Thanks for the clarification Tim.
I think they've all been matrix metered, I'll give the other modes a go...

When I'm using these long lenses it tends to be for fast moving subjects (Usualy motor racing or birds on the wing) and I have enough of a problem trying to get them focused (or even in frame :blush to adjust exposures on the fly.

Unfortunately my bank balance doesn't go to the K7...
Perhaps they'll drop enough in price in 5 years

Most modes default to Aperture priority without an A setting.
I get the same results in the specialist modes (sport, autoprogram & macro all defaulting to AV) or AV itself.

TV, M & B would depend more on me, than the metering, I suspect

Indeed it is.

But I also can't see why EV comp should be required. With fixed aperture the TTL metering should have no option but to have the right aperture!

I feel EV comp should be for situations where the background requires compensation to get the subject right, not as a leave on whilst I'm using this lens.

When photographing Superbike racing, there's not a lot of time for checking things.

Mike

In my collection of older lenses for my K100D are two with no aperture control. A 500mm CAT and a 1000-4000mm telescope with T2 mount.
With both of these I've found my camera consistantly underexposes by a good 2 stops.
I can understand my manual apertures are not read on the crippled mount, but surely this doesn't apply when the lens is fixed aperture...

Is there a work around, without just over-riding the exposure (2 stops is as far as it goes, and it can get left on if I change lenses in a hurry)

Mike

I can't understand the need for new lenses some people show. Auto focus is a nice extra perhaps, but not in any way essential. Even auto aperture is not totally essential, though it does add a lot to the usability of a lens especially when the subject is changing rapidly.
In addition I'm not upset about having to use third party lenses, as long as they work OK!

If you want extreme magnification digi-scoping is probably the way to go these days. My budget system works as a heavy 1000-4000mm zoom (without a TC) I not had a decent play with it since I upgraded my tripod (A very sturdy tripod is required) but initial results are reasonably promising. The neighbor's outside light (at night) shows it can take sharp photos, but distant subjects have so far been rather low contrast probably due mainly to traces of evening mist etc.

I'd expect Pentax to have a very poor return on investment if they were to develop a longer lens.

Mike

You could try: http://cgi.ebay.com/62mm-62-mm-IR-720-nm-720nm-Infrared-Infra-Red-Filter-/320439...

I'm not sure if it counts as a quality filter, but the 920nm one I got seems to work OK, and arrived reasonably quickly. The cost is low enough it won't break the bank if your not happy with the quality.

Mike

I was playing with a reversed 28mm stacked on a 80-200 zoom this morning.
Somewhat extreme for normal use. Full width was ~6.5-7.5mm (dependent on the focus setting) at the wide angle end of the zoom dropping to around 3mm at the tee end. A little care is needed doing this as focus has the lens only 3-4cm away from the subject.

If your on a tight budget, reversing/stacking lenses offers you the chance to use all sorts of cheap manual lenses. I've got a screw mount 50mm for this to make sure I don't spoil my Pentax rear element. (I know a replacement f1.7 is available for very little but mine has history - I've had it over 25 years)

Mike

I recently got a new IR filter for £10 via e-bay (China), which gives workable results for a dabbler like me. (I chose a 920nm one too cut out all visible light - I'll probably treat myself to a 720nm one later to get faster shutter speeds)
Whilst surfing about IR photography, I've come across sites going into UV photography which percked my interest.

Unfortunately normal glass blocks a lot of UV, lens coatings block more. I might get some results with one of my oldest lens if I took of the coating, the M42 28mm perhaps (£5 from a charity shop with Hoya skylight & a nice case)
Then I found the UV pass filters are rather expensive - I found one for only £170 but it doesn't block IR which the camera is more sensitive to so I'd need a Hot filter as well...
UV will have to wait.

BTW IR is picked up by all 3 colour channels of the camera. The Red channel is not surprising brightest, but even blue responds quite well.

Mike