Low light, night and Astro photography

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Peter Connan
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Low light, night and Astro photography

Post by Peter Connan »

At the request of ExFmen, this thread is intended to provide some pointers and tips in terms of technique, equipment and PP for early-morning and late-afternoon photos, as well as night star photography. Essentially photography when the sun is below the horizon.

Before I even start, I want to state that in my opinion the most important piece of equipment for all photography under discussion here is a tripod. It is very difficult to do any of this without one.

I will start with sunrise and sunset photos.
The biggest challenge here is that, while the sky is still easily bright enough to photograph, the foreground is very dark, and it is difficult to get detail there.
To get detail in the foreground, there are basically three possible approaches that can be followed. In order of difficulty (and reverse order of effectiveness), these are:
1) Take a single exposure and "lift" the shadows in post-processing:
This is the method I use. Here, the important thing during the photography is to ensure that you have the exposure as light as possible without blowing the bright areas, and to shoot at the camera's base ISO. This allows the most leeway to lift shadows without introducing excessive noise. I use Lightroom5 and lift the shadows with a combination of adjustment brush and graduated filters. Camera age and quality (read price) is important here. The newer full-frame cameras leave a lot more leeway for this type of processing than older or smaller-sensor cameras.
2) Use graduated neutral-density filters while taking the photo: The idea here is to reduce the amount of light from the bright areas hitting the camera's sensor. In many ways, this is perhaps the method delivering the most natural results. The drawbacks are that good filters are expensive (they can cost the same as the difference between a mid-level and a pro-level camera), and they are only suitable for situations with a relatively flat horizon. On the other hand the use of filters can cause running water and blowing clouds to take on beautiful smooth appearance.
3) Shoot a series of photos at different exposures and blend them together. This is called HDR. Many modern cameras have a built-in HDR function, but very few of these give a RAW file output suitable for further editing. Thus the best method is to take a series of shots and post-process them yourself. However, I have never done this as I do not have suitable software. I do know that this method is not really suitable for situations where there are moving objects in the frame.


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PRWIN
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Re: Low light and night photography

Post by PRWIN »

Peter I use number 3 as it is fastest for me and gives me much more control on the foreground and background, some times I only take one shot then HDR it in post processing, now I have you all confused =O: =O: =O:

Here are some links

This works well in landscape for good depth

http://www.digitalcameraworld.com/2015/ ... photoshop/

HDR

http://photofocus.com/2014/06/06/blendi ... andscapes/

This is the one I use the most, part of the process in blending the fore ground and sky

http://www.digitalcameraworld.com/2012/ ... -exposure/

For Starscape photography a good intro to multiple photo combination.

http://petapixel.com/2013/03/18/how-to- ... to-finish/

Long exposure well that is going to be trial and error as it will depend on the amount of time you want the lens to be open ISO and speed


The best setting to start with in starescape is like Peter says is around ISO 6400 shutter speed 30 sec and f-stop as low as possible for the lens , mine is 5.6, from there you can adjust the shutter speed or ISO till you get what you want. If your camera can't handle a high ISO adjust that first and of course a very steady camera.

If there is a moving subject then go with a single frame and HDR it in photoshop, sounds crazy I know, but this the way I do it, each person will and develop there own ways of doing this type of photography, must say I have started HDR all my photo,s to a extent as it brings out a better dynamic range which I like in my photo,s -O-


http://prwinnan.wix.com/prwinnan-photography
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Flutterby
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Re: Low light and night photography

Post by Flutterby »

Thanks Peter and Peter!! lol \O \O


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PRWIN
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Re: Low light and night photography

Post by PRWIN »

ExFmem here is a demo

Using this method belowe to a degree and HDR

http://www.digitalcameraworld.com/2012/ ... -exposure/

AS is from camera Raw

Image

Fore ground HDR and lightened

Image

Background HDR and darkened

Image

Finished photo,Both photo combined in photoshop

Image

This was taken with one photo, what is normally done a photo is taken late afternoon at sunset when the light is good for the foreground and one when the setting sun is at it,s best and then both are combined using the above tech in photoshop


http://prwinnan.wix.com/prwinnan-photography
ExFmem
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Re: Low light and night photography

Post by ExFmem »

Perfect! Thank you both so very much for taking your valuable time to help us improve our skills. ^Q^ :ty: :ty:


Peter Connan
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Re: Low light and night photography

Post by Peter Connan »

So here is a demo of my first method:

Photo straight out of camera:

Image

General exposure adjustments done:

Image

Adjustment brush used to lighten the foreground some more:

Image

Slight tint added to clouds using another adjustment brush:

Image

Final photo after a slight crop and sharpening:

Image

As you can see, my adjustments are a bit more conservative than Peter Winnan's above. This is a matter of personal taste.

Some things to point out though:
Increasing exposure will add noise. Depending on your camera's sensor, the amount you want to lift exposure by and the intended use (eg. web share or large print) this may or may not be a problem. This applies both to my method, and the example shown by Peter above where an HDR rendering is done of a single photo.

This is where the other two methods (filters and multi-exposure HDR) score, as you are not increasing exposure. So for large prints, it may be better to go the technically more challenging routes.


Peter Connan
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Re: Low light and night photography

Post by Peter Connan »

So now on to star photography.

Again, there are more than one approaches. Basically you can go the equipment race method (like me), or the PP-heavy route.

If you want to go the equipment race method, you will want a full-frame DSLR, preferably of relatively low resolution, which is good at very high ISO's. Probably the best option right now (if you have the money for a dedicated camera) is the Sony A7s (we don't know how good the new Nikon D5 is yet, it may surpass the Sony), but recent Canon and Nikon full-frame cameras will also do well. Both Nikon and Canon also have dedicated Astrophotography models with specialised filters to increase the transmission of the faint colours seen in nebulae. and a fast (IE one with a large maximum aperture) wide-angle lens.

The wider the angle of the lens, the slower shutter-speed can be used before the stars start visibly streaking. This obviously translates into more light gathered.
The faster the lens is, once again, the more light it gathers. The Nikkor 14-24mm f2.8 is a favourite of many people who do this. Even some Canon users use this lens with an adaptor. I use a Tamron 15-30mm f2.8 and can heartily recommend this lens for full-frame users. It is said to be better than the Nikkor mentioned above. Other good choices are the 20mm f1.8 primes and the Rokinon/Bower/Samyang 14mm f2.8, although you need to make sure you get a good copy.

If you want to do this with a crop-frame camera, your best option is the Tokina 11-16 f2.8.

Other equipment you will need are a tripod (again), something to cover your camera's viewfinder, possibly an intervalometer (if your camera doesn't have one built-in), a piece of cloth and some rubber bands (this is to keep moisture (dew) off your camera) and something to determine direction (either knowledge or equipment).

The other very important thing to consider are the conditions. Firstly, if you want to capture the milky way, take note that in the southern hemisphere it is only visible from about April to around September (I only learnt this very recently). Secondly, you need very dark skies. The darker the better for capturing the greatest number of stars, but some light may be useful if you want to achieve something else. Thus it is handy to know the state of the moon as well as the time it rises and sets.

In the beginning, it is easiest to set up the camera while it is still light enough to see what you are doing. As Peter said, manual mode, 30 seconds, highest ISO you are comfortable with, aperture as wide as your lens will go with reasonable quality. Focus is critical. I now focus on the stars using live view and manual focus, and make sure that AF is switched off. Some people pre-focus on something as far away as possible and then tape the focus ring down.

Take a few exposures to confirm your settings. Zoom in tight on some stars in the corner of the frame to make sure the stars aren't streaking too much and use the histogram to check exposure as it is very difficult to judge it in the dark otherwise. Keep in mind that at these high ISO's any exposure adjustments will quickly generate a lot of noise.

Next (if applicable) is to take a few exposures while providing some light onto the foreground. This can be done in a variety of methods, of which my vafourite is to shine a powerful headlamp or small torch into the palm of my hand, using that as a reflector.

What I do then is to put the camera on continuous drive mode and lock down the remote cable for at least 100 exposures. This gives you a number of options later.

Image


Peter Connan
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Re: Low light and night photography

Post by Peter Connan »

Just to indicate how much light is needed, these photos (on the post above and below)

Image

Are a 30 second exposure at f2.8 and ISO between 5000 and 8000.

The hundred photos can now be used in three ways:
1) They can be stacked together to create a star trail.

Image
This can be easily done with the freeware program StarStax

2) They can be turned into a time-lapse video (LRTimelapse is great, and is available as freeware in a limited form).

3) using Photoshop, the photos can be stacked in a complicated manner to reduce noise to almost nothing.


Peter Connan
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Re: Low light and night photography

Post by Peter Connan »

Some fun can also be had by fiddling with the focus and/or zoom rings during such long exposures.

Image

Image

Image


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Mel
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Re: Low light and night photography

Post by Mel »

Fascinating read! O:V

Thanks for sharing your expertise with us, Peter and PR \O \O \O


God put me on earth to accomplish a certain amount of things. Right now I'm so far behind that I'll never die.
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