Sunday, November 29, 2009

Part 2: Photography with Imre Z. Balint: Episode 3 – Sensitivity

The topic of sensitivity in itself is quite simple to understand and demonstrate, but gets much more involved when tying it together with aperture and shutter speed to achieve the image you want. With a little practice though, it’s not that hard to master... or at the least, become proficient at getting the right settings.

When I was editing my video, I wish I would have left a section in that discussed some ISO settings for varying lighting conditions and how I generally evaluate a scene when I take photos. So at the least here is the written version (although I may just make a video addendum to episode 3 later).

General ISO Setting Guidelines
In regard to setting the sensitivity of my camera, I usually base it on the amount of available light and use the smallest ISO value I can for that situation:

ISO 100 – For lots of light, usually outdoor shooting on sunny days
ISO 200 – For outdoor shooting on cloudy days
ISO 400 – Bright indoor conditions
ISO 800 and up – Dark indoor conditions or night shooting / astro-photography

Now I want to really emphasize that the above should only be considered a general guideline, and because photography can be both an art form and require bending of the rules to get what you want, you may likely disagree with the above... frankly so do I. For example, when I shoot longer exposure images (e.g. star trails or aurora), I prefer to use ISO 100 to reduce the amount of noise in the image. But some photographers may like to get crisper details in their aurora photos and use 1600 or 3200 ISO instead to increase the shutter speed.

This also does not take in account if you’re using a flash. When I work in my studio, although usually a dark place, there is an ample amount of light when the strobes go off. So in that case, I’m back to ISO 100.

Aperture can also affect what ISO setting you may need. I enjoy macro photography, but when you get close to tiny subjects (like insects), the depth-of-field (DOF) also decreases. So I up my f-number to something around F8 or F10 (to increase DOF)... but that of course restricts the amount of light passing through the lens. Therefore, even if it’s a sunny day, my shutter speed may become too low for me to hand-hold my camera without getting a blurry image. To compensate, I raise the ISO value higher to get a shorter exposure.

Steps to Consider Before Taking a Photo
This brings me to how I evaluate a scene before I take a photo. Again, this is just a general guideline, but a good starting place if you’re new to photography. And I want to highlight that I most commonly use the Aperture Priority (that “A”) setting when taking pictures; the steps below assume that.
  1. First I begin by evaluating how much light is available... in other words, I look around.
  2. Based on my observation, I set my ISO to a level where I believe I’ll get a decent shutter speed and the least amount of digital noise in the image.
  3. I set my aperture to my liking. At this point, I check what my shutter speed is, because as mentioned earlier, the aperture setting could force me to either open wider or turn up the ISO. In addition, I often set my aperture before setting my ISO, so again, this is where you’ll likely end up forming your own style when taking photos.
  4. Yup, I take my shot.
Although these few steps are at a basic level and don’t include such things as special needs (e.g. tripod, flash, etc.) or composition, it’s an easy place you can start.

Links to Sites on this Topic:
And now for some useful website links that detail camera sensitivity and digital noise:
http://www.iso.org - The standards organization
http://en.wikipedia.org/wiki/International_Organization_for_Standardization - Wiki on the standards body
http://www.photoxels.com/tutorial_iso.html - About the ISO setting
http://www.dpreview.com/learn/?/key=sensitivity - About ISO on dpreview.com
http://en.wikipedia.org/wiki/Film_speed - About film speed
http://en.wikipedia.org/wiki/Image_noise - Wiki on image noise
http://www.photoxels.com/tutorial_noise.html - About sensor noise

Saturday, November 28, 2009

Photography with Imre Z. Balint: Episode 3 – Sensitivity

You guessed it! The next installment of my photography series - Episode 3: Sensitivity - has been uploaded to YouTube. Look below to view it now or visit my channel to watch it in HD.

This was a shorter episode as it quickly discusses what the sensitivity of a camera is (those ISO settings), and what affect it has on image quality when you turn the setting higher. As I'm pooped for the day, I shall write my supplemental blog post to accompany this video tomorrow, so keep your eyes peeled! Till then, please rate my video (5 stars!) and remember to subscribe to keep up-to-date with my uploads.


Tuesday, November 24, 2009

Merlin (aka Pigeon Hawk) Photos

Around 5:15pm yesterday I stepped outside to capture this female Merlin perched high atop a neighbor's tree. To get "close" enough, I grabbed one of my scopes and set it to about 1000mm (its focal length range is 650mm to 1300mm), which translates into about 2000mm as I'm using a four-thirds camera (Olympus E-3). As the sun had just set, there wasn't much available light, but I'm still pretty happy with the pics. Some of my camera settings were: ISO 800, shutter speed around 1/30-1/60, spot-metering, mirror lock-up set to 2 seconds; scope is manual focus.

If you're new to photography or just enjoy it in general, then I recommend you check out my YouTube Channel, as I have created a photography series where I explain and demonstrate many of these topics.






Sunday, November 22, 2009

Part 2: Photography with Imre Z. Balint: Episode 2 – The Shutter

As promised, here is the supplemental post to accompany my video on YouTube. One of the major topics I'd like to address here is the interplay between the aperture and shutter, as the two go very much hand in hand.

But first, something that I didn't mention in my video is that shutter speed is measured in seconds or fractions of a second (for "usual" everyday type photography and not specialized work). For example, the majority of cameras (although this may depend on your specific model) will show a number like 60 to represent a shutter speed of 1/60th of a second. For long shutter speeds getting into whole seconds, this is usually shown as 2", which in this example means two seconds.

If you watched episode 1, then you learned that the aperture of a camera controls the amount of light that may pass through a lens by restricting it using an iris diaphragm. As for the shutter, it controls the duration of time that light may strike the sensor (or film). The combination of aperture and shutter speed is what provides you with the exposure you want (along with depth of field - DOF, which the aperture controls). Below are some general things to keep in mind about shutter speed and aperture:
  • When the aperture is wide open (small f-numbers, small DOF), the shutter speed is faster as more light can pass through the lens.
  • When the aperture is stopped down (big f-numbers, big DOF), the shutter speed is slower as less light can pass through the lens.
  • The "A" setting or aperture priority mode allows the photographer to set the aperture to what they want specifically, and the camera's computer will figure out the appropriate shutter speed. I personally use this setting the most as I can control the DOF.
  • The "S" setting or shutter priority mode (sometimes listed as Tv on some models for "time value") allows the photographer to set the shutter to a specific speed, and the camera's computer will figure out the appropriate aperture to use. The downside of this mode is that depending on the amount of available light, a proper exposure may not be possible (e.g. too little light in a dark room, shutter speed set too high, but the camera can't open the aperture any wider to let more light in, so the picture becomes under-exposed). On the other hand, a popular use of this is in sports photography where the shutter speed is set low enough to blur the background to give a sense of motion (e.g. a photographer follows a runner, so the runner is focused and sharp, but the background is a blur). Another example is at airshows where the photographer wants to get blurry propellers to show them in motion (more pleasing than to see blades standing still on an aircraft in flight!).
  • In general, when shooting things like the night sky (e.g. for star trails and auroras), the camera is generally in full manual mode, and the aperture is set wide open (small f-number) and the shutter is set to many seconds... in some cases many minutes. This helps capture as much light as possible; DOF is irrelevant as stars are far enough away that lenses are set to focus to infinity. By the way, this is basic astro-photography, it only gets more complicated from here and more on that in the future.

And now for some links:
Next week's episode will be about the sensitivity (ISO, digital noise, etc) of a camera. So remember to subscribe to my YouTube Channel to stay up-to-date with new videos, and bookmark this blog as well.

Saturday, November 21, 2009

Photography with Imre Z. Balint: Episode 2 – The Shutter

Well in record time I managed to finish episode two of my photography series and it has been uploaded to my YouTube Channel. I've embedded the video here, but if you'd like to see the more impressive HD version, then check out my channel directly.

Since it's a bit late now, I'll be adding my supplemental post tomorrow morning. I have a bunch of interesting links and thoughts to share, including connecting the use of aperture together with the shutter. Enjoy, please rate (5 stars!), and subscribe!


Monday, November 16, 2009

Photography with Imre Z. Balint: Episode 1 – Aperture

Yeay! I finally finished my first webisode of a series I’ve always wanted to do about various topics in photography. The first subject I discuss is aperture, a very important aspect of taking great pictures. In my video I show what an iris diaphragm looks like, which is the mechanical part in a lens that controls the aperture that either restricts or permits additional light to penetrate the lens (thus light that hits the film or sensor).

In a (tiny) nutshell, here’s a summary of aperture:
  • The aperture of a lens controls the amount of light that can pass through it to the film or sensor
  • Larger aperture = more light passing through, smaller aperture = less light passing through
  • This sounds odd, but: larger aperture = smaller f-number, smaller aperture = larger f-numbers (inverse relationship)
  • Depth-of-field (DOF) is how much of an image is in focus
  • Large apertures (smaller f-numbers) means smaller DOF; small apertures (larger f-numbers) means larger DOF
  • Different lenses behave in different ways; wide angle lenses generally have large DOF even when small f-stops (aperture wider open) are used.
What can different aperture (or f-stop settings) be used for?
  • When shooting portraits, it’s often more pleasant to blur the background with only the subject in focus, thus smaller f-numbers (wide open apertures) are used.
  • When shooting subjects a short distance away (e.g. within 5 meters) with a telephoto (aka zoom) lens, DOF is usually quite small, however, at the same aperture setting when shooting a subject at a large distance (e.g. 20 meters or more), the DOF becomes larger. So DOF also depends on distance, not just the aperture setting.
  • Most lenses have f-stop “sweet spots” where a particular or certain range of aperture results in a sharper photograph.
Some resources on aperture:
To see my video in HD along with other clips, please visit my YouTube Channel; don’t forget to subscribe and rate 5 stars!