f2.8 vs f4.0 lenses for astrophotography

Discussion in 'Photography Forum' started by CamoHunter870, Feb 18, 2015.

  1. CamoHunter870

    CamoHunter870 Elite Refuge Member

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    I've recently got the interest into taking night shots/astrophotography and possibly looking at getting a lense if needed or keeping with what I have right now.

    Reading a number of astrophotography tips, it seems like a f2.8 lense is "required" but how much better results will I get with a f2.8 over a f4?

    Currently I have a 12-24mm f4 and 24-120mm f4 for my D90. Looking to upgrade in 12-24 months to FX (610/750) so I'd mainly be using the 24-120 on the FX body in the future since the 12-24mm is geared towards DX (probably keep my D90)

    Looking to maybe sell my 18-105mm and turn that money towards a new lense perhaps a Sigma 24-70 f2.8, Nikon 35 f1.8 or 50 f1.4 or something that would be nice for astrophotography along with general use as well.

    Haven't had a time to research much but figured I'd get input from here to start with :tu
     
  2. huntersdad

    huntersdad Elite Refuge Member

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    I'm not an astro photog (nor did I play one in another life), but I think 2.8 is the minimum and most prefer something faster. If memory serves me, you want the most light hitting the sensor for the correct SS without getting trails - unless that's what you are after. More simply put, for astro, you'd rather have 1.4 at 15 secs gathering alot of light than 2.8 at 15 secs, losing 2 stops of light and missing some of the less bright stars.

    That's kinda what I've gathered anyway.
     
  3. CamoHunter870

    CamoHunter870 Elite Refuge Member

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    Looking to do both star trails and sharp shots of the Milky Way so yes, I believe your right were the faster the better.

    Looking at the reviews on Nikon's 35mm f1.8G right now and with $100 rebate, not too bad of a price and what I'm looking to spend.
     
  4. Mike Bons

    Mike Bons Senior Refuge Member

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    I have dabbled with Milky Way shots before. Having a FF camera that performs well at high ISO is just as important as a fast lens.

    For a great value lens I would look at the Samyang/Bower/Rokinon 14mm F/2.8 lens. Its very sharp and reasonably priced around the $300 mark.

    If you are will to spend more money, this looks like a great lens for what you are looking for, and should be out soon. http://www.bhphotovideo.com/c/product/1083947-REG/tamron_sp_15_30mm_f_2_8_di.html

    Here are a few Milky Way shots I have done. The first is shot with the Sigma 35mm F/1.4, the rest are with the Canon 17-40 F/4 all on the Canon 6D. I light the foreground with a hand held flash.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  5. huntersdad

    huntersdad Elite Refuge Member

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    Mike, What kind of exposure times are these? Mine star pics never look like this.
     
  6. schlag

    schlag Senior Refuge Member

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    They are great. The backgrounds really help make the picture.
     
  7. CamoHunter870

    CamoHunter870 Elite Refuge Member

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    Awesome shots Mike :tu

    Those are the shots similar to what I'm hoping to get along with star trails.

    I've heard good reviews on the Rokinon and at the price, tough to over look.
    Only thing I'm hesitant about it is I believe it's manual focus on Nikon.
    AF isn't needed for astrophotography but for other uses, it would be nice so that's way Im leaning towards the Nikon.

    Sigma's 35 f1.4 is the best of the bunch but out of my price range.

    Looks like the Nikon rebates end at the end of Feb so have until than to decide.

    Thanks for the info
     
  8. 1Duck slayer

    1Duck slayer Elite Refuge Member

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    Nice shots Mike. I have always liked this kind of photography. Good luck Camohunter870 and share some photos. I have seen some cool shots done in the mountains. Probably my favorite with the mountains in the foreground.
     
  9. Mike Bons

    Mike Bons Senior Refuge Member

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    Thanks for the comments everyone. The top one, shot with the sigma was a 15 second exposure, and the bottom 3 were shot with the 17-40 at 17mm were all shot at 25 seconds (I believe). The top one is actually a vertical pano that I stitched together. The issue I have is that the 35mm isn't wide enough for this type of thing yet the 17-40 isn't fast enough and its soft when shot wide open. Therefore I am considering the lens suggestions I made earlier as well.
     
  10. Mike Bons

    Mike Bons Senior Refuge Member

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    You can get the Nikon version with the focus confirmation chip in the Rokinon.
     

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