Wednesday, May 23, 2007
Do You Need A Full-Frame D-SLR?
There are significant advantages to D-SLRs that are designed around sub-full-frame image sensors. Before you decide that only full-frame will do, consider all the angles.
What's The Catch?
The single biggest disadvantage of a sub-full-frame sensor is the crop of the image circle. If you bolt your trusted 20mm to a body with a socalled 1.5x magnification factor, you'll get an image that doesn't look nearly as wide as you were expecting. The appearance would be closer to what you'd expect to see from a 30mm lens attached to a 35mm film camera. This clearly is a disadvantage at the wide end, but it's not a fatal flaw. Because of the ever-increasing demand for widerangled lenses, manufacturers have stepped up and designed lenses that are specifically made for these cameras. The professionally oriented lenses are excellent performers and capable of professional results.
Okay, so you've decided that you simply need the full-frame. Nothing else will do. Obviously, these cameras have some definite advantages.
Resolution. First and foremost, resolution is the primary advantage of a camera equipped with a full-frame sensor. If it's an absolute necessity that you have the most resolution possible, a full-frame sensor is your tool. The 16.7-megapixel Canon EOS-1DS Mark II has pixels to spare.
Noise. A key aspect to image sensor design is the size of the individual photosites. A large, full-frame sensor The EOS 5D features Canon's latest full-frame image sensor. The camera is can accommodate large photosites with plenty of space in between them. As electronic components within a box full of other electronic components, the sensor generates heat, and it's surrounded by hot components. Heat creates noise and noise degrades image quality. To reduce noise, it's important to have the ability to reduce heat, and to reduce heat, the sensor must be able to dissipate that heat. Larger photosites with space between them keep heat and, therefore, noise from becoming a problem.
Dynamic Range And Color. The larger photosites on a full-frame sensor are analogous to buckets filled with photons instead of water. The more photons you can capture, the better the overall image quality. Just like buckets left outside in a rainstorm, a larger photosite can capture more photons than a smaller photosite. With more photons, the dynamic range and color fidelity are superior. Smaller image sensors that have the photosites crammed together to get a higher-resolution sensor are more likely to have dynamic range and color problems than the larger full-frame sensors. Of course, as engineers cram ever increasing numbers of photosites onto the full-frame sensors over time, those sensors will have the same inherent problems, but currently full-frame sensors have an advantage over sub-full-frame models.
We can't emphasize it enough: there's more to a camera than the image sensor. Still, the image sensor is at the very heart of the camera, and it's a key element in the chain to produce your finished image. Image sensors should play a large part in your decision-making process when you're planning on buying a new camera, but there are plenty of other important elements to consider as well. In the end, no one camera out there is “the best.” It's all about finding the best camera for you.
Page 3 of 3