalkEmount Regular

    103
    May 12, 2012
    Leicestershire, U.K.
    Ben
    BTW, just for a laugh while talking of MF for sports, just imagine how this Pro was managing when I noticed him at Wimbledon tracking the action with an old Rolleiflex:

    9210419398_6eab81ecdf_c.
    Odd one out... by Pam & Ben, on Flickr
     
  7. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    Nice find! Well, the Rolleiflex user is using the sports finder, so what's not to like? :D
     
  8. Bimjo

    Bimjo Super Moderator

    Oct 28, 2011
    Washington State
    Jim
    Yeah, assuming he's practiced with it I imagine he gets a pretty good keeper rate. Does look strange in that setting though. :)
     
  9. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    I do not see me shooting spots, I mostly need a zoom for some park shooting, and bringing closer while in the streets daily. The cheapest AF lens is at 260 euros while I think there would be way cheaper mf alternatives. What I am gonna miss with outdoor photography with manual focus? Would it be too hard to focus on slightly moving duck in a river, for example?
     
  10. Electric Shepherd

    Electric Shepherd TalkEmount Regular

    103
    May 12, 2012
    Leicestershire, U.K.
    Ben
    Sounds like you could get by with a MF zoom. There's a bit of skill involved vs AF, but you could get a very cheap zoom lens to practice with and have lost very little if you can't get on with it.
     
  11. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    Thats my guess indeed. I am looking for some zoom (55-200,70-300 or something like that) to take out to walks that is manual (as this will reduce the cost).
    What are your suggestions around 100euros ebay prices? I can give a bit more if I can also take more focal lengths like (18-200)
     
  12. gio

    gio TalkEmount Veteran

    382
    Sep 12, 2012
    Manchester, uk
    in days of old, sport was not all that difficult, you pre focused, read the distance from the lens, chose your shutterspeed to get as wide an aperture or fast a shutterspeed as possible and that was it,just waited for the action to arrive at your chosen spot, no zooms in those days, just pick a spot to focus on the seen a lot of action
     
  13. Electric Shepherd

    Electric Shepherd TalkEmount Regular

    103
    May 12, 2012
    Leicestershire, U.K.
    Ben
    Do you already have any legacy glass adapters?
     
  14. alaios

    alaios TalkEmount All-Pro

    Jan 11, 2013
    Düsseldorf
    Alex
    PK to NEX and MD to NEX
     
  15. Nex Tex

    Nex Tex TalkEmount Regular

    46
    Jul 25, 2013
    There is a very cryptic reference to phase detection, and I've only had the Nex for two so I honestly haven't tried it and don't even know its capabilities. Is this explained any where?
     
  16. LightCentric

    LightCentric TalkEmount Regular

    28
    Mar 17, 2013
    Saginaw, MI
    Andy Richards
    I couldn't find anything in the pdf that Sony gives you with the camera. David Busch has a book out on the NEX7 which does a pretty good job of explaining how phase detection and cotrast dection works and the differnences. You might also try Googling the two terms. I'll bet you will find an explanation.

    One thing I learned that was a definite PLUS for me is that because of the contrast detection AF, you can use a linear polarizer on these lenses and they are significantly less expensive.
     
  17. Amamba

    Amamba TalkEmount All-Pro

    Apr 13, 2013
    SE MI
    I am unfamiliar with PDAF on Nex, but from what I understand it's not the same as the dedicated PDAF circuit on DSLRs, so it's not going to be as fast.

    Another thing to watch out for is that while PDAF is faster, it can also be less accurate than CDAF.

    When I traded Canon for Nex, my stills keeper rate went up and my action keeper rate went down.
     
  18. Nex Tex

    Nex Tex TalkEmount Regular

    46
    Jul 25, 2013
    On the Nex 6, is phase detect on by default or does it need to be turned on? Is it always on for apertures faster than 6.3?
     
  19. Amamba

    Amamba TalkEmount All-Pro

    Apr 13, 2013
    SE MI
    I own two zooms, Minolta MD 70-210/4 Macro, and Kiron 80-200/4.5 Macro, along with Kiron MC7 2 x converter.

    The Minolta is slightly heavier, but it also has slightly better IQ. I took Kiron with me on vacation and generally had no problems taking photos of running kids. For what you want to do, either of these lenses coupled with a good teleconverter and a tripod/monopod would give you maximum range and flexibility without breaking the bank.


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