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Thread: DP-1 desaturation at higher ISO's.

  1. #1
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    DP-1 desaturation at higher ISO's.

    Just a question about the desaturation of images at higher ISO's

    Do you think that it is a function of the SPP, or the sensor itself?

    Uwe Steinmuller (on his excellent site (Digital Outback Photo) thinks that the SPP desaturates at higher ISO's as part of chromanence noise reduction.

    I noticed that there is a gradual loss of saturation as the ISO is increased above 200.

    Software, or sensor????

    What do you users think??

    BTW I am returning my DP-1, and hopefully will get a replacement soon.

    Thanks again.

    Martin

  2. #2
    Senior Member Brian Mosley's Avatar
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    Re: DP-1 desaturation at higher ISO's.

    Hi Martin,

    there's an interesting article here, which may explain what's going on with the Foveon sensor at higher ISO's
    http://www.bogost.com/blog/technical...d_creati.shtml

    Hope you don't mind me asking, why are you returning your DP-1? and what are you hoping to replace it with? it's not clear from your message?

    Kind Regards

    Brian

  3. #3
    SimonL
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    Re: DP-1 desaturation at higher ISO's.

    These colour shifts have always bothered me and are the main reason I haven't bought a DP-1 yet. They're not easy to correct in PP and, frankly, are a serious flaw on a £550 camera.

    Admittedly I would only be using ISO 400 or 800 for pictures destined to be monochrome in their final state but it still bothers me.

    Thoughts anyone ?

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    Senior Member Brian Mosley's Avatar
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    Re: DP-1 desaturation at higher ISO's.

    Hi Simon, I'm less concerned about the colour shifts at high ISO (since I'd do as you - switch to monochrome if necessary), than I am about good 3rd party RAW support.

    I'm not happy with the way SPP handles colour in general - and white balance in particular... and SPP is written with 'inside knowledge' - I'm hoping that Qimage Studio will help to produce much more accurate colours - but Mike has been surprisingly reluctant to discuss DP1 support so far (Qimage Studio already supports the SD14)

    I'd wait a little while longer, and expect (as Amin suggested recently) the price to plummet - and hopefully at least one good quality 3rd party RAW converter to arrive.

    Kind Regards

    Brian

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    Re: DP-1 desaturation at higher ISO's.

    Thanks all of you for your input.

    Brian - I am returning the DP-1 since I have noticed those white lines in the corner of several images, and it appears, as you pointed out, that this is probably due to a defective sensor.

    I do most of my work in color, and the desaturation issue is of concern. Perhaps some RAW conversion support by third parties will reduce this effect, if it is due to the conversion software.

    I shall probably wait to replace it with either another DP-1, or perhaps an Olympus E420 + pancake lens.

    Thank you all again for your input.

    Martin

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    Re: DP-1 desaturation at higher ISO's.

    Quote Originally Posted by Martin S View Post
    I do most of my work in color, and the desaturation issue is of concern. Perhaps some RAW conversion support by third parties will reduce this effect, if it is due to the conversion software.

    I shall probably wait to replace it with either another DP-1, or perhaps an Olympus E420 + pancake lens.
    if colour is really your thing, i think you'd probably be happier with the Oly.

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    Re: DP-1 desaturation at higher ISO's.

    Thanks Cam for the comments.

    I have been following your threads for a while.

    Have you finally made the decision to go with the E420+pancake????

    Being in Paris, you have some of the great street scenes all around you. Do you think that the 420 will work for those scenes?? Or would you need something smaller - ie DP-1, GRIID, GX-100????

    Thanks.

    Martin

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    Re: DP-1 desaturation at higher ISO's.

    Martin,

    it's my boyfriend that is going for the Oly (and he'll probably get the E-510 -- damn!) but i may get to borrow it or inherit it when the E-520 comes out... my own splurge on a larger form factor (still quite small|) is looking to be the discontinued Epson R-D1S Rangefinder

    for street scenes and candids on the metro, the GRD/GRDII are best. quiet shutter and they can blend into the background. no one takes you seriously. the DP1 is just too damned slow for me in that regard, but i love the way it draws for b/w at high ISO so i'm practicing. when all goes right, the images are stunning and i prefer the bokeh sometimes to the huge DOF of the Ricohs. huge DOF has its advantages, though, when all you're doing is shooting blindly and never know where your next focus point will be. i have all three and use them quite a bit.

    although b/w is really what i use, i do notice colours, and there's no doubt that the DP1 fades in bad lighting or high ISO. for the little colour work i do, this doesn't bother me in the least. in fact, i actually *like* what it does!

    but if i was really into colour, the Oly's seem the most natural IMO. really spot on. although i really love the DP1 images, i think it would be a pain to constantly have to worry about what it was going to do, colour-wise.

    eta: Brian just posted some pics in the Colour Accuracy thread which shows where the DP1 *does* shine. if you were only shooting low ISO... and the DP1 seems to carry more detail in the high ISO than the Oly. ach, maybe you should stick it out with the DP1? go over, look at more images. decide for yourself. i'll shut my mouth now.
    Last edited by cam; 28th April 2008 at 07:25. Reason: to add

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    Re: DP-1 desaturation at higher ISO's.

    Cam:

    U do not have to shut your mouth.

    U have been most helpful. Tell your boyfriend that the 510 is far too big for him (not really), and that the 420 will be more useful for your type of work.

    I used the DP-1 briefly, and you are correct. In bright light it really shines. But in low light, well that's another story.

    One of the other helpful people on this great site referred me to an article which attempts to explain the color shifts of the DP-1 at ISO 400 and above. It appears to be related to the Foveon sensor itself, and not the Sigma RAW conversion software. Therefore, third party software for RAW conversion may not make any difference in color shifts. As u mentioned for B&W work, the shift is of no concern, and high ISO work looks interesting.

    Honestly, this is one of the most friendly, and helpful group of people on any photo site that I have encountered.

    Hope to meet u in Paris, or NYC.

    Many thanks for your helpful suggestions.

    Martin

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