Posts Tagged ‘photo’

A Return to Stereograms

4 April 2018

I have mentioned working on stereograms previously. These last couple of weeks have seen me focused on them.

Stereogram created from drone video taken at Wickahoney. See text for details.

Most that I have done before are close-ups, if you will, or portrait oriented.

I wanted to play with stereograms some more, this time focusing on landscapes. My goals were, first, to get them working consistently and second to hopefully work out any rules unique to stereograms.

In my mind’s eye, I remember sitting on the floor at my grandparent’s with a big box of stereograms and a now antique viewer. I would pick out a card with it’s two slides, read the caption, drop it in the holder, and clap the stereoscope to my face. I remember being fascinated how I could see a 3D version of a scene and how it contrasted from the pictures on the wall.

More, I remember most of them were landscapes.

Now, I’ll grant you my memories of those images are likely rose colored by time and they may not have been as fantastically 3D as I seem to remember. Most indubitably, though, there were hundreds of landscapes and not so many of flowers, people, or objects.

My goal in this recent project was to create valid 3D landscape stereograms. I also needed to work out what the limitations were, and how best to create a pleasing image that was also 3D.

Like this one:

One of the spots that overlooks Swan Falls and the Snake River Canyon, looking downstream from the dam.

Or this one, where the red rock formation just pops out at you:

Looking at Swan Falls Dam and the Snake River Canyon. The red rock is very prominent in the foreground.

What are the rules?

Aside from standard landscape photography composition “rules” I felt there must be some additional guidelines that would drive the composition.

As it turns out, there are, and there aren’t.

One of the things that you need to keep in mind when creating stereograms is:

  1. Take a picture of your subject. Remember where the center of your picture is on the subject.
  2. Take a step to the left. I usually stand with my feet just more than shoulder width apart. After taking the first picture, I move my right foot to touch my left foot then move the left foot so I am again standing with feet apart.
  3. Aim the camera at the exact same point on the subject as before.
  4. Take another picture.

That is my way of getting paired, handheld pictures. The first picture taken thus becomes the “right” picture (as in taken from the right) and the second becomes the “left” picture. The key to assembling the stereogram is the right picture goes on the left side and the left picture goes on the right side.

You can, of course, do it stepping to the left instead. In this case the first image becomes the left picture and the second becomes the right picture. No biggie, just get into the habit of doing it the same way each time.

There’s times a question arises whether or not the middle and far parts of the photograph actually show as 3D. Sometimes they do, sometimes they don’t. Sometimes they work if you have some decent foreground detail, other times you don’t need that foreground to make it work.

Willow Creek, off Black’s Creek Road. Notice the apparent differences in 3D impact in this compared to the Swan Falls stereograms.

And then, there’s the issue of anything that’s moving…that’s likely to produce “ghosts”, faint or translucent objects in the photo. Your main scene, the one you want to see in 3D, has to be still. Trees moving in the wind, clouds passing by overhead, cars on the road, people moving…all those and more need to be avoided.

One way to avoid natural movements such as clouds and water ripples is to use a long exposure time. That way, things get “smudged” smooth. Ripples on water, for example, become a soft flat surface and clouds become featureless.

Interestingly enough, I have one stereogram (below) where the two angles are such that one shows the parked truck and the other doesn’t, and yet the truck is solid in the stereogram view. It’s not a translucent ghost due to being in only one of the paired images. Yet another stereogram I’ve done freezes a car in one picture but it’s not in the other and this time it shows as a ghost car. Go figure. That’s what I mean about “there are and there aren’t additional guidelines.” More likely I haven’t figured them out yet.

Notice how the black truck is in one image but not the other, yet still comes through in the stereogram as solid, not as a ghost image.

By the way, the Wickahoney stereograms were all pulled from a video created by orbiting my DJI Phantom 4 around the midpoint of the ruins. You do remember that a video is merely a string of still images played back rapidly? Each pair, in this case, were pulled from about 1 second apart, e.g. one would be from 13 seconds into the video, and the second of the pair would be from 14 seconds into the video. When doing this, creating a stereogram from a video, you want to be sure the video still image isn’t blurry due to the drone moving too fast, to continue this example.

Stereogram from Wickahoney drone video.

One thing I did discover is that if you use a zoom or telephoto lens to enlarge something in the distance and make it part of your foreground or the middle distance in the photograph, you have to displace the camera location much more than a single step to one side. A problem I encountered was I could properly displace the distant solitary tree but the mountains behind it shifted significantly. They shifted enough that even though I could get the tree to be reasonably 3D, the more distant mountains were blurry.

A wide angle lens, though, works great and lets you really bring in some foreground:

Snake River Canyon from an overlook at Swan Falls, looking upriver from the dam.

And that’s as far as I’ve got. I’ll be going out and shooting more landscapes, as well as some closer subjects.

I think I know how to apply this technique to video as well and plan to try it with the video used to make the above Wickahoney stereograms. That’s for another time, though.

Advertisements

A Return Update

5 March 2015

It has been a weird beginning to the year for me.

I fully meant to return to this blog well before now, but somehow writing for my blog just wasn’t a priority. From time to time, I’d think of something to write about, but I just never sat down and actually did so.

From an amateur radio standpoint, I’ve been working to develop something I refer to as The Thumper. It’s based on something I read about in a blog post where the ham described his fondness for CW (Continuous Wave, aka Morse Code) and an on-the-air experience meeting a group of deaf learning ham radio and cw. The original Thumper was mentioned only in passing, and described as “a device that attaches to their forearm and taps them to indicate the Mose Code being received.” I have various issues with LED displays and my current tactile transducer setup leaves much to be desired. For The Thumper, I’d started by utilizing an Arduino driving a RC servo and while that does work to an extent, it has an inherent speed limitation that I don’t like. Almost anything over 10 wpm keeps the servo at the end of travel, making it impossible to detect the characters. I’m now looking at using a vibrator similar to those in cell phones, compliments of a good friend and fellow ham. Although not what I originally envisaged the vibrator does show better promise and a nice theoretical response to faster CW speeds. Coupled with a LED, it may turn out to be the best solution for me to listen to the radio. I know, but the combination might turn out to be better than the parts. Right now, I’ve only got the Arduino driving the vibrator. Still to be done is receiving and converting over-the-air CW signals provided via the audio jack of my radios.

Plans are under way for more Owyhee explorations, and while doing that I fully intend to try HF radio work from way out in the middle of nowhere. I’m building an end-fed, multi-band wire antenna that should be tuned to each band: 10m, 20m, 40m, and 60m. It’s only mobile in that you can easily carry it coiled up in the vehicle, to use it you have to park and deploy it. We’ll see how that works in practice, but I’ve got good expectations. I’ll be focusing, of course, on CW and PSK but when solo. If I have a friend along, I’ll be trying some phone work as well. More than likely, I’ll be band scanning and if I hear anything, I’ll pause on that and see if I can contact the other person.

Photography-wise, I’m currently teaching a beginning photo class, but with a twist. In all my previous classes I noticed that there was never a deaf or hard-of-hearing person attending. This time, I told the community education group that I would teach a beginning class in sign language. When I shared this idea with the few deaf community members I knew, the enthusiasm was outstanding. In the end, due to various reasons, there were only three in my class. We’re having a blast and there would have been at least two more were it not for an age limitation posted on the community education web page. That limitation didn’t apply to my class, but that exemption information was not passed on to the people that wanted to sign up. Word’s starting to get out there about this class, though, and I’ve mentioned I’ll offer it again, the same way. One of the reasons for doing this is that I just felt like turning the tables on the regular offerings…they’re oriented towards hearing people, the deaf have to get an interpreter. This time, though, it’s the hearing that have to get an interpreter if they try to attend.

I have also been investigating the use of the Shutterbug Remote with my Pentax K3 DSLR. Testing with an iOS device showed that the remote works well with the K3, but I’m getting crashes using the Android version of the app on my Samsung Galaxy Note 4. Testing with a Samsung Galaxy S5 shows it works reasonably well with that phone, so now I’m trying to determine whether or not it’s a setting, a FW, or a HW issue with my Note 4. An email to the developers has not provided any response, so I’m very unimpressed with the customer service aspect of their website. Enough that I’m not providing a link to it. It would be really nice to get this remote working with my phone as it’s a great little device which when used as an intervalometer provides better timing control capabilities than the built-in intervalometer mode of the K3. If I can’t get it working, I’ll definitely have to create an Arduino intervalometer or something.

I’ve built a new woodworking bench (above) in my garage along with a DIY woodworking bench vise (below). These will come in handy when I start building the Vardo.

On the Vardo front, I’ve started gathering materials to modify the trailer for the Vardo. It took me a while to figure out the best way to use my flatbed trailer for the Vardo, and still be able to easily use it as a flatbed trailer. One of the things I had to deal with was me being “greedy.” The flatbed trailer is 12’ by 6’ and I had been doing my designing based on that entire area.

Image of a 6 foot by 12 foot utility trailer with one pair of wheels. Sides are an open framework of angled metal. Tail gate is about 4 feet tall when up and contains a metal mesh. Parked next to a blue-green 1992 Chevy Blazer in front of the garage in the driveway.

This is the new utility trailer that will become the base for the Vardo. I’m especially happy to get the all metal bed.

I was going to have a big Vardo that had luxurious room inside. Kind of a contradiction to my original plans for a simple, cozy Vardo, actually. As a result, one of the things I had to figure out a way around was the six tie-downs on the trailer bed near the sides. I finally realized that they provided a perfect way to fastend the Vardo to the trailer, a la pickup campers: straps built onto the framework of the Vardo that connect to the trailer tie-downs via turnbuckles. To do that meant I had to narrow the width of the Vardo box to fit inside the tie-downs enough that I could hook them into place and tighten. It’s only a 6” loss in width, give or take, but it also freed up the solution to another issue: I wanted to put the same kind of mesh that I had on the tailgate along the sides of the trailer. That way, things put in the trailer wouldn’t roll out under the existing side rails. And I could use that now open area to store poles for awnings, and other such gear.

I’ve been doing quite a bit of fishing lately, for rainbow trout. Normally I would catch and release trout, but my wife and I have found that we like the fish. I’ve learned to fillet them so that we don’t really need to worry overmuch about bones while eating. Only about 15 minutes from my house is a great little pond where, so far, I’ve always managed to catch my limit every day. I didn’t use to fish that much, or to enjoy it, but I’m finding I do. I’ll probably go fishing rather regularly while retired, using that to supplement our diet with fresh fish on a regular basis. It’ll be interesting to see how the fishing goes as the weather warms up.

K3 First Light – M42

17 December 2014

To paraphrase the narrator in a YA fantasy trilogy, “Say what you will about the Pentax K3. Say that the K3 is fast.”

All images here are shown without any post processing other than to convert from RAW to JPEG. I did resize them smaller to save space but you can still see the noise and M42 for comparison.

Sunday I got up about 0300 to get a drink of water and looked out the window at the night sky. It was so clear, the stars were so bright, I could see Orion, and it was 30° F.

I went back to bed. I lay there, thinking how great the night sky was. I thought about my new camera and how it would be a great chance to check ISO vs shutter speed. I thought about how I would set up that test. I thought how Orion was right there. I thought how I really should go out and take some astrophotos.

After the third time through all that, I thought, “Geez! Quit thinking about it! If I’m going to think about it this much, I should just get up and do it!”

So I did.

M42, the Orion Nebula, aka the Great Nebula in Orion, taken with my new Pentax K3, 400mm, 5 sec., f/5.6, ISO 1600.

M42, the Orion Nebula, aka the Great Nebula in Orion, taken with my new Pentax K3, 400mm, 5 sec., f/5.6, ISO 1600.

I mounted my Tokina 400mm on the K3, set up the tripod, connected the cable release, and went to work. My plan was simple: to run a series of shots to explore the results of different shutter speeds applied to each available ISO suitable for astrophotography.

First of all, this was from my driveway, which is not exactly a dark sky site. The light pollution isn’t all that bad, fortunately, but it’s there: you can’t see the Milky Way, but you can make out M42, the Great Nebula in Orion, as a fuzzy patch.

Given the 400mm’s small field of view, I decided to make M42, the Orion Nebula, my target because it was right there in plain sight, at a comfortable angle, and easy enough to line up on. Since this was just a test to see what I would get, I set up everything and did the shooting without checking each image immediately afterward. After all, I just wanted to see what each combination of ISO and shutter speed would give me. Plus it was 30° F and getting colder.

From experience using my K10D, and to some extent my *ist DL, I knew that I needed to expose for 10 or more seconds to get anything. I wanted to see how much noise there was at the higher ISOs. I decided that I would test with the following string of shots:

ISO: 51200, 25600, 12800, 6400, 3200, and 1600

Shutter speed: 30, 25, 20, 15, 10 seconds

The remaining variables were constant: aperture was wide open at f/5.6 and the focus was manually set. Since this 400mm doesn’t have an autofocus or auto-aperture, the K3 required me to manually enter the focal length. There was no setting on the K3 for 400mm but there was 600mm so I used that. Afterwards, for just the photos posted here, I used an EXIF editor to correct the reported focal length (changed from 600mm to 400mm) and effective focal length (changed from 900mm to 600mm).

The first new thing I played with was the focus. The Pentax K3 has Live View, and I was eager to try that. My 400mm is fully manual, so I set the camera to manual focus mode. Then I made sure the aperture ring was turned to 5.6, wide open. Next I focused through the eyepiece as best I could, triggered Live View and zoomed in on one of the stars visible. Watching the Live View, I adjusted the focus ring on the 400mm until I had the sharpest possible view of the star. I don’t think it was perfect, but it was definitely at the best possible focus.

The next step was to compose my shot. I was using a cable release to avoid any shaking from pressing the shutter release. For the timing, I wanted it to be consistent, so rather than using Bulb mode I used Manual mode and set the shutter speed to each of the desired values as the shoot went on.

I started with ISO 51200 and 30 seconds. Then I went to 25 seconds, 20 seconds, 15 seconds, and finally 10 seconds. At that point, I dropped the ISO to 25600 and worked my way back up the exposure times. Next, ISO to 12800 and downward on the speeds…you get the idea. I shot all the times against each ISO before changing ISO settings.

At the top of this post I mentioned that the K3 was fast. I’m used to every 30 second exposure needing 30 seconds to store the image to the SD card. Even with my old, non-high speed SD cards, storage to the card even with noise reduction on was still well under 30 seconds. It even seemed to speed up as the shoot went on, perhaps due to the cold?

While changing the ISO, I accidentally went to 5 seconds exposure when I moved the wrong wheel. I was about to change it back to 10 seconds when I decided, “Why not?” So for the end of the downward run at 3200 and the upward start to 1600 ISO, I had two 5 second exposures.

It wasn’t until the next later that morning that I actually looked at the pictures to see what I got. The results, as they say, were nothing short of astounding. For one thing, I flat out did not expect to get the purple/pink of the nebula in the images. I simply had never tried imaging M42 with the 400mm before. Hades, I hadn’t even expected that simply with the 400mm I could achieve a “classic” image of M42! I thought you needed a big telescope for those.

At only 5 seconds of exposure at 1600 ISO, I fully expected the whole image to be black, with maybe a couple of stars showing up. That was NOT the case and I was floored with the result.

The unprocessed (other than to convert from RAW to PNG) 1600 ISO 5 second image is at the top of this post. Even the 3200 image below is awesomeness.

M42 Orion Nebula Pentax K3, 400mm, f/5.6, 5 sec., ISO 3200

M42 Orion Nebula
Pentax K3, 400mm, f/5.6, 5 sec., ISO 3200

There is more noise with the 3200 than the 1600 ISO, as would be expected, but more of the nebula is visible in the 3200 ISO shot, again as expected.

At first I didn’t expect to see star trails, but then I realized that the field of view through the 400mm is so small that it would take less exposure time for the stars to move across the image than for, say, a 135mm lens. Or a 50mm.

At the higher ISOs, the image is actually washed out from being overexposed! I absolutely did not expect that. Things really only start getting visible in the 10 second 51200 ISO exposure.

M42, the Great Nebula in Orion, buried in the overexposure. This is the first image (see text) where M42 is truly visible in a test image. Pentax K3, 400mm, f/5.6, 10 sec., ISO 51200.

M42, the Great Nebula in Orion, buried in the overexposure. This is the first image (see text) where M42 is truly visible in a test image.
Pentax K3, 400mm, f/5.6, 10 sec., ISO 51200.

Working through the images afterwards, it was very noticeable that there is a line in the sand related to noise and it’s at the 12800 ISO vs 6400 ISO point. This is clearly evident in the two images below.

Showing the dividing line between ISO 12800 (left) and ISO 6400 (right). This is the point where the noise level really drops between ISOs. To either side of this line the noise level is gradual, here it's somewhat abrupt.

Showing the dividing line between ISO 12800 (left) and ISO 6400 (right). This is the point where the noise level really drops between ISOs. To either side of this line the noise level is gradual, here it’s somewhat abrupt.

All in all, I am very pleased with my new Pentax K3 camera. I certainly didn’t expect to get such a “classic” image of M42 with just the K3 and my old manual 400mm Tokina. And with the pink/purplish glow of that nebula, to boot! This camera has several tools such as internal stacking that are ideal for astrophotography and I’m really excited to play with them.

Hmmm. I wonder what’s possible with my Classic Celestron C8 mounted on the camera? Or even just with the K3 plus 400mm piggybacked for tracking. ISO 1600 for 3 seconds each, stacked? ISO 3200?

I can’t wait to get out and try again now that I know what this Pentax K3 is capable of.

The best of the season to you all!

See you next year.