DP merrill

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can someone put me in the picture re these cameras from Sigma,some customer reviews say they are fantastic image quality when you get it right etc,whats the big deal with them
thanks
 
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They use a special sensor designed by sigma called Foveon.
It has some advantages, some disadvantages.


Sensor just convert photons into electrons, mostly independent of wavelength across the visible spectrum (although they are more sensitive to red and IR wavelengths than blue and UV). TO get colour there is normally a colour filter that has red green or blue transparent plastic that cuts all visible light except for those colours. Red light that hits a red filter passes through, but if it hits a blue filter it is blocked- throwing away that light information. What you get is an array of pixels where each pixel has a luminance value for a single colour. In order to get every pixel to be every colour you have to complex demosaicing algorithms that can interpolated colour values across neighbouring pixels. This reduces the amount of colour information reducing the chominance resolution. You also throw away a lot of light.


The Sigma Foveon sensor has no colour filter.Every pixel records every colour. This is done because the different wavelengths can penetrate different thickness of silcon so there are photon wells and ADC readouts at 3 or more different depths. The readouts from the different lengths can be reconstructed, although this in itself is somewhat complex. The shallowest layer will contain blue light with some red and green, the middle layer more green light but some red, the lower layer will be mostly red. getting accurate colour is not as trivial as the sigma slides suggest.


In theory the foveon sensor can give better colour resolution and less light is throw away. This is somewhat true but the complexity of the sensor itself creates limitations. The sensor is more expensive to make, and so far that has forced them to be smaller sized. Sigma crop sensors are 1.7X crop compared to the standard 1.5x (Nikon, Sony, Pentax, Fuji, Samsung) or the 1.6x crop for canon (the canon 1.6x crop was done because canon originally wanted a 1.3x crop sensor between APS-C and FF, the 1.5x APS-C crop is an official standard dating back to film).

Sigma currently can't scale the sensor to FF at affordable costs. Sigma's previous DSLRs have been extremely expensive using a foveon sensor at 1.7x crop!)

I think the sensors are also CCD based which leads to much higher noise at high sensitivities compared to CMOS. The dynamic rnage is also much less.


The images do have good colour and fantastic acuity/sharpness.
 
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can someone put me in the picture re these cameras from Sigma,some customer reviews say they are fantastic image quality when you get it right etc,whats the big deal with them
thanks

The Foveon sensor is the difference which has been explained. Basically it is a bit like a high end medium format camera. Best used under IS0 200 to photograph static subjects and probably best confined to a tripod. The image quality in prints up to 24x36 for £300 will rival a D800. If you can get past limitations like no usable high ISO or terrible software, battery life and slow write times it is a very good camera for portraits or landscapes or macro with the DP3M.
 
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thanks DP.
been reading more about them and it seems if your prepared to put up with a hell of a lot of weaknesses of the camera and shoot in a limited way some of the images can look amazingly good.
you know for £350 i think i may give one a shot:).
the DP1 seems to pull because of the 28mm equiv,be good for streetish style I'm guessing,out of the 3.
has anyone owned one here?
 
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cross posted Above&Beyond.
thanks for reply.could i get away with it for street do you think,i Know i will have many many misses but for the few keepers i would like to try?
 
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I wouldn't use it for street photography you will find it very frustrating. 50 shots or fewer per battery, autofocus is sketchy, sometimes weird colours. I'd get a Fuji X series or some fast autofocus micro four thirds camera. Think of the most horrible camera you've ever used and the Sigma is worse. I've got the DP2M and carry about 6 batteries and have to edit it in the Sigma Photo Pro software which has been designed by someone that hates the end user. My Xpro 1 is far better for street.
 
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oh thanks A&B,so you have the 2.what do you use yours for?

The Sigma compliments my D800 when I want to shoot landscapes as it makes some of the best black and white photos I've seen due to the sensor. It's strictly tripod only and low ISO but the detail is lovely and sometimes I think it's a D800 file it's that good. I tried it shooting people quickly and other applications but it is terrible. I'm not saying it couldn't be done but I wouldn't want to do it. The IQ for the price is amazing but the operation can be hard to live with.

The Xpro1 is my go to low light camera and produces nice clean files at high ISO and the viewfinder and size are nice for street to compose the images. Operating it reminds me a lot of a Leica M9 that I used to have. These Fuji X series cameras are great and the lenses are usually top notch.
 
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I have a DP1 merrill and the image quality is fantastic out of it, it renders micro contrast and colour unlike any other digital camera out there. Better micro contrast seems to be what gives it a more 3d feel, bayer sensor cameras tend to look flatish because of the bayer filter.
Like other people have said it's not too far off a d800 d800e for perceived resolution, which means if you wanted you could print very large.
I didn't get it for the resolution but rather the lack of a bayer and AA filter which is what gives your files a different look, in some ways more like medium format film, though still can't quite get that Velvia 50 6x6 colour or feeling of depth!
It does have some significant drawbacks compared to a modern digital camera. The battery life is terrible the two batteries get me about 70 100 shots, though I don't mind means I take less photos and saves me time processing them in photoshop :) other thing is the file sizes are huge 40 to 50mb Raw files and you can get 80mb tiffs from the raw, if you use it a lot watch your hard disc space evaporate.
The write times are insane 15 seconds to write a RAW, though you can shoot about 7 in a row before buffer fills up, but you get no preview until they are written to card. I started shooting film again so appreciate that I can see the picture after 15 seconds and not two weeks!
There isn't a camera in the price range that delivers anything close to the image quality, if you can live with the drawbacks (having shot film again they don't really seem like drawbacks anymore) it's a superb camera.
 
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Dpreview has a nice writeup of the camera, but look at the conclusion page - more cons than pros!

http://www.dpreview.com/reviews/sigmadp1/

It is a shame that Sigma haven't addressed the issues with this series of Cameras, if it had a good user interface, the write speeds were boosted, the software for processing improved, the Battery life increased then it would improve the usability of the Camera no end.

It is quite telling that when you read up about this camera people always say that when you get it right the quality of the images is amazing.
 
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The interface is not bad, you get use to it after 1 full days usage. Most review sites will only spend 3-4 hours at max.

Write speeds hasn't improved becasue it produces 40MB+ files. Lightroom does decent job handling the files, however processing through Sigma Photo Pro will give you the best result. General processing isn't as bad as they claim, because with this camera you wouldn't be shooting +100, more like 20-30 in 1 outing.

The IQ is simply breaktaking.

Here is sample shot from the 1st generation 4mp Sigma DP1 Full Size.
 
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Thanks.its a very tempting camera by the sound of it,a bit like an untamed stallion that once trained could be a great ride.
The other question would be which focal length.the 28 mm equiv sounds useful
 
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