Most cameras of this age work this way as standard, press the shutter button half way to activate the light meter. I dont have a K2 but in the K1000 and KX the meter doesn't stay on when you take pressure off the shutter button. Its probably not broken.
If the lenses are PK / PKA bayonet fitting, yes - if they are autofocus as well, this is a bonus, as that too should work. If they are M42 screw-fit, then you'll need an adapter, and all functions (zoom, focus, exposure) will be strictly manual.
Before you attach it to your camera you must check the trigger voltage first, never use an old flash unit until you check the trigger voltage with a multimeter, most old flash units have a huge trigger voltage that will damage your camera.
Very simple to check the voltage on that Sunpak 622, turn on your volt meter and set it to about 200 volts DC, turn on your Sunpak flash and apply the RED lead to the bottom contact, apply the Black lead to the side of the hot shoe and look for the ground, usually a small metal piece on the side. Now look at the meter, if it shows a voltage of 6 volts or less then it is safe to use on your camera, if voltage is higher, say 12 volts or more, don't use it. A high trigger voltage will certainly mess up your camera in the long run. Even if it has a safe voltage of 6 volts or less, you will only be able to use that flash in Manual Mode, the newer cameras will not sync or recognize an old flash unit.
I have an old Vivitar flash unit that I can safely use on my Canon XTI because the old vivitar has a trigger voltage of 5 volts, safe for all newer digital cameras.
The voltage across the points when fired is very high on old style flashguns if you try this on a modern digital camera you may fry the electrics in the camera. Get a flash gun that is compatible with your camera Have look at the Yongnuo range.
Yes, if it is a K style bayonet, it will work - Pentax allows any K mounted lens to work with all their cameras from the K1000 from 1976 to the present... BUT - don't expect auto anything... including zoom or metering... but it should allow you to use it at least... Assuming the Lens is a K mounted lens... (you can't use it if it is a Nikon F or AI style, or Canon, or Minolta, which all use a bayonet style mount...)
This is probably the single most commonly encountered error among compact and bridge digital cameras. It may indicate that your camera needs repair (or replacement). Before you go that route, however, there are several things you might try. These are not foolproof and they're not guaranteed: if your camera needs professional repair then it needs professional repair.
There are many causes for this. One is impact, caused by dropping the camera or knocking it against something, especially with the lens extended. Another is dirt or grit in the works, jamming it. Ironically, one of the most common sources for the dirt or grit is the camera case. Cases tend to accumulate dirt and lint and other stuff, which eventually get transferred to the camera. Another cause is the camera getting turned on while the lens is obstructed. This can happen if the camera gets turned on inadvertently while in its case or a purse or other confined space.
Cross your fingers and try these steps in order.
Warranty: If your camera is still under warranty, take advantage of it.
Power: If you have an AC power adapter for your camera, use it. This is not the same thing as a battery charger, but instead a device intended to power the camera for a long time on AC power. If your camera has a Lithium-ion battery pack, make sure it's fully charged. It your camera uses AA or AAA batteries and you're using rechargeables, put in a fresh set of alkalines instead. The purpose of this is to get the maximum power to the motor. Try turning on the camera.
Air: Using a bulb-blower if you have one and a can of compressed air if you don't, try cleaning the area around the lens, where the segments normally extend. Be careful not to blow more grit into the works. Try turning on the camera.
Orientation-1: Still using the power source from the previous step, place your camera on its back on a hard flat surface like a tabletop with the lens pointing straight up. Try turning on the camera.
Orientation-2: If the previous step didn't work, turn the camera over so that the lens is down, and try turning on the camera. Sometimes the extra effort of lifting its own weight will jar it free.
Jiggling: This is pretty much the last resort, but since your camera is out of warranty and nothing else works, so what do you have to lose? Jiggle the lens with a fingertip as you turn the camera on. Side-to-side, up-down, clockwise-counterclockwise. Don't push down on the lens so hard that you keep it from extending.
Like many cameras, the K-30 requires a memory card. And like many cameras, it doesn't come with one (though some stores may bundle a card and other accessories).
The K-30 can use SD, SDHC, or SDXC cards. It's up to you what type, size, and speed card you use. Some people like to use one big card to hold all their pictures. Some people like to use two (or more) smaller cards so that if something happens to a card they don't lose all their pictures.
You can use any brand, though personally I would stick with the major brands.