:)

Ordered my D700 at the end of last week. Should be getting it Wednesday. More updates as they come!

Nailing the Exposure (3 of 3)

Sorry it's been so long since I've last blogged. Winter break was a blur and I'm back on campus now.

Our last component of exposure is shutter speed, or the time it takes for the mirror to go up and down and the image to be captured.

This is the last variable that I change while shooting and is my most often changed variable. So to recap: I set my ISO depending on the environment - base ISO (typically 100 or 200) for outdoors in sun and 800-1600 for dimly lit, interiors. I then set my aperture for the depth of field that I want. f/1.4 - f/2.8 for shallow depth of field, and f/3.5 and up if I need more depth of field. Remembering that the lower the number, the more light that enters. Lastly I set my shutter speed.

Shutter speed, as mentioned before, determines how fast your shutter *clicks*. This determines how long light can enter the camera and how long the shutter is recording for. A slower shutter speed lets more light in and a faster shutter speed lets in less light. Therefore, typically you will need a slower shutter speed in darker settings and a faster one in bright settings.

Shutter speeds are typically stated as a fraction of a second. If your camera reads "8000", it means that your shutter speed is 1/8000th of a second. 40 => 1/40th of a second and so forth. If your camera reads 1", 2", 3", etc. it means 1 second, 2 seconds, 3 seconds, and so forth.

Fast shutter speeds have these perks:
Help eliminate lens blur due to camera shake
"Freeze" action

The general "rule of thumb" for shutter speed was that you want to have at least 1/focal length as your shutter speed in order to prevent camera shake.
e.g. A 50mm lens should be shot at a shutter speed of at least 1/50. 105mm lens at 1/100, etc.

So why use slower shutter speeds? It seems like they do nothing! Wrong! Here are a few perks:
Let more light in allowing you to get a better exposure
Allow you to purposely "blur" images via panning
With a combination of flash and rear curtain sync, a slow shutter can show motion while freezing motion
Make awesome light trails, light graffiti, and star trails!
The one caveat is that you most likely want to have a good tripod support system to shoot with slower shutter speeds in order to eliminate camera shake (blurry images!)

I'll end with a few sample images and explain how shutter speed was used to make the image.

A slow shutter speed (1/30) was used for this image along with a panning motion to have a sharp car with blurred background

A long shutter speed (30") was used for this image to capture streaks of cars as they passed by.


A long shutter (1/8) with rear curtain sync and flash used


A fast shutter (1/1000) used to freeze the action of the race

Nailing the Exposure (2 of 3)

Today we'll be discussing the second of three variables, ISO.

ISO goes back to the film days when different films had different ASA/ISO speeds. You could buy a film with an ASA/ISO rating of 16, 50, 100, 400, 3200, etc. You could "Push" the speed of your film while sacrificing image quality. ISO back then referred to the sensitivity of the film to light and in today's digital world refers to the sensitivity of the image sensor to light.

A higher ISO speed/setting means more sensitive to light (brighter image, all other variables held constant) and a lower ISO implies less sensitivity to light (darker image, all other variables held constant)
You can test this out my setting your camera to Manual mode and setting any aperture/shutter speed. As you increase your ISO you'll notice that your exposure becomes brighter. Of course, as with the other two variables (aperture and shutter speed) ISO has both its pros and cons.

ISO is the first variable that I change whenever I enter my shooting environment. Using ISO 800-3200 when I'm indoors with artificial light and ISO 100-400 when I'm outdoors with plenty of sunlight. I think it's pretty self explanatory why, but if you haven't caught on… Use a lower ISO when there's plenty of light, because you'll be able to maintain a good aperture/shutter speed at pretty much any ISO and a higher ISO when you have poor lighting conditions, because you want your sensor to be more sensitive to light in order to obtain a better aperture and shutter speed.

Pros of ISO
As mentioned earlier, ISO is the first variable that I set. A higher ISO allows me to increase my shutter speed or aperture than a lower ISO would allow. Think about darker environments when you need a 1" shutter speed to get a good exposure at ISO 100. Definitely not hand holdable and if you're caught without a tripod, good luck with the shot! But by increasing ISO to 1600 or so you can maybe squeeze off a 1/15 shutter speed that is handholdable with good technique.
I know you're thinking now, so why can't I just use any ISO that I want and always have a faster shutter speed or stop down my aperture? Well, here come the cons.

Cons of ISO
If we could shoot at any ISO we wanted with no trade off to image quality, all photographer would rejoice and there would be no need for new cameras with better high ISO capabilities and we'd all be a happy bunch. The biggest trade off of higher ISOs is image quality and noise. As you increase your ISO, your image quality will go down and you'll start to see noise or graininess in your photos [especially in shadows and dark spots]. Newer cameras are getting better and better at having better image quality at higher ISOs and that is one of the biggest upgrades that newer, more expensive cameras give over the older cameras [high ISO, low noise]
Although, noise can be decreased by ensuring that you "nail your exposure" (what we're trying to accomplish here). Because perfectly exposed images tend to have less noise than underexposed/overexposed images.

Quick summary:
Low ISO, GOOD; High ISO, BAD [in terms of image quality]
Low ISO, darker & less sensitive; High ISO, brighter & more sensitive [to light]
ISO 100-400 outdoors (100 on sunny days, 400 when cloudier or closer to sunrise/sunset)
ISO 800-3200?6400?12800?25600? indoors (unless you have a D3, D3x, D700, or 5dMk2 I wouldn't suggest shooting over ISO 3200 :] )

A quick example:
This image was taken at ISO 800

ISO 1600

ISO 3200

ISO 6400

Get it now? :) Next time we'll be covering the third and final variable to exposure, shutter speed.

Gear Changes

You may notice that I've shifted quite a bit of my gear around. Thought I'd do a small rewrite of my first post about my gear.

Changes that have been made in the past few months:
Sold D200 body for D90 body
Trying to sell Tamron 17-50 f/2.8, replaced by Nikon 17-55 f/2.8 AF-S
Sold Nikon 80-200 f/2.8 AF-S for Nikon 70-200 f/2.8 AF-S VR
Bought Nikon 55mm f/3.5 AI'S

Sell Nikon D200 body for Nikon D90 body.
Back in August, Nikon released the new D90. The first ever dSLR to offer HD video recording capability. I remember a year ago when I told myself, man I wish my camera could take video like a point and shoot. Fast forward a year and here we are with my new D90 that can record at 24fps @ 720p HD resolution!!! It was a big decision to make between the D90 and the D200. The D90 adopted the same sensor from the Nikon D300 (Nikon's current professional DX body) and has a lot better low-noise, high ISO performance. I feel that the files are usable up to ISO 3200 with less sacrifice to image quality. It may be important to note that the video capability was definitely a perk, but not the main reason for buying the camera. One big sacrifice I made with the D90 is build quality. The D90 is built well, but definitely not 'like a rock' like the D200 is. Because of the switch, I also converted back to SD cards from CF. I also had my MB-D80 battery grip from my D80 lying around (wouldn't sell on forums) and it just so ended being compatible with the D90 so another plus!

Nikon 17-55 f/2.8 AF-S over Tamron 17-50 f/2.8. Don't get me wrong, the Tamron is a true performer!!! The Nikon is slightly sharper and has slightly better color rendition, but it's fair to say these lenses are optically close. The big perk was in build quality. The Nikon feels sturdy and tough. I would not fear damaging the lens. Ultimately the reason why I switched was because I found the 17-55 at such a steal that it was worth the $300 difference to upgrade.

Nikon 70-200 f/2.8 AF-S VR for 80-200 f/2.8 AF-S. Will never look back to the 80-200 AF-S. I thought that that lens was sharp… the 70-200 will blow it away by a mile! This baby is razor sharp at 2.8 and only gets better by stopping down. The addition of VR is incredibly helpful as well; especially with recording videos. Also found this lens at a great price and was able to sell my 80-200 so I jumped on it.

Nikon 55mm f/3.5 AI'S. Cheapo, old-school, manual focus lens. This lens is just FUN! The ability to use it as a 1:2 macro lens and practicing my manual focusing skills are a definite plus. This lens actually does not meter on my D90 so I need to guess and chimp for my exposure. It's fun to try and guess what settings to use and see how my exposures are. Definitely a learning lens. Also is great on my N90s film camera.

That's all for now, stay tuned for part 2 and 3 of Nailing the Exposure: Shutter Speed and ISO.

Nailing the Exposure (1 of 3)

As mentioned before, there are three key components to exposure. Aperture, ISO, and shutter speed.

Aperture is the size of the opening (allowing more or less light in to the sensor)
ISO is the sensitivity of the sensor to light
Shutter speed is how long the shutter remains open (mirror up, mirror down *CLICK*)

A typical analogy is that of a hose. Aperture is the size of the opening of the hose, ISO is the quality of the hose and shutter speed is how long the hose is left open to let water in/out.

Each variable works together in creating the exposure, but each has its pros and cons. In this post, we're going to focus on aperture.

Aperture
Aperture, as mentioned before, is the size of the opening. This variable is typically measured in f/ stops and is limited by the lens that you use. A smaller f/ number, means a larger opening. Counter-intuitive, I know. Each lens has its own "maximum aperture" which is the smallest f/ number that it can be stopped down to. The lower the f/ number, the more expensive the lens typically is.
There are two types of lenses: fixed aperture and variable aperture. Fixed aperture lenses have one f/ number and remain at that f/ number throughout the zoom range. Variable aperture lenses are found typically on lower-end zooms / kit lenses. These have a maximum aperture that changes as the focal length/zoom changes. (e.g. a 18-55 f/3.5-5.6 lens will have a maximum aperture of f/3.5 at 18mm and f/5.6 at 55mm. The max aperture at 19-54mm will be somewhere within 3.5-5.6)

Enough about the technical stuff. Let's get to the nitty gritty.
Aperture affects how much light comes in and depth of field.
A bigger aperture (smaller f/ number) allows more light to enter. Allowing you to use a faster shutter to capture an image. Therefore, bigger aperture = brighter, smaller aperture = darker.
Which raises the question, "Why would I ever want to lower my aperture? Don't I want a lot of light?" leading us to the next effect that aperture has on the image: depth of field.
Depth of field refers to the "depth" of your image. Ever see portraits where eyes are in focus and ears are out of focus? The blur is caused by a large aperture (small f/ number). A larger aperture will reduce your depth of field (make more shallow). f/1.2-f/2.8 will give you great subject isolation, but are difficult to use at times because a slight error will cause your image to be out of focus, because the depth of field (dof) is so thin/shallow. For group shots, you'll typically want to use an aperture of f/4 or lower to make sure everybody's in focus and for landscapes you'll want to use f/8-f/11 to ensure that EVERYTHING remains in focus.

Getting Started

Why buy a dSLR you ask? Digital SLRs provide the high quality photos that [film] SLRs provided long ago with the capability to instantly review images and have them on your computer easily without having to develop and scan film. dSLRs are still a bit behind the superb quality that film has, but with newer full-frame cameras like the Nikon D3, D700, Canon 5d mk II, 1D mk III - film-like quality is almost attainable.

dSLRs provide several advantages over standard point and shoots.

• Complete control over your camera. The ability to set shutter speed, ISO, aperture, and color balance. This insures that you get the best image possible [technically speaking]
  
• Higher FPS [frames per second]. Love to make flip books? Take action shots? Here's where FPS is handy.
  
• High quality images. A common misconception is that the more megapixels the camera has, the better quality the image will be. In fact, it is the sensor that determines the image quality. Megapixels simply determine the pixel density. dSLRs use larger sensors than standard P&S [point and shoot] cameras yielding greater quality images.
  
• Interchangeable lenses. I have a different lens for every occasion. The fisheye for ultrawides and fun, a zoom for a nice walk-around lens. My 85mm f/1.4D for portraits. Each lens plays its part as a brush does for a painter.
  

Once you decide to get your dSLR there are a few things to know.

There are four modes that you should typically shoot in. P, A/Av, S, and M. These stand for Program, Aperture priority, Shutter priority, and Manual respectively.

Beginners, please skip the AUTO mode of consumer dSLRS and feel free to set your camera straight to P. The camera will adjust everything but the ISO.

Aperture priority is where you set the aperture and ISO and the camera will automatically adjust the shutter speed.

Shutter priority is just the opposite. You set the shutter speed and ISO and the aperture is automatically chosen for you.

Manual mode is where all three variables are set manually and the exposure is completely in your hands.

Metering

There are traditionally three types of metering: Matrix, Center-weighted, and Spot.

Matrix metering pulls information from the whole scenes and attempts to expose the image according to the entire scene.

Center-weighted metering exposes the image for the central area of the image.

Spot metering will meter for the center of the frame and nothing else.

White Balance

Auto white balance may be a good place to start. Advanced users can venture into shooting a grey-card to preset white balance or tweaking the white balance through menus. One last alternative that I highly prefer is setting white balance on the Kelvin scale.

The Kelvin goes from 2,500K - 10,000K (2,500 being cooler and 10,000 warmer) Tungsten lighting tends to be around 2,800K. Fluorescent 4,000K, and Daylight 5,700K.

That's all for me for tonight. Until next time!

Random Shoots

Have had a lot of random shoots lately. A lot of small group pictures and a random shoot with Limee.

I've recently upgraded to the Nikon 17-55 AF-S f/2.8 from my Tamron 17-50 f/2.8 and I am loving it.

Coming soon: Writing a beginner's guide to exposure (ISO, Shutter Speed, Aperture) am hoping to shift this blog into a semi-beginner's guide to dSLRs and photography.

Here are some of the pics from my recent shoots.

Turkey Run State Park, Indiana with Small Group




Photoshoot with Limee