In the good old days, we had 35 mm cameras, medium format cameras, and large format cameras. Since cameras nowadays have a digital sensor instead of film, we’ve been graced with a variety of different sensor sizes. APS-C, DX, Four-Third, full-frame and the various sensor sizes of compact and bridge cameras. But for many amateur photographers, full-frame is considered the holy grail. Why is that?

Full-frame? We used to simply call it “35mm”!

It seems a bit strange that the former 35 mm format (24×36 mm) is now called “full-frame”. As if there were nothing more above it, because after all, something can’t be fuller than full (see the pint of Guinness…). When Oskar Barnack “invented” the 35mm format at the Leica company, it was not taken seriously by photographers for a long time. They were used to really large film formats like 8×10″ (20x 25cm) or at least 4×5″ (about 9×12 cm). Or at least roll film with an image format of 6×9 cm. 24×36 mm was ridiculously small. And the smaller the film format, the worse the image quality.

Apart from some wickedly expensive medium format cameras, the full-frame camera, i.e. a sensor with the dimensions 24×36 mm, is considered the measure of all things in digital photography. And many an amateur photographer would like to “upgrade” to full-frame someday. But why actually? What are the arguments in favor of full-frame? And what might be against it? I’ll have a go at an analysis.

  • The large sensor has better noise characteristics than a smaller sensor

This is true provided that both sensors have approximately the same number of pixels. This is because the noise characteristics do not really depend on the sensor size, but on the size of the individual light-sensitive photodiodes. With the same number of pixels, the larger the sensor area, the larger these photodiodes can be. A full-frame sensor with 40 million pixels does not necessarily have better noise characteristics than an APS-C sensor with 24 million pixels!

  • The large sensor enables a shallower depth of field at the same aperture

Absolutely! Due to the larger reproduction scale of the large sensor, the depth of field is shallower at the same aperture. But this is both an advantage and a disadvantage. While portrait photographers may be happy about it, it is more of a disadvantage for landscape photographers. In landscape photography, you usually want everything to be sharp from front to back. With a small sensor, however, this is already possible with medium f-stops, whereas with a full-frame sensor, you often need f22 or even f32 for this.

But you shouldn’t expect a quantum leap in this respect when switching from APS-C to full-frame. However, the difference in depth of field between full-frame and a compact camera is enormous.

  • The large sensor has advantages when using super wide angle lenses

The shortest focal length of lenses for APS-C cameras is currently around 10 mm. This corresponds to about 16 mm for full-frame. However, 16 mm is by no means the end of the line for full-frame cameras. Canon, for example, offers a wide angle zoom from 11 – 24 mm. That doesn’t sound too dramatic, but in the super wide-angle range, one millimeter less focal length already makes a considerable difference in the angle of view. So if you like to work with super-wide angles, you actually have more options with a full-frame camera.

  • The large sensor has disadvantages when using telephoto lenses

Wildlife or sports photographers often need very long focal lengths. For the same angle of view, the focal length on a full-frame camera must be about 1.5 times longer than on an APS-C camera. This means that with the same initial aperture, the required lens you need is significantly larger, heavier and, above all, more expensive than a corresponding lens for an APS-C or Four-Third camera. However, this is only true under the assumption that both camera types have the same number of pixels. Otherwise, you can of course make a corresponding crop from the photo taken with a full-frame camera.

  • Full-frame is larger, heavier and more expensive than APS-C or Four-Thirds

This is clearly the decisive disadvantage of full-frame.

A short summary so far

Looking at the arguments so far, there is no clear winner or loser. Those who don’t care about the price and weight of the equipment can decide according to their personal preferences. For most people, however, the price and for many the weight of the equipment are a decisive argument. In both categories, the cameras with the smaller sensors are clearly in the lead.

Manufacturer policy

In addition to the above considerations, there are a few other points to consider that are completly unrelated to sensor size, but are nevertheless indirectly related to it.

As a rule, the full-frame cameras of the respective manufacturers are also their top products. They are usually characterized by

  • Robust, splash-proof bodies
  • robust construction
  • very fast auto focus system
  • Very high frame rate
  • Large, bright viewfinders offering 100% coverage of the frame

These features often lead photographers who would be well served with a smaller sensor (e.g. sports photographers) reaching for a full-frame camera because they need the very high frame rate as well as the fast autofocus.

On the other hand, these cameras are aimed at a rather conservative group of buyers. Professional photographers value tried-and-true features that they are familiar with and do not want features that have not been tried and tested very much. Therefore, there are many features not found on full-frame cameras that users of cameras with smaller sensors have long since become accustomed to (this will, however, probably change in the future). These include, for example

  • Articulated LCD (and if you happen to know a better word for this, please let me know, it was the best I could find…)
  • Touch Screens
  • GPS receiver
  • Icon shooting modes (landscape, sports, portrait, macro … )

Of course, these different features of the various cameras don’t really have anything to do with the sensor size. But with the decision for or against full-frame, you have to accept the one or the other.

As always I’m looking forward to your comments and thoughts on this topic.