night time long exposure tips sought

Discussion in 'Open Discussion' started by btaylor, Oct 6, 2016.

  1. btaylor

    btaylor Mu-43 Regular

    48
    Sep 5, 2016
    Ben
    Wonder if any of you guys can give me any tips with the following please. I took two long exposures recently of different cities.

    The first one I'm happy with - the buildings are relatively sharp, there's some nice light features, and there's reasonable detail.
    29519468573_cc6e3a6245_k. P1010835 by Ben Taylor, on Flickr

    Second one I'm not that happy with. Just seems not that sharp, bit blotchy and not much detail.
    P1010863 by Ben Taylor, on Flickr

    My question really then is how could I have made the second one as good as the first? Or at least better.

    There's loads of differences but not sure which of them it is that made one obviously a better shot. Most factual details you can glean from flickr, only facts I don't think you can glean are:
    Direction - first (good) one was facing approx south east and second (bad) one was facing approx east edit: west.
    First (good) one camera was resting on a wall. Second (bad) one camera was on a tripod (velbon sherpa).
    Time - relatively same - first (good) one about 7:05pm, second (bad) one about 7:15pm, so after sunset but not much.
    The first (good) one I think I could have forgotten to focus entirely, I was preoccupied with setting it up steady (BBF , but also focus priority is on...?) The second (bad) one was manual focussed to infinity.
     
  2. BosseBe

    BosseBe Mu-43 Regular

    109
    Aug 7, 2015
    Stockholm, Sweden
    What I can see from the EXIF is that the first is a 1/25s exposure and the second a 1/8s, that might explain the blown out sky.
    Also you are using different lenses, PL25/1.4 and P14-140/3.5-5.6, so that might be the biggest difference.

    I hope someone more knowledgeable than me chimes in with more ideas.

    /Bosse
     
  3. btaylor

    btaylor Mu-43 Regular

    48
    Sep 5, 2016
    Ben
    The first one is 25 seconds, not 1/25 of a second. The second one is 8 seconds. I think the blown out sky is because I was facing west, i.e. It was the remnants of the sunset.
    Another difference that I can't control is that the buildings are obviously further away, but would like to find out how to best get sharpness on buildings if they are far away on this situation, i.e. is it more likely to be motion blur or focus blur , or if it's the limits of the camera/lens and it's not going to be doable?
     
  4. Nathanael

    Nathanael Mu-43 Veteran

    401
    Oct 12, 2015
    #2 is out of focus.. That's like 99% of the problem.

    #2 is a scene with higher dynamic range since you're facing the sun. You can shoot bracketed exposures (HDR mode) or you can just shoot RAW and pull up the shadows a lot.
     
  5. btaylor

    btaylor Mu-43 Regular

    48
    Sep 5, 2016
    Ben
    Hmm, thanks. Definitely? So setting focus to infinity isn't the best plan then?
     
  6. Nathanael

    Nathanael Mu-43 Veteran

    401
    Oct 12, 2015
    Definitely out of focus. The m43 lenses don't really have a true infinity (except some of the Oly pro lenses). If you turn all the way towards infinity in MF mode, you will pass infinity and it will be out of focus. So you need to focus on something.

    Edit: Also probably better to shoot at ISO 200, as that's the true "base" ISO for the G7. That should increase your dynamic range a bit.
     
    • Agree Agree x 2
    • Like Like x 1
  7. btaylor

    btaylor Mu-43 Regular

    48
    Sep 5, 2016
    Ben
    Thanks.
     
  8. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    Yep, just to second Nathanael's comment, #2 is clearly out of focus. Simply relying on the on-screen infinity focus is not a good strategy. Instead, use the focus magnification, set it to its highest amount, and adjust focus while magnified to ensure focus is where it needs to be.

    My second tip would be to shoot a bracketed series of images. M43 cameras don't have the best dynamic range, and so pushing the shadows even a little bit can lead to the presence of noise. But by bracketing the images and merging them in post, you retain a lot more shadow detail that gives you more leverage to adjust the image in post. Another benefit to doing this is reduced overall noise through image averaging. Because the noise patterns will be different on each image, the merging process will yield a less noisy image.
     
  9. Joe Smith

    Joe Smith Mu-43 Regular

    128
    Mar 6, 2016
    Virtually no modern lens has a true infinity focus stop. And there's a reason for this. B&H has a nice article on this: Who Killed Infinity Focus?
    I guess you could safely rely on the autofocus in the second image if you choose some nice contrasty structure somewhere in medium distance.
     
  10. btaylor

    btaylor Mu-43 Regular

    48
    Sep 5, 2016
    Ben
    Yes, cheers, I'm conscious of the advantage of an HDR image created through a bracketed series of images.
    Would you recommend (manually) doing processing on the individual images in the series in photoshop before merging them, e.g. cranking up the shadows on the underexposed ones, before merging, or just let photoshop do its thing during the merge and it will take care of that?

    Also I guess the answer to this might be "try it" - but is it better to over/underexpose through modification of shutter speed, or by modification of ISO? I know if I put my camera on "A" mode (aperture priority) it modifies the shutter speed when using the auto bracketing function. However if I put it on "M", and set the aperture and shutter speed, will this force it to auto bracket using ISO - advantages/disadvantages of the latter?
     
  11. Petrochemist

    Petrochemist Mu-43 Top Veteran

    655
    Mar 21, 2013
    N Essex, UK
    Mike
    IMO the second one would have benefited by waiting another 30 minutes or so, as well as improving the focus. This would have helped darken the sky for the classic blue hour shot you managed in the first.
    The lights in the first also have nice star burst effects from the aperture (which probably helped with the focus).

    I've been trying star shots on & off over the years & consistently find infinity focus is harder than you'd expect!
     
  12. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    Regrading manipulating the images, I typically just modify the merged image. If you modify the individual images prior to merging, you run the risk of messing up the exposure balance.

    As for the under/over exposures, I always modify shutter speed, as I want to keep the ISO as low as possible. I typically will shoot my HDR/panoramic images in M mode.
     
    • Informative Informative x 1