You're really asking on the wrong forum - there are no doubt Canon forums where someone will instantly know the answer.

Thye stop down pin on M42 lenses is actiavted by a plate on screw mount Pentax cameras. It doesn't work at all on K mount cameras, so they are used in stop down, manual mode. That is, we simply set the aperture we require, having set the lens to M (manual) - in this instance the auto/manual switch is referring to aperture control.

Don't know about the Helios lens as there are quite a few variations covering many years.

I'm sure you'll get good use out of it Simon. It seems it was a good time to buy!

I've just had a look at the SRS website and although some lenses have gone up in price, there are plenty that have not.

At any given time the only answer IMHO is to look around as prices do move, in both directions, and the only point it matters is when we are actually ready to buy.

If too few people buy at a high price, then the price will fall. If things are in very short supply and there's an excess of buyers the price will rise. Supply and demand rules!

It crossed my mind that if there is a readjustment of prices on the way it might be because Hoya-printed packaging has now worked its way through the system.

That is, however, pure speculation on my part.

You're talking about HDR here Ernest.

First, you need to take your pictures. Keep the camera firmly on the tripod and simply take up to 7 images of different exposures. This can be done using Av mode. Set your desired aperture (if you changed this the different shots would have different depth of field and the result would be odd)and use the exposure compensation button to make exposures three steps under, as metered then three steps over. Your choice whether you use full EV, half EV steps or whatever. You could also use manual settings of course.

Then you let Photomatix combine and tone map the images.

There are other ways to do HDR with in-camera settings or less exposures, but the 7 exposures route IMHO gives the best result. I use full stop steps.

This is the fifth annual edition of our Photo Society yearbook, with a fair share of Pentax pictures within. However, I don't put in any details of the equipment used as this book is all about having a record of who was around this year, and what sort of photography they did.

Perhaps when I'm old and doddery some nice person will call round and bring me a copy of the 25th Edition....who knows? But for now it was me sat up till the early hours this morning until, finally, I was ready to upload the finished book to Blurb.

http://www.blurb.com/bookstore/detail/3106849

In theory, a lens is sharpest wide open, but we know that isn't true. That is because we don't have "perfect" lenses.

In practice, stopping down two stops often gives best results, but modern zooms can actually keep on improving right down to f16. The better the lens, the more likely it will be that the "two stops down" rule-of-thumb will be close to accurate.

Photodo, EPZ and PU all have lots of lens tests and charts that show us what we might expect from any given lens.

You should have the CDs that came with your camera, so at the very least you will have Pentax Photo Laboratory.

It intrigues me why you wanted to shoot in RAW if you weren't sure what to do with the files. What shortcoming are you hoping it will solve, or is it just having a go to see what it's all about?

In any event, it will be an interesting path of doscovery, so have fun!

Bavarian monks would survive the winter on a diet mainly consisting of the beer they brewed themselves. Lots of calories for sure....

It's a crack in space-time after all, you're seeing something different to what I'm seeing....