Full frame vs. crop factor.

Q: IS IT BETTER TO HAVE A FULL FRAME CAMERA BODY WITH FEWER MEGAPIXELS OR A CROP FACTOR CAMERA BODY THAT HAS MORE MEGAPIXELS?

A: I have seen a lot of questions like this one. Crop or full frame? What does “equivalent” focal length mean? Which is better? Is a 12 MP full frame better than an 18 MP crop sensor? And so on and so forth.

Get a full frame camera. Take the sensor out and put a smaller one in there. Same camera. Same lens. Now just a smaller sensor. Light comes through the lens and covers the full frame sensor area. Now that you have put a smaller sensor in this camera (and no, you can’t actually do this), you now see less of the image being projected by the lens.

Or, look at your computer monitor. Put strips of black paper across the top, bottom, and sides. You are now seeing less of your screen. You have now made a “crop sensor” from your “full frame” screen.

Where “equivalent focal lengths” come into play is all based on the size of 35mm film. Back in the film days a negative made by a 35mm camera was 24mm x 36mm. As digital started coming of age it was very expensive to make a sensor of this size. So smaller sensors (cropped sensors) were made but put in 35mm (full frame) camera bodies. A 50mm lens no longer had the same field of view that it had when you shot film. It was 1.5x that, or 1.6x that. Or whatever the “crop factor” was for the sensor. We had to figure out how to speak about this so we talk about “equivalent” focal lengths. If you put a 20mm lens on a 1.5x crop factor body, then it was “equivalent” to putting a 30mm lens on a 35mm full frame film body. This language is sort of confusing and misleading. The lens is still 20mm. It hasn’t changed optically. With a crop sensor you are just seeing less of it. It’s like putting the black paper around your computer monitor. Your screen resolution is the same as it was before. You’re just seeing less of it.

Now, which is better? Full frame cameras typically perform better in low light, give you your full field of view on your lenses, and are typically found in better camera bodies. That’s not gospel, just a wide brush view. I live in the wider range of lenses so I prefer full frame cameras. I prefer the higher ISO performance they achieve. If I had to buy a new DSLR today I would only look at full frame bodies. So, for me, I prefer a full frame camera. Not saying that it is necessarily better than a cropped sensor.

If you love wide-angle lenses then full frame is for you. If you love longer lenses then maybe cropped sensors are for you. If you are shooting with a 200mm lens on a crop factor body and wanted that same field of view on a full frame, then you’d have to jump to a 300mm lens. Can’t you just crop a full frame? Yes, you can. But you are throwing resolution away. Let’s say you have an 18 MP full frame and an 18 MP crop sensor. With the cropped sensor you get that field of view at 18 MP. With the full frame you have to crop “resolution” out of your image so you may end up with a 10 MP or 12 MP image.

At the end of the day it’s not megapixel numbers that count. It’s the quality of the pixels. Now we start getting into the size of the pixels and blah blah blah blah blah. OMG shoot me. If I were going to go into a car analogy I’d start talking about horsepower versus torque. Or something. Not sure.

I restarted my career on the back of crop sensors. I shot those for five years. It’s what was available when I started again, and it’s what I could afford until I got my D3. Going forward with my career, any new DSLR that I will buy will be a full frame camera. That said—I love the little Fuji cameras that have a crop factor. My medium format camera isn’t equivalent to a full frame 645 film camera. I could get a full frame 645 digital back but I’d have to sell a few of my kids to do so. I say all this to say: I personally and professionally use a mix of full frame cameras and crop sensor cameras. I care more about the quality of those sensors than the size or the quantity of pixels on them.