We had to postpone this report because the initial Sigma software we got showed strong color casts like this:
Green color cast in corners
We sent the original RAW file to Sigma (actually used in this review later) and they acknowledged the problem. Although we never heard back from Sigma what the real reasons were. In the end it may not matter because Sigma posted a fix (published at DPReview) for Photo Pro that seems to keep this problem in check. We think the problem mostly shows in photos taken in overcast situations. This review actually uses all the images taken before we postponed our review but now processed with the latest Photo Pro software.
Sigma DP1 a new camera concept
In some way the new Sigma DP1 is a great concept. Use a small P&S like camera, insert a larger DSLR sensor (here the Foveon sensor of the Sigma SD14) and add a good lens. Larger sensors can mean less noise and more image quality.
Sigma decided to use a fix focus 28mm f/4 lens. While this maybe a popular choice we would like to see a top 28-70mm f/4 zoom lens. Maybe to get a smaller lens the sensor could even be slightly smaller. Also the decision to have a good optical viewfinder (although optional with the DP1) is a good idea.
We hope and expect that other vendors will copy this concept and in the end we may even see a true Mini-Leica of the digital age (smaller Leica M8 with autofocus and more).
First observations
Good
- Lens is quite good
- CA (Chromatic Aberrations) quite good for 28mm
- Light and compact
- Image quality per pixel quite excellent
- Shoots RAW
Depends on you demands
- 4.6 MP resolution (yes the DP1 sports 3x4.6MP pixel sensors because each pixel has 3 sensors for the RGB channels) is not much these days but only an issue if you want to print quite large. Files seem to upsize quite well.
Not so good
- handles more like a slow P&S digicams:
- AF not fast
- Hard to compose on the LCD in sunlight (better use the optical viewfinder, but it does not show any data)
- Old style workflow in Photo Pro (compared to Lightroom 1.4.1)
- Histogram hard to read
- No live histogram (at least we did not find one)
Los Gatos test shots
Note: We shot the same scenes as usual but because we use a 28mm (35mm equivalent) lens the normal vantage points could not be used.
Ristorante @ISO 100
Crop @100% magnification
This is the same file we used to show the "green cast" produced by the old Sigma Photo Pro. It is quite improved. We think there is still a minor color cast in the right lower corner. This is hard to verify because scenes very often show different WB (white balance) in the frame (different light sources). Overall the picture looks very good in terms of detail and colors are not bad either. On the other side pictures at 4.6 MP easily look sharper at 100% magnification compared to 10-21MP files.
Note: We use our Detail Extractor 2.0 and this will show more grain in an attempt to pull out more detail.
You can download the original RAW from here (~14MB).
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Antique store @ ISO 400
@ 100% magnification
The ISO 400 shot is quite ok. We don't think though that the noise level is as good as with today's entry level DSLRs (Nikon D60 or Canon Rebel XSi/450D).
ISO Test
We converted Sigma Photo Pro and then sharpened with the same level in Detail Extractor 2.0 and some low EasyS Plus settings.
Note: Detail Extractor shows both more detail and more grain. This way we can see how much real detail is available.
Bear Coffee Shop
Sigma DP1 |
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ISO 100 |
 ISO
200 |
ISO 400 |
ISO 800 |
Photos at ISO 100-200 are just fine. At ISO 400 it gets more grainy and also the Photo Pro software desaturates the images (result of color noise removal we guess). ISO 800 may still produce nice B&W images.
Note about high ISO noise: Many people ask why they should worry about noise at ISO 800 or more if they only use 400 ISO at max. This is of course a good question. In the past we did not care either. Then we changed our photographic style and make now often use of Tonemapping (learn more about HDR and Tonemapping). During this process we brighten the shadows and this brings out the noise otherwise seen at way higher ISO. It often starts to matter at even ISO 200 photos.
First conclusions
- Applause for the new concept
- Size and weight are great but look into a Nikon D60 or Canon Rebel XSi/450D using even the kit lenses and you have a much more responsive camera (ok they also feel big compared to the DP1).
- Long way to go to make a camera of this type into a Mini-Leica of the digital age.
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