Tuesday, July 25, 2023

Jack and Papa Capturing Moon and Planets

While our grandson Jack stayed with us last week, he and I went out one evening to take our Weimaraner, Luna, for a walk on the east shore of White Rock Lake and to try capturing the 3-day old crescent Moon, Mars, Venus and Mercury over the iconic Pump Station. 

We were partially successful. Jack got in a dozen or so shots with my Nikon D750, starting with some test shots and then bracketing to try and get both the properly exposed lunar crescent and also the rest of the lunar surface lit with Earthshine. As explained below we didn't quite get what we wanted. Had the mosquitoes not chased us off, we might have eventually got it but Luna was getting impatient anyway so we put the camera away and went for our walk. 

Unfortunately, the brackets didn't get us quite enough dynamic range to get both Earthshine and a lunar crescent that showed any detail. In the end, a single shot had the best overall exposure and detail that we were after. Although the lunar crescent is heavily over-exposed, the Earthshine-lit surface is still visible. And although Mercury is lost in the haze over Dallas, in addition to dim Mars and bright Venus you can just make out the stars of the "front-end" of the constellation Leo the Lion with it's brightest star, Regulus. 

Here is the final shot and below is a version that is labeled. Enjoy!

Photo by Jackson Eaton




Photo by Jackson Eaton






































As always, click on image to view full-screen.

Friday, July 21, 2023

Bedroom Camera Obscura Timelapse


Building on the project described in my last post which involved creating a camera obscura out of a bedroom with our grandkids Olivia and Jack, we have taken the project to the next level: video!

For this, we used Olivia's pinhole lens which with its larger aperture allowed shooting shorter exposures. That let us maximize how many frames we could capture in a given amount of time. I re-framed the view in my Nikon D750 to take advantage of the wall space on the right and we then set it up to take one ten-second shot every 12 seconds. At the end of an hour and 10 minutes, I stopped the camera, having taken 348 images. 

The next step was loading the images on the computer, cropping to a 16:9 ratio and adjusting the exposure a little in Lightroom plus inverting them vertically, then using LRTimelapse to render a 4K video. The last step was adding titles and music (Pounded Piano by Podington Bear) in Da Vinci Resolve. 

This was shot at a busy time in the backyard, with our Weimaraner Luna coming and going and with the grass being  mowed. The timelapse also captures clouds floating by and the shadows of trees and such moving. 

This is short but pretty cool... Enjoy! 

Best viewed full-screen. 

Wednesday, July 19, 2023

Olivia, Jack and Papa Build a Camera Obscura Out of a Bedroom!

Last week, our granddaughter Harper stayed with us (see previous post). This week, it is her brother Jack and cousin Olivia. They are also attending Dallas Parks & Recreation Outdoor Adventure Camp during the day and in the evening we're having other adventures with them. While Harper's camp was focused on photography, this week the focus at camp is on archery. Linda and I don't have a lot of archery experience so our evening adventures are things that are more in our wheelhouse. One of those is photography. :-)

Optics: the principle of the camera obscura.
Engraving, 1752. Wellcome Collection
Tuesday evening, the project was to build a camera obscura. If you aren't familiar with the term, it's an ancient discovery that by having a darkened room with a small hole in a wall or window, a view of the outside scene is projected onto the opposite wall. The image is inverted (sky below, ground above) and in practice is pretty dim. In this digital age, as an alternative to sitting for a long period for your eyes to become dark-adapted enough to see the image, you can capture it with a camera capable of taking long-exposure photographs. 

 There are various tutorials available online on how to create a camera obscura out of a room in your house and capture the image on a camera. We used this one from the George Eastman Museum. It's very clear and easy to follow.  

Outside view of Camera Obscura
In choosing a room to use, we went with the master bedroom. Not only does it have a window with a reasonably interesting view (our backyard) but there is just that one window and although the room has glass doors facing our patio, there is a storm shutter that (mostly) blocks all the light from it.

While the kids were at camp, I masked off the outside of the window which was simpler than trying to tape plastic over the inside. Using cardboard, a black tarp, some plastic bags and gaffer's tape it was pretty quick and easy to block out all light from the window. It ain't pretty, but it's functional. 

The next step was to make lens boards with pinhole lenses. After the kids got home, we sat down to fashion them from cardboard, washers and gaffer's tape. Olivia's has a smaller hole (aperture) which would potentially give a sharper image but requiring much longer exposures; the aperture on Jack's was a bit bigger. 

Next, we finished prepping the bedroom. Initially, we just used towels on the floor to block light coming in through doors and a towel hung over the bathroom door since it had a bigger gap, let more light through. Later, we tried painter's tape. 

As I mentioned, the image in even a darkened room is a bit dim. Given that it takes about a half-hour for our eyes to become dark-adapted after being in a brightly lit room, it wasn't really practical to stay locked up in the bedroom for that long given the kids still needed to get showers after a hot day at camp and we hadn't yet had dinner. Not to mention the impatience of a 12 year-old and a 10 year-old. :-D

Instead, I pulled out my Nikon D750 with a wide angle lens and we captured the view with exposures ranging from 30 to 55 seconds. Of the images below, the first was taken before dinner while it was still pretty bright outdoors; you can see there is still direct sunlight on the fence. It was also taken with Jack's pinhole lens with it's slightly larger aperture so the image is nice and bright. The other two were taken after dinner so it was getting a bit darker outside; there is only a sliver of direct sunlight on the fence. The first one is with Olivia's pinhole lens, the second with Jack's. 

These images have been inverted vertically to emphasize the "normal" view of the backyard but that means everything in the room is upside down with the bed on top (lit blue by the sky) and the ceiling fan down "in the grass". Also, notice that the entire inside of the room is the "camera". Pretty cool!

Shot early evening with larger aperture


Shot later in evening with smaller aperture


Shot later in evening with larger aperture


We have a few other ideas for the camera obscura, interesting alternatives to explore, so stay tuned... we might have more to share soon!

As always, click on an image to see it large.

Friday, July 14, 2023

Harper and Papa Chasing the ISS

UPDATE: Keep reading for the "rest of the story" but here is the same image as below but cropped vertically to focus attention more on the ISS trail. Enjoy!

Our granddaughter Harper stayed with us this week. During the day, she was attending Dallas Parks & Recreation Outdoor Adventure Camp and the theme this week was photography. As I am an avid shutterbug I also spent a little time each evening with her, messing around with cameras, talking about how to take good pictures, etc. 

As I was checking to see what the evening weather would be with the idea that we could maybe take some night sky shots, I noticed that Tuesday evening the International Space Station (ISS) was going to be passing over. Even better, it would be rising just over downtown when seen from up by White Rock Lake. That night around 9:00 pm, we headed up to Winfrey Point and set up my Nikon D750 with an Irix 15mm wide angle lens. Once the camera was set up on the tripod, I let Harper take all the test shots and then we set the camera to shoot a sequence of 20 second shots. ISS was going to be visible for about 7 minutes, only 3 of which would be visible to the camera facing due west. After it passed overhead, we also tried capturing shots to the northeast but lights and trees were in the way.

The next day we loaded the captured images into Lightroom and I did some basic edits for exposure, contrast, etc. and then we loaded them as layers in a single image in Photoshop. As each layer contained a section of the ISS flyover, our goal was to follow instructions from this online article to stack all the images to end up with one image with a full track of the ISS, from when it was first visible (about 10 degrees above the horizon) until it passed out of the camera frame. 

Unfortunately, while the weather report had been for clear skies, there was actually a lot of haze on the horizon and clouds across the path of the ISS. Here is the result of just stacking all the images.

Harper thinks this version is kind of cool and I agree. The streaks of the clouds are pretty surreal and the airplane trails and the few star trails convey a lot of action.  The problem is that you can only get glimpses of the ISS trail as it is mostly obscured by the clouds. Even where it might have been clearly visible in one frame, once we stack all the other frames on that then some or all of it is obscured by the clouds. 

That led us to research other ways to achieve what we were after. With the help of ChatGPT, we learned some Photoshop techniques that allowed us to selectively mask out everything but the ISS trail, stack those and combine them with a base image that included the foreground with the lake and downtown Dallas and in which most of the clouds were to the right. We also removed a couple of airplane trails so that the ISS trail is the "star" of the image.

Here is the end result. It's not exactly what we intended to shoot - the ISS trail is spotty and the gaps don't always match the cloud gaps in the base image - but we are pretty happy with it. 


This was just the start, though. Now we are watching out for other nights when the ISS will fly overhead where the skies are clear and it will pass over an interesting foreground like the lake and downtown in this image. More to come!

If you are interested in finding out when the ISS flies overhead where you live, there are many resources but one of my favorites is the Heavens Above. Here is the ISS Visible Passes chart and here are the details for the flyover we captured

As always, click on an image to enlarge. Clear skies, y'all!