Wednesday, February 25, 2009

Lulin


Comet Lulin: 100mm, f/2.8, ISO3200, 6 seconds

I had planned on calling it quits with Comet Lulin after a few successful attempts (one, two, three), but knowing that in a couple of weeks that this thing will effectively gone forever and that it's just about at its brightest and highest in the sky for me... I had to get one more round of shooting in.

Finding this was no picnic. The goal was to shoot it at 100mm, so I first focused that lens as near to infinity as I could, picking a lit target about 1/4 mile away. I then carefully swapped the lens for my Sigma 30mm f/1.4, making sure to not adjust the 100mm's focus.

It took about 10 minutes of blind shooting to find and center the comet - it's very tiny at 30mm. I then carefully swapped lenses again, back to the 100mm. I needed to make a couple more adjustments to get it just right. Then, I attached my cable shutter release and sat inside behind my sliding glass door, shooting one 6-second shot after another, about 60 in all.

This shot here is a crop from one of those shots with a little bit of post-processing. I plan on spending some time in the next couple of days stacking the images (fully described here) to remove as much noise as possible. I'm optimistic with this set since the comet was much higher in the sky and further from the light pollution.

I'm already impressed with the length of the tail in this shot. More comet goodness should be on the way.

Canon 40D, Canon 100mm f/2.8 Macro, Bogen 190XPROB Legs, 322RC2 Grip Action Ballhead

Monday, February 23, 2009

1950


You find the coolest stuff in forgotten places.

Please view on black.

Saturday, February 21, 2009

Stargazing



Please view this large, on black

I went out driving last night, trying to escape the light pollution of my neighborhood so I could shoot more stacks of Comet Lulin. My last attempt (here and here).

What I found was basic:
1. You can't escape this much light pollution by driving 30 minutes
2. When you drive 30 minutes away from home, it takes roughly 30 minutes to get back.
3. The sky moves fast. Before ya know it, your front yard view is in your back yard.

There's no comet in this shot, but if you'd like to see how I shot the thing so far, check my blog post.

Shot with Canon 40D and the *very* fast Sigma 30mm f/1.4.

Wednesday, February 18, 2009

Comet C/2007 N3 (Lulin) - 67 Image Stack: f/2.8, ISO3200, 2 seconds


This shot was the product of 67 individual 2-second photos at ISO3200, f/2.8 of Comet C/2007 N3, aka "Comet Lulin."

This comet's green color comes from a type of carbon and cyanogen, a poisonous gas. View this shot to get an idea of how insignificant this comet is in the context of the whole night sky. If you look closely, you can see the faint tail of the comet extending to the lower-left.

Equipment used: Canon 40D , Canon 100mm f/2.8 Macro Lens, Bogen/Manfrotto 190XPROB Tripod Legs, Bogen/Manfrotto 322RC2 Grip Action Ballhead

I shot these in the early morning hours of February 18, 2009, from 12:15AM to 12:25AM EST from my deck, (an hour north of Philadelphia, PA), with a horribly light-polluted sky. Weather-permitting (and it's not looking cooperative over the next few days), I'm planning on finding a darker area to shoot this comet once more, with hopefully even better results.

This wasn't a very well-planned event. I never head about the comet until a couple hours prior from fyngyrz's post. To find out when it would be visible here, I used this interactive sky chart to get my bearings as to where I'm looking, and this page to find out where the comet currently was (look for the downloadable PDFs). 3AM would have been a better time to take this, with the comet higher in the sky and further away from the horizon's light pollution, but this camera gear doesn't pay for itself - I had to wake up at 5:30AM.

Now, from what little I know about astrophotography, it's important to take your shot quickly to avoid star trails - within a second or two. You'd be surprised how quickly those starts move across the sky. To take shots this quickly, you have two options: a very high ISO, and a very wide aperture. Ideally, you go with both. Now, as with anything in photography, there's tradeoffs with both of these options.

With the high ISO, you're introducing a lot of grain. My Canon 40D goes up to ISO1600 with a "pushed" ISO3200. By "pushed", it's really just ISO1600 that's boosted in-camera one stop brighter. Pushing introduces a lot more noise than would be present at the already-high ISO1600.

With the wide aperture, you're more likely to get chromatic aberration (CA). Ideally, I'd like to use my f/1.4 50mm wide open. However, due to the CA that's introduced at that aperture, I get very distinct bands of purple fringing around every star, ruining the shot. I find that this CA drops significantly at f/1.6, almost going away at f/2.0.

So where did I end up with these options? Well, I took to series of shots - one with my 50mm f/1.4, and one with my 100mm f/2.8 macro. With the 50mm, I tried f/2.0 to reduce the CA, and with the 100mm, I used its widest aperture of f/2.8.

Each of the individual shots of this comet are (necessarily) terrible. The grain makes them almost a waste of time to look at. There are several types of noise introduced by the shot including: high ISO, sensor heat, and atmospheric - each of these degrade the image. However, these noises are random. The underlying image that I'm shooting isn't. It's possible to remove the noise with a process called "image stacking."

Basically, image stacking involves layering several photos of the same subject on top of each other, varying the transparency of each photo through the stack, with the most transparent being at the top. You blend the photos together with a subtraction algorithm so that anything that doesn't exist in the other photos -- the random noise -- is ignored. It's a tedious process, but well worth the time, because you're getting what would otherwise be an impossible shot.

To image stack for the comet in this series, I took 67 individual photos, each at ISO3200, f/2.8, and 2 seconds. I then used Apple Aperture to crop them down to the size you see here. I was as careful as I could be to line up the crops with each other - remember, the earth is spinning fast enough that within 20 minutes, the comet will move out of frame! Lining these up took a considerable amount of mind-numbing time. After cropping, I brightened them up a half stop, then exported them all as JPGs.

I then used the image-stacking software called Lynkeos to automatically line up the photos better, then stack them together. I could have done this manually with Photoshop, but was more than happy that Lynkeos did a fairly decent job on its own. I exported from Lynkeos to TIFF format, then post-processed with Photoshop and Aperture to get the most out of the shot that I could.

I plan on stacking the shots from my 50mm in the next couple of days. It'll be interesting to see how that extra stop of light makes a difference. Unfortunately, the comet will be much smaller due to the wider focal length.

iPhone Photo of the Day, 2/18/2009: Lines



I was trying to get away without any post-processing outside of the iPhone, but ended up bumping up the contrast and exposure in Flickr.

Tuesday, February 17, 2009

Fun With the iPhone Camera


After reading Chase Jarvis' post, 5 Tips for Making Great iPhone Photos," I thought I'd give it a shot. I bought the two apps he suggested, Camera Bag ($2.99) and Pano ($2.99), and so far haven't been disappointed.

Camera Bag gives you a bunch of presets to transform your iPhone into one of several types of historical cameras. This shot here was given the "Lolo" preset (apparently a knock-off of the old Loma toy cameras, though I'm not that familiar with them). I'm also a fan of the "Helga," which tries to make your shots look like they were taken with a Holga camera.

Pano is a very powerful photo stitching app, allowing you to stitch together up to six photos, side-by-side. The rightmost sliver of the photo is laid semi-transparently on the left side to help you line up the next shot. The exposure blending and seam-joining is top-notch. I'll post a shot when I come across something interesting to shoot.

One great thing about being able to shoot and post-process your shots in-camera is that you can then upload them to your Flickr account with such apps as Darkslide, or using Flickr's email upload service.

It's weird when you get excited about degrading the quality of your $300 iPhone photos to look like old camera snapshots, but hey, it's made me interested in using the thing. I'm looking forward to posting more on-the-go shots with my new toy.

Into a Thousands Pieces


Shot from outside the Camden Adventure Aquarium.

Canon 40D, Canon 10-22mm f/3.5-4.5

Thursday, February 5, 2009

Harris' Law

Harris' Law states:
At some point, all humanity in an online community is lost, and the goal becomes to inflict as much psychological suffering as possible on another person.


Due to some in-fighting, the Flickr group DeleteMe Uncensored imploded the other day. I'm not sure what the fighting was specifically about, but the way it ended was - in true DMU style - hilarious. One of the admins made everyone an admin. Of course, then came the free-for-all of several of these new admins racing to ban everyone else in a sort of online riot.

Shot with Canon 40D, 50mm f/1.4

Monday, February 2, 2009

Spot



Shot at the Adventure Aquarium, Camden NJ. There's a bunch of this stuff on the wall towards the end of the exhibits.

Low light handheld shot at f/2.0, ISO3200, 1/25sec

Canon 40D, Sigma 30mm f/1.4

Sunday, February 1, 2009

Made the Front Page of Explore

Click to see the original
This is pretty cool - I've made Flickr Explore several times now, but this is the first time that I've made their front page. Since then, the shot has been getting faves every few minutes, and has gotten as high as #1 on Flickr Explore for 1/31/2009. Very cool.

I know, I know, all this proves is that I satisfied some random "interestingness" algorithm, but it's still cool. Lots of real people are clicking through and marking it as favorites, so it's not entirely artificial.

When the photo was on the front page, it's amazing how much traffic it was getting.