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Digital SLR Guide News, Mar. 2007 - The Mighty Olympus
March 29, 2007
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Digital SLR Q & A
Question: How do aperture and shutter speed change with the amount of available light?
AnswerIf you're reading this newsletter for the first time, I encourage you to go back and review some of the previous issues before you dig into this month's Q and A.
Why? Well, I'm going to be digging into some fairly low-level photographic concepts here, and I've been building up to this point over the past couple of issues.
If you don't read those issues first, a lot of what I cover here might seem confusing. It's like trying to learn how to swim by jumping into the deep end of the pool.
Having said that, let me help you on your way:
OK - ready to get started?
You have two ways that you can control the amount of light that lands on the sensor of your digital SLR camera: you can make the aperture of the lens wider or narrower, and you can make the camera's shutter stay open for a short or long period of time.
Now we're going to toss in the most important variable: the amount of available light.
Let's begin with the most common scenario: you're taking a photo on a bright sunny day of a static subject (I'll talk about moving subjects in a later issue of the newsletter). In this case there is plenty of ambient light so you're not going to have to open the aperture wide or keep the shutter open for long for the sensor to collect enough light.
Remember, the amount of light we're after here is just enough to create a balanced exposure. If we let in too much light we wind up with an over-exposed photo, and if we let in too little the photo will be under-exposed.
Let's start by setting a fairly narrow aperture of f/16. Since there is plenty of light outside, the correct shutter speed for a correctly exposed photo should be about 1/250th of a second.
Let's add this information to a table that we can build upon as the light changes:
This is a good start. But imagine now that instead of a bright sunny day, it's partly overcast. If we just leave the camera set to f/16, 1/250 we're going to wind up with a photograph that is under-exposed, since the ambient light is dimmer.
We now have one of three options:
In the December issue of the newsletter, I talked about how apertures are measured in f-stops. Well, we're going to take that concept a bit further today and delve into stops of light.
When you begin to think about the amount of available light in terms of stops (rather than just saying "whoah, it's BRIGHT out here!") then the changes you have to make to aperture and shutter speed to get a correct exposure start to make sense.
In order to keep things simple for now, I'm only going to be using a half-stop scale.
Here's the aperture scale with half stops (full stops in bold):
And here's the shutter speed scale with half stops (full stops in bold):
Let's say that the difference in the amount of available light between a clear day and one that's partly overcast is one FULL stop of light. Let's also go back to our three options for changing the camera settings, and add some more details:
And here's how our camera settings might look when we apply each one of these three different options:
That's enough tables and numbers for you to kick around for now. Even if you're using your camera in AUTO mode, you can still see the aperture and shutter speed settings the camera is choosing in the viewfinder.
Pay special attention to these two numbers as the amount of available light changes, and you'll begin to understand how aperture and shutter speed work together to create balanced exposures.
Learning ResourceIf you take a lot of pictures of your family members, then have I got a web site for you.
It's called Best Family Photography Tips and is chock full of tutorials about how to take photos of babies, children, siblings, individuals and groups.
The man responsible for the site is Robert Bezman, a professional photographer who works in and around Chicago.
Unlike the Digital SLR Guide which focuses on the cameras and gear that you need to take great pictures, Robert's web site is all about technique.
Once you havea new digital SLR in hand, I encourage you to browse through Best Family Photography Tips to find out how to improve the portraits that you take of your loved ones.
How and WhenSorry folks - no how and when this month. I simply ran out of time due to my illness.
I also sometimes run out of ideas for this section of the newsletter and the web site, but now you can help.
I've added a digital SLR tip request form to the site. If you've ever felt perplexed about a camera feature or specific technique, please go ahead and ask.
The tip request form is completely anonymous (even I will never know who you are), so you can submit any question you have without having to be concerned that it's a "stupid question".
So go ahead - ask away - my brain and other visitors to the site will thank you for it!
Cameras and Accessories
Latest Digital SLR(s)
This show is always the time when camera manufacturers announce all of their latest models, including many that are still in production but are soon-to-be-released.
This year was no exception, and saw the confirmed introduction of 3 new digital SLR camera, along with a host of "pre-production" models.
The four new cameras announced at PMA were a high-end professional camera from Canon (the EOS 1D Mark III) and two new models from the Olympus company, which never ceases to surprise me with their level of innovation.
Since the Olympus cameras are better suited for the consumers this newsletter is for, I'm going to focus a bit more on them and will let you go looking for more information on the EOS Mark III if you so desire.
The two new Olympus cameras (to be released in June and July) are the E-410 and the E-510.
Besides including many of the features that are common on digital SLR cameras today (including 10 megapixel sensors), these two pack in a bunch of additional features that are designed to produce better images and make the cameras more versatile.
Both feature the Olympus dust control system (called a SuperSonic Wave Filter) and live view LCD screens (that allow you to preview an image before you take it). Even though this feature is quite common on compact digital cameras, it is NOT on SLRs and these two cameras join a very select group of live view digital SLRs.
Finally, the E-510 will also include a built-in image stabilization system (already available on cameras from Pentax, Samsung and Sony). The image stabilization reduces the effect of camera shake and helps you take clear photos in low-light conditions without using a flash.
The big news about the E-510 is that it will be the first digital SLR camera to include ALL of these special features. While the Sony A100 came close, it lacks the live view LCD screen that will be available on the E-510.
Even bigger news is that both cameras will retail for less than $900, making them enticing options to consumers seeking a new digital SLR camera.
Digital SLR Camera of the Month
Aimed at the semi-professional market, the Nikon D200 has all the bells and whistles that you could possibly hope for in a digital SLR camera.
Key to this camera's appeal are its fast 5-photo-per-second continuous shot rate, 11-point autofocus system and instant response times. You'll notice that the theme of these features is SPEED.
But it doesn't stop there. The polls are in and users of the D200 are just plain thrilled. In a comparative analysis of several different user review web sites, the D200 has emerged as the top rated digital SLR camera, due to an impressive number of rave reviews.
If you're just beginning your journey into the world of digital SLR cameras then the D200 is probably a bit much - you really don't need all of the features and functionality that this camera offers.
If, however, you've been using a digital SLR camera for a couple of years and feel like you're ready to make the move to the next level, then the Nikon D200 is sure to please.
Accessory of the Month
It's a lens, but not a lens in the traditional sense because...well, it's flexible. Literally.
Lensbabies come in a variety of mounts so they can attach to cameras from different manufacturers. The images they produce are completely unique and use what's called "selective focus".
You are actually able to twist and turn Lensbabies so that singular elements in your photos are in focus while the rest blurs out completely.
If your photography is all about capturing crisp, clear, life-like images then Lensbabies are definitely not the right accessory for you. But if you're branching out into more abstract forms of photography and want a lens that can really enhance your creative vision, then it's worth your time to take a closer look at these amazing lenses.
In ConclusionI'm getting my hands on the (relatively) new Canon EOS Rebel xTi in the next couple of weeks so keep an eye out for the complete guide sometime next month.
Having spent the past month sick, it's my sincere hope that my health will now return and I'll be able to continue to produce new articles for the Guide.
Thanks to all of you who've written in to provide your feedback and encouragement. It's always nice to hear that the information that I provide in the Guide is helping you to navigate the murky waters of digital SLR cameras and lenses.
And as always, if you find there's someting missing or are still perplexed by some of this technology even after you've read the pages of the Guide and some of these newsletters, then please feel free to contact me and ask whatever unresolved questions you have.
Thanks for reading, and happy picture-taking!
--Chris Roberts, Your Digital SLR Guide
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