State of the Art - Ultra-Compact vs Digital SLR

2007.11.06

Every once in a while, it is fun to compare completely different things just to see where they are relative to each other. Among digital cameras, we have the ultra-compact models on one end of the spectrum and the digital SLRs on at the opposite end. For former are designed to provide good-enough image quality in the smallest package possible, the latter as designed to be uncompromising and produce the best image quality.

Technologically, DSLR cameras have a serious advantage over much smaller camera: Size. Specifically, the size of their image-sensors. Larger image sensors have an advantage because of their greater surface area which can gather more light. Considering image quality alone, no matter what we can obtain with a small sensor, we can also go better with a larger one. Basically, whatever technology exists to make the best sensor for an ultra-compact, the same technology could be used to make a sensor for a DSLR. If the number of pixels remains unchanged, the DSLR will have larger pixels and therefore its images which show less noise and greater dynamic range. Well, I'm over-simplifying a little, but not by much.

So here we go again, we have another silly pointless comparison between one of the latest ultra-compact digital cameras and one of the latest DSLR cameras. For those who missed it, we did this before in the full review of the Fuji Finepix F30. As we saw in that comparison, the F30 turned in quite an impressive performance if we ignore the sharpening artifacts. Here are unmodified 100% crops of matching ISO of the Fuji Finepix F50SE and the Sony Alpha A700. Results are discussed below.

Fuji Finepix F50SE	Sony Alpha A700
ISO 100
ISO 400
ISO 1600

It is easy to see that the colors are not the same between the two cameras. Both were set on automatic white-balance, both on auto-exposure, taking pictures of the same scene under the same lights. Neither of them reproduced the true colors, but the Fuji Finepix F50SE did much better. For reasons I do not understand yet, DSLRs get the white-balance of incandescent lights more wrong. Perhaps fixed-lens cameras can read more sample-points when computing white-balance because they can read any point of the sensor, while DSLRs have to rely on a dedicated sensor which provides less sample points. Note to self: investigate this further.

In this comparison, the advantage of the ultra-compact seems to stop at better white-balance. Even at ISO 100, the Alpha shows a slightly sharper and smoother image. Although it cannot be seen in these crops, this scene has more contrast then either sensor can capture. The rendition of overall tonalities favor greatly the DSLR which clipped less highlights.

At higher ISO, the DSLR leaves the ultra-compact in the dust. Noise levels increase much more rapidly with the F50 than with the A700. Although both cameras keep a relatively good amount of sharpness across ISO, the Sony Alpha A700 still produces a usable ISO 1600 while the F50's equivalent crop is a mess.

The final word is that current digital SLRs produce images with much less noise and better sharpness when equipped with a good lens than ultra-compact cameras. Not only that, this image quality gap has apparently increased in the last few years. This can only be explained by the rapid expansion in resolution among fixed-lens cameras. Do not forget that differences between DSLR cameras and ultra-compacts are numerous, image quality is just one of them.

• Digital Camera
• Technology