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Star trail pictures

Posted: 25 Dec 2011 19:49
by Peter Connan
There are a few very good photographers on this forum, and I would like their advice.

In late March next year I will be on Kubu Island during a dark moon period, and I would like to take one of those star trail pictures, preferably with one or two Baobab trees in it. The challenge is that I have never tried anything like this before, and have no opportunity to practise it (there is just too much light pollution here), and I will have only one opportunity, and that only if the weather is good.

Therefore I need a lot of advice, and would like to ask the following questions:
1) I have two cameras, both Nikons. The one is an old D100, the other a new D7000. I do however have a power source for the D100, and could thus power it from the dual battery via an inverter, but for the D7000 I only have a battery. I would prefer to take the picture with the D7000, but wil it's battery last or should I rather use the D100?
2) I have two lenses, a Nikkor AF 28-105 f3.5-4.5 D and a Nikkor AF 80-400 f4.5-5.6 D VR. Which should I use, and at approximately what focal length?
3) I would prefer to take a single picture using long exposure noise reduction rather than a series of exposures that are later stacked, as I do not have the software to stack, nor do I have a programmable (or any other) camera remote. What ISO, f-stop and exposure time should I be looking at?
4)Will the vibration of pressing the shutter release button spoil the photo, or is the disturbance of short enough duration not to cause problems? IE do I need to squeeze a remote into my non-existant budget?
5)I undestand that I need to "paint" the tree/s with a torch, how powerful a torch and for how long?

Any other advice would also be welcome.


Re: Star trail pictures

Posted: 25 Dec 2011 22:04
by Grootseun
Pete , ek het vriend wat n awesome fotograaf en tegniese man is met die tipe dinge , as jy wil gee my n lui more dan gee ek jou sy telefoonnommer

Re: Star trail pictures

Posted: 25 Dec 2011 22:35
by Jorrie
Firstly and most importantly, you a need a much faster lens. f3.5 will not give good results.
At a minimum you need a f1.8 lens for star photography and even that is touch and go, but you will get results with it.
I use a f1.4 50mm Canon lens, only because the f1.2 is too expensive for me.

The NIKON D7000 in my opinion is the better bet (though I do not know the D7000 that well ), but you need the right lens!!!! Solving the power supply and battery problems is a minor when you want to take pics of the stars. It requires a lot of patience and practise.

Focusing is another important issue which is also very difficult to get right. You need to go to infinity and then a touch back, but to get that right is tricky and will take a couple of shots. Smaller lens openings could solve the focusing problem, but requires longer exposures.

I suspect that you will be very disappointed if you try to use a f3.5 lens. I tried with a f3.5 lens to photograph the northern lights in Tromso, Norway and it just did not work. Only when I used a f1.8 lens did I start getting results. With a f1.8 lens exposures of 20 to 35 seconds are the order of the day for star shots, but it will not work for star trail photos as you will require much longer exposures. When that happens you will need to reduce the lens opening to f2.0 or maybe even smaller, it all depends on the ambient conditions of the night.You will need to experiment.

The techniques where you can throw in a flash to light up the foreground also takes some time to get ríght. Do not use a very powerful flash, it will beach out the foreground. Once you use a proper sturdy tripod with a remote trigger the judder caused by the movement of the mirror is not an issue. Try to get a remote trigger.

With all these types of photos you need to operate the camera in full manual mode, play with the lens opening and the shutter speed, use a sturdy tripod on stable ground with no movement in the vicinity, play with the focus, and preferrably use a remote control trigger. You therefore need to know your camera and lens really well. If you try to trigger the camera manually it might induce unwanted movement.

When next we meet we can discuss this topic in greater depth and I can give you some tips. I am also sure there are lots of others that will give you similar or even better advice.
Herewith two pics for later discussion.
This pic of me was taken by a pro, Kjetil Skogli of Norway, he used the flash technique with the northern lights in the background. Afterwards he tought me the technique, but it is quite difficult to get right.
Skogli.JPG (1.34 MiB) Viewed 4794 times
This picture was taken with a Canon 450D, 50mm lens, Manual, f1.4, 21 sec exposure, ISO 400. The result was not very good.
_MG_2506ed.jpg (240.31 KiB) Viewed 4794 times
I would suggest that you really try to get out in the dark and practise before the time. Take a lot of photos with different settings a check your results. Being a digital SLR lots of photos is not a problem.

It is also useful to run a Google search on the topic as there are lots of pros out there willing to share their knowledge.

Another subject you may wish to experiment with is lightning - equally challenging, particularly in daylight conditions.

Re: Star trail pictures

Posted: 26 Dec 2011 08:50
by Chris Skinner

Re: Star trail pictures

Posted: 26 Dec 2011 12:43
by Peter Connan
Thanks Chris, that's exactly the type of info I was looking for.

Jorrie, there will be no money for fast lenses between now and then, or really any other type of kit. Fortunately I do have a reasonably sturdy though very old tripod (the previous owner, who also happens to be my father, reckons it's probably at least 35 years old). I might be able to stretch to a remote, but I don't know what it costs yet. But essentially I have to make it work with what I have. One of the main problems with the D7000 is that since it is so relatively new, that pirate stuff just isn't available yet.

It seems though as if most of these types of pictures are taken at around f4, the problem is seeing to set up the shot, but I will try and do that while it is still light, and mark the position of the tripod.

Driko dankie, ek sal jou later bel.

Re: Star trail pictures

Posted: 26 Dec 2011 14:19
by Jorrie
Peter, when setting up in the dark use a torch with a red lens. It will solve the night blindness problem.

Re: Star trail pictures

Posted: 26 Dec 2011 19:57
by Peter Connan
Thanks Jorrie

That picture of yours of the northern lights is excellent, but not what I want to do (although I would be interested in understanding the technique).

This is more what I have in mind:
startrail.jpg (81.09 KiB) Viewed 4760 times
From what I can gather, these are generally taken with wide-angle lenses, at around f4-f5, lowest possible ISO and very long exposures, ranging from 30 minutes to several hours. Focus is adjusted to the hyperfocal distance (for my lens at 28mm and f4, that is 10m), and this will mean that everything from 5m to infinity should be in focus. The camera also needs to point pretty close to due south, so I will have to brush up on my magnetic declination.

My guess is that ambient light must play such a large role in this that it would be almost useless to go and practise somewhere, except there, so I am just going to have to try and hope for the best.

Does anybody know how long the D7000's batteries will last under these conditions, or do I need to test?

Re: Star trail pictures

Posted: 13 Jan 2012 23:13
by Jorrie

Hoe gaan dit met jou beplanning vir jou fotos.

As jy wil kan ons een aand uitgaan en gaan speel met kameras en lense sodat jy 'n gevoel kan kry. :coolphotos:

Laat my weet.


Re: Star trail pictures

Posted: 15 Jan 2012 19:27
by dieselfan
Hi Peter

Most cameras require a bulb mode when going over a couple of minutes - check yours. The picture you posted was done over a few hours or most likely using bulb mode. There are even some home made bulb kits for pretty much any gear, no need to fork out loads of cash.

Another tip I always use when doing long exposures is to use the 2 / 10 sec shutter delay, this will prevent any camera shake from pushing the shutter. Mostly I use 2 sec.

Remember that ISO and shutter times are directly proportional eg. ISO100 @ 30 secs = ISO200 @ 15 secs. The lower ISO results in less heat generated by the sensor so a cleaner image, but longer exposure needed due to half the light. Using a faster (smaller aperture) lens like a 2.8 or 1.5 is BONUS as it lets in loads more light but most apertures will be shot at your SPECIFIC lens' sharpest setting. On mine thats around 5.6. Check out lens reviews on your gear and see what aperture gives the best LPI.

You don't need expensive lens' , my one lens is around 40k yet done properly will give almost the same result as my kit lens for this type of picture. The advantage the pricey gear brings though is I can autofocus in almost nil light so have a better hit ratio, otherwise manual focus to infinity.

Using an inverter for a couple of hours can easily flatten your battery, try to get the 12v charger unit for your cam. I ran a timelapse video for over 12 hours with hardly any voltage drop but using my inverter flattened the Discos battery in a few hours.

As for south, take note of the sunset direction and time of year. Get yourself a Casio Pathfinder / Protrek watch. Ordered mine from Amazon took 2 days and I paid 30% the local price.

Re: Star trail pictures

Posted: 16 Jan 2012 07:18
by Peter Connan
Dankie Jorrie, maar ek dink ek moet maar my eie toetse doen. :biggrin:

Roy, thanks for your advice, however I need to reiterate: I need to find a way to do this with the equipment I already have. No extra equipment will be purchased for this.

However, it seems your inverter is pretty power-heavy, as mine is regularly used to charge camera batteries overnight, and even with the fridge and tent lighting running off the same battery, I have never had an issue. But off course I do have the luxury of a dual battery which powers the inverter.