Sigma DP2Q vs DP2M Part 2: Highlight headroom


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After several forum entries regarding the narrow dynamic range of the Quattro, especially the small reserves in the highlights, I started my own comparison with the DP2 Merrill to literally see for myself. The whole venture turned out more difficult than I initially thought. At the first try (aperture priority), exposure times didn’t match. At the second try, I took pictures with both cameras in M-mode, adjusted equal aperture setting, ISOs and exposure times, but the pictures had different levels of brightness. Since I worked with natural light at the first and second try, I had to exclude this potential error source at the next attempt. I didn’t take any chance at the third try: M-mode and artificial light. The result: the Quattro is less sensitive at equal ISO level than the Merrill. Only if exposure for the Quattro pictures is set to +0,67 in SPP or Lightroom, the shots of both cameras look similarly bright.

Sigma DP2 Quattro VS Merrill

I took 5 pictures with both cameras respectively: one with correct exposure according to DP2Q’s histogram, and four that were overexposed by 1, 1.33, 1.67 and 2 stops respectively. All photos were taken at ISO200, the native sensitivity of both cameras, where the dynamic range is highest. Subsequently, I tried to restore details in the highlights with negative exposure in SPP 6.0.6. For every overexposed picture, I adjusted negative exposure exactly with the value that the photo was overexposed with. Specifically, this means that for a photo overexposed by 1 stop, negative exposure of -1 was dialed in.

Sigma DP2 Quattro - korrekt belichtet / correct exposure (volle Auflösung - full resolution) Quattro, correct exposure

Sigma DP2 Merrill - korrekt belichtet / correct exposure (volle Auflösung - full resolution)
Merrill, correct exposure

Sigma DP2 Quattro - überbelichtet +1 EV / overexposed +1 EV (volle Auflösung - full resolution)
Quattro +1

Sigma DP2 Merrill - überbelichtet +1 EV / overexposed +1 EV (volle Auflösung - full resolution)
Merrill +1

Sigma DP2 Quattro - überbelichtet +1.33 EV / overexposed +1.33 EV (volle Auflösung - full resolution)
Quattro +1.33

Sigma DP2 Merrill - überbelichtet +1.33 EV / overexposed +1.33 EV (volle Auflösung - full resolution)
Merrill +1.33

Sigma DP2 Quattro - überbelichtet +1.67 EV / overexposed +1.67 EV (volle Auflösung - full resolution)
Quattro +1.66

Sigma DP2 Merrill - überbelichtet +1.67 EV / overexposed +1.67 EV (volle Auflösung - full resolution)
Merrill +1.66

Sigma DP2 Quattro - überbelichtet +2 EV / overexposed +2 EV (volle Auflösung - full resolution)
Quattro +2

Sigma DP2 Merrill - überbelichtet +2 EV / overexposed +2 EV (volle Auflösung - full resolution)
Merrill +2

Let’s now turn to my interpretation of the results: the DP2Q picture overexposed by 1 stop could be effortlessly restored. With the „overexposure correction“ feature* enabled in SPP 6.0.6 (only available for editing Quattro X3Fs) you get satisfying results even for restoring pictures overexposed by 1,33 to 1,66 stops. Photos that are overexposed by 2 or more stops are beyond remedy even with „overexposure correction“. The DP2M seems to have 1/3 to 2/3 of a stop greater reserves in the highlights. Considering the fact that all DP2M shots are more exposed by 2/3 of a stop due to higher sensitivity, the DP2 Merrill’s or rather the Merrill sensor’s highlight headroom is greater by 1 stop.

* this feature was disabled in this comparison

  1. […] first part dealt with a comparison of the DP2Q and the DP2M with regard to noise performance, the second part was about highlight headroom and in the third part, I will go into the matter of shadows. Without […]

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  2. […] I have already compared the Quattro and the Merrill with regard to noise performance and highlight headroom, the only thing left to scrutinize are the shadows, particularly the noise in them. A short […]

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  3. […] I lost sight of the color rendering topic, because I focused too much on noise performance, highlight headroom and noise/dynamic range in the shadows. Considering the light conditions light-hungry Foveons need […]

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  4. […] the exposure in SPP to check whether the Merrill’s color saturation increases when using the dynamic range advantage of the Merrill sensor (approx. 2/3 of a stop). I exported the photo taken with the Quattro once with color mode […]

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