Optimum kit for star trail photography

[Ed Hurst]

Hello chums,

I recently tried my hand, for the first time, at star trail photography using my Pentax 645D. The approach I was taking involved taking a series of frames then stacking them later - to avoid excessively long exposures. This is partly because of the noise inherent in such exposures and partly because the 645D, despite having a menu option that purports to allow the function to be turned off, in fact will not allow you to shoot over 30seconds without compulsorily firing off a dark frame for noise reduction purposes - which of course would lead to long breaks in the trails.

I used an exposure of 30 seconds @ f3.5 using ISO 1600. As you can imagine, the files were somewhat noisy (though not as bad as you'd expect - the 645D is actually ok at quite high ISOs). The quality was not what a user of medium format is seeking... Clearly this camera is not the ideal tool for such a task.

This got me wondering what the optimum equipment would be (I plan to have another go and am willing to hire equipment for the task). On the one hand, the issue might involve cameras that allow long exposures at low-ish ISOs (without the dark frame being fired after every exposure) - which might suggest the much vaunted P45+ is the ideal beastie. The other option is to use a camera that allows the use of moderate exposure lengths (say 30secs to 1 minute) at higher ISOs, which might suggest a Nikon D4 or D3S or D800 might be the optimum (I am thinking D800 because of the ability to use an ISO of, say 800, with 1 minute exposures - though going up to ISO 800 or above might suggest that the D4 or D3S would have a noise edge, with lower resolution).

Needless to say, without any hands-on experience of any of these pieces of equipment (I only have the Pentax 645D and a Canon 5Dii), I am finding it hard to judge. Before hiring equipment and paying for flights to the Australian outback, I would appreciate advice here. My question, in short, is what equipment will give me the best possible results - if that is defined in terms of high resolution with low noise. For the purposes of simplicity, let's exclude technical cameras from the options if that's ok with you...

In case it's relevant, I am looking at doing something very wide angle (but rectilinear, not fish eye). Something like the angle of view achieved by the 25mm lens on the Pentax 645D or the 24mm on the blad...

I have assumed that the IQ180 or IQ160 are not the ideal solution here because of the need for long exposures or high ISO - if the goal is get high resolution with low noise - that wonderful sweet spot we all seek... but happy to be corrected here.

Any advice much appreciated.

Best wishes,

Ed

P.S. I have started using my Gitzo, Cube and RRS slide combo and I am in love!

 

[Enda Cavanagh]

Would also be very interested to get some info on this

 

[GrahamWelland]

For a single exposure with medium format? P45+ without a doubt.

Practically speaking, get yourself a full spectrum D800 and it'll render multiple short exposure images that you can stack for star trails. That was my choice. You'll get to capture the true colours of the stars vs just white that you'll get with anything else.

I have an IQ160 and it basically sucks for this, even in sensor+ mode. The D800 (or a D600) will do a lot better at high ISO.

D600:

D800 full spectrum:

 

[Ed Hurst]

When you say "full spectrum D800" do you mean the regular D800 (as opposed to the D800E) or something else?

Great shots by the way!

 

[Paul2660]

Graham, nice shots, on the D800 full spectrum, now long the exposure (or was it a stack) and what iso. I have wondered how the D800 will do in night work at the higher iso settings. Stacked or not.

Ed:

Here are a few more thoughts from my experience.

Equipment: Medium format or 35mm
I would consider 35mm, Canon or Nikon. I have hundreds of hours on Canon, 5DMKII, and 1D MKiv. I have not yet tried the D800. Most MF can't handle the longer times, and even the KING, the P45+ has pretty harsh limitations outdoors. 35mm is much cheaper, and you have a much larger selection of lenses that will give a decent exposure wide open or close to it. Hint you want to be as wide open as you can, to pull in as many stars as possible. On the Mamiya side, I don't know of any wide angle lens that is any good wide open, the 28mm, 35mm, 45, and their Phaseone branded cousins are all very soft in the wider aperture ranges.

File size, when stacking I have found raw is best since if you shoot jpg, then any stuck pixels are permanent. Many raw converters will handle some if not all stuck pixels on 35mm raw files. When stacking, using a series of 35mm raws converted to jogs or tif will take up plenty of space, a MF file stack will take a lot more. Most times you are going to crop anyway as the edges tend to be pretty bad.

Noise, as already pointed out, really only one MF camera can do it, the P45+ and IMO only in perfect conditions. The MF cameras will take a dark frame and that has to be as long as the pervious exposure so 40 minutes means another 40 minute dark frame and if the battery runs out, the both frames are lost. MF without the dark frame will look terrible. 35mm depending on the brand can do very well, up to around 2000 iso. Canon's 5D MKII will do this easily unless you are working on a very hot night or in high humidity. I have yet to see what the Nikon D800 does. So if you want to stack I feel the 35mm is a better solution since you can take your stacked exposures and not have to wait on the dark frame. Canon allows some of the dark frame to run in the background but if you start a 40 minutes series say at 1 minute each, you will soon buffer out. Nikon locks you out till the dark frame has run like Phase.


Stack--no stack:
I started without stacking, just leaving the camera open for up to 1 1/2 hours. This works, but as I progressed, I realized that working with the moon is much much better, and much light painting is needed. The moon adds a wonderful color to the shot and gives the sky a great blue hue. Without moonlight the sky will often times take on a warm tone, amber and ruins the shot. It's also very hard to take out without altering the star trails.

Stacking is more work, much more work, but you get so much more control. For example, on a night with a slight breeze, stacking works much better as odds are one of the many exposures will have less wind noise (if you are working in the desert this is not that big a deal, where I live trees are always in the shot). The trick is to figure out how long the stack exposure needs to be and at what iso.

When leaving the camera open for single long exposures, I tended to use the base iso. With stacking, most times, you will need to be at higher starting iso, like around 200 to 400. However I will many times need to be at 800 to 1000. Here the noise features of the camera are very important. You are still shooting raw, but it just helps to have a camera that handles high exposures without excessive noise and here MF is just not going to work, even the P45+. Stacking will also bring in a lot more faint stars (with wider apertures) You have to experiment and each night I shoot it take a while to dial in the correct settings for that evenings shoot. Due to the raw file sizes again stacking on the MF cameras just takes up too much data IMO even if you work at base iso and you still have the mandatory dark frame and these will create "gaps" in the trails. Gaps can be taken out, but it just adds more work to an already involved process.

With a stacking process, I can work with almost a full moon and the results are just amazing and so much better than just leaving the camera on for one long exposure. You end up with shots that look like the non sky portions of the shot were taken in full daylight, then with the nice blue hue to the night sky, most people think they are faked. But they aren't it's really amazing to see what the camera can capture vs. what the eye can see.

Remember also, the moonlight/sky combination may just not allow a great compromise and you find that to get the exposure for the sky just right, you are repeatedly underexposing the foreground. With a stack, you can just shoot a few longer frames that take the foreground, you then can combine these later on with the stack composite for the sky.

I use the Dr. Brown stack modes methods to combine the files in CS5 or 6 but you have to have the "extended" version of the software. The stack modes are extensions and you can download them free from the Dr. Brown website, and if you can't find them I can send them to you.

The other thing to consider is the "dark exposure noise reduction" or "dark frames" on these cameras are mainly to handle stuck pixels, not noise. The noise is a factor of the sensor design and some cameras will handle it better than others. It's much easier to handle the noise than stuck pixels as they will be Red, Green, Blue or white. Over time even with a good 35mm, you are going to get some stuck pixels and on a warmer night, you will see them sooner than later. They are a real pain to remove and you can end up with hundreds of them.

So far, with Canon and the 5D MKII, I can usually get through a night without too many stuck pixels, my 1D MKiv was even better, but I sold it to get the D800. The 1D MKiv was limited by the 1.3 crop factor. I want as full a view as I can get since I know some of the image will end up being cropped.

This is just one workflow, that works. I am know there are many others.

Hope this helps.
Paul Caldwell

 

[Paul2660]

I also wanted to add, that for Milky way shots, everything I posted in the previous post goes out the window. Moonlight will kill the milky way so it's best to either time your work so you can shoot the milky way after the moon sets or on a moonless light.

Here I tend to start at iso 1600 and quickly get to 2000 or even 2500. The reason is you leave the camera open at the lower iso long enough to get a shot, you will get motion blur i.e. milky way trails and that is hard on the eyes. Usually 30 seconds is about as long as you can go and I tend to try for less time that that. Again here, being as wide open as you can helps a huge amount.

Paul

 

[Shashin]

So, Ed, what is stopping you going over 30 seconds with the 645D? I routinely expose for 3-5 minutes. Why not try 15 minutes? Or even longer? I would also lower your ISO, you really do not need 1600. So far, I am not sure you can say the 645D is not the right camera yet. And there is a whole processing chain the has not been addressed--astrophotography has additional techniques that are needed beyond what daylight photographers do.

Are you shooting without a moon? That will also make an impact on the results. you may want a bit of a moon to give you blue skies rather than red skies from air glow.

But after test your 645D, a D800 would be the next step. But that is no miracle camera either--without a darkframe, hot pixels are really striking. But CMOS is better than CCDs for this type of work.

BTW, ambient temperatures are going to make a big impact on noise.

 

[GrahamWelland]

When you say "full spectrum D800" do you mean the regular D800 (as opposed to the D800E) or something else?

The D800 has the IR filter replaced with a clear filter. The star trails are coloured due to the varieties of the IR content in addition to visible. It's a stack of long exposures which is tough to do with MF due to the enforcement of dark frames.

Also, everything Paul said too. You could shoot a single long exposure using the P45+ for star trails but I find it more efficient to stack multiple shorter images shot wide open (the example I posted was something like 16+ 4min exposures) and combine them in Photoshop. I use the same Dr Brown stacker action but you can basically do it yourself by loading each image as a layer and then use lighten as the blend mode (or statistics if you have extended edition). I also shoot one reference frame lit for the foreground and blend that in too. No noise reduction / dark frames when shooting these - there's a 1s break between images due to the intervalometer.

For star fields you need high ISO to capture sharp stars - exposure < 30s and pretty much wide open. ISO 1000+ -> 3200. The more light / fast ISO, the more stars you'll get.

I can't speak to the abilities of the Pentax (which sounds usable) but for Phase One & Leaf backs this really isn't their forte. I REALLY wanted to be able to do this stuff with my Alpa or DF but in the end I had to just break down and get one of those nasty D800 DSLRs. My D800 has the full spectrum and passive sensor cooling mods - Spencer's Camera in Utah build these. You don't have to go to this extreme and any decent recent DSLR will perform well at this stuff. I also use an unmodified D600 and a Fuji X-Pro1 for this too.

 

[Ed Hurst]

Hi Shashin,

Thanks for the questions/ideas...

My issue with long exposures of a few minutes and upwards is noise - even after running the files through noise reduction software, and even in cool ambient temperatures. Using very long exposures (to allow for trails to be captured in a single frame) or high ISOs yields, in my experience, files that are noisier than I want. I would gladly use exposures of 2 minutes and stack them if I could take a sequence without the camera interrupting the sequence for dark frames, but the 645D does not allow that. Stacking 30 second exposures seemed like a good approach, but requires high ISOs to capture anything. So I am caught in a bind between long exposure noise or high ISO noise. The solution seems to lie in a camera that allows low noise use of high ISOs, a camera that produces low noise files from very long exposures or a camera that allows the use of exposures of around 2 minutes at medium ISO (say 400) without dark frames interrupting the sequence. I don't feel the 645D, or indeed most other medium format digital solutions, seem to meet these criteria - though would love to be corrected.

All of the above is based on shooting without the moon - I will certainly try shots with the moon's light and see if that changes the equation. Thanks for the idea

I do feel that the D800 might be the way forward. Re. your point about d800 and the advisability of dark frames - I am all for a dark frame - just want to be able to take one at the end of the sequence and use it rather than being forced to interrupt the flow of shots.

 

[Ed Hurst]

Graham and Paul - thanks for your advice - I will study what you have said with care as well

 

[GrahamWelland]

I do feel that the D800 might be the way forward. Re. your point about d800 and the advisability of dark frames - I am all for a dark frame - just want to be able to take one at the end of the sequence and use it rather than being forced to interrupt the flow of shots.

No long exposure noise reduction when image stacking with the D800. The blending merge will help with noise suppression anyway. Ditto when I do light painting I don't use it either.

I only ever use it when I shoot a star field image. If I were shooting a single long exposure for a star trail image then I also would not shoot a dark frame.

 

[viablex1]

For a single exposure with medium format? P45+ without a doubt.

Practically speaking, get yourself a full spectrum D800 and it'll render multiple short exposure images that you can stack for star trails. That was my choice. You'll get to capture the true colours of the stars vs just white that you'll get with anything else.

I have an IQ160 and it basically sucks for this, even in sensor+ mode. The D800 (or a D600) will do a lot better at high ISO.

D600:

D800 full spectrum:

man thats bad *** graham!!!!

I keep looking at these from spencers

 

[Bill Caulfeild-Browne]

Despite the digital revolution, film might be the best option....
Bill

 

[viablex1]

Man would be great to have a thread or even links to good resources to understand how to do this I have a night shot I am dying to get just to show he stars in back of it.

matto

 

[Shashin]

Despite the digital revolution, film might be the best option....
Bill

Reciprocity is an issue there and well as film buckling during exposure. Still, it certainly can be done.

 

[Shashin]

My new years resolution is to work more at night with MFD. All with the 645D:

 

[Giorgio]

This video is a little bit dated (2008) and a little bit long but its very informative.

O'Reilly Webcast: Secrets of Digital Night Photography - YouTube

I hope this helps.

 

[GrahamWelland]

Despite the digital revolution, film might be the best option....
Bill

Bill,

This is definitely easier with film if you want the multi-hour star trail shots. Literally a case of setting up and letting it run for hours without any concerns of sensor noise, dark frames, etc etc. and also medium format platform so long as you've got a fast and sharp enough lens near wide open, i.e. f/4 or f/5.6 etc.

In this respect, I'd agree that sometimes film is more flexible! :chug:

 

[Zerimar]

For single long exposure shots the P45+ Hands down. I own this and use it on a H2 which shutter works in 1/3 stops up to 18H 12M… Also the P45+ can be powered by a canon dual charger to power the back for long periods of time..


An example using a P45+ with a 1 hour 26 minute exposure.

1 hour 26 minutes, Peaks. by RickrPhoto, on Flickr

exposure stacking also is a very useful method in my experience, and both are useful in certain situations. I would suggest using the stacking method over a single exposure if it is within a week before or after a full moon, and the moonlight would wash out the sky of the image in a single exposure. Ironically a week before a full moon is one of the best time to do star trail landscapes..

This example was a stacked exposure taken with my 5d mark II over 3 hours. Also you gain the ability to edit further with the stack, I.E. a car drives through your frame which you may or may not want the light painting effect.. just grab a shot with or without it from the series and tada… easy fix.


Monument Valley Star Trail by RickrPhoto, on Flickr

If I was looking to invest in a new system specifically for long exposure night photography, I would personally suggest a D800E as you can stack the images pretty well, and it seems overall easier. The P45+ needing to do a dark frame, not to mention the difficulty of guesstimating what exposure to use, then having to wait twice as long to see if you were right could possibly leave you without any shots.. where as stacking lets you use the camera twice as long in the same spot to get longer trails..

 

[GrahamWelland]

Rick,

I was looking at the first P45+ image you have there which is very impressive. I've been meaning to give my P25+ a long work out like that for star trails but I always end up pulling out the Nikons for these.

One thing I'm curious about, and this is genuine interest and NOT a criticism, is that I notice that there is a slight bump at the beginning or end of the trails and I was wondering if this was perhaps shutter bounce or maybe bumping the camera/tripod? I never bother with mirror lock up with these types of shots and I probably should cover the lens when I trip the shutter myself to avoid these issues - so hence the curiosity about your shot so that I know what to look out for.

Btw, I also recommend the CH-910 Canon battery pack for the P+ series. Very useful if you can find it plus it's handy as a travel battery charger. It's nice to be able to mount 2x batteries and even change one of them half way through if need be.

:thumbs: