Long exsposures - how he is doing it??

[D-B-J]

Standard picture bracketing. Probably uses a wireless shutter remote with the functionality of being able to do interval shots in a series. Then uses some sort photo software to blend all the images together.

As i have already mentioned, In theory I know what he's doing, but I want to see/read a guide for it..
Thanks for the help.

Location - You want a place outside far way from the city. Then locate the North Star. The North Star is the only star that does not rotate in the sky. You want this star to be in the middle of your frame.
Time - The best time is during a New Moon where the sky is darker.
Gear - Camera, remote shutter cable, tripod, image stacking software

Settings - I don't think there is anyone setting for this, there is some math equations that can help zero in on the desired settings but I don't know it. I would start off with trying F/4, ISO 800 and 30sec. You can play with your F-Stop and ISO in order to help get a nice 30sec exposure. Once you start capturing nice 30 sec exposures that shows some star movement, set your camera to continuos shooting. Then plug in your remote shutter button and lock the bottom in the shutter clicking position. The camera will now continuously shoot 30sec star trail photos. The more photos you take, the brighter or thicker the star trails.

PS: Place you lens on manual focus and set it to infinite.

In my experience, that is not enough light. I typically start at 1600, f2.8, and 30 seconds, and adjust from there. Also, be careful of setting your focus to infinity. I did that once, and all the stars were oof. It's best to turn it just before infinity, and then zoom in on the LCD to check focus.

Good luck!

Jake


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[sonicbuffalo]

Wondering if the "Bulb" setting came into play?

 

[TCampbell]

The star colors are not natural - at "best" he might have an application that considerably stretches the difference between color temperatures of the stars. When we say a star is a "red" star, what we really mean is that it has a slight red tint to it. A "blue" star has a slight blue tint. There are a few extreme stars... red carbon stars ("Hind's crimson star" in the constellation Lepus just below Orion is such an example -- that star is as red as the color the tail lights on your car ... no kidding.) But red carbon stars are rare.

Immediately I realize the images have been strongly modified... but I considered that the star trails themselves might have been real and only the colors were adjusted.

Cameras will generally see much more colour in the stars than our eyes. Our eyes have rods & cones on the retina that give the light sensitivity. One of these (I forget which) provide colour information whilst the other is more sensitive. In low light situations our eyesight is basically monochrome. when using a telescope with it's greater light gathering power the visual colour in the stars is significantly more noticeable.

With the camera setting other than aperture/shutter speed/ISO in normal positions shots of the stars will often show significant colours. Though if the star is overexposed this tends to get lost as all the colours fill up to maximum.

I suspect the saturation was turned up on his camera to maximize the effect, but most of my junk shots of stars show very obvious colour.

The second & third shots are clearly Photoshopped. To get the second would take 24hrs of frames to stack, without the sun coming up or near the horizon. Whilst there are places/times where this is possible the foreground is not consistent with them.

Stars are effectively black body radiation sources... they are not merely emanating light at some specific wavelength, they are emitting light across the full visible spectrum (and when you take a spectrum of the star, you do see full spectrum light, but you'll see some wavelengths emit a bit more than others giving the "white" light a bit of a color cast.) The star's temperature gives it the color cast. Hotter, more energetic stars have a "blue" cast. Cooler, less energetic stars have a "red" color cast. There's not much issue with rods & cones for stars because stars are effectively point sources of light. Due to their extreme distance they do not appear to have a "surface" area to us. The only exception to his is carbon stars. This is a class of star that has churned enormous amounts of carbon in their atmospheres and are effectively filtering out most wavelengths other than the reds. These are usually variable stars with a period of variability around 800-1000 days. The reddest of them (stars like "Hind's Crimson Star" in Lepus -- a bit south of Orion) can appear as red as the tail lights of a car -- but only during the right part of it's variable period (then it becomes more orange.) But these carbon stars do not appear "white" with a bit of a red or orange tint... they actually ARE red or orange.

Nebulae, on the other hand, are spread out across enormous distances. We see these in black & white (Some people detect a faint hint of color and a few people are especially sensitive to color -- but that's rare.) We can only bring out the color in these objects with long exposure images.

But back to the stars in those photos... those colors are not natural even for time exposures. They've been exaggerated. A color camera will not bring out those colors in stars.

 

[petrochemist115 140]

There's not much issue with rods & cones for stars because stars are effectively point sources of light. Due to their extreme distance they do not appear to have a "surface" area to us. The only exception to his is carbon stars.

Yes stars are all point light sources. Carbon stars are not an exception to this, the only exception is the sun. All others are at least 4 light years away. Rods & cones have nothing to do with visible surface, it is purely to do with the light levels and most stars are very dim to the unaided human eye. Through my moderate scope the colours of many stars are noticeable to the eye. Double stars are often best for observing this as the two different colours close together are easier to recognize.
As per my previous post I agree the colours have been exaggerated, but this only needs the saturation to be turned up. Easily done to this extent in camera. Contrast has probably been boosted too, but my shots have all been with light polluted skies so I find that harder to judge.