ND Filter at Lake Erie

Monday, 6 February 2012

On the drive home from Cincinnati i pulled off I-75 at a Exit 5 near the Consumers Energy power plant where i had been working a lot this summer. There's a small parking lot where you can walk to Lake Erie. I've taken some pictures there before when the lake level was way down. I was still a little bummed out with some of the pictures i took in Tennessee, using my homemade ND filter.
I made an ND filter for my camera from a piece of welding glass, but when i took pictures of the rivers and Laural Falls i forgot to set my camera to RAW. That means that i had to spend a long time in Photoshop and the pictures still never turned out very good, the colors were all off.

So i walked along Lake Erie and took around 25 pictures. The exposure times ranged between 4 and 15 seconds. I couldn't really tell by looking at my camera how well they turned out because with the welders glass they all had a green tint to them. Here's what they looked like directly out of the camera.
But when i got home and processed them with Photoshop i was really happy. This time they turned out much better.

This one i converted to black and white.
Here is just a normal photo i took with the ND filter not on.
The ND filter allows you to open the lens for a much longer time then you would normally be able to, creating a glassy effect on the water.
This picture is definitely my favorite.

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Welders Glass ND Filter

Sunday, 11 December 2011

I was reading online about a cheap alternative to a Neutral Density (ND) filter to use for photography. An ND filter is basically sunglasses for your camera. It decreases the amount of light that gets through, thus allowing you to keep the lens open longer. Neutral density filters can cost as much as $400 for a really nice one.

The cheap alternative is to use a welders glass. They type of glass that welders for eye protection against the bright light created during welding. So i went to Lowe's and bought one.

Then because my new camera only has a small lens i decided to cut the glass down to about 2" x 2".

And make a type of "dark housing" to fit over the camera lens. I used a piece of PVC pipe and a permanent marker to color it black.

Then glued it together.

I used a rubber band to hold it onto the camera and some cloth on the edge so it wouldn't scratch anything.

The two main problems with using the welders glass is that it is not as high a quality as an ND filter and that it has a green tint. This is what the image looks like right out of the camera. This was a 64 second exposure during the day.

But in Photoshop this can be corrected, mainly by adjusting White Balance and Tint.

That design was not the best, it was too big and heavy. So i tried to simplify it.

I started with the same 2" square piece of glass that i cut from the larger glass. But then i used pliers as a kind of glass nippers and slowly broke off corners until it was round.

I sanded and filed the sharp edge. Then just as before i glued it to a PVC pipe i colored black, inside and out. But the key difference is this time is that i glued a foam ring to the inside of the PVC.


I sanded the foam down until i could slide it onto the outer lens, but with just enough pressure that it wouldn't fall off.

I plan to use it when i'm in Tennessee to take pictures of some waterfalls.

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CHDK

Monday, 12 September 2011

This all started when i searched Google for "how to take pictures of stars." Lots of links came up for this program called CHDK. CHDK - Stands for Canon Hacker Development Kit.

The short explanation is that Canon cameras have the hardware ability to do all of these cool things but the software installed by the factory doesn't allow for it. This is a free program that allows the camera to function at the limits of its abilities. It was created by many different people over the years and it all started by people just wanting to get RAW images from their camera. It has been evolving and added onto ever since.

If you are interested in how to install it onto your camera go here: How to Install CHDK. It seems a bit complicated at first but it's not too bad. Just "prep" your SD card, add the program and any script files you'd like and you're done.
I installed it onto my old Canon PowerShot SD770 IS. This is a great camera, with a battery that lasts a long time.
Here's the 5 main things that i was interested in doing:

• Intervalometer
• HDR pictures
• Very long shutter speeds
• Very short shutter speeds
• Motion detection

Screenshot at start-up
Main menu


1st - Intervalometer

Intervalometer basically means "takes many pictures in a row with a timed delay." I used the script file called Ultra Intervalometer.

Once your script file is loaded, you adjust the settings at the bottom. You can see that this is set up to take a photo every 10 seconds. Here's what the menu looks like.

Here's what the screen looks like while the file is running. At the bottom left corner of the screen you can see it counting down before it takes the next picture.
I did this from the walkway near 12 mile over I-75.

I set the camera up during my car ride from work. This was 150 pictures, taken every 10 seconds. Then using a program called PhotoLapse 3, a video is created by stitching all of the pictures together.

I did this by setting my camera and tripod on the roof of the garage and operated the camera through my upstairs window. The bad thing is that the exposures didn't adjust as it got darker, which is why it fades to black at the end. Next time i'll try and fix it so that it starts taking pictures of the stars at night.

This is the camera set up on the beach at Lake Erie for time lapse photos.

It has millions of possibilities. In the future i plan to attach the camera to balloons or a kite and have it take pictures every couple of seconds while it flies over my house.




2nd - HDR Photos

To create an HDR image you take several pictures of different exposures and combine them to create one great picture. It's a little difficult to explain and i think it's very difficult to do right. But the goal is to create an image the way our human eye sees things. Our eyes can see detail in shadows even when looking into a sunset, HDR photos try to do the same thing by taking the best parts of multiple images.

Bracketing menu.
You can see that in one picture the shadow area might look great, then in another picture the sunny area might give the best detail. By creating an HDR photo it combines all of the best parts into one great photo. Here's 5 photos i took, without moving the camera. Using CHDK i just hold down the shutter button and it automatically takes the pictures at different exposures.
After you have these photos you can use several programs to combine them. I tried using several different programs. Picturenaut worked ok, but i think Photomatix is the best. They both have free versions.
Once the images are combined, then you screw around with Tone Mapping, save the image, then adjust it further in Photoshop. Here's the final result.
The sunflower isn't a great example. The whole point is to take HDR photos in complex light and dark settings. This one i took on the beach of Lake Erie is a little better.
I'm still working on creating just one HDR image that i like. I'm slowly getting better.



3rd - Long Shutter Speed
This is something i have done before, but i was limited to the settings in the camera. This is the heart of CHDK, it enables the camera to operate at its hardware limits.

When i took pictures with my cameras before, the maximum i could keep the lens open was 8 seconds.
Flashlight in the backyard

Dry ice

And for what i was doing, 8 seconds was alright. But with CHDK it allows the camera lens to stay open for much longer, over 1 minute.

I took this picture outside of work one cloudless morning before dawn. I had the camera set on my mini tripod and opened the lens for 25 seconds.
Now to get the best result, this should really be done with a DSLR camera with a big lens to let tons of light in. Here's a professional example. This took several hours to take.

This is what i was trying to create.
The cool thing is this shows why you should only follow the North Star, everything else moves in the sky.

The photo i created doesn't look that good. The problem was that my camera would not record the image fast enough. I left the lens open for 50 seconds, but after the shot was taken it took 40 seconds to record and take the next shot. That's why it looks like many dots instead of smooth lines.
I later bought a faster SD card (class 6) that records at 20mb/s but it was just as slow. That means that the problem is in the camera and there's really nothing i can do about it.
I've found that the best program to combine all of the photos into one is coincidentally called StarTrails. It's really fast, really simple and it's what i used to create the image above.

Here's the video created from those same pictures.

Here's other photos of the highway using long shutter speeds.






4th - Short Shutter Speed

This is the menu that i use the most. Here you can adjust the shutter speed, ND filter (a sort of digital aperture) and ISO value.
I tried shutter exposures between 1/1000 and 1/20,000. The camera was set up in front of a glass with water dripping down. Both the camera and glass were in the kitchen sink.
I took about 100 pictures in total, using the intervalometer to automatically take one photo right after another. I was was holding two flashlights on either side of the glass and also had the flash turned on. Otherwise the pictures came out way too dark.
F-Stop = f/8
ISO = 80
Exposure = 1/1000
I probably should have set the ISO a lot higher. I think that would have made everything end up in better focus.
This one was at 1/1500 of a second.
Here's what the process looked like. Notice how it's daylight outside. That wasn't enough, i still needed the flash, the light on, my big 3 million candle power flashlight and another LED flashlight held real close.
The result was this. Now notice how dark it looks outside, when it was really sunny. That short of a shutter speed needs tons of light.

Here's the tap turned on a bit faster.

This one didn't turn out as well as i hoped. I tried to get the starting of a lighter. Again with the fast shutter speed i needed more light.



5th - Motion Detection

Motion detection is a script file and it can be used in many different ways, from taking photos of lightning or used as a trail camera.

Here's what it looks like when the motion detection script is running. It's a little hard to see but the whole screen has green boxes covering it, and instead of face detection it is now motion detection. Once you input the sensitivity, and movement will cause the camera to take a picture.
The cool thing about the motion detection is that you can put the camera on a tripod, aim it at an approaching storm and when lightning strikes it will take a picture, capturing the lightning bolt. It might be a while before i get a picture of that. It's sort of a right place at the right time kind of thing.
Anyway it's been great to experiment with and i've enjoyed having the ability to do all this stuff without buying a really expensive camera. It's created tons of new possibilities.

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