It depends on the image quality you want/need. The image quality at 12,800 isn't sufficient for me. I'm attempting to take pro level photos, not souvenir shots. OK is not good enough.

John just mentioned using a high enough ISO to stop camera shake. But camera shake is not the defining problem in gig photography, it's the movement of the subjects, so the shutter speed has to be faster.

Of course, you could retain the noise if you wanted to........

I think the only reason you're not quite there yet is that you don't believe me.

In the end, I got part way there and had to come back home. Something cropped up. Got another one on Wednesday. Bit better lit there, actually.

However, I do agree with you. If it wasn't for me doing gig photography I wouldn't need f2.8. Paying for f2.8 isn't money well spent if you don't need it.

And to your question, would I take some at f4, the answer would have been no, as I know how far I can push the ISO, and f4 would have been quite useless at this venue. Of course, if the venue is much brighter then I could use f4, and you wouldn't see a great deal of difference in IQ, as long as it was a lot brighter, so that I could use 1/250 sec, f4, and ISO 6400. So, in other words, it would have to be brighter than any of the gigs I have shot at so far!

Anyway, now you understand why it's necessary. But I do wonder why Pentax didn't develop the f4 lenses first, as they would be more popular than the more expensive 15-30 and 24-70 f2.8 lenses.

I haven't got much time to answer at the moment, as I'm just getting ready to go to photograph a gig!

I don't think some people have quite grasped the reason why an f2.8 lens is better, even necessary, when shooting gigs. The example of a night shot at ISO3200, for example, is almost impossible at a gig. Here's why..........

Firstly, the artists are moving. Bit of a bugger, I know, but it does mean that a minimum shutter speed to freeze the movement is required. Although this can be reduced for the less-lively performers, a shutter speed of 1/25 secs gives you a reasonable chance of getting sharp images, although if there are multiple performers all doing their thing, even that can be difficult. Take quite a few shots, get a few keepers. Nobody mentioned shutter speed, but at gigs it's most important.

Now, I know the venue I'm going to tonight. The lighting is poor, though not the worst I've been to. The best one I have been to, with the best front lighting, allows me to take images at 1/250 s, f2.8 and ISO 3200-4000. That's the best! Tonight, I'll be lucky to shoot at ISO 6400-8000. There is a dark corner, usually where a bass player or lead guitarist will tend to stand. I may go to ISO 8000-10000 there, and may even have to shoot a slower shutter speed, take more sots and just hope I get some without movement.

There is a noticeable difference in image quality above ISO 6400/8000. The noise increase means that the noise reduction in pp will show an increased softening.

In some very dark places, I've had to shoot at 1/100 sec and ISO 12,800. The images end up rather soft. But when it gets like this, you either take them and just realise they won't be great. Better than nothing, though.

I'm sure you know all this anyway, except, perhaps, the numbers involved with the K-1.

So, now imagine shooting at f4. Only in the very best lit places will it not affect the image quality.

OK, gotta go shoot bands now!

Indeed. I use the K-1 and f2.8 lenses for gig photography.

There, that was easy to answer, wasn't it!

I did a non-scientific test of high ISO noise in the range 3200 to 12800, in particular, as a comparison between the Sony A7Rii and the K-1 before buying, as I was, primarily, going to use it for gig photography.

As far as I was concerned, the K-1 was "better." By that, I mean that there was less, more manageable, noise.

I was shooting a gig in December when some kind soul in the crowd decided to throw beer. Covered me, the girls next to me, and my K-1 and 15-30.

Apart from the smell for a few days, the gear was left unharmed.

Yes, good luck, Mr Carrot, with whatever problem you have which forces the sale.

It's a lovely lens, one I have which I don't use enough. The images you have posted have given me a kick up the arse to take that lens out again......when it stops pissing down, obviously.

OK, so had a some time, and checked the focus microadjustment values. The camera does, indeed, recognise the TC and 300 as different to the 300 alone. Moreover, I had set different settings for them. So, all good there.

As I thought the combo with the TC might be front focusing by a tad, I've made a readjustment, and we'll see how that goes next time I go out!

Maybe, John.

I must admit, I cannot remember whether i did that when I got the TC. It was quite a long time between uses, enough time for me to have forgotten. Some time soon, I'm going to check!!

I had stopped down.

I assumed there would be a difference in the micro adjustment when using the TC. I had a feeling it was just front focusing, but I haven't had chance to prove that theory yet. Don't worry, I will before deciding to buy the 150-450!