Ohiwa Harbour by Rod Topperwien - Photo Review



"Our local harbour in Ohope, NZ brings some unique opportunities to capture lights from all different sources. In this case we see the reflections of man made lights, light of the sun reflected off the moon and the heavenly beings - the stars. In my opinion it was a nice unique opportunity to have all three sources cohabiting."

Shot at: F2.8, 15s, ISO3200, 16mm

Thoughts by Reviewer

I’m going to start with the things I love about the picture and then move on to the ones that could use a bit of fixing to make the image perfect.

  • The first thing that caught my eye and that I absolutely love is the subject itself. The sky above the body of water with the clouds just moving along the way, it’s stunning.

  • The second thing is the composition. I find it very pleasing as you have the clouds coming in from the right of the frame and they’re almost dragging the stars with them. Maybe the frame could’ve been moved a bit to the left but seeing there’s some sort of a town on that part of the image, the better choice may have been evading the light pollution and sticking with the composition you chose.

  • Lastly, I find that you nailed the colour of the sky, it is a perfect blue colour, really sticking out with the greyish clouds.

Now that we have that out of the way, let’s take this image a few levels higher.

Shutter Speed and ISO

The most challenging part of photographing the stars (also knows as astrophotography) is the long shutter speed and high ISO which results in a considerable amount of noise being introduced to the image. (Shutter speed = duration that the sensor on your camera is being left open to capture light on the final image, ISO = your camera sensor’s sensitivity to light, the higher the number, the higher the sensitivity and the noise in the final image)

Starting off with the shutter speed – there’s a few things you have to keep in mind while trying to figure out the best shutter speed for your situation. Not adjusting your shutter speed can lead to a lot of problems in your final image. If you set your shutter speed to, let’s say, 5 seconds, any movement in that period will be captured by your camera. So if you have an unsteady tripod or if you move it while the camera is capturing the image, the final image is going to turn out blurry and/or it will have so called “light trails”. This happens because your camera is holding its shutter open and exposing the sensor for a longer period of time and it captures every movement that happens in that window even the little shakes from your tripod or whatever your using to keep the camera (or device with which you’re capturing the image) steady. I’ll leave a picture below that shows light trailing.


This picture shows cars passing by and capturing their rear lights from one edge of the frame to the other during to a longer shutter speed.

The point is, when photographing stars with a longer exposure time, you have to be aware of the steadiness of your stabilisation device.

Another thing is star-trailing. Star-trailing is an effect caused by earth’s rotation. As the earth rotates the stars stay in the exact same place so now you have the trajectory of earth’s movement captured in your image and the stars look like thin curved lines. The effect becomes more visible when you’re using a longer shutter speed as the earth changes its position even more.

In your image you can see the star-trailing just beginning to happen, the stars when zoomed in look more like oval shapes rather than dots. Star-trailing can be easily mistaken with little movements of the stabilisation device and vice versa.


How you can fix it is by keeping the shutter speed around 10-20 seconds maximum, to avoid the earth moving too much and your stars looking like ellipses or even lines, and of course, by keeping the camera as steady as possible while taking a picture.

Exposure

Even though the sky is correctly exposed, the water and the town aren’t. I would fix this by using a technique called bracketing, which means shooting an underexposed picture, a perfectly exposed one and an overexposed one and then combining them in post processing.

Basically, what you do is take the elements from the picture which are perfectly exposed and then add elements from the over and underexposed pictures. For example, take the sky from your image as it is correctly exposed and then add the water from the overexposed picture to the original one as it will be brighter then.

Vignetting

If you look at the corners of your image you will find that they are a lot darker than the rest of the image for no apparent reason. This is called vignetting. It usually happens when shooting on the widest aperture on your lens and if the lens is not meant for your camera or if it is simply built like that (usually happens on cheaper lenses). This mostly occurs when the lens opening is too small for the camera’s sensor and due to that a portion of the light on the edges of the aperture doesn’t hit your sensor properly.

You can fix this in post-processing by applying lens correction made for your specific lens or simply by brightening the edges of the image.


A visual representation of the vignetting, I’ll leave the complete finished picture down below.

Colour-correction

Lastly a thing that you can fix in post processing is the look of the colours in the image. I love how the sky looks but the other elements could use some fixing - The water could be made a more blueish colour rather than the grey one and the little town could use some colder tones in its lights.

The recap

All in all, a solid picture, good composition and great idea, a few technical errors to fix but you have great potential. I left the final photo below after some fixing. To be honest, there wasn’t much I could do since it is a JPG file but I hope it gives you more of a general idea on what I was aiming for.


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#astrophotography #photoreview #photocritique #feedback

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