Correct John, I fix the lens to the tripod using the lens tripod mount. Problem is it's too far back and the combo is still very much lens heavy.

I have thought about fitting the camera to the tripod and the lens to a monopod but it's a very unwieldy (almost impossible) arrangement to use.

I think it fairly true to say that if you balanced a 50Kg static load on top of any modern tripod, the legs would not break.

It's also true to say that with a 3.5Kg static load, the legs of some tripods would certainly bend, if only by a small amount.

In my case, I have a Manfrotto 055PROB + 822RC2 ball head which is a fairly well respected combination.

It's torsional stiffness is very good, but it will not stop my 135-600mm zoom (4.5Kg on its own) from waving about unless I am very careful. That's probably worst case scenario becasue the lens + camera combo is very front heavy and very long.

For me, lens & camera balance + tripod torsional stiffness up to about 10Kg are the most important.

Good question . . . and I don't know the answer. I'd need to make some more tests on a static object. The 'shake' I saw in the images may have been due to the the natural rotation of the moon, albeit very slight.

I'd say it was probably due to the mirror return, but I don't know.

With a max of 3.5Kgs (I'd double that at least for future requirements) you have plenty of choice. Personally, I love Manfrotto gear. It's rock solid and will last a lifetime so buy wisely. If you didn't get them with the tripod, I'd get the spiked feet for the legs too. Even the standard rubber cups can allow movement when you have a big lens fitted.

The Manfrotto 322RC2 Heavy Duty Grip head seems similar. It'll only support up to 5Kg though. Maybe not strong enough for the Sigma 50-500mm lens + camera body + grip etc.

To answer your question we'd need to know the total weight of the heaviest combination you are likely to want to support.

I use a Manfrotto 488RC2 mostly. It's good for up to 8Kg but it won't hold my SMC Pentax 135-600mm zoom steady. That's more to do with the positioning of the tripod mount on the lens than my tripod or head though.

It sounds to me as though you might benefit from a general photography course, rather than a K10D focussed (no pun intended) course.

Search out your local adult training centre or local photographic society.

Once you have the basic knowledge, you can then apply that to your K10D, or any other camera.

Many years ago I witnessed a trainee electrician ask "Is this (3 phase supply - 440 volts 100 amp) live?". His supervisor replied " I don't know, cut through it and see".

The trainee did what he was advised and cut through all 4 wires. He was on a step ladder at the time. The resulting explosion threw him off of the step ladder, welded his cutters together, and shut the factory down for 2 hours whilst the damage was repaired.

The moral: To trust is good, to check is better.

If this is a contrived 'joke' pic . . . it's funny.

If it's for real . . . I hope there were no kids around at the time who might just try it for themselves.

No, I haven't done anything silly . . . but this guy did. Read about his experience here.