I do not use the built in flash very often but I find it handy on holiday when I want to travel light. Looking through the files I found this example taken in Italy in 2013. The contrasty dappled light was tricky so I used the built in flash on the K5II that I had at the time (probably dialled down but I cannot remember now). A bit harsh but a better result than with no fill at all.

I have an FLM Centerball which has the neat form of a ballhead but an extra knob to permit movement in one plane only. Avoids the stress of seeing heavy kit fall over when the friction was not re-tightened before letting go

Would it not work if all three flashes are set to manual - so no pre-flash? Then just set the power output on each to get the effect you want.

Very nice relaxed expression on both shots, which is the most important thing.

With a single flash you could minimise the shadow by pointing the flash straight up to bounce off the ceiling but this would give less modelling to the face. A better solution would be to sit your son on a stool some distance from the background.

Very impressive. I particularly enjoy the lighting and detail in the second one.

Just a couple of things to add (which you have probably already thought of anyway). Try to get to the venue early enough to take some shots of the table presentation, flowers, cake etc. before the guests arrive and muck it up. Folk put a lot of work into these things and like to have it recorded. Even if you try to avoid using it, do put your flashgun in the bag together with a simple diffuser (perhaps a Stofen or similar). You may need it for any speeches or presentation of flowers and for the dancing towards the end of the evening. For the dancing try a couple of shots from either a low angle or high. It often gives a better result and avoids the ranks of people filming it on their phones.

The same lesson was brought home to me a while ago. I was showing a photographer friend a portrait that I had taken and was describing to him the lighting setup I had used. He interrupted me to say 'I know - I can see it all reflected in the eyes'.

When I bought my K1 I stopped using the K5II. I enjoyed playing with my new toy and I particularly enjoyed the dual card slots (I use one for RAW the other for JPEG). I was perfectly happy with the IQ on the K5II but when SRS were clearing out the last of the K3s for a nice low price it seemed too good an offer to pass up and I traded my K5II for a K3, which has dual card slots of course. Now I find that I use my K3 as much as I use the K1, depending on what I'm planning to shoot. If the occasion demands and I don't have to lug the kit very far I take both. I find that APSC is easier to use for group shots; it is all too easy to get caught out by insufficient DoF to get everyone in focus when using FF. Just a matter of getting used to the difference and getting the settings right to suit of course but it takes a bit of getting used to.

Make sure that you only copy the file that ends .bin to the SD card and not the whole download.

I found a couple of old receipts from 2010 and 2011 and prices were just as high then. I paid £449 for my DA15mm (as a grey import!) over £1k for my K5 with 18-55 kit lens and over £1k for FA31mm. These things seem to go in cycles.