Perhaps you should also look up 'irony', Amin

Well those are very good, Dan, I remember them from when you posted them originally.

Certainly large birds, further away, will place less of a demand on the AF speed, than smaller, closer ones that are changing direction frequently and suddenly.

But technique is also, of course, paramount, and yours is clearly not lacking.

I didn't think mine was, at the time, either

It's certainly amazing that sports photographers of old managed to take any sharp photographs at all. I suppose they practised and practised, and got very, very good, at the things that mostly we only need to do some of the time these days.

And good luck to them - but I bet the average amateur had nothing approaching that level of skill.

For landscapes and architecture, of course, AF is irrelevant, and for street shots where mood and subject matter are most of what is important, and wide angle with lots of depth of field takes care of most of the rest, it's very nearly so.

So citing HCB isn't perhaps the best example to choose here. A 1940s sports 'tog, much more so, maybe.

I don't think this is really fair, George. None, I suspect, of those engaging with this topic here, is foolish enough to suggest that AF speed is the be-all and end-all of all things.

If we only wanted a simple camera where we had to do everything ourselves, we could have one of those for twenty quid or thereabouts.

It's not that unreasonable, when paying closer to £1000, to expect that the automatics are both capable and reliable on the one hand, and on the other, to expect that they enable us (with a lot less skill than the uber-focusers of old) to do things we'd never consider attempting with the £20 alternative.

It's in that rarefied corner of the performance envelope that the arguments are relevant. And there are enough variables to make it a genuinely difficult thing to assess.

Your point is well taken, I'm sure, but it's a touch facile to rubbish the whole AF-speed argument just by saying "well HCB never needed all this new-fangled gimicry, so what's the fuss about".

You can't really tell until you get the pictures on to the computer.

I was on a boat trip last year and the seagulls were flying circuits round the boat for ages. I took about 100 shots, and on the LCD lots of them looked great.

When I looked at them properly though, only a very few were usable.

For aircraft in flight, the K10's AF is more than adequate. For birds, I really don't think it is. Birds change direction and speed much more suddenly than aircraft, and they're a lot closer, so a small change of direction will have a proportionately large effect on distance.

I can't imagine anything that places more demands on the AF system than birds in flight.

Indeed. I would soooo like to give the guy that wrote that part of the manual a good slap for that omission.
There've been quite a few cases of the SR switch breaking off, though, haven't there? For that reason alone, I'm more than happy to leave it in the On position permanently.

Having no wired remote, one of the delayed or IR modes is a must for me if I want to completely eliminate shake, so it's always automatically off when I'm doing anything on the tripod.

Ironically, forgetting to switch SR back on, after testing it with it off, has lost me several hand-held shots due to uncorrected shake

When I did my original tests, not having a wired remote, I had to use my finger on the button to release the shutter, and, not surprisingly, there was a small amount of shake clearly visible on all the shots without SR. That shake was of course absent with any of the delayed modes.

The same small amount of shake was also present with SR on - from which I concluded that the amount of shake was too small for the SR system to either notice it, or be able to correct it. But it was certainly no worse with SR on, in fact I couldn't tell the difference in the amount of shake with SR on or off.

I never got round to getting a wired remote, so I was never able to complete the test, as it were.

So thanks for this - very interesting that (assuming you were using the wired remote release for all of your tests), SR does *not* seem to be switched off automatically with the wired remote, unlike all the delayed modes and the IR remote release.

Before this thread disappears into history, with my view that there's no evidence that SR causes shake still firmly in place, I just thought I'd ask...

... did anyone who claimed it does, carry out any repeatable tests after we talked here last?

If so, be afraid, very afraid.

That's actually on the mainland.

I'd be extremely interested in both your method, and your results, Bret, if you care to repeat them.

Well said, sir.

People that have known me in these parts for a while will remember that I have a bit of a hobby horse about this topic, so I trust they'll forgive me for jumping back on my favourite bandwagon

But really, the fuzzy logic is what goes on in people's heads, methinks. This 'explanation' - that so many people seem to be able to 'remember' but can never cite an actual reference for - is one without a shred of actual evidence for it.

The whole point of SR is that it measures the shake, using accelerometers in the body, and then decides how much to move the sensor to counter the shake.

Whether it then applies some algorithm based on the type of shake expected, I don't know, but despite looking quite carefully for empirical evidence of SR causing blur, I've found none (I wrote it all up here a long time ago, so it'll be searchable if you're interested).

I recall that MattMatic also did some tests, and established that unstabilised SR can be worse than no SR at all, but to the best of my knowledge, there's really no evidence that stabilised SR causes any shake at all.

The trouble is, there has never been an official explanation for Pentax's recommendation to turn SR off on the tripod, and thus, mixed with anecdotal evidence of people getting blurred pictures for unknown reasons, urban myth is born.


As I've said before, I concede that the recommendation in the manuals is suspicious, and of course I may be completely wrong. But in the absence of some careful repeatable experimentation that gives actual evidence, I shall continue to hold the view that stabilised SR does not cause shake.