Sunday, March 17, 2013

Las Vegas and Neutral Density Filter

Las Vegas Blvd
Las Vegas taken from the back side of the main strip during sunset using an ND filter at 2min exposure, the lights from oncoming traffic was too bright so using an ND filter helped reduce the cars bright lights while giving a chance for the lights on the buildings to shine thru.

Supposedly PANSTARR was to be visible on the skyline at sunset on this pretty evening but I could not see it. so I decided to try some long exposure using a B&W ND 3.0 filter which is 10 stops. The trick to using a neutral density filter is to take an exposure reading first, say f16 and the camera says it'll shoot it at 30s, now apply your filter to the lens, then use a chart or an iphone app which helps you figure out how long to keep shutter open, my advice is try not to go over 30s because that greatly adds noise to image. ND filters can be fun to play with as they can really create unusual images, they are good fort scenes where you want to create light trails, smooth waterfalls and add blur, combining them with a flashgun can add drama.
ND Filter Chart

I'm not going to go into great detail about all this because its been done to death on the internets but you can google it. Its fairly simple and in some cases I do trial and error, i've been doing it for a while now, that by looking at my cameras exposure I can sort of tell how long I need to shoot for now. The chart above assumes the following. without the nd filter on, take a reading, make note of the exposure (shutter speed) look at chart, now apply your nd filter, put camera in manual mode, dial in the proper shutter speed value, connect a remote trigger if going over 30s or use self timer with exposure delay and fire away. But what I do wish to say is don't use cheap filters reason being, the glass is inferior. I now have a collection of these filters, ranging from $15 all the way up to $250 and I can assure you the B&W filters are top of the line and hence produce a much better result.
How not to use ND Filter
So a friend asked me recently what should I buy? I told him since you are just getting into it don't buy the most expensive and dont get the cheapest one. He said? why are they not all the same? is glass not glass? my flat out reply to this is NO. its about quality and how the glass is made and what went into it. Above is a perfect example of this. This image is exact same shot as the first one but using a Variable ND filter that goes from 2 to 8 stops. I wanted to see if this $15 Variable (meaning you can rotate to adjust the amount of light it lets into the camera by simply turning it) ND filter could compare to the B&W 10 stop filter, aka Black Glass. The variable ND filter had some sort of odd reaction when i pushed it to the limits at 8 stops and it some how bent light. now would this happen with a regular cheap 8 stop filter, most likely no. The notion of simply caring with you one ND filter is nice especially if you can adjust how many stops you want problem is the more stops you use the worse the image gets in some odd distortion, so in reality this kind of filter is good for a few seconds, going past 30s will get ya ugly results. But I simply wish to emphasize, you get what ya pay for. So the N-ND filter could not match the B&W but I think if you just used its to reduce a few stops you would get decent results. I've not had much good experience with the V-ND filters so i recommend getting an ND filter kit, something that you can buy that comes with usually 3 to 4 filters, a CPL, than 1,2, and 3 stop nd filters.

Saturday, March 16, 2013

Star Photography at Mojave Desert and Valley of Fire

I travel to Las Vegas about 4 times a year for work and photography related products. Being in conferences all day and not having eaten all day because its just too crazy busy leaves me exhausted but this time I decided I was going to do it no matter what. I rented a car and drove out to mojave desert and the valley of fire state parks. These locations are really not that far from las vegas, one of 50min and the other about an hour and a bit, all depending who deep you go into the park.!i=2410422447&k=GjkrbK2&lb=1&s=A
The Seven Sisters Gaze into the Universe
This was my first ever attempt at astrophotography. I had read up on it, looked at several tutorials so I had an idea what to expect and I believe for the most part I did okay, the only thing I forgot was my green bubble leveler but i just used the camera's horizontal leveler to get past this. One of the things I quickly realized and there several which I'll get into all starts to look the same...the stars don't really change they are just there, it not like i can take it from the side, below or look for a better angle, the stars are up there and thats it.
Taken at Valley of Fire and processed with Lightroom
So what makes one star picture different than the other? It all comes down to composition, its about places items in the foreground. Being up by the mountains they all start to look similar on the horizon. But in the Valley of Fire there are exceptional rock formations and using a simple 9 volt LED light I was able to light paint 2 large rocks known as the seven sisters int he first picture. I set the camera to iso 5000 at 2.8f on my trusty Nikkor 14-24mm wide angle lens, set it to mirror up mode and took the shot. while shutter was open I used the led light to light up the rocks for about 10sec. Even though I was about 60 miles from Las Vegas you could still see a faint glow of the light from the city. So in the second picture I aimed the camera southward.
Mojave Desert is about 1.5 hours from Las Vegas
This one above and below were taken at the Mojave desert which was a bit further and again I aimed the camera southward reason being was to avoid light pollution plus I liked the stars more in this direction. A wisp of clouds rolled in but I did not notice this until I looked at in lightroom. A far bit of post processing work was done, to remove airplane trails, apply color filters to give it drama, give impact to the milkyway and reduce noise. shooting at iso 5000 will add noise which I could not help but with the magic of photoshop I was able to reduce it.

3 images stitched using Autopano Giga in Mojave Desert
 This one above I opted for something different, I found a cactus plant so i put it in foreground than took 3 shots, panning across the horizon in portrait mode. The milkyway was so vast and large that I really wanted to try and grab as much of the sky as possible. I'll tell you its very difficult to align the vertical shifts when panning as its totally dark, can't see anything thru the viewfiender and I dont have panoramic ballhead mount to help figure out how many degrees to turn by so all this was done by touch, trial and error and just trying to feel my way thru it all and I believe this is the most rewarding experience. Standing there looking at the stars one simply can't help but to be awestruck by the beauty of it all, the utter silence..until you hear a coyote howl! the cold starts to creep into your feet and bones. I was lucky it was only like 45 degrees and maybe 5 knots of wind. The night was beautiful. I want to give a shot out to Dave Morrow, as I used his under the stars lightroom presets to help me give color and drama to my images. I found them some what accurate in adding color. Even though the sky and stars may not really have had these colors its all about creating a mood. A fair bit of digital blending went into these images as I have to mask in luminosity layers to help bring out the detail int he milkyway.
A raw image right from the camera, airplane trails on every image
I wanted to show you one last picture, this is unedited, straight from the camera as is. Although its okay I feel its nowhere near as dramatic as the others I showed you. There was not a single image that I took where you could see several airplane light trails, so these have to be photoshopped out, fairly easy to but all of them have it. next create 6 to 9 luminosity layer masks which help give definition to the milkyway and help reduce the light pollution and finally adjusting color balance, finding that right white balance to give the picture mood.

Some final thoughts I'd like to part with to help you do something similar.
1. pack warm clothes especially gloves, you will be standing out in the darkness with the wind blowing on you!
2. Divide the focal length by 500 to figure out how long to keep shutter open, so in my case shooting wide at 14mm / 500 gives me 30 seconds. you can apply this formula to anything, reason being you dont want star trails, anything longer than this and the dots in your pictures end up looking like airplane trails
3. obviously use a tripod if its windy lower the leg extensions, lower the center of gravity will make it more stable or hang your bag from it, you don't want camera shake, this will ruin your shot.
4. experiment with the iso but 5000 seems to be a sweet spot for a dark scene if you have light pollution from a city and its in the picture, and I'm referring to that yellow glow on the horizon than shoot at 3200 iso 
5. use a remote to trigger the shutter or self timer, in my case i put my Nikon d800 on mirror up mode and fired away.
6. use red lights, whatever you do avoid using a white flashlight. you are eyes will get used to the darkness and your photon receptors become finely attuned to the darkness around you, takes about 30min at which point you'd be surprised how much you can see on a moonless night under the stars. Red light has ZERO effect on how you see but the moment you flash that bright white light to look at something, your receptors freak out. its like someone turning on the lamp while you were fast sleep, it almost hurts. I used a RED LED bikers light thingy which clips onto anything, I highly recommend this.
7. keep a good flashlight with you or head lamp to help you walk or hike a path int he darkness to your location, once you find you spot don't use it anymore, go red!
8. Remember how to get back to you car! waling out into the desert, between canyons and rocks in total darkness can be very dangerous if you can't find you car. I used my iphone's GPS to spot mark location of my car.
8. Try and find cool architecture or rock formations to put in the foreground of your camera, dont just shoot into the sky but instead explore and look around you, what can you add, dark silhouettes can add drama and convey thoughts this is easier said than done and its something I work on all the time.
9. and finally share your pictures! let everyone see the magic of the universe.