Camera Maker: Canon
Camera Model: Canon EOS 60D
Lens: EF-S18-135mm f/3.5-5.6 IS STM
Image Date: 2016-12-07 22:16:38 (no TZ)
Focal Length: 64mm
Aperture: ƒ/8.0
Exposure Time: 30.000 s
ISO equiv: 100
Exposure Bias: none
Metering Mode: Matrix
Exposure: aperture priority (semi-auto)
White Balance: Auto
Flash Fired: No (enforced)
Orientation: Rotate 270
Color Space: sRGB
There are several reasons the buildings and trees don't look sharp.
Other objects in the image appear sharp... such as the sign and lamp post.
>>>> 30 second exposure... you're going to see a lot of flare effects from the building lights. That's part of what makes the buildings look less sharp. (Unlit or less well-lit portions look sharper than brightly lit.) If you have a "protection filters" on the lens, it might be contributing to and increasing flare from the lights.
>>> 30 second exposure... the tree branches and leaves likely moved a bit during exposure, even if it seemed there was no breeze. It's always risky using a long exposure with foliage that's easily moved.
>>> 30 second exposure... also might have been some vibrations due to traffic, even when using a tripod (carbon fiber tripods are better than metal, with respect to transferring vibrations, but even so might not have completely resolved it).
Kissel vonKeister wrote:
Turn stabilization off when you're on a tripod. If it's perfectly still it CREATES movement.
Actually, that's not the case with
most Canon lenses.
>>> 30 second exposure... with image stabilization on, might have caused some loss of sharpness, though I doubt it in this case. Most more recent Canon IS lenses self-detect when there is no movement and turn off IS automatically. The result is exactly the same as if you turn it off manually at the switch. But, sometimes IS can cause a slow "image drift" that can be problematic with long exposures... or with very precise framing... or with video. So, yes, it probably would have been better to turn off IS, just to be safe. It really served no purpose in this case. (Note: I have no idea how third party and other OEM lens stabilization systems work.... this only applies to Canon OEM lenses. And there are a few Canon lenses... mostly older models... where IS absolutely
must be turned off at the switch, when fully locked down on a tripod to eliminate all movement, including: EF 28-135mm IS, EF 300/4L IS, original EF 100-400L IS, original EF 24-105L and the long discontinued EF 70-300mm IS. With these particular lenses, if there is no actual movement for it to correct and IS is left on, it will go into sort of a feedback loop where it actually causes movement.... which you'll see as rapid jumps and shaking in your viewfinder. Won't damage the lens or camera, but will make a mess of any images.)
So, in the end I think various softness "issues" in the image can mostly be traced back to the very long exposure. Flare, subject movement blur, camera vibration/shake blur, IS movement.... they all are possibilities and all are compounded by the very long exposure.
You could have used a higher ISO and much faster shutter speed, minimizing the risk of subject blur from flare, movement, and vibrations. While it's often tempting to use the lowest ISO possible to minimize noise in images, you have to weigh that against other factors such as these. Next time, go ahead and make that 30 second long exposure at ISO 100, if such a long exposure is required.... but perhaps also try some shorter exposures at ISO 200 (15 seconds), ISO 400 (8 seconds), 800 (4 seconds) and 1600 (2 seconds).
But, even at ISO 100, a 30 second exposure just seems way too long for shots such as yours. Notice the other night shots many folks have shown are using a much faster shutter speed, even when using ISO 100. I suspect you relied upon auto exposure, which might have caused way longer exposure than actually necessary, when the camera metered the overall scene as "very dark" and tried to lighten it up too much. I notice you have no Exposure Compensation at all dialed in (which is one way to stop the camera from over-exposing a predominantly dark scene... another way is to switch to manual mode and simply make your own settings).
So length of exposure is another thing you might want to experiment with and "bracket", when making night shots. Leaving the ISO set, you might want to shoot one stop, two stops, even three stops under... then have those to choose between. In this case, with 30 seconds as the "full" exposure, 15 seconds would be one stop under, 8 seconds two stops, and 4 seconds three stops. With experience, as you learn how your camera and lens perform at different settings, as well as what settings render things as you want to see them, you'll probably be able to do less bracketing in the future. But for now, it's probably a good idea to experiment a bit. Your camera has means of setting up bracketing automatically, but for occasional, simple situations such as these, I often find it quicker and easier to just make the adjustments manually.
Your camera has Long Exposure Noise Reduction feature, too, which you might try for the longer exposure shots. HOWEVER, it's very important to be aware how Canon's LENR works.
First, when it's enabled LENR only works on exposures of 1 second or longer (if you rarely do 1 sec. and longer shots, it's easy to forget you have LENR enabled). And, the way it works is that immediately after the first exposure, the camera will make a second exposure of the same duration, but with the shutter closed. The camera then uses this second "blank" image to identify noise, which it then "subtracts" from the first image.
So, when you use LENR it will actually take twice as long to make an image. That 30 second shot would actually take 60 seconds... 8 seconds will take 16 seconds.... etc. If you forget LENR is enabled and why things are taking so long, then cancel the second exposure before it's complete (such as by turning off the camera or removing the battery), the camera will discard both that second exposure AND the first one you made! More than a few people have been confounded by, 1. why it was taking so darned long and 2. why their long exposure images had disappeared completely when they cancelled the 2nd exposure.
Also, when taking multiple long exposures be sure you have a well-charged battery and/or a spare. Keep an eye on the battery condition indicator. The camera draws power continuously while making these exposures... holding the shutter open, powering the sensor and holding the mirror up out of the way. As a result, you'll get a whole lot fewer shots per charge, with extra long exposures. And, if battery power drops too low during that 2nd "blank" LENR exposure, you'll lose both images the same way as if you'd cancelled the shot yourself.