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Forum: Pentax DSLR Discussion
04-01-2007, 09:23 PM
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The problem with V/HPN (or FF/BB issues or any of the banding threads) may actually be the internet.
Front focus and back focus are terms used by large format photographers for an entirely different matter.
Some careful searching turns up a lowly Canon user with a customer service complaint that involves some perceived mis-focusing issue, bad repair response, a slew of snailmail exchanges, an escalation of the situation, some back slapping and glad handing, that damn focusing chart and the users willingness to spill all the dirty laundry into the public domain of the internet.
That was Pandora's box for the FF/BF issue and every half-baked wannabe engineer started experimenting (I use this term very loosely) with auto-focus on their own cameras and the rest is tortured history.
The truth with FF/BF is that one must operate the camera significantly outside normal conditions for auto-focus and metering, employ a chart that violates many of the 'auto-focus fails here' rules listed in the manual, and have a pretty poor understanding of optics and light to 'see' that failure.
I won't comment further, regardless of who comes screaming--that's the way those that 'see' the issue deal with those that don't or who don't have problems and state same. They shout them down with disparaging labels like fanboy etc. I can ignore them.
Banding in the larger sense, as in wide bands of improperly converted data has been addressed and probably was a manufacturing shortfall---it's solved, so what??? Hey, snot happens!
V/HPN issues are the latest matter. I'm not about to spend good money chasing the IEEE papers that detail the condition. And that's for two reasons: I don't see the problem and I've underexposed/overdeveloped several hundred digital images in the last few days to prove I don't see it. I've had three other dSLR users-P,C & N shoot an extra 300+ images for cross comparison too-they don't have it either!!! A full gamut of subjects, pushes from 1 to 5 stops.
And frankly, I know Push/pull techniques of photography: and I have approximately 50,000 film images (B&W, slide and color PRINT-about 7500 published) to prove it! Home developed for the majority, carefully noted in several dozen spiral bounds.
And the second reason: The IEEE papers have a synopsis that one reads to determine paper content. We, as users don't have access to the specs for the chips-namely voltage and current values. All the 'public' numbers in these papers speak in relative terms-specifically a -60db difference between the optical signal and the chip bias current. Without knowledge of the actual operating voltage/current it would be a guess as to weather the V/HPN effect occurs in the range of voltages/currents of normal image signals generated by normal operation of the camera. Or if extra-normal pushed(underexposed) capture works in the range or the problem area.
Heck, we don't even know for certain if the problem chips are actually making it into the camera--they could have been superseded before production even started!!!!
From empirical testing, I would tentatively say there is no correlation between the V/HPN of the engineers and what we as photographers see. Or more succinctly: some people need to learn proper exposure and RAW conversion along with more mainstream editing techniques; they are mucking-up their own photos from ham-handed editing.
I could go on and on and on, for instance the yellow light metering problem. That one is almost too easy: yellow light isn't quality light-it's all one small band of emissions/frequencies, at low intensity; why would anyone expect the meter to function properly in such a region?
This will be my last post in 'technical' areas like those discussed above. I'm probably qualified to understand and capable of doing such technical things but I'm not fully up to speed with the pentax cameras--I don't work for Pentax. And I don't want to be unless they have some spare cash around to pay for my services.
Read your manuals, use your camera(s). If you find something that doesn't work properly, and you have tried to make it work properly ( to your best understanding) but it doesn't, call Pentax and discuss it with a real technician. I for one won't be around to 'consult' through any forum on such matters[--I'll still help with photography.]
Do threads like this help and/or should we have a spokesperson voice our concerns: NO and NO! The reasons are stated and obvious!
We're photographers, we take photographs; we should continue to do that until something actually happens to SIGNIFICANTLY impede that task. |
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Forum: Pentax DSLR Discussion
04-01-2007, 08:30 PM
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Both Dylan and Hendrix; but the reference is to something much more recent...
Trolling really; for like minded people.
The signature doesn't allow a proper phrasing which involves 4 of something then a fifth and a very leading cliff-hanger video image and the entire song set to an excellent ethereal sound track.
Read the signature like four voices:
There must be some kind of way out of here
...Said the joker to the thief
. . . There's too much confusion
. . . I can't get no relief...
And it helps if you hum the missing music when you reach the end of the text.
And that is just to damn big a hint!:cool:
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Forum: Pentax DSLR Discussion
03-31-2007, 06:26 AM
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What the heck is film?
In the good old USA 'pressing' was something you did to uncurl prints and make dress slacks (pants) have a crease and look nice.
'Pushing' and 'Pulling' film are the techniques of underexposing/overdeveloping and overexposing/under developing to gain a pseudo-speed advantage and control excessive contrast/excessive saturation developed by photographers experimenting and expandingsimilar techniques from the work of White, Adams et al known as the Zone System.
Just as a point of reference the dSLR CCD (the chip itself) has a native or preferred ISO (speed) rating--a single number. Generally it's thought to be at or within one stop of the bottom end of the cameras range of ISOs. On the K10 that would be ISO/ASA 100.
The top of the range, at 1600 is therefore a 4 stop push! And correspondingly 3200, 6400 and 12800 are then 5, 6 and 7 stop 'pushes'. The rapid increase in digital noise when moving from ISO 100 to ISO 1600 seems to bear-out this assertion rather well.
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Forum: Pentax DSLR Discussion
03-30-2007, 05:48 PM
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Larry,
I'm actually trying to understand 'just this problem'--the one right here in this thread. I see the lines on two different calibrated monitors. What I need to know is what is the foreground object, what exactly, did you do to the image file from the moment it was written to the card until it appears here in the forum.
The posturing and hand waving and howling don't provide those answers. Nor do any of the links and references.
This image has been reduced to fit the forum format-what else?
These are the same questions Pentax will ask.
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Forum: Pentax DSLR Discussion
03-30-2007, 12:16 PM
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We can avoid the shouting and abrasive behavior of 'over there' if we stick to the facts and pertinent related issues.
Pattern Noise, vertical or horizontal is a well know and reasonably well understood physical phenomena (Google 'Vertical Pattern Noise' and scan for proceedings of IEEE--i.e. technical papers). Most of these authors and all of the reviewers of such proceedings are experts in the field.
There are two solutions: hardware remodeling (preferred), and software re-write(probably necessary for legacy equipment--i.e. that camera in the consumers hand). The software solution is problematic: is there sufficient memory to hold the required code? Is the camera CPU sufficiently fast to execute the code without a noticeable increase in lag time between shot and writing to card/reviewing on LCD?
Currently the assumption is that enough space exists and the CPU is sufficiently fast. (Read the GordonBGood thread at DPR; he appears to have the requisite knowledge of the subject to effect a software solution, independent of Pentax).
That pretty much covers the facts, so what are the issues?
Two issues remain that matter: "Should V/HPN be addressed by the camera manufacturer?" and "does every user require the fix?"
The answer to the first question will be based strictly on market conditions: Do enough users operate their camera in a manner that will cause them to experience V/HPN? In this regard, it's counter productive for either side to 'shout down' the other as such shouting cheapens the argument with useless and meaningless human noise.
Common sense says that if you need a solution to V/HPN then a direct approach to the manufacturer will be more productive than any forum rehash of the issue. Following onward: a loud, persistent, demanding mob outside the front door will gain more than a single dilettante whispering in some minor functionaries ear over cheese and crackers.
The answer to the second question is simple logistics and a method exists for rapid deployment; common sense says that if a fix is developed then it should be made available to everyone.
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Forum: Pentax DSLR Discussion
03-30-2007, 07:18 AM
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Forum: Pentax DSLR Discussion
03-30-2007, 07:09 AM
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How much 'push' in photoshop (or other editor); how much personal experience with push/pull shooting/processing in general (including film)?
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