The Pentax K-x has a myriad of functions, bells and whistles, and most of them can be accessed in several different ways. Many of these functions cannot be combined with each other, while others work only with certain lenses, or on certain file types.
The manual provided with this camera was written for dummies. It painstakingly steps the user through all the functions and menus, button by button, but fails to give enough details about what each function really does, and it also fails to organize the whole picture. So I decided to write this alternative manual. It is not intended to replace the Pentax-provided manual, but to give the photographer a quicker, clearer basic guide to use this camera, and some advice. Also, I can write some things Pentax cannot very well write into their manual, such as how to use Ricoh lenses, or how to live with the camera's quirks and shortcomings.
My manual includes many of my own preferences and opinions, which you may or may not find useful. On the other hand, my manual does NOT list all the bells, whistles, options, functions, settings and configurations of this camera. Use the Pentax manual for that.
So I repeat that my manual is not complete. By all means, do read the Pentax manual completely, several times. If you find any discrepancy between what I have written, and the Pentax manual, then the Pentax manual prevails, except in the few cases where I explicitly mention that the Pentax manual is wrong!
The first K-x'es were delivered with firmware version 1.00. They have a nasty problem, apparently expecting all batteries to have the same voltage, or something in the line. Pentax didn't explain what happened. Anyway, the cameras would either totally reject all or most rechargeable batteries, or would accept them, but run only for a very short time before telling you they are empty. Pentax fixed the bug, or made a workaround, I don't know. Anyway, the cameras work perfectly with rechargeable batteries after you download the firmware version 1.01 from the Pentax website, and load it into the camera.
Please refer to the Pentax manual for the names and locations of all the controls. I will only give some practical advice here.
Power switch: I suggest to configure the power light to OFF. After doing that, you can use the K-x power switch exactly like you would use the shutter lock switch on an old mechanical camera! You can leave it ON almost all the time, and set it to OFF only when you want to keep the camera from shooting black pictures inside the bag, when you bump it around. You have to switch off the LCD for that to work well. When you do so, the camera will come to life as soon as you touch the shutter. You will see the indicators in the viewfinder, consuming little power. You can shoot a picture, and if you have Instant Review on, you can review it, and after a few seconds the LCD will switch off again. The camera will then consume very little power, for one minute (by default setting), and then will switch itself off. For the next photo, you just touch the shutter, and there you go. It works like a charm, and beats shuffling the rather stiff power switch on and off all the time.
An additional bonus is this: When you use lenses that don't tell the camera their IDs, and you have shake reduction enabled, the camera will ask you to enter the focal length every time you switch it on. That gets old pretty soon. If instead you leave the power switch on, the camera will remember the lens focal length even when switching itself off!
If you change to another lens, of the sort that doesn't have an electronic ID, you must switch the K-x off and on, to prompt it to ask you for the new focal length.
Lenses: Pentax advertises that this camera can use ALL Pentax K-mount lenses ever made. This is true, sort of, but different lens types have different restrictions. K-mount lenses come in many different flavors. The most modern ones have autofocus capability, have no aperture ring, and have an electronic ID that tells the camera name and personality of the lens. Everything works with these.
Older lenses lack one or more of these features. Some have no autofocus capability. You can manually focus them. Others have no electronic ID. These force you to manualle tell the camera their focal length, when you mount them, in order to use shake reduction. Also, by telling the camera the focal length, you will get it correctly registered in the EXIF data of each image file. But with these ID-less lenses, the K-x cannot correct distortion or chromatic aberration. It can do that with modern lenses.
Many lenses do have an aperture ring. As long as it has an "A" position, and you set it to this position, it works just the same as a lens without an aperture ring. But if your lens does not have an "A" position, or if you don't use that setting, the functionality of the combination with the K-x is severely degraded.
Even screw mount lenses canbe used, through the original Pentax adapter (alternative adapters have been reported to have issues). I don't have any such lenses or the adapter, so I can't give you hands-on reports, but certainly operation with such a lens is very basic, since there isn't any way for the camera to stop down the lens.
Most K-mount lenses produced by third party manufacturers over roughly 20 years have in fact the so-called Pentax-A/Ricoh mount. These lenses have an additional contact pin, which is used only by Ricoh cameras. This pin can catch in the focus drive hole of Pentax autofocus cameras, such as the K-x. Before trying to mount ANY Pentax-A/Ricoh mount lens on the K-x, make sure the lense's Ricoh pin does not have any of its cylindrical portion protruding above teh level of the mounting surface. You can check this by sliding a hard, sharp-edged object, such as a steel ruler, flat over the lense's mounting surface and againt the Ricoh pin. If the ruler easily pushes the pin in from the side, and then slides over it, the pin is OK. If instead the ruler collides with the pin and can't push it in by running sideways against it, then this lens will likely catch on the K-x, and be very hard to remove! To use such a lens on the K-x, first remove its Ricoh pin, by removing the entire mount from the lens, removing the Ricoh pin and the resistor connected to it, and then re-installing the mount on the lens. You might want to close the hole with some hard epoxy glue (liquid steel), to keep the K-x focus drive coupler to catch in that hole, but it's easy enough to pull back the coupler during lens mounting and dismounting by either setting the K-x to manual focus, or by pressing the lens release button.
If you already made the mistake and tried to mount a Pentax-A/Ricoh lens, and now can't remove it, don't despair. The K-x lens mount is made of steel, and the electrical contacts of lenses are pretty thin and not very strong. Set the K-x to manual focus to retract the focus coupler, and gently but firmly force the lens off the camera. The pin on the lens might be bent, broken or otherwise damaged, but usually will not sustain any damage, and it's unlikely that the K-x will suffer any significant damage from this. But "unlikely" is not the same as "impossible", so do not mount a Pentax-A/Ricoh mount lens in teh first place, until you have either removed the Ricoh pin, or made sure it is short and rounded off well enough so it won't catch.
Flashes: The K-x has a small built-in flash, which works well but is of course very limited in power and also in usability, given that it is mounted right on the camera, which is the worst possible location for a flash. The camera can instead use external flashes. Automatic operation is supported only for modern P-TTL compatible flashes. Flashes with older types of automatic operation, such as true realtime TTL as with the Pentax LX and the AF-280T, will not give any sort of automation between the flash and the K-x. But they can be used in manual mode, or in any automatic mode the flash may have, as long as it doesn't depend on camera functions.
The AF-280T and similar flashes, mounted on the K-x, will display the flash ready signal in the viewfinder, and will trigger, but that's about all. They will not indicate in the finder whether the exposure was successful, nor will there be any control of the flash power by the camera.
The camera supports wireless remote control of compatible flashes. Also, of course, any flash can be remoted by using an extending cable from the hot shoe to the flash.
It's best to analyze step by step what happens when you take a photo:
1) Selection of lens focal length: You do this by mounting the proper lens on the camera, and if the lens is a zoom, by setting it to the focal distance you want. The K-x does not have any sort of power zooming, so this is an entirely manual, simple and straightforward operation, and doesn't need further discussion in this manual.
1b) You choose how to compose the picture. This the same as with any camera, so I won't dwell on this subject.
2) The focus is set, defining exactly at which distance the sharpness will be optimal.
3) The aperture will define how much light will get through the lens, and also has several side effects.
4) The shutter time will define for how long that image can act on the sensor.
5) Exposure starts. During it, the shake reduction might be active, moving the sensor to keep the image steady.
At this point, the amount of charge on each pixel are perfectly defined. This is where optics end, and electronics start.
5) The CMOS image sensor will read out each pixel, applying a gain factor (ISO setting, sensitivity), and digitize the individual pixel charge values, feeding them into the camera's computer.
And this is where electronics end, and software starts!
6) I understand that the software will first eliminate any pixel values that are incorrect due to sensor defects, and replace them by interpolated values. I'm not positively sure this is done at this stage.
7) If the K-x is set to save the images in raw mode, it will now simply write a big file to the SD card, that contains each pixel value in 12 bits resolution, along with full information on camera settings and suggested values for processing that data. If instead the K-x is set to save in JPG mode, a lot of internal processing is done before saving the file.
8) If instant preview is selected, the camera will show the image on the LCD for a short time.
Let's now see how to properly do each of these basic steps!
If your lens supports autofocus, you can switch between manual and automatic focus with the focus mode lever. If your lens does not support autofocus, of course you are locked into manual.
In any case, auto or manual, the K-x makes use of the autofocus sensor. This sensor has 11 fields. You can select whether you want to use the center field only, or manually choose any of the 11 fields, or let the camera automatically choose one among the 11 fields, or let the camera automatically choose between just the 5 fields closest to the center. This selection can be done either from the control panel, or from the menu, or after pressing the OK button. This seems to work with all types of lenses. But I found the automatic spot selection modes mostly useless, because one has no way to know which spot the camera is using for any given spot! And except in special situations, it's pretty fumbly to manually select the most convenient spot for every picture. So, to avoid suprises, I find myself setting the autofocus area selection to just the center spot, almost always. This keeps things reasonably under control.
But not completely! You STILL don't know EXACTLY where the autofocus sensor is looking. A few days ago I got the rare opportunity to shoot a picture of a rather rare animal. I got the face and eyes totally blurry - but the animal's tail is tack sharp!
Advice: Don't blindly trust the autofocus sensor. Use it as a help, as a tool, but don't let it decide the focus point in each and every photo. Be a photographer, not an appliance operator.
The K-x has several autofocus modes. You select these from the menu only. You can choose single, continuous or automatic. In single mode, the camera focuses just once when you touch the shutter button, and freezes that setting until you press the button fully to take the photo. This is by far the most useful mode, and I suggest to use this by default. In continuous mode, the camera will refocus all the time while you touch the button, trying to follow moving objects. This can be useful for moving objects, indeed, but typically tends to pull the subject out of focus just before the shutter fires. Use it only when necessary. And the automatic mode simply makes the camera switch between continuous and single, on its own, and this can be VERY confusing. It's the default setting, and I don't recommend using it!
Autofocusing: After you ave set up the above, autofocusing is simple: Aim the camera so that something is at the selected focus spot, that is at the exact distance you want to focus on. Touch the shutter button. The camera will focus there, indicating it's ready by lighting the focus indicator in the finder.Then fully press the button to take the photo. Note that the object you focus on CAN be your main subject, but it can just as well be anything else that just happens to be in the same image plane, and closer to the location of the chosen focus spot!
Manual focus: With a manual focus lens, or with an autofocus lens but setting the focus mode lever to manual, you can still use the full functionality of the focus sensor, but you have to rotate the lens focus ring by hand. Even with autofocus lenses, this will often allow you to make a better photo. When manually focusing, use the in-finder focus indicator as one tool that tells you when the lens is precisely focused on some unknown spot of an imprecisely known focus sensing area! It's helpful, but needs real careful use, unless you like wildlife photos with blurry eyes and sharp tails. It's better to train your eye to discern focus on the matte screen. The plus point of this is that you see focus all over the frame, at any object you want. And the minus point is that the matte screen of the K-x really isn't good enough to allow precise focusing. It will get you close, but it will hardly get you to the exact optimal focus. The autofocus sensor is much more precise, but unfortunately with that uncertainty as to where exactly it is looking! These camera would be really improved if it had an additional focusing tool, such as a split image area on the screen. This split-image might be located off-center, to avoid interfering with the camera's sensors. Two vertical split image tools on the sides of the screen would be really great! But as it is, you have to do with a combination of the matte screen and the autofocus sensor, and even resort to the old method of measuring the distance with a string and setting the lens to that distance, according to the focus scale printed on it!
Don't forget good old photography basics, such as hyperfocal focusing. Older lenses have the proper scales for that. Even with lenses that don't have such scales, and while using autofocus, you can do something close to hyperfocal focusing by letting the autofocus lock in on some object at the proper distance, a weighted average of the distances to all important subjects in the focus, rather than focusing right on your main subject.
Beeper: By default, the camera will beep every time the focus sensor detects focus. This is VERY annoying, and also it is confusing, because the beeper beeps for a fixed time, regardless of how long the subject remains in focus! I found it basically useless. It would be useful if it would beep for as long as the focus sensor detects correct focus. Fortunately it can be disabled from the menu. For most photographers, I would suggest to disable it.
Avoid wrong focusing! The Pentax manual contains a gross mistake. When placing your main subject out of the image center, the manual tells you to pan the camera to your subject, have it focus there, then pan back to compose the image, and shoot. This is wrong! It will result in the focus plane passing BEHIND your subject, not THROUGH your subject! Lenses do not focus at a certain distance, all over the field. This would imply a spherical image "plane", but the image plane of usual lenses is NOT spherical! Instead it's pretty flat, for good lenses. If it weren't, you couldn't shoot a sharp photo of a painting, for example. So, for off-center subjects, the lens needs to be focused on the plane that passes through the subject, and is perpendicular to the axis of the lens. You can do that by composing your image and then manually focusing to get your subject sharp on the matte screen. You can also select the proper focus sensor spot to have the camera autofocus on your subject, but this is uncertain because you don't know exactly where the focusing areas are located. Or you could set the camera to 11 area autofocus, and pray that it will choose to focus on your subject and not on something totally different! But panning to the subject, focusing there, and then panning back to take the photo, will result in a slightly wrong focus setting, every time, guaranteed! If you are shooting at a small aperture, and only want to print a postcard-size photo, the slight focus error might not be noticeable. Anyway, for that kind of work you don't need a K-x. But for quality work, the focus error is very noticeable!
Catch-in focus: You can select catch-in focus from the menu. When manual focusing in this mode whith the shutter button fully pressed, the camera will shoot when the autofocus sensor detects focus. This is intended for situations like when you want to get a picture of the winning horse precisely passing through the finish line, but I have also found it useful for shooting macros of flowers swaying in the wind. The flash can eliminate motion blur in this situation.
Special case: Live view: In live view mode, the K-x locks up the mirror and sends a sample image from the CMOS sensor almost in real time to the LCD. With the mirror locked up, it cannot use the autofocus sensor. So it uses the image from the CMOS sensor instead for focusing. Since this sensor has high resolution and color capability, it allows to play tricks such as recognizing faces in the photo, and focusing on them. You can set this up from the menu, and there you can also choose to still use the autofocus sensor for autofocusing, even in live view mode. That will interrupt live view for autofocusing, of course. I don't have much use for this, so I haven't experimented much with it.
Up to this point, everything has been pretty simple. But now it starts getting complex.
The basic exposure controls in a digital camera are three: Aperture, shutter time, and sensor sensitivity. These can be controlled in a confusing number of ways in the K-x. In addition, this camera adds refinements such as highlight and shadow correction.
First, the basics: Aperture is expressed in f stops, as a fraction of the lense's focal length. If you are using a focal length of 30 millimeters, and set the lens to an aperture of f/8, then the diameter of the light beem at the optical center of the lens will be 30/8=3.75 mm. Lens aperture affects the picture in several ways:
1) It controls how much light passes through the lens. If the diameter of the little hole doubles, the hole area cuadruples, and so the amount of light quadruples. This would be a two-stop increase. The ratio between single f stops is the square root of 2. The K-x can control apertures in half or thirds of f stops.
2) Depth of field varies markedly with aperture. The smaller the hole gets (larger numbers), the more even is sharpness for objects that are at different distances.
3) The basic image quality varies with aperture. A very small hole (large number) causes loss of image quality due to diffraction, which is a physical fact of life and does not depend on lens quality. For practical purposes, the K-x starts loosing quality when the lens is stopped down to f/11. At f/16 the quality loss is already very noticeable, and at f/22 it's outright horrible. This is valid when you want to make full use of the sensor's resolution! When you don't need that, such as when printing postcard-size photos or publishing your photos on the web at 640 pixels width, even f/22 is still acceptable. On the other end of the scale, there are no diffraction problems, but lenses loose sharpness and contrast due to their design and manufacturing imperfections. This effect is highly dependent on the particular lens. The Pentax 18-55mm kit lens remains surprisingly good even all the way open, and so do some other high quality lenses, but most lenses do fall off a lot in quality when used fully open, and only come to a good image quality when stopped down about two stops from fully open.
As a result of all the above, lens aperture should be set to f/8 or thereabouts when you don't have constraints regarding light level and depth of field, and you can deviate from this value, all over the range, as required by the light or by the depth of field you need. But you should understand the implications listed above.
The aperture of the lens is set by the camera by means of a little actuator that has to work through several linkages in the lens. This is NOT a very high precision system, and when the lens is not of very high quality, or has the linkages slightly worn or bent, the actual aperture might differ significantly from the one the camera is trying to set. This results in misexposure and in getting all the effects of a different aperture than you thought you had. Be aware of this problem.
Exposure time is expressed as a fraction of one second, or as full seconds for long times. The K-x can do from an ultrafast 1/6000th of a second, all the way to 30 seconds, and you can set it to "bulb" mode for even longer times. But at long times the CMOS sensor gets very noisy, so this is not very useful. The time is pretty precise over most of the range, but at the shortest shutter times it can be less precise.
The implications of shutter time are rather simple: The longer it is, the more light gets to the sensor; and if anything moves (the camera or anything it is looking at), the more blur you get. Also, at long times, the image becomes noisier (grainier) because of the sensor pixels accumulating random charges from thermal effects.
The aparent sensitivity of the sensor is apparently only controlled by selecting the gain of the charge amplifiers on the CMOS sensor. The higher the sensitivity, the less light is needed on the sensor to make a photo, but the more noise is added by the sensor. This is simply because a given amount of random thermal charges on the pixels gets more amplified if the sensitivity is cranked up. The sensor of the K-x has particularly low noise, allowing to use a pretty high sensitivity, but the basic principles still hold true: More sensitivity equals more noise. The K-x can be set to sensitivities from ISO 100 to ISO 12800.
The exposure metering system: The K-x has a composite light sensor that can be set to measure the light either at the center spot of the image, or over most of the image but center weighted, or separately in several areas, which the camera will use to recognize the type of scene and make some clever and other not so clever decisions as to which are it should give more weight than to others. This choice is available from both the control panel and the menu. With manual aperture lenses, multizone sensing is not available (don't ask me why!).
The light level measured by the sensor is used by the camera to indicate exposure settings in the finder, also on the LCD if it is switched on, and to control some or all exposure adjustments. Let's now sort out the mess of the many different modes. You select them by rotating the mode dial.
In manual mode, you manually set both the aperture and the shutter time, using the e-dial, and using the Av button to switch between aperture and time. You also manually set the sensitivity, after pressing the ISO button. The camera assists your settings by telling you in the viewfinder how much you will be under- or overexposing, according to what its exposure meter is telling. This mode allows you to do everything you want with the exposure, without any interference by automatic bells and whistles, but is also the slowest to use.
In aperture priority mode, you manually set the aperture with the e-dial, and the camera sets the shutter time according to the light level measured. By pressing the Av button you can use the e-dial to tell the camera to set a higher or lower time, up to three steps in each sense (exposure compensation). You can either manually set the sensitivity, or you can let the cmaera choose it automatically. In the latter case, you can tell the camera an upper limit for sensitivity, to prevent getting overly noisy images. All these sensitivity settings are available after pressing the ISO button, of course. I find this mode, and with manual ISO setting, to be the most suited to my use. It's quick to use, and still allows almost complete freedom. Compared to manual mode, it simply removes from the photographer the slavish work of making the shutter time agree with the other settings. Most of the time, it works great.
In shutter priority mode, everything is like above, except that you adjust the shutter time while the camera sets the aperture. This is useful in some cases, when you need to force a constant shutter time on several successive shots, for comparison purposes, or to measure the speed of an object by measuring the length of its blur mark on the photo. But generally it's less useful than aperture priority, because it gives the camera much less control range. A typical lens will only allow to control the light over a range of about 1:30, and if you want high image quality, this might reduce to as little as 1:4! Instead, shutter time can vary over a much larger range. In both aperture and shutter priority modes, you have full control through adjusting one of teh interacting settings while watching the camera set the other. So the results will normally be the same. But in aperture priority you typically will need much less adjusting of the e-dial, making that mode more convenient in most cases.
In sensitivity priority mode, you adjust the sensitivity with the e-dial, while the camera selects both aperture and time according to the measured light level. You can influence the camera's decision by pressing the Av button and rotating the e-dial for exposure compensation, but you cannot change the balance of aperture and time. This is just a disguised version of Program mode, having the sensitivity setting relocated, and I wonder in what situation it could be useful. I have found no use for it so far.
In program mode, the e-dial is disabled, unless you press the Av button to use the e-dial for setting the exposure compensation. You can set the sensitivity, or let the camera select it, just as in aperture priority and shutter priority modes, but there your options end. The camera will select the combination of aperture and time according to a preprogrammed curve, which usually isn't optimal for your photographic situation. Program mode is useful for dummies who don't like to think and learn, and for a real photographers it might be an emergency mode when the photographic situation can change with the blink of an eye, and the ability to instantly take a shot is more important than the quality of the photo. In all other cases, stay away.
The K-x also has a lot of "picture modes" and "scenery modes", which set a specific kind of exposure mode (usually program mode with specific curves) along with several processing options. I find these modes to be useful mainly to cause confusion as to what the camera is really doing. They do nothing that you couldn't do as well or better by using one of the modes above, under your full control.
The K-x offers several functions that act before any digital processing of the image data. The Pentax manual is very sketchy on what these really do. So we can only experiment and guess.
Highlight compensation: You can enable this feature either from the control panel or from the menu (through the D-range settings). This feature is intended to reduce the saturation of the lightest areas in a photo. Pentax doesn't tell how it works. Apparently what they do is switching the CMOS sensor readout amplifiers to a lower gain, when the individual pixel contains more than a specific amount of charge. Probably they then apply a softening function in software, to avoid a strong step change between the pixels read out at higher or lower gain. However they do it, it works pretty well, and the use of this feature is highly recommended. But when it is enabled, you cannot set the lowest sensitivity, because this function needs it to fall back on, with the lightest pixels! Still, my recommendation to use it stands.
Shadow compensation: This is supposed to be the same thing for the opposite end of the range, for the darkest areas. You can enable this function the same way as the one above, but you can also set it to any of three levels. In my test shots, I have seen little effect of this function, and the effect has been mainly to light up the deepest shadows - but bringing a significant amount of noise into them! I think a photo with deep black shadows looks better than one with brownish shadows full of colored speckles, and so I don't find this function very useful. I prefer to leave it off. If you need to really look into shadows, better use the High Dynamic Range Recording function.
Shake reduction: This great feature works by sensing the camera shake, probably through three accelerometers, calculating in real time how much the image will move on the sensor, according to the focal length of the lens, and then moving the sensor by means of a three-axis actuator to make the sensor follow the moving image! In the good (?) old days of mechanical cameras, this would have sounded like science fiction. But here it is. According to what I have read (I haven't tested it), the K-x will reduce the effects of the camera's view axis rotating left-right, up-down, and the camera rotating around this axis. It will NOT compensate for the camera shifting left-right, up-down, or front-back. So it implements three-axis stabilization, not full six-axis stabilization. In practical use this means that it will reduce camera shake very well for objects located far away, but not much for those located very close. I would suggest to leave it on at most times, but turn it off for macro work, when using a tripod or some other support, when following moving objects by pulling the camera along, and maybe also when you are constantly switching lenses that don't have electronic ID, because with shake reduction enabled, you need to manually input the lens focal length every time you install such a non-ID lens. Keep in mind also that this function gives you shake REDUCTION, not ELIMINATION. Don't expect it to do miracles. But it comes pretty close to that!
Drive mode: Accessed through its button on the camera, this selection lets you choose between normal mode (one photo shot when you press the shutter), or continuous shooting at high or low speed, or time delay triggering at 12 or 2 seconds delay, or remote control operation, or exposure bracketing. Continuous shooting is for the photographer the same as a machine gun for the soldier: You aim roughly and press the trigger, then start sweeping (the aim, the focus, or anything else). The machine does the rest. The soldier will kill more people and destroy more things with a machine gun than with a rifle, and the photographer will have a greater chance of hitting the best moment. Back in the days of film, continuous shooting was far too expensive for me to ever try it. But now with the K-x, it doesn't cost much money, and so I have found it very useful!
Time delay triggering is best known for taking pictures including oneself. But a more useful application for this is avoiding camera shake. Set to 2 seconds, you mount the camera on a tripod, press the shutter button and move away. The mirror comes up immediately , and the shutter releases two seconds later, when the vibration from the mirror motion has already died off (hopefully).
I can't write about remote control operation, because I don't have one.
Exposure bracketing is quite useful. You can select how far apart the exposure values will be, and with the EV compensation you can shift the trio of exposure values up and down the scale. The menu gives additional selections, such as the number of shots, and the order in which they are shot. I chose 3 shots, in the order of -,0,+, and I typically set the exposure values to 2/3 stop difference between each and the next. And usually set the whole series offset to the minus compensation side, with the EV compensation, because my K-x tends more to overexpose than to underexpose.
One quirk with bracketing mode: You must keep the shutter button pressed, until the three shots have been done! Otherwise the camera will just shoot one or two, and then go from there the next time you press the button!
Using Flash: In all of the modes described in some detail above, you use the internal flash by manually popping it up when you want to use it, by pressing the UP button. The camera calls this "manual flash discharge", but this is a bit misleading because the flash will still be automatically controlled by the camera, producing very well controlled exposures.
By pressing the flash button, you get a selection of flash modes: Manual is the basic mode (but is automatic!), then you can add red eye reduction to that. Apparently in this mode the camera uses a shutter time of 1/180, even if the finder display tells you the time it would use if no flash was there! Then you have the SLOW mode, which truly allows you to set a longer shutter time, or to let the camera set that longer time, to combine the flash with ambient light. The fourth option adds red eye reduction to this. Then you have a mode which allows slow shutter speed but fires the flash at the end of the exposure, to get nice photos with moving objects trailing some marks. Finally there is a wireless mode, which I can't try for lack of a wireless flash.
In picture modes instead (not recommended), the flash options you get are: Automatic, in which the camera will pop up the flash whenever it thinks it could be useful. Not recommended at all, because the shock of having the flash pop up into your face is rather hefty. The second mode is manual, when you pop it up when YOU think it could be useful, and the flash power is still controlled by the camera. Then you have selections of any of these modes combined with red eye reduction, and finally wireless flash.
In the menu you can configure the camera's green button to one of several functions. I find it most useful to configure it for optical preview. That way, it works like a plain old depth-of-field preview button, to stop down the lens to the set value and let you judge the depth of field in the finder.
The AF/AE-L button also can be configured to several settings in the menu. I found it best to configure it as exposure lock button. In any automatic mode (aperture, priority, shutter, sensitivity priority, and program mode) you press this button to freeze a measured exposure value, then recompose the picture and shoot with the frozen value. This comes in very handy in all sorts of high contrast scenes, to take the exposure measurement at a place that has the overall brightness which you want to depict well, and take the whole photo with the setting for that area. I use it all the time.
Distortion correction: With lenses that have electronic ID, the K-x can correct the barrel or pincushion distortion. This is usually a good thing to do for photos involving straight lines, such as architecture shots, with lenses that aren't very straight, such as zoom lenses. But it takes some processing time, limiting the shooting speed. With high quality lenses, or when shooting only crooked things like trees and clouds and birds, it's irrelevant. The setting is available from the control panel and from the menu.
Chromatic aberration correction: With lenses having electronic ID, the K-x can correct the chromatic aberration, reducing or even eliminating the fake color margins around sharp contrasty edges. This can really improve the image quality of a modest lens, in any photo having a contrasty subject. But this too costs processing time. Setting is available from teh control panel and from the menu.
Right after taking a picture, the K-x can display it on the LCD, for review. I recommend to keep this function enabled, and also enable the display of the histograms along with the photo. And I do mean this in plural: Make the K-x display the color histograms! This is a marvelously useful tool to quickly check that there was no saturation in any of the three colors. If there was, immediately press the UP button, which will delete that image, then correct the exposure (usually by adding a negative EV compensation), and take the picture again. It's very easy to get pictures with some color saturating many pixels, and such a picture will have totally washed-out, horrible colors! It's hard to notice this, until it's far too late, when you are NOT using instant review with color histograms.
The time for which the instant review should stay on screen can be configured in the menu, and is a matter of your preference and quickness. I use 5 seconds. If you want to get to the next shot while it's still displaying, just tap the shutter button.
You can choose either in the control panel or in the menu the format in which you want to save your files. The options are PEF, DNG and JPG. Both PEF and JPG save the sensor's captured raw data, complete, without loss, for external processing. PEF is Pentax' own format, while DNG is a more widely established standard. Apparently both formats contain the same useful data, so I suggest using DNG to be more compatible. If instead you select JPG, you will get image files ready to use directly from the camera, and the camera will do the whole processing internally. There is a wealth of settings that affects how the camera processed the image data to create the JPG files, and which have no effect whatsoever on the raw data stored in DNG or PEF files. However many of these settings are saved as parameters in the raw files too, so that external image processing software can use these parameters to process the raw data just like the camera would have done it. This is useful, specially because it doesn't involve any commitment: The user can later decide whether or not to use any of the parameters configured into the camera and stored in the raw files! JPG files generated by the camera are instead pretty final: Any manipulation done on them later will most likely degrade their quality.
So, if you will use raw files, you don't really need to care about setting up anything that follows here. But if you choose to save JPG files, or both JPG and raw files, you need to understand and set up all the following too.
White balance: The CMOS sensor detets red, green and blue light separately. Depending on the light source illuminating your scene, the contents of the three colors varies. You can compensate for this by using white balance, which will simply apply scaling factors to the red, green and blue outputs of the sensor. If you are a dinosaur like me and come from the film world, you will probably remember that most film was balanced for daylight, which was clearly printed on the film boxes, but that some was balanced for tungsten light. The K-x has those same two settings, available when you press the WB button, but in addition it has several more: Shade, Cloudy, four kinds of fluorescent light, Flash, and three special settings. Of the three special settings, one is pretty crazy, as it will exaggerate any odd light color. Useful perhaps if you want redder than red sunsets, I suppose. Another setting is manual white balance, which allows precision results by taking a shot of a white paper lit by the same light you will shoot in, and letting the camera calculate the settings from it. You can also tweak the settings, but that's hard to get right. And the least useful of all white balance settings is the one teh camera defaults to: Fully automatic. In this setting, apparently the camera averages the whole picture and calculates parameters to even out all the color. The white balance will change from every shot to the next, which is a big nuisance. It works well only when you are shooting gray concrete walls, or a scene with perfectly balanced amounts of each color! Otherwise, use this mode only if you want the camera to bleach the sky when you make a picture that is 2/3rds blue sky, or the bleach the green when the picture is mostly green grass, or to make the skin pale if you do a closeup of a face. Not my cup of tea. My suggestion is to either set it to daylight and leave it there, so the K-x will work just like a film camera loaded with daylight film; Or else to use the correct preset for each kind of light you shoot in. And for precision work, such as photographing a paint catalog, of course you would use manual white balance with a white paper as reference.
Even when shooting in raw mode, it's useful to set the correct white balance, so that the processing program will get basically correct color scaling factors to start with.
Color Space: This setting scales the color values to limit the range of possible colors to a certain extension. The K-x offers two settings: The default sRGB is best if you mostly want to watch your images on the computer. If instead you want to print them, with a good printer that has a wider color range than computer monitors, use adobeRGB. This is selected from the menu.
Contrast, Gamma, saturation, hue, color, sharpening: This is one of the more confusing areas of the K-x. These parameters are managed through the "custom image" selection, available both from the control panel and from the menu. There are seven custom image setups: Bright, Natural, Portrait, Landscape, Vibrant, Muted, and Monochrome. Each of these seven settings has a fixed color response, leaving the other parameters to the user. The color responses are shown on a graph: "Natural" uses a straight, undistorted color response. "Bright" slightly exaggerates the contrast in the blue-yellow axis. "Portrait" has a higher base saturation. "Landscape" is a combination of "Portrait" and "Bright", having both higher base saturation and higher blue-yellow contrast. "Vibrant" has an extreme green-magenta contrast, "Muted" has a low base saturation and even further reduced green-magenta contrast, while "Monochrome" has zero base saturation.
Each of these seven base modes have default settings for saturation, hue, high/low key, contrast and sharpness. The user can vary all these settings, while little markers indicate the default settings for each mode.
It's rarely useful to change the hue setting. The saturation can be tweaked a bit to compensate for dull or overly Disney-like subjects. The high/low key setting is quite useful to place emphasis on lighter or darker areas of the image. It's not clear to me if this simply adjusts the gamma, or distorts the response curve. The contrast does what one supposes it would do. The sharpness seems most neutral at the -1 setting. At zero, it already seems to oversharpen a little. Sharpness can additionally be changed by selecting "fine sharpness" with the e-dial. Apparently this reduces the radius of the unsharp masking routine in the camera.
The monochrome mode is special in that teh saturation slider is replaced by a color filter selector, and the hue slider lets you select the toning of the image, from sepia to blue in several degrees.
My preferences are either the Natural mode with all sliders in the default positions but with fine sharpness enabled, or when I need more punch without overdoing it, the Bright mode, but moving the sharpness slider down to -1 and also setting fine sharpness.
You can do all these adjustments while watching the effects applied to the last photo you shot, on the LCD screen. And the best part is that you can set up each of the seven modes to suit specific tastes or applications, and then quickly select any of them for each shot.
In scene mode the above settings are replaced by fixed user-selectable presets, while in picture mode the fixed presets are picked by the camera according to the mode. You have to take what the presets give you. Not recommended.
Tools for messing up your photos: The K-x offers several such tools. You can select cross processing, with several presets, or let the camera choose them at random. This is basically a function to totally demolish the colors. I suppose this is what an endlessly bored photographer might want to do, as his last action before finally commiting suicide. Or perhaps a mischieveous rascal would enable this function on his sister's newly obtained K-x, to scare the... well, erhm, to scare something out of her. I can't see a much better application for this "feature".
The digital filters also contain such mess-up tools. Worth of mentioning is the "toy camera" function, which ridiculously degrades image quality. Nasty boys having a sister with a K-x might want to try this mode. It is even configurable. "'Retro" mode adds a margin (what a way to loose pixels!) and toning. "High Contrast" looks a bit like the infamous Fuji Fortia film. "Extract color" instead is quite a bit more artistic: You select a specific color, and a degree of strength for the effect, and you will get a mostly black-and-white picture with a specific color preserved and standing out. Nice. But gets old fast. Could be useful for some technical applications. "Soft" is again just a tool to degrade image quality. The "star burst" filter adds those star-like flare produced by diaphragm blades and scratched lenses, in a controllable way. A matter of taste, I guess. "Fish eye" produces a strong image distortion that is NOT really like what a true fish-eye lens produces, as it only distorts the image center, and leaves the corners unaffected! And finally there is the "custom filter", which allows doing several kinds of nonsense at the same time...
Back to more useful settings: You can decide the quality at which your final work of art is saved, by selecting the pixel count and the compression level of the JPG file. Again, this can be done both from the control panel and from the menu.
And speaking of useful things: You can choose high dynamic range recording, from the control panel or from the menu. This will make the camera shoot three versions of an image in quick sequence, at different exposure settings, and assemble them into a single image that takes the darker areas from the image exposed the longest, the lightest pixels from the image exposed the shortest, and the remaining ones from the normally exposed image. The result looks rather bland as it has a low contrast, but it does contain more information and detail than a normal image. Properly processed and printed on a printer that has a high dynamic range, such an HDR image should look very good. Alas, I don't have a suitable printer to test it.
And that's it, in a nutshell! There are many nuances, exclusions, interactions, quirks with specific lens types, and so on. Check the Pentax manual to find out about all of them. This manual hopefully has helped you understand this camera a bit better, and get it to work for you, instead of it getting you to work for it!