Sigma DP1 Review
Here you can see a generated GretagMacbeth ColorChecker chart, place your mouse over any of the labels below it to see the color reproduction in that mode. Select a camera/setting combination from the 'Compared to' drop-down to comparative boxes inside each patch.
The Sigma DP1's JPEG engine produces very muted, washed-out colors. Out-of-camera images can certainly do with some extra saturation in post processing but ideally you capture your images in RAW format and adjust colors in the conversion process.
|Sigma DP1||Compare to:|
Artificial light White Balance
It is fair to say that White Balance under artificial light is not one of the DP1's strengths. Auto WB is not particularly reliable, nor are the presets. So if you have to get your whites as neutral as possible you should always work with the custom White Balance setting and a gray card. But even then the white balance can work quite inconsistently. There can be quite visible color differences between shots, even though the light has not changed at all.
White Balance works more reliably and consistently in daylight but your safest bet is to always shoot in RAW. The Sigma Photo Pro Software allows you to adjust White Balance quite comfortably.
|Incandescent - Auto WB
Red: 12.0%, Blue: -8.4%, Poor
|Incandescent - Incandescent preset WB
Red: 8.7%, Blue: -4.2%, Average
|Fluorescent - Auto WB
Red: 1.7%, Blue: -5.1%, Average
|Fluorescent - Fluorescent preset WB
Red: 8.2%, Blue: -6.8%, Average
The DP1's built-in flash is pretty weak. Even using Auto ISO it will only give you a maximum reach of 3 meters. If you stay close enough to your subjects and experiment a little with the settings you can produce some usable results. Flash exposure can be a bit troublesome but luckily you can adjust it manually.
Be careful if you use the optional lens hood as it will partially shade the built-in flash. If you want to avoid this problem and get some more flash power at the same time you should consider investing £50 in the external flash EF-140.
The DP1 offers movie capture at a resolution of 320 x 240 pixels (the actual capture size is 320 x 212 pixels, there black bars above and under the video image) at 30 frames per second, which seems an anachronism when some fairly simple compact cameras can capture video in HD format. One could be forgiven for thinking the Foveon sensor was not designed for capturing moving images and the video was bolted onto the camera as a bit of an afterthought.
The movies are recorded in AVI format and work out at about 700 KB/sec. The maximum movie size is 2GB which will give you approximately 60 min of footage.
Sample movie: 320 x 240 pixels @ 30 fps
Click on the thumbnail to view the movie
Distortion and other image quality issues
In our studio test the the DP1 exhibits admirably low distortion considering the camera sports a 28mm (equivalent) lens - 0.4% barrel distortion (click here for test chart) will be visible on straight lines close to the edge of the frame but is well within acceptable limits.
Thanks to the unique design of the Foveon sensor the DP1 resolves a remarkable amount of detail considering the image output size of not even 5 MP. On a per pixel basis it leaves most DSLRs behind it and is miles ahead of any small sensor compact camera in the market. However, for at least some of this advantage the 'traditional' Bayer sensor cameras can compensate with their significantly higher resolution. So while at pixel level the DP1 provides visibly more detail than the competition at identical viewing size this advantage shrinks quite significantly.
While there is a lot of detail in DP1 images the appearance of JPEG output is very muted and desaturated, lacking any 'crispness'. Unfortunately altering the shooting parameters (such as saturation or contrast) will only improve this marginally. You'll typically require a couple of steps in your imaging software to give the DP1 JPEG output some 'punch'.
Ideally though you shoot in RAW and make all the necessary adjustments during the RAW conversion. Usually the 'Auto' setting in the Photo Pro software will work fine and do the job. As a bonus you'll typically also increase the tonal range of your images. Compared to the results you can get from a RAW file the DP1's JPEG engine performs so poorly that one can only assume it has been a very spontaneous afterthought and been stuck on the camera in the very final stage of development.
The lens occasionally produces some hardly noticeable color fringing and there is some vignetting at F4.0 but other than this there are only a couple of (relatively) minor issues to report on. We quite regular found signs of lens flare and red channel clipping in our DP1 images.
The DP1's lens is quite prone to flare. This is probably caused (or at least contributed to) by the protruding front element of the lens. We shot a few hundred real life images and found that when shooting with the sun right (or at an angle) in front of you flare is a fairly regular occurrence. By far the most effective counter-measure is the use of the optional lens hood, it is certainly one of the more useful accessories for the DP1.
|100% crop||28mm (equivalent), F9|
Red channel clipping
The DP1's Foveon sensor is generally quite sensitive towards reds and in extreme situations this can lead to a clipping of the red channel, resulting in a purple/pinkish color on subjects which in reality are bright red. Unfortunately there is not an awful lot you can do about this other than to be aware of the problem. When it occurs you might want to try and reduce saturation in the menu (or during RAW conversion). You can later pull up the green and blue channels again in your imaging software but to be honest it won't make too much difference and you'll always end up with colors which are not entirely representative of the real scene.
|100% crop||28mm (equivalent), F4.5|
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