Samyang 14mm, focus confirm works for stars?

YellowJerseyYellowJersey Posts: 3Member
edited June 2015 in Other Manufacturers
Does the focus confirm chip for the Samyang 14mm 2.8 work when shooting the stars? Or is it too dark for it to pick up anything?

Comments

  • MaxBerlinMaxBerlin Posts: 86Member
    Use live view and magnification on a bright star and focus for the tightest light then compose
    My non-commercial blog:

    https://sonyvnikon.wordpress.com/
  • kanuckkanuck Posts: 1,300Member
    After researching this lens on DXO I was shocked to see if receive a high score of 27. It certainly must be good value for the money. Could you tell me how it has been as a performer for you? I have heard it is fantastic shooting at night for stars etc. That's probably why you were inquiring about the star trails here. Any regrets or complaints at all? I might pick one of these up this summer. Thanks :D
  • YellowJerseyYellowJersey Posts: 3Member
    I actually haven't used it. I'm currently torn between this and the Tamron 15-30mm 2.8. I was just curious to know if the focus confirm chip actually confirms focus when shooting in such dark conditions or whether you have to check focus manually.
  • IronheartIronheart Posts: 3,017Moderator
    No DSLR AF system with any lens will accurately focus stars, IMO, and in my experience. @MaxBerlin gives the best advice.
  • kanuckkanuck Posts: 1,300Member
    edited June 2015
    Sounds like you need to adapt a similar strategy to when you are using a big stopper or heavily stacking ND filters to find a focus point. I have used MaxBerlin's advice and it does work so +1 for that.
    Post edited by kanuck on
  • IronheartIronheart Posts: 3,017Moderator
    Or focus before plopping the NDs
    @YellowJersey, what we are saying is critical focus for astrophotography is always done manually using live view, with any lens. Make sense?
  • PB_PMPB_PM Posts: 4,221Member
    I've found that manually setting focus to infinity worked well with the 24-70mm F2.8G (for astrophotography), but I suppose that using liveview could work as well.
    If I take a good photo it's not my camera's fault.
  • spraynprayspraynpray Posts: 6,290Moderator
    I have the 14mm Samyang/Rokinon/Bower and yes, it is very good for nightscapes, but still has some coma (although less than many lenses costing 5-10 times more). The 24mm f1.4 is excellent too. @MaxBerlin said it right for focussing, that is the best method period.
    Always learning.
  • Spy_BlackSpy_Black Posts: 79Member
    My biggest criticism of Samyang is that, for a company that makes only MF lenses, not one has a calibrated infinity stop. More annoying is the fact that this is fairly straightforward to do in production. Why they don't do this is beyond me.
  • YellowJerseyYellowJersey Posts: 3Member
    Or focus before plopping the NDs
    @YellowJersey, what we are saying is critical focus for astrophotography is always done manually using live view, with any lens. Make sense?
    Makes sense.

    A bit of a quibble, though. I don't want this to overshadow my gratitude for the help you and everyone else has provided, but just for future reference, perhaps answer a primarily "yes" or "no" question with "yes" or "no" before going into the explanation. I'm getting the impression that the focus confirm chip isn't going to be of much if any use for shooting astro, but PLEASE just tell me that it will or won't work in an unambiguous fashion before providing your helpful tips (which are genuinely helpful and appreciated) on how to achieve the desired result.

    Thank you to everyone who replied. I hope that doesn't come across as sarcastic. Consider this question answered.
  • heartyfisherheartyfisher Posts: 3,181Member
    edited June 2015
    @yellowjersey : the thing is there was no yes/no answer to your question because you asked an illogical question. The answer was given to get your desired outcome even though you asked an illogical question. :-) (good job forum members !)

    You seem to think that the focus confirmation chip can "see" if something is in focus. Which it doesnt. It just tells the camera that told it what distance to focus at that it has reached that focus distance.
    Post edited by heartyfisher on
    Moments of Light - D610 D7K S5pro 70-200f4 18-200 150f2.8 12-24 18-70 35-70f2.8 : C&C very welcome!
    Being a photographer is a lot like being a Christian: Some people look at you funny but do not see the amazing beauty all around them - heartyfisher.

  • IronheartIronheart Posts: 3,017Moderator
    The focus confirmation chip is a misnomer. It is only there to assist with metering, reading the aperture. (Purists will say it provides EXIF data on non-pro cameras as well) Focus is confirmed via the onboard PDAF system in the body, and will work with a lens with no chip in it whatsoever. However, there's a margin of error for the focus. Even when its confirmed, you can still shift focus a small amount while still reading that it's in focus. For normal photography this "slop" is absorbed by the DoF. HOWEVER, for astrophotography achieving proper focus is so critical, the onboard PDAF is insufficient, even if it worked in such low light, which it doesn't, with any lens. Which is why you either focus by eye, or via live view zoomed in, when you are shooting stars. Or you wind up with blobs instead of pinpoints.
  • spraynprayspraynpray Posts: 6,290Moderator
    My biggest criticism of Samyang is that, for a company that makes only MF lenses, not one has a calibrated infinity stop. More annoying is the fact that this is fairly straightforward to do in production. Why they don't do this is beyond me.
    I heard that too but must have been lucky because my 14 and 24's hard stops are at infinity.
    Always learning.
  • kanuckkanuck Posts: 1,300Member
    edited June 2015
    My biggest criticism of Samyang is that, for a company that makes only MF lenses, not one has a calibrated infinity stop. More annoying is the fact that this is fairly straightforward to do in production. Why they don't do this is beyond me.
    I heard that too but must have been lucky because my 14 and 24's hard stops are at infinity.

    Yes the Polar AE 14mm F2.8 ED AE (Nikon AE/Auto Exposure) version is supposed to have hard stops at infinity now. At least from what I can see from the macro images taken of the product from my local shop's website in town here. I am going to pick one up fairly soon so this is fairly significant for me...

    Post edited by kanuck on
  • spraynprayspraynpray Posts: 6,290Moderator
    I am going to pick one up fairly soon so this is fairly significant for me...

    Make sure you have a return policy as I hear (rumour) that quality is variable. Again, I have had no problems. You may want to check the coma on stars to see if it is good enough for you. I don't like mine, but it seems better than anything else I've seen so far. If you don't blow night shots up too far, you can't see it.
    Always learning.
  • IronheartIronheart Posts: 3,017Moderator
    Beware of the infinity stop on this lens. There are numerous sites and videos that describe how to adjust it, since it is rarely correct from the factory. This one seems fairly popular:


    As you why you should probably just move the infinity focus past the actual infinity mark, and achieve critical focus using the live-view-zoom method, this is as best of an article as I can find on the topic. Basically an infinity hard-stop will never be accurate due to thermal expansion and mount tolerances:

    http://www.bhphotovideo.com/explora/photography/features/who-killed-infinity-focus?

    We used to get by in the "old days" because the DoF of film was more forgiving. Ah well...
  • Spy_BlackSpy_Black Posts: 79Member
    "We used to get by in the "old days" because the DoF of film was more forgiving. Ah well..."

    I don't know about that. I use a roster of MF lenses, some of which I've owned for over 35 years, from 20mm to 300mm, and they all nail ∞ on my D5100 and D600 bodies. They do this in summer and in winter. So in all honesty I can't say I buy this thermal issue on the part of manufacturers. I think it has to do with the way their AF systems work.
  • IronheartIronheart Posts: 3,017Moderator
    edited June 2015
    I have some old MF lenses too, and if you point them at the stars at night you will see just how "nailed" they really are. The thermal issues will be more apparent the longer the lens. I agree the main reason for AF lenses not to have a hard stop is due to the way the AF systems work. I was referring to MF lenses. I am talking minutiae here (think mice knuckles) and only in astrophotography will it have any real impact on the final image.
    Post edited by Ironheart on
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