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By Michell Bak, 13th of April 2008.

The Sony Ericsson K850 is Sony Ericsson’s best camera phone at the moment. In this camera shoot-out, we’ll do a completely unfair comparison, and put it up against the entry-level Nikon D40 d-SLR camera. Both ‘cameras’ feature a flash and an auto focus LED flash. But what makes these two competitors different? Let’s have a look at each one.

The Nikon D40 is an entry-level d-SLR camera. The camera sensor in the D40 is a CCD-sensor produced by SONY with the dimensions of 23.7 x 15.5 millimetres (3:2 format). The sensor holds an effective 6.02 mega pixels (3008 x 2000 pixels), which gives us about 16,377 pixels per square millimetre.

The K850’s sensor is a CMOS-sensor, also produced by SONY, with the small dimensions of 5.22 x 3.91 millimetres (4:3 format). The sensor holds an effective 5.04 mega pixels (2592 x 1944 pixels), which is equivalent to about 246,879 pixels per square millimetre.

A simple calculation will show that the D40’s pixels are about 15.8 times larger than the pixels in K850’s sensor. In theory, this does also mean that the D40’s pixels get almost 16 times the amount of photons (light) as K850’s pixels. Let’s look at this in another way. In the picture below, you’ll see the size of the two sensors compared to each other. This may look unbelievable, but even so, it is real.

If this is true, and the difference is that huge, then how come the mobile phone manufacturers keep saying that the phones’ cameras are on par with regular consumer cameras? Well, first of all, it’s a trick to get more people to buy their products. But secondly, this is because of the extremely noise reduction in mobile phones. As you’d expect, you will have significantly more picture noise in pictures shot on a K850 (or any mobile phone, for that matter) than on the D40. And while there is more picture noise, there will never be 16 times as much as on the d-SLR because of the noise reduction in the small mobile phone sensors.
Is the noise reduction good for your pictures? Yes, and no. Obviously, it can enhance the outcome by removing the unnecessary noise levels, however, it often removes important details in the picture along with the picture noise. While the manufacturers are constantly enhancing the noise reduction functionality, it will never get perfect, and it is always recommendable to buy a camera with a large sensor to avoid the picture noise.

First-hand preparation

Before being able to do fair comparisons of the pictures produced by each camera, I had to make sure that the focal length of the cameras was equivalent. The SONY IMX020-sensor used in the K850 has a default focal length of 5.18 millimetres. In order to do a fair comparison, I’d have to calculate what the focal length on the D40 had to be set to.

23.7 millimetres divided by 5.22 millimetres on the K850 equals 4.54 – by multiplying this number with the focal length of the K850, we’ll get the equivalent focal length on the Nikon D40, which ends up at about 23.5 millimetres. It was not entirely possible for me to set the focal length on the D40 to that precise value, so the focal length differs a slight bit in the samples (23 – 24 mm).
The aperture of the K850 is fixed at f/2.8, whereas the aperture on D40 was variable, going from f/9 – f/3.8.
Other than that, all pictures have been shot with automatic settings.

The shoot-out begins

The following samples are 100 % crops. By pressing the thumbnail, you can load the full size picture. None of the full-size pictures have been edited in any way.

Sample 1. Pictures taken through a window at angle. It’s a sunny day outside, so there is no substantial need of extra light. Due to the large sensor and pixel size on the Nikon D40, the camera won’t need a slow shutter speed, so it freezes the picture with a shutter speed of 1/2000 seconds. The K850’s pixels, however, will need a lot more light, hence the slower shutter speed at 1/125 seconds. It’s clear to see that the K850 shutter speed was too slow, leaving the picture over-exposed and discoloured.

Sample 2. Indoor picture with focus set outdoors. By doing this, the indoor elements will get dark, because the camera sets a fast shutter speed to deal with the outdoor lighting. Both cameras handle this quite well – the shutter speed on the K850 is at 1/640 seconds, which is acceptable, while the shutter speed on the D40 picture is at 1/320 seconds. The latter seems to be a perfect choice, as it does not darken the indoor elements as much as on the K850, hence less picture noise. Both cameras seem to produce more than acceptable colours with only little colour fringing on the D40, while the K850 does a bit worse in regards to colour fringing.

Sample 3. Another outside picture shot through a window. The picture contains high amounts of details, such as people and various trees. Both pictures are quite good in terms of light (well, a slower shutter speed would have made the K850 picture better), but the K850 falls a bit behind in terms of colour reproduction, where its outcome is a bit cold compared to the D40’s picture. Due to the small camera sensor on the K850, it lacks important details, however it performed better than I had expected. The D40 – of course – nails the K850 in terms of picture details and there is no evidence of colour fringing, where the colour fringing on the K850 picture is quite evident, especially at white areas.

Sample 4. Indoors macro picture about 15 centimetres from subject. Surprisingly, the K850’s colour reproduction is slightly better than the D40’s colour reproduction in some areas. The low aperture at f/4 on the D40’s picture makes only parts of the text sharp, whereas the K850 is a bit different, even though its aperture is even lower at only f/2.8. This is one of the obvious differences between d-SLR cameras and ‘regular’ cameras. Based on this, it’s pretty much a tie-breaker in terms of sharpness, even though the K850 over-processes the edges. The slow shutter speed on the K850 at 1/20 seconds also made it harder to do a sharp picture, compared to the shutter speed on the D40 at 1/60 seconds. A shutter speed of 1/60 is about as low as you should go when taking pictures with the camera in your hands. If you go much lower than this, it is recommendable to use image stabilization or to put the camera on something solid.

Sample 5. An “easy” indoor picture with straight lines and not too many details. The colours on the K850 picture are more saturated and bit more like reality, whereas the D40 picture suffers from a slightly blue hue. Nonetheless, the D40 picture is much sharper than the K850 one, and there is practically no picture noise in the left part of the picture. The problem with small sensors and the picture noise produced because of this is evident in the picture by the K850. Apart from that, the K850 generally did a good job.

Sample 6. Indoor picture in bad light conditions, flash used on both pictures. Pictures where the flash has been used on the K850 often end out looking a bit blurry and extremely over-processed. The K850 isn’t perfect when it comes to adjusting the power of the flash, and you’ll often end up with pictures where the ISO level and shutter speed is out of place. The D40 easily nails the K850’s washed out colours and lack of detail.

Sample 7. Macro picture with flash fired on both pictures. It is quite obvious that the K850 isn’t very good at adjusting the power of the Xenon flash, discolouring the box and blackening the background. What’s also noticeable is the noise level in the upper right corner of the K850 picture, whereas the D40 picture has no picture noise whatsoever. The small sensor in K850 again results in lack of crucial details and lots of noise. Another thing that bugs me about using the flash on K850 is the shutter speed, which seems awfully fast. It is in fact at 1/250 seconds – please note that it is only needed to have a shutter speed at about 1/60 seconds when using flash.

Sample 8. Indoor picture with good lighting. It’s obvious to see that the K850 lacks details and that the picture outcome is discoloured and a bit blurry due to the extreme noise reduction feature (which doesn’t seem to help!) as well as the software sharpening. Also, please note that the bags in the background are visible and not too noisy in the picture by the D40, while it’s almost impossible to get a good look at them in the K850 picture.

Sample 9. Indoor picture, bad lighting conditions, no flash used. The K850 picture has been redone three times to get the optimal picture, yet it fails to impress. The noise level in the K850 picture is extremely high, and it’s blurry even though I held the phone in my calm hands, and redid the shot three times. I’m surprised by the fact that the shutter speed is at 1/20 seconds, yet it did not activate the flash. Having said so, the D40 picture is not perfectly, but there is significantly less picture noise (quite amazing with a shutter speed at only 1/40 seconds!) and it’s as sharp as it gets without the use of the built-in flash.

Sample 10. Macro picture, set up to test the depth of field of the cameras. The D40 is the obvious winner in this one, and delivers a sharp result with excellent colour reproduction and a very nice depth of field effect, with an aperture of f/4. The K850’s colours are a bit pale, and it generally doesn’t give much of the effect, we were looking for.

Sample 11. Macro pictures in bad lighting conditions without flash. Before commenting on these, I’d like to say that I accidentally moved the D40 a bit closer to the subject after having focused, hence the slightly blurry result. It is still possible to see that the D40 does the best job in terms of colour reproduction, though. The black colour is too bright and unconvincing in the K850 picture. Once again, the noise reduction in the K850 eliminates important picture details, such as on the edges of the word ‘Nikon’.

Sample 12. Outdoors picture in great lighting conditions. Both cameras perform quite well here in terms of colour reproduction. The D40 is a bit too bright in some areas, whereas the K850 is too dark in some. Overall, the D40 picture looks the best, though. Colour fringing is a huge problem with the K850 pictures, and this outdoors picture is no exception. Apart from that, the K850 does offer a slightly more detailed picture.

Conclusion

When it comes down to it, will camera phones do as your primary camera? Well, not really. The compact sensor size in mobile camera phones is a huge disadvantage, meaning that the outcome is basically the result of some heavy software processing. If you want serious photography, then go for a d-SLR camera or at the very least a high-end compact digital camera. Mobile phone cameras are – as of now – only useful for point & shoot pictures. Hopefully, we’ll see something spanking hot in the future that can replace compact cameras.