Here are some useful pieces of information regarding the K100D, which will probably apply to some extent to other models as well.
As you know the K100D offers two ways of releasing the shutter (wireless and cable switch (CS-205)) and both accessories are not exactly cheap, at least not here in New Zealand.
Regarding the wireless remote, note that Pentax uses the same infrared code as some SONY remote controls. I have successfully released the shutter on my K100D with my SONY remote control (the exact button will vary between different models of remote controls). It also works with a generic (universal) remote, if it is set to use the correct codes. I was surprised to see that using a remote control this way even supports arbitrarily long exposures in "bulb mode"; as long as you keep the button on the remote pressed, the shutter stays open.
Regarding the cable switch, note that the little plug is a standard 2.5mm one that is often found on mobile phone earphones. If you get such a cable, building the switch yourself is quite easy, see for instance "
Build your self Pentax Cable Switch F".
The second option for the cable switch is to buy a cheaper replacement. I found the Yongnuo RS-C1 and it works nicely, but there are other replacement switches as well.
Yes, I would prefer to have "Pentax" written on my remote controls and also wouldn't mind to support Pentax by forking out some money for the original switch, but here in New Zealand the remote controls are prohibitively expensive.
Just a reminder, as you have probably know this at one stage: If you apply exposure correction (something I do quite often), the automatic ISO setting is disabled and ISO 200 is chosen. If that's not what you want, you need to set the ISO speed manually.
You may not be aware of the fact that ISO 400 has a bit more headroom in the highlights then ISO 200, so when choosing ISO 200 you are giving a away a bit of the potential dynamic range. Since the noise at ISO 400 is very well controlled, it appears to make sense to set the camera to this speed and avoid ISO 200 unless you are after minimal noise, but I hope someone else will shed more light on this matter.
Its in the manual, but here's another hint: When navigating in the menus, note that you can use the wheel to switch between the menus. That's a lot quicker than moving up and down to reach the menu switching position. I'm sure you are already saving clicks by moving up (when you are at the top position) to reach items far down in the menu. Getting to them from the bottom, instead of from the top, is often far quicker.
Although all the relevant information for using manual lenses is contained in the manual as well, some may find this tutorial (
K100D (Super) Pictorial guide to using manual lenses [imgs]: Pentax SLR Talk Forum: Digital Photography Review) on how to use such lenses on the K100D useful.
Here's another piece of information that you may use at your own risk: Although the manual advices against it, you can actually use rechargeable CR-V3 accumulators in your K100D
if they are
voltage-regulated to 3V. Some claim these cells last longer, don't loose their charge as quickly when not used, better withstand cold temperature and even speed up autofocus performance. See e.g.,
https://www.pentaxforums.com/forums/pentax-camera-accessories/37963-report-k1...tery-life.html. My 2500mAh NiMH accumulators seem to last forever and I'm very happy with the AF performance. Forum member bjsmith makes a
compelling argument against the use of rechargeable CR-V3.
Although PENTAX REMOTE Assistant Version 1.0 (
Pentax Imaging - Software & Firmaware Updates) was not designed for the K100D, most of its functionality works fine (Version 3.0 doesn't work). In order to directly upload images to the computer, just make sure that you set the quality level to "RAW" with the camera menu. Otherwise, the transferred .PEF files have an intact preview but scrambled up contents. Using the "auto save mode" is very useful if you are shooting a series of test images, e.g., in order to calibrate the autofocus, because you can immediately analyse them on your computer without triggering the transfer manually or selecting a file name.
You can use an old flash on your K100D provided that it doesn't exceed the maximum voltage tolerated by the K100D. How high that maximum is, seems to be a bit of a mystery. Some claim it is 30V, according to an ISO standard, it should be 24V, some say you should be OK below 10V. Note that Canon EOS models should not be exposed to voltages higher than 6V. You can either find the voltage emitted by a flash in this
list of strobe trigger voltages or
measure it yourself. Make sure, though, to use a digital meter. Some cheap analog meters have too low internal impedance causing voltage drop and thus will report a number which might be grossly too low.
There is a way to use flashes with too high triggering voltages by either using a
Wein Safe Sync Hot Shoe Adapter or some wireless slave trigger which is controlled but not physically connected to the camera, the latter having the advantage of allowing more useful lighting angles.
Did you know that you can
find-adjust the AF system of your K100D?
Here's how you
change the focusing screen on a K100D.