You may have to check that using aperture ring is set in the Custom Menu and if there are any other restrictions set for when the aperture ring is used. I know the camera doesn't know what aperture is set because of the adapter, but it may be blocking other stuff. I think it's on a Sony that you have to set allow use with no lens to use adapters, otherwise a warning pos up saying no lens attached.

Also check that focus on half press is set.

All nice for me... it's a good job they can't blink

It was probably just because it was different after using the F*300. It's not as re-assuring and spins right round. I can use it OK and from what I remember from the F*300 it's a lot easier to switch between AF and MF. Not an important point really you wouldn't notice it if you hadn't just switched from F* to DA* ....possibly I shouldn't have mentioned it

All the Pentax 300mm's are good..... but only 300mm and not zooms which is very restricting. I'm currently trying an 80-400mm Tokina which is a very small lens and nice to use. The shots I've put in the gallery were the F*300mm which I sold on here last year.

The DA*300mm which I now have is slightly better wide open, nothing in it at f/5.6 and beyond. It's a bit messy for MF. AF is OK.

I still have the A*300mm which is slightly longer and gives an 11% bigger picture, but needs a 6mm extension tube to focus closer than 4M. Nice MF lens though and very small.

For motorsport I would have thought a fixed 300/400mm would be very restricting and a zoom more useful. The 55-300mm is a good lens, but a pig to MF (for me anyway). The 80-320mm was better for MF but I wouldn't trust a SH one, the barrels become wobbly. Shame really because it was great in bad light and probably the only zoom that is excellent at both ends and in the middle. The famous Bejersey Zoom of a few years back. Fabulous bokeh.

There's a 135-400mm Sigma in Classified at present, not a great lens, but can be good in good light. Then there's the more expensive Sigmas.

Supposed to be a good lens. I've got the CZ 135mm. There shouldn't be any problems, it should have the A/M switch which opens and closes the diaphragm.

Leave it set on M and open and close the aperture with the aperture ring. You should be able to set it up to at least f/5.6 and still focus, probably best (with it being a std. lens) to use the Green Hexagon for focus.

It may still be OK at f/8.... for f/11 and beyond either open up the aperture ring and then focus then close down again OR open and close via the A/M/ switch. Personally I'd just use f/5.6 and leave it closed all the time.

Cheap and accurate.... doesn't need batteries a SH
Weston Euromaster, make sure it has the Invercone.

My favourite is the Gossen Sixtomat Digital it works like
an SLR you can set Aperture Priority or Shutter Priority
and it gives you the other setting (speed or aperture).

In Shutter Priority if you hold the button down it analyzes
the contrast range and shows the coverage with marks against
each aperture within the scene at the bottom of the meter, as
shown on the front of the brochure. (Similar to a Histogram).
Probably about £180 New.

Edit: Park Cameras

It would probably be better if you told us the make and focal length of the lens, so we will have an idea of what's needed for it to work.

A pre-set for instance often doesn't have anything protruding from the back and it doesn't matter where the aperture markings are.

I've got a pre-set on which the mount was held on by 4 equally spaced screws and I rotated it 90deg so that the aperture markings are at the side where I can see them better than under the flash housing.

Eventually the weight and bulk got too much for him and he found that he could get better results with a 400mm lens + 1.4x TC

So he sold the 600mm

You've got quite an expensive tripod and head, which makes it easier..... not quite as easy as handholding a 300mm +2X TC though

This is the one with the stay..... it's a 6x7 and he actually considers TWO tripods first

Where have all the clouds gone????

http://www.sat24.com/