I presume you have adjusted the dioptre adjustment on the viewfinder?

I use the related site www.ephotozine.com for this - you can upload one picture per day.

It sounds a bit of a doubtful description, are you sure it is a Pentax lens or is it just a K mount lens suitable for a Pentax such as the ME Super? The description is vague....

The first f1.7 Pentax standard lenses were made for the M series cameras, such as the MX, ME, ME Super, etc., and they are marked SMC Pentax-M 50mm 1:1.7 and they take 49mm filters. They are outstanding lenses, so one in good condition is worth buying for a moderate price, maybe as little as £20 if you are lucky.

Later manual focus lenses are marked SMC Pentax-A and these can be used with all exposure modes even on the latest digital bodies.

Certainly a high shutter speed will arrest motion. You could also try panning with the action at slower speeds to give a real sense of movement.

Yes, you can do what you describe, Arthur, but the lens operates at full aperture regardless of what is set. You seem to have assumed that the lens will stop down when you release the shutter, but it doesn't unless you use a different procedure that has been fairly extensively covered in these forums.

Have you tried setting the system to Av, keeping the camera with the same field of view and varying the aperture ring to see what happens then?

Or, take some pictures and check the depth of field of your image. To make it obvious, I'd suggest using say f8 or f11 and then repeating your test and take the pictures. Then see the DOF and you will see that there is hardly any because the aperture will be f1.4 in all cases.

You're right to run tests like this, there's no substitute for finding out things first hand. One of the ADAPS members showed me a an extensive set of slides he'd taken to demonstrate the effect of aperture on DOF and very impressive it was too. After that, he had a very clear idea of what it was all about!

So I found myself on this mathematics forum, reading all about base 13....

Fascinating, so thank you Arthur for the added insight!

I would guess that the 42 is the Ultimate Answer, to Life, The Universe and Everything.

The question is, of course, what do you get when you multiply 9 by 6, hence the thought that there's something fundamentally wrong with the universe....

You're probably right, George, it's much too difficult for me.....

With the MX, you set an aperture and that is what you get.

With the digital bodies you have to manually stop down the lens to achieve the set aperture, using the stop down switch.

I think the MX suits the process more naturally....

No I don't mind at all, people disagree with me all the time!

You are quite correct that I was also initially confused by the instructions for using M and K lenses (although perhaps you will allow that the mysterious language of the manual doesn't help....)

The reason I sold some of my M series lenses and indeed cameras was a different issue. I had increased my M collection to write an article, and having done that the excess items were then sold to make way for the next project. Unfortunately something has to give in the quest for financial sanity!

The MX is still a firm favourite, and it lends itself naturally to the ergonomics of M lenses. I do find using A lenses or later more convenient on the DSLRs, and I do believe the M and K lenses are, relatively speaking, "fiddly" compared to the more modern optics.

I suppose it depends on how the individual photographer wants to work, and indeed on the type of photography being undertaken.

So I guess I retain some of my blind spot, but I do find that there is a lot to agree with as well in what you say, George!