wow great stuff.
ive being playing around the tc80 and as noted you get gaps. thats because of the delay between the 5min shots which are set as 1sec incrmenets and it wont let you choose 0 as a commad. the best way to avoid it is to pay close attention at the countdown and with carefull attention you can be quicker than 1sec in getting the mirror back up.
your findings of iso400 @5.6x 5min are my exact same settings. also by using so many frames you actually average out any noise problems.
I am at a loss for words. I am just dumbfounded by the awesomeness of this shot. Probably one of the most spectacular shots I have seen in this forum. What a great way to usher in a new year. Bravo! Bravo!
parsons wrote:
wow great stuff.
ive being playing around the tc80 and as noted you get gaps. thats because of the delay between the 5min shots which are set as 1sec incrmenets and it wont let you choose 0 as a commad. the best way to avoid it is to pay close attention at the countdown and with carefull attention you can be quicker than 1sec in getting the mirror back up.
your findings of iso400 @5.6x 5min are my exact same settings. also by using so many frames you actually average out any noise problems.
It's actually not just the 1 second delay (with a super wide angle the a fisheye the stars don't move much in a second, the longer the lens, and the further from polaris the more of an issue it becomes). The biggest problem (with a super wide) is the blend mode. In each exposure, on each end of the trail you get some bleed from the star light, like a little gradient. The 'maximum', or 'lighten' mode only takes one set of the gradient, the 'screen' mode adds it to the gradient of the adjacent exposure so that you end up getting the same as in the middle of the trail, and the gaps disappear (almost entirely).. but you get loads of other issues.
Oh, for the screen mode thing to work out right you have to do a 'linear' conversion of the raw files, so make everything like blacks, brightness, contrast, etc. zero, and use a linear curve. Otherwise you're going to affect that tiny gradient! Wish I knew how to write programs.. then I'd write one that did all this properly
Floris,
Great idea for the image. Looks nice but some noise reduction and dark frames would help the image more. I can see several "hot pixels" and the foreground appears a bit noisy. Other than that nicely done.
I have never really cared that much for star trail images but this one is dazzling Floris. The detail on the valley's floor and the distant color is what blows me away though. Fine work!
Randy
Klaus Priebe wrote:
Floris,
Great idea for the image. Looks nice but some noise reduction and dark frames would help the image more. I can see several "hot pixels" and the foreground appears a bit noisy. Other than that nicely done.
Thanks Klaus, I took two dark frames, but they actually hurt the image more than help it I've found. Because of the contrast enhancement, the magenta sensor bloom in unnoticeable (that's all the dark frame would really do for me), and by using the dark frames I was getting some other weird effects. I definitely have some hot pixels to remove, and haven't done any noise reduction (except for chroma in ACR), though I'm not sure how much I want to do on the foreground, as it'll be near impossible to separate out the noise from the salt plains texture. It's only really distinguishable from the natural texture in the deep shadows. If you have any suggestions I'd love to hear 'em, seeing as you do a fair amount of astrophotography
So I really should be studying for an exam I have in a few days.. but just to illustrate what the trails should look like with what I've so far found to be the best (yet very time consuming) technique.. here's a 100% crop of the stars from the first 3 exposures combined. No noise reduction except chroma in ACR and no sharpening. Also, I could probably do some CA fixing on the bright stars, haven't decided yet.
Notice the lack of gaps (well, if you look really really hard you might be able to see one or two, the color change in some of them I cannot explain..)
Randy Walton wrote:
I have never really cared that much for star trail images but this one is dazzling Floris. The detail on the valley's floor and the distant color is what blows me away though. Fine work!
Randy
Thanks Randy I've generally felt the same way, the trouble is that the foreground in most of them you see around isn't exciting or meaningful.. so I do them sparingly when I get some inspiration
I'm not sure if it's clear to most people, but the title actually references the star trails as well as the motion of the salt plains that cause the buckling that form the little ridges.. I like to combine 'invisible' forces with my star trails to give you something to think about. (I've only done two others, but with a similar kind of theme - at the racetrack and of a bristlecone).
