Digital Camera Basics

Memory cards, megapixels, gigabytes - oh my! Tech Talker explains what you should look for when buying a digital camera.

Eric Escobar
4-minute read
Episode #29

Digital Camera Basics

Lately, I’ve been receiving a ton of questions from Tech Talker fans about different aspects of digital photography. So I will answer many of these questions in this episode.

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Memory Cards

One of the most frequently-asked questions is about SD or Secure Digital memory cards. If you own a digital camera you’re probably familiar with what these look like, but if not, here’s an example. As of right now, SD cards are the most widely used type of memory cards in most cameras—and for good reason. They’re small and fairly inexpensive.

Many of you have come to me with the same question: Which type of SD card is best?” Well honestly, that’s really hard to say because it depends on many factors. But let me give you some pointers on what to look for in a memory card so that you can make an informed decision next time you’re shopping for one.

The first and most obvious aspect to note is the card’s capacity. This is generally measured in gigabytes (abbreviated as GB). Currently, a 16GB card will run you around $20 at most stores. I usually suggest buying the largest card that makes sense. For example if you have a sophisticated video camera that can record high definition video, I would suggest a 32GB card. But if you’re just a casual photographer, then size really isn’t an issue unless you’re going on vacation for months at a time! Check out my episode called How to Store Large Amounts of Data for tips on where to house all those pictures and videos.

It would be great if the size of the memory card is all you needed to consider when choosing one. But there are a few other things you should keep in mind. The first is the class of the memory card. Any class of memory card will work in a device that accepts SD cards, however a higher class of memory card will help your device to perform much faster. The “class” refers to the write speed of a memory card. Most cards are class 2 or 4, these numbers relate to how many megabytes can be written to the card per second. So to put this number in perspective, a standard picture taken by a typical digital camera will be about 5 megabytes. So for those of you who just snap pictures every now and then, a class 4 memory card will allow you to take a photo about once a second. Now if you had a class 10 memory card, it would have the ability to take 2 pictures per second.

This really isn’t a limitation for most digital camera users, but if you’re trying to shoot video or a burst of pictures to try and capture that awesome athletic pose in mid-air, then a class 10 card might be more of what you’re looking for.

Another thing to consider when choosing a memory card is the difference is between SD, SDHC, and SDXC. The HC stands for high capacity and the XC stands for extended capacity. This just means any card over 4GB will be called HC and any card over 32GB will be XC. For cameras purchased in the past few years, they can accept pretty much any card, whereas an older camera might have some trouble.

Hopefully that answers all your questions on memory cards. Now let’s move on to megapixels!


If you go to the electronics store and see the display of various digital cameras, you’ll quickly notice that the main thing that gets compared across every camera is megapixels. I’ve talked about this in a previous episode, but just as a refresher: a megapixel is 1 million pixels and each pixel is a dot of color. So the more megapixels you have, the bigger you can blow up the picture before it gets fuzzy. This causes many people to think “Awesome! So I just want a ton of pixels!”

Whoa there, cowboy! Not so fast.

Having more pixels isn’t necessarily better. For example, a standard point-and-shoot camera may cost about $100 and will give you 12 megapixels. But a Canon Rebel SLR (the much bulkier option) can cost more than $700 dollars and will give you the same amount of megapixels. So what gives? 

On a bigger camera there is more room for the sensor that captures the light as it comes into your camera lens. Which means there is more space for better equipment. And what that means is that even though they will still take a picture with the same amount of pixels, that the bigger, more expensive sensor will capture the light more accurately than the $100 camera.

Next there is the question of noise. Putting pixel sensors close to one another creates a lot of heat which can create “noise” or distortion on your photos. This is another reason why the larger, pricier cameras are better because they have the room to space out their sensors, thereby cutting down on the visual noise.

Another huge difference in image quality will also depend on the type and size of lens you use. Generally speaking, the lenses available for the bigger cameras are much better, and sometimes even interchangeable, unlike most standard digital cameras. I’m not knocking those relatively inexpensive cameras—after all, I like my little Sony Cybershot just fine. But my girlfriend, on the other hand, has a fancy camera and her pictures are pretty spectacular. The quality is clearly better than on my little point-and-shoot.

When it comes to digital cameras, the best advice I can give you is to try out many different types to see which works best for you. After all, you may want something you can slip into your pocket or you might want something that you could take more professional photos with. That’s totally up to you.

I’ve just barely scratched the surface of digital photography in this episode, so if you want to know more about this subject, feel free to send me an email at techtalker@quickanddirtytips.comor head over to theTech Talker Facebook page and post your question there.

Until next time, I’m the Tech Talker, keeping technology simple!




Memory card image courtesy of Shutterstock.

About the Author

Eric Escobar

Tech Talker demystifies technology and cutting edge devices so that even the most tech illiterate can understand what's going on with their computer or gadget — and what to do when something goes wrong.