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632 reputation
413
bio website tempel.org
location Munich, Germany
age 50
visits member for 3 years, 8 months
seen Dec 17 at 8:21
Been programming for about 30 years. Started with BASIC, Pascal and assembler on 8 bit computers, later C, Modula-2, C++. Now mainly a Mac programmer, favoring REALbasic for its ease of use, where possible. Also doing iPhone development.

Mar
16
comment What does fast/normal/slow mean for Pentax auto-iso?
A related question would be: How does this setting compare to the Program Line setting? I suppose that while we do have the "Program Line" setting to control how the P mode selects whether to keep the aperture open or closed as much as possible or keep the exposure time as short as possible, the ISO curve does a similar thing for the other modes (Av, Tv).
Mar
16
comment What does fast/normal/slow mean for Pentax auto-iso?
From my own testing, I get the impression that the rule is simply: "Slow" and "Fast" curves raises the ISO setting one LV step later or earlier compared to the "Normal" curve. Could be wrong, though, as I only tested with P mode so far. Feel free to prove my theory wrong :)
Mar
16
comment What does fast/normal/slow mean for Pentax auto-iso?
For your testing, keep 2 things in mind: 1. Set the Program line to Normal if you're P mode. 2. I do not believe the aperture affects the behavior directly. Instead, it decides on whether to raise ISO or instead lower exposure time or open the aperture when it has still room to work with the ISO value. So you need to adjust the lighting every time you switch a setting, then see at which point it rather changes ISO over the other parameters.
Mar
6
comment What's the difference between P mode vs. Av or Tv?
Yep, saw your question too late. But happy to see it still helps.
Mar
6
revised What's the difference between P mode vs. Av or Tv?
added 120 characters in body
Mar
6
answered What's the difference between P mode vs. Av or Tv?
Jan
9
answered What can I do about Pentax superzoom 18-270 autofocus problems?
Dec
20
accepted How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
Dec
20
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
@jrista, thanks for all your info. Yes, I'm going into areas that are not practical for my current needs. But I also was looking for a definitive answer on my topic, and the first replies were textbook answers that were not even complete. I'll now accept your answer and officially finish this question by that. I could post a separate question about CRI, but I am not even sure what to ask, exactly. Since you have a better understanding, maybe you like to ask it yourself and answer it then? Sorry, I'm just feeling very unsure about this all right now.
Dec
20
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
@RHall, that issue with matching the pigments correctly sounds reasonable. Isn't that also the "illuminant metameric failure" effect I mentioned earlier? Also, how do you suggest I make a color checker from existing paintings? I cannot pinpoint the colors in a painting exactly for measusing - it's simply not practical. And I cannot paint a new picture because the paint color are not available any more.
Dec
19
awarded  Yearling
Dec
19
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
@AidenG, see my update about CRI. That's what I had in mind: That there are cases (though, unlikely when I use "good" light sources) where a simply white balance does NOT fix the colors. Also, the RAW converter would not know that it would have to correct certain spectral areas individually to correct such a bad light source. That's what I meant with not "trusting" it. I meant that I may need more control over what the RAW presets can do. Hence my suggestion of a color chart that would probably deal with such low-CRI errors. But it's theoretical, not really practical issue, I admit.
Dec
19
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
@RHall, okay, but what about CRI, see my updated question. I am still not convinced that a simple white balance can fix all kinds of color inaccuracies, and what I just learned about CRI supports that. Of course, as you pointed out, a good light source would not cause this problem. I just like to get some confirmation on my findings.
Dec
19
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
BTW, I appreciate your effort writing this long reply. However, it's too general for me. I have added a new "CRI" section to my question. If you could comment on that, it would great. I realize that I keep dragging this along but as an engineer, I like precise solutions, and so far it's been all rather "oh, just calibrate your monitor, trust the RAW converter, and nothing can go wrong" like answers. I like to understand it, not just follow advice blindly.
Dec
19
revised How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
adds section about CRI
Dec
19
revised How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
clarified that I have a calibrated monitor
Dec
19
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
I have calibrated my monitor (which is a cheap one that doesn't even cover the entire brightness range!), but I still claim that this is useless in repro work because I do not even remember the colors when I post-process the images on it, so I cannot "adjust" them when I cannot tell what the colors were in the original. And at the place where I'd do the repro work I only have a MacBook Pro with me, and its screen is even worse that the Dell monitor I use at home, so even comparing a painting right there is probably not very accurate.
Dec
19
comment How do I ensure good color reproduction when photographing paintings with a mid-level DSLR?
I can rent an i1 color calibration device from Calumet (where I would also get the lights). I've used the ColorMunki before, but its software only works with monitor screens and printers, both of which it can control. How would I use that on a painting that already has its own colors? I guess I'd need different software than that what comes with the device. I guess I would then give the software my image from the camera and let it see certain colors on the painting so that it could match them. Not very practical with already finished paintings, though.
Nov
13
asked When to choose in-camera HDR mode versus Exposure Bracketing
Nov
13
comment What is the cheapest method to perform HDR?
@tech, in my camera, a Pentax, the HDR option is only available if I choose to take pictures in JPEG mode but not if I'm in RAW mode. Maybe that's the same on your camera.