Quadrantids Shoot Questions

Thanks all for the sharing of the post, tis much appreciated. I've received a few questions about the images and figured I'd take a moment or two to answer them to the masses even though I've responded directly already. The first question I'll address here was actually the most recently received, but for a bit of background on my process, I decided to answer it first.

What is image stacking, and how does the PhotoShop action work?

Essentially – image stacking is layering a series of images together so that you can then process them as a set. Because I shot from a tripod, and the illumination on most of the foreground objects stayed the same throughout the shoot, the sides of the houses, the chimneys, the trees, all have a consistent illumination. The sky is mostly black, except for where the stars are in any given shot. In each shot, they move just a little bit, not doing much more than adding a bit of blur to the star rather than a discernible trail in any given image. By stacking 683 of them, that lets the stars move through their arcs, the process pulling the brightest pixel from the column of images.  Now, PhotoShop doesn't have to actually stack all 683 at once, you start with a new PS document and fill it with black. As you run the automated batch process against your folder of images, PhotoShop grabs each one, and copies it into the "new" file, and then applies a lighten action to get the brightest pixel at each location. So, after processing the one image, the "processed" image looks just like the first one… from here, the changes are more subtle. The action closes that first image and works through each successive image, merging the new layer into the previously processed image and brightening fairly small areas.  Over time, this yields the streaks. 

 

Why 683 images? Why not a 3 hour exposure?

Okay – so that is a shortened version of the question, but the essence is the same. Why do folks stack rather than using longer exposures or a very long exposure?

I've not searched for an answer but a few quick reasons come to mind. First off, early digital cameras had more noise the longer the sensor had to gather data to process, so to avoid this extra noise, you had to keep your exposure times short. Even now, there are settings in DSLRs that enable or disable long exposure noise reduction on images; so there is still some noise generated by a longer exposure.

Another practical reason is that most cameras' longest exposure time (excluding bulb) is 30 seconds; but again this changed with the advent of intervalometers (such as my canon TC-80N3) – devices that allow you to set exposure time, time between exposures, and number of exposures, greatly simplifying time lapse photography. There are even firmware builds (such as Magic Lantern unified, available on several Canon bodies) where countless additional features can be added to your DSLR. Without one of these devices (or a firmware modification), it is easy (as I did, see yesterday's post) to set the camera on continuous shooting and just slide the latch to lock the shutter into the "shoot" position… the camera dutifully shoots till it runs out of battery or storage.

Test shots are much easier to evaluate in shorter exposures. You can always do the math and calculate how a longer shot needs to either have the aperture cranked closed, or iso lowered, or both; but why not just go ahead and do 25 or 30 second exposures?

Flexibility in post processing pops to mind as well. I is fairly easy for me to process 180 or so images:

MeteorHunt2
instead of the full 683:

MeteorHunt1
(Click either to enlarge)

It nets a very different result. I could also skip sections of images to add some gaps… hmmm… spelling out a secret message in morse code anyone?

 

So, did you actually capture any meteors?

Yes, I think… well, one… maybe. How's that for decisive? LOL  Well, based on info discussed in yesterday's post, I think I ended up with one meteor, and one satellite.  Both came from the lower portion of the image towards the upper portion… both were caught in multiple frames. The first item I saw was what I think was a meteor:

Meteor

(click to enlarge)

and what I think is a satellite – tho it may be a faint meteor. It is a longer trail, but the trail is pointy at the end, so it may have been a more glancing blow to the atmosphere – but while it is faint – the trail goes all the way into the tree… so perhaps tis a satellite after all:

Satellite

(click to enlarge)

There are gaps in both due to them being captured in two frames each. There is a slight pause between closing the shutter and re-opening it. I got "lucky" both times – LOL

If anyone can give me a bit more info on meteor vs. space junk, I'd appreciate it.

All for now – keep those questions coming!

Thanks for reading!

Vosonic VP8860 Multimedia Viewer adds Canon 50D RAW Support

Not sure if you've considered a multimedia viewer for your bag, but with the 15.1 MP images comin' out of my Canon 50D – long days of shooting can burn through CF cards pretty quickly. There are numerous options out there, Epson probably the most mainstream, but I went with the Vosonic. Quite a few factors led to that decision, but I'll save that for another post. Short version – I'm a huge fan of the VP8860.

Today they finally released a firmware update for the VP8860 that supports RAW files from:

  • Canon EOS 50D
  • Canon EOS 5D Mark II
  • Sony Alpha 200
  • Sony Alpha 900

The firmware update can be found here on the VP8860 Firmware download page and you can read aobut the viewer on the VP8860 Product Page

Thanks for reading!

Canon 50D Shutter Actuations Counter (and Canon 40D too!)

Just a quick post before knocking off for the evening.

Saw a post today on canonrumors.com that had a link to a site that has a free piece of software that can read the (until now) Canon Support territory of how many actuations a shutter has. The idea is pretty basic – it uses the EOS Utility drivers (you put this .exe file in the same directory as the EOS Utility) to access the information from the camera. You plug in the camera to your computer with a USB cable, turn it on, close the EOS Utility if it starts, then start this application. Click the "Get Count" button and voila!.

This program accesses information from the Digic III processor (or the Digic IV) so the app will work on the 40D, 50D, and the 5D Mark II, but not on the 30D, or 350D,400D, etc…

It was interesting to see that my 40D has 27,010 actuations, but how accurate is it? Well, my 50D shows 3,961 – which shows 4 more than the highest image number. This results from some "remote shooting from PC" which counts as a shutter actuation, but since the file is saved directly to the computer, so the compact flash card count doesn't get increased. So I'd say that the 27k actuations reading on my 40D is pretty accurate.

This is only for the PC, not for the Mac, but you can read all the details here.

Thanks for reading!

Canon 50D Firmware 1.0.3 and Adobe Lightroom 2.1

Okay – two updates for the 50D.

Firmware Update – 1.0.3

First up the firmware 1.0.3 has been released. You can get to it here.

It is upposed to correct the err99 problem that some folks have experienced.

Adobe Lightroom 2.1 Released

Previously Canon 50D RAW support was only due to a "release candidate" version of Lightroom. That is their version of a "beta" release. The full 2.1 release has official support for the 50D RAW format, and my quick tests seem to show that they've improved the noise reduction, but I've not really had a chance to compare apples to apples. You can get that upgrade here (you'll need to be a licenced owner, or you can download a trial). You can choose Win or Mac version in the "latest updates" column to the right.

Thanks for reading!

Canon 50D RAW support from Adobe

Well – you’ve got to love the internet. I had recalled that the 4.6 RAW release candidate from Adobe supported several new cameras completely and thought it covered the 450D – after a bit of googling, I found that 4.6 does have "preliminary" RAW support for new camera models including both the 450D and the 50D.  I already had the 4.6 update and PhotoShop CS3 happily opened up the 50D files… You can find info about it here:

labs.adobe.com/wiki/index.php?title=Camera_Raw_4.6

UPDATED:
Well – the Adobe RAW 4.6 release candidate has become an official release with full support for the 50D (the release candidate only had . Rather than post links to all the different flavors – (Win, Mac, Win + DNG, Mac + DNG), you can see them all here:

http://www.adobe.com/support/downloads/new.jsp

As for Lightroom support – it turns out it too is out there. Lightroom 2.1 ‘release candidate’ (their name for final beta) has the same camera support as the 4.6 update, so you can read about it and get the download here:

http://blogs.adobe.com/lightroomjournal/2008/09/

It is now downloaded and installed on my computer – and a quick test (as I need to be focusing on "work" right now) came out just fine.

More ISO tests to be blogged about this evening…

Thanks for reading!