Ever heard of a “full frame” camera? Today we’ll learn just what this means by taking a look at camera formats, racking up some serious photo geek cred, and finally deciding if the expensive cameras are worth the heavy pricetag.
Be warned, this is a particularly geeky article! While it’s not too technical, some readers may be intimidated by all of the photography lingo within, unless you’ve been keeping up with all of our series of photography articles, or are just really photo savvy. Check it out!
Full Frame and Cropped Sensor: What Does This Mean?
Digital cameras render images based on information captured from image sensors, like the one
shown above inside this Nikon D70. (Edit: Reader Fred says “All you can see is the mirror and the eyepiece prism reflected in in, the sensor is behind both the mirror and the shutter on that DSLR you have pictured.” Regardless, this is where the sensor lives, when it is not covered by these things!)
Light, much like it does anywhere else, harmlessly passes through the lens, refracts, bounces around, and exits again. Without the presence of a photosensitive material (in this case, a sensor, in some others, photo films) that light doesn’t end up doing much of anything. Indeed, even in the presence of photosensitive materials, the light that doesn’t strike the sensor doesn’t really end up doing anything useful to the photographer.
This active imaging area is what gives you your photo when you open and close the shutter—your lens captures more light than you can use on your limited size sensor, and throws away the rest. Note the rectangular shape of your photograph, and compare it to the shape of the sensor in the image above, and you can quickly piece together what’s going on inside your camera.
Most common DSLRs use a sensor that’s smaller than the potential image area of a 35mm strip of film—the size of this image area is called the “format” of the camera. 35mm was a standard format for film, and this size is roughly what we mean when we call a camera “full frame.” The format for your “ordinary” DLSR is called APS-C, or “Advanced Photo System, Type-C.” A Nikon D40 or the D70 we showed above are both typical APS-C cameras and have sensors smaller than a full frame—some call this a “cropped frame.” So what can we expect when using one versus another, and how do they stack up?
What’s The Difference In The Two Formats?
You may have a knee jerk reaction of “a bigger sensor has GOT to be better!” This is not necessarily the case—at least, the truth is very nuanced.
All things equal, full frame cameras at the same distance have a larger image area. This means that if you attempt to take the same picture at the same distance, your cropped frame camera will crop your picture. That’s bad, right? You’re automatically getting less image in your shot.
Here’s where things start to get murky. A larger sensor does not translate to higher pixel density—in other words, you can have a 12MP cropped frame sensor or a 12MP Full frame sensor. In this image, with the photographer shooting at the same distance, the full frame is able to resolve less detail than the cropped frame because the lens is interpreting it as if it was farther away. Does this mean that the full sensor is worse at resolving detail? Kind of, but not really. It does mean that an identical shot with all other things equal on a full frame will mean you’ll be squeezing more detail into a smaller slice of your image area. Can you just get closer? Yes, of course you can.
Here’s a related side note. If you’ve ever had a hard time taking a picture with a cellphone camera, and find that you have to back up a long, long distance—chances are it’s because of the camera’s limited sensor size cropping out so much of the detail.
So what do full frame format cameras do well? Without a doubt, they have to be good for something to justify the expense. (Just wait until we take a look at that!) Because full frame sensors are larger, they can gather more light, and can be made more sensitive, allowing higher ISO numbers to create better images in low light environments. In addition to this, the individual cells (called photosites) on the sensor are broader and deeper (so to speak) and allow a more nuanced, richer image to be captured, and not just at night. (Note that this doesn’t increase the image size or the number of colors in an image—it only makes the sensor more accurately read the colors in the frame.)
As we’ve discussed in previous entries of Photography with How-To Geek, higher ISO exposures usually create more noise in an image—and larger sensors only allow for the creation of more noise. Look at it this way—in a light critical situation, the smallest variance in light can be detected and recorded. With extremely high ISOs, the light is recorded practically at the individual photon level, so the slightest change in light can create image noise. Cropped sensors receive somewhere around full stop of light less light than a full frame sensor—more light hitting your sensor means a less grainy image. This is achieved by having a larger photosite—larger individual cells for gathering light on the sensor. A full frame sensor with a lower megapixel rating will have less noise than a full frame with a higher megapixel image. This also means that a full frame with 12MP will have considerably less noise than a cropped frame with 12MP. A greater pixel density will always mean greater noise at high ISO settings, and cropped sensors tend to have greater pixel density.
Because nothing in photography is simple, there is one more advantage to the full frame format, and it can be sort of confusing. Because the sensor is larger, the focal length changes compared to a cropped frame sensor. This allows photographers to take shots of far tighter, closer shots than possible with smaller frame images. If you can imagine a full frame format camera oscura with reflected rays focused from a small object, it begins to make sense. Smaller formats mean that they have a smaller area to focus on, and therefore require more distance to properly cross and meet again in focus.
Why Are Full Frames So Expensive?
The sensor shown above is the largest format in the image depicting the various format sizes, and perfectly illustrates the exponential cost increase for larger sensors. You may ask yourself why, if there are so many trade-offs, would full frames be prices so much higher than cropped frames?
The answer lies in the manufacturing process of the sensors themselves. The larger the frame, the greater the probability of it having a manufacturing defect, based on total surface area alone. It’s more difficult to produce a larger sensor defect free, because one tiny defect ruins the entire sensor. Smaller sensors have a smaller area of continuous space to be defect free. In addition to this problem of greater chances of manufacturing defects over surface area, the process itself can be considerably more labor intensive. For this very reason, the cropped frame has de facto ousted 35mm as the new standard mostly as a function of the affordability.
So, Do I Actually Need a Full Frame Camera?
That’s a tough question to answer. If you’re a hobbyist photographer, you probably can’t justify the expense of a $3,000-$5,000 camera just for taking pictures of sunsets, birds and neat looking trees. If you’re very serious about your photography and hoping to become a professional, the additional benefits of richer color, lights and darks could be a boon. But simply buying more and more expensive equipment will not make you a better photographer, but taking lots of pictures and learning about the camera you have most likely will. So, even very serious amateur photographers should spend a long time pondering if a full frame camera is right for them.
Professionals will get the most mileage out of a full frame camera, not because they’re going to need to use the full frame camera more often or they’re going to always need the increased capacity for light, etc. Simply because a full frame takes a different image than a cropped frame format camera, many choose to include full and cropped frame sensor cameras into their toolkit. A true professional will use the right tool for the right job, and sometimes that tool is a full frame camera, and sometimes it isn’t.
There are professionals and talented amateurs alike that swear by one format over another—it can prove to be a very personal decision depending on the kind of photos you want to take, and the habits you have. If you have your own reasons for loving the full frame format or hating it, feel free to tell us about it in the comments!
Image Credits: Sensor Klear Loupe by Micheal Toyama, available under Creative Commons. Nikon D70 by Rama, available under CeCILL license. Sensor Sizes Overlaid by Moxyfyre, available under Creative Commons. Belomo MC 17mm f2.8 Ojo de Pez para Full Frames by Mauro Fuentes, available under Creative Commons. Full Frame Sensor vs 1.6 crop by Steve Koukoulas, available under Creative Commons. Me and Shana by Jeff Wright, available under Creative Commons. Nikon D3S review by Mukul Soman, available under Creative Commons. Macro Full Frame by Gustavo Duran, available under Creative Commons. Project 366 – 358/366 March of the Cameras HBW by TheSussman (Mike), available under Creative Commons.
Eric Z Goodnight is an Illustrator and Graphics Geek who hopes to make Photoshop more accessible to How-To Geek readers. When he’s not headbanging to heavy metal or geeking out over manga, he’s often off screen printing T-Shirts.
- Published 09/21/11