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Old Sep 3, 2009, 2:06 PM   #1
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Default Help me think about what cameras do.

Hi. I'm shopping for a camera. My research has left me feeling like an underexposed pixel with six noisy neighbors. I need additional light, clarity, and sharpness in order to compare cameras.

I am a painter. My primary use of a camera is to record visual phenomena. (I am not interested in pictures, and I am not interested in sports or family vacation shots.) I am interested in color and light. (Secondarily, I am interested in framing issues/composition, POV, horizontal and vertical panoramas, very very large format or the equivalent, and time-lapse.)

I've been looking at digital photographs for the last month or so. Here is what I've noticed (in general -- not in all photographs). Please help me put this into proper perspective vis-a-vis digital photography in general, and camera selection specifically.
  • Hues are oversaturated throughout the color range, but especially in blue, green, and red. I had a printer once that hyped "vivid" color. "Vivid", of course, comes from the root word for "life", but I find these colors anything but lifelike -- they are the visual equivalent of plastic. What should I look for in order to get the most life-like, natural, realistic saturations?
  • In flesh tones there is often a pronounced banding of hues. I am a bit of pixel-peeper. It appears this is less an issue of the contour between hue-areas (the boundary is often soft), as resulting from some kind of assumption about hue being superimposed on the object being represented. (There was a child's portrait posted on these forums which showed this clearly as one scanned the breadth of the forehead.)
  • Shadow colors are very poorly represented. (I paint shadows every day, and am very interested in the color of shadows.) They are muddy, noisy, and often (particularly in fleshtones) too highly saturated in orange.
  • Highlights (luster lights) show no color (hue). This is true for all photography that I know, and is one of the easiest ways to tell if a painting has been copied from a photograph or observed from life. Is it possible to record the color of highlights?
  • Generally, scenes lack whatever it is that makes us perceive atmosphere. This is a delicate thing. I think it has much to do with properly rendering saturation and tone (degree of lightness and darkness).

Responses and answers to those questions will help me look for a camera. I am shopping in the $300-$400 (US) range. I worry that I might end up with what for me is an expensive investment but which won't do what I want it to do. I intend to use it to record light and color. My subjects will range from indoor portraits (and still-lifes) to landscapes and dusk and dawn scenes. I don't need hyper-detail (I limit my interest to what we can see with the naked eye). Some zoom (6x?) is of course useful, but I don't need a lot of zoom. I am willing to learn how the camera works (). I will mostly be viewing the images on computer monitors*

*Ancillary question: what is the best budget method of getting the same color across monitors? I use Apple's OS X's built-in display calibration. It is a huge improvement on doing nothing, but doesn't create matched color or provide an easy way to tweak the settings.

Many thanks for taking the time to read and think about this. Feel free to correct any faulty assumptions I've made, and to change the vocabulary to one more appropriate to the craft of photography.
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Old Sep 3, 2009, 3:47 PM   #2
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In general, saturation is something that can be tuned to your taste, though becasue of the Bayer filter used on most image sensors, reds and blues tend to be artifically enhanced sometimesm especially reds.

From what you say you want, I think you might be best served by taking a look at the Sigma SD14 dSLR, or even the Sigma DP2 P&S. They use a Foveon image sensor that can detect the full spectrum of light at each pixel. I think you'd be more satisfied with one of these than with anything else.
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
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Old Sep 3, 2009, 3:51 PM   #3
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Except that they are notorious for having poor color accuracy that's hard to correct in Post Processing unless you get the White Balance "just right" to begin with, due mostly to that sensor design's poor ability to better separate Red, Green and Blue at a given pixel location. If you want more accurate colors without a lot of work, I'd avoid models using Foveon Sensors.
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Old Sep 3, 2009, 4:18 PM   #4
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(Edited -- initial response changed after looking at the SD14 sample pics.)

Wow! As in, "H... C... Wow!". I just looked at the SD14 sample shots on the web site. Am I mistaken, or are those not some of the best portrait shots around. In any case, the color (afaict) is ___exactly___ what I'm looking for. I still haven't found a price, but moving forward:

How hard is it to get the White Balance "just right"? Why is it hard to correct in Post Processing?
Is there any alternative to the Foveon Sensors with the same possible color rendition but which is more "fool proof" or correctable? (IOW: JimC, given your warning, can you suggest something else?)

Thanks for the advice and suggestions. Exciting.

Last edited by Kriekira; Sep 3, 2009 at 4:34 PM.
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Old Sep 4, 2009, 2:41 AM   #5
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A few comments/suggestions:

1. Look into getting a camera that can shoot in RAW mode. It gives you hugely more flexibility in colour processing.

2. Learn about "Expose To The Right" as a way of optimising your exposures for digital processing. Combine this with RAW shooting and you will be amazed how much you can do in the shadows.

3. Get a monitor calibration device. (Absolutely essential.)

4. Get a good colour monitor. (Advice that I will soon be trying to take myself, but it is horrendously expensive to get a good one.) Unfortunately the new Apple high-contrast/deep-black monitors look great but are hopelessly inaccurate.

A UK site to browse to get the idea of the monitors you should be looking at:

5. The Foveon sensor is a wonderful bit of technology, but there is a lot of "fanboyism" surrounding it. Fans refuse to admit that it's not the be-all-and-end-all. When it comes to colour - looking good is not the same as accurate. Both Bayer sensors and Foveon sensors have their own unique issues when it comes to colour accuracy.This is why the cameras and new monitors are so over-saturated and high-contrast. People love over-saturated images with very high contrast, they look great to most folks. But they are not accurate - so annoying for you.

6. Brace yourself. Colour accuracy is expensive. Even the very basic stuff is going to cost you way more than you wanted. (I just hope you aren't going to need colour-accurate prints too.)

Last edited by peripatetic; Sep 4, 2009 at 2:48 AM.
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Old Sep 4, 2009, 8:52 AM   #6
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Hey Krieka.

The issues surrounding color accuracy can be quite complex. In the case of the Foveon sensors used in the Sigma models mentioned, each pixel location is sensitive to red, green and blue, via layers designed to be sensitive to each of those colors.

The primary benefit of that approach is that you eliminate the color interpolation process you need to perform for Bayer type sensors (where each pixel is only sensitive to one color and you need to look at the values of adjacent pixels in order to "guess" the correct RGB Values to associate with each pixel location during the demosaic process).

So, in theory, that should make the Foveon approach much better. In practice, they've always had some issues with color discrimination between the 3 layers, requiring very powerful software with complex algorithms to convert from raw to a usable image. Now, Sigma's software has gotten *much* better over the years, and you don't see as many complaints in some of the popular forums as you used to about color problems. For example, hue shifts in different lighting (or even in the same image if you had a wider range of bright to dark in it), color shifts as ISO speeds change and more. But, I still see some threads complaining about color problems (for example, red channel clipping, hue issues with both red and blue depending on lighting conditions and more). In perfect lighting, they can have very high color accuracy at lower ISO speeds. In more complex conditions, it can become increasingly difficult to achieve good color accuracy (although newer models have continued to improve, and Sigma's software has continued to improve).

Even the latest offering (DP2) appears to have a lot of complaints about color casts; sometimes only in image corners (my guess is that it might be due to a bit of vignetting from the lens, where hue is shifting because the corners are slighter darker). But, newer software from Sigma will probably get a handle on it, as they continue to refine the latest Sigma Photo Pro offering for it. I can imagine the algorithms for determining what values to assign to red, green and blue are very complex (despite the lack of need for color interpolation from multiple pixel locations like you need to do with Bayer pattern sensors). Dave Coffin (the author of dcraw.c) even excluded the foveon sensor processing from being licensed as open source (even though all other portions of the code are open source), due to the complexity of the algorithms to try and get accurate colors at each pixel location in different lighting conditions, mostly because of poor color separation between sensor layers from comments I've seen from Dave (in other words, it's so hard to do, he withheld that portion of code in order to make a profit on it for commercial products wanting to use it).

Sigma owners tend to be quite passionate about the color from their cameras. You'll have to make up your own mind, as they tend to be hotly debated cameras.

Unfortunately, given your budget, the Sigma cameras mentioned by TCav are going to be out of your price range, even if you decide they're a good match for what you want to shoot, in the lighting you want to shoot in.
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Old Sep 4, 2009, 9:13 PM   #7
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The eye can see a contrast of 1,000,000:1 no camera or computer can show this in fact using a mounter you will have 255 leaves of red, blue, and green, this is in 24 and 32 bit mode. Your mounter/OS/viewer program will be lower that your camera. What you are looking for can not be done with film ether, you get ether shadows or highlights not both.
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