you don't need to hold the lever during the exposure, only while metering.

I use it this way:

1. centre subject in frame
2. flick DOF preview with finger, check exposure is correct and take the opportunity to check the DOF as well while you're at it
3. adjust shutter speed/aperture as needed
4. release DOF preview switch, compose and shoot


It's literally exactly the same as using a Spotmatic series, just that the meter on/off switch is now the DOF preview lever.

The more things change, the more they stay the same.

buris,

good thought. However if my understanding of the K mount is correct it shouldn't matter.

The original K mount works thusly

As you look from the back of the lens, there is a small actuator on the right hand side which activates stop down. This is spring loaded so that it defaults to the "stopped down" position.

When this actuator is in the up position (as it is when composing) the lens is wide open.

When the shutter fires, the camera moves a cam out of the way and the lens stops down to shooting aperture. The aperture it closes down to is determined by the position of the aperture ring.

The cam always moves all the way and the final size of the aperture is determined solely by the position of the aperture ring. How it gets there doesn't matter since the shutter is closed during this process.

In later models with the KA mount this was modified as you say, but in true Pentax style the modifications are unimportant to cameras which can't make use of them.


As it happens I have two examples of the SMC-M 50mm F2. One is the early version with classic M series diameter based stop down, one is a later one which was obviously built with some A series components since it stops down like an A series lens (see Bojidar's KMP for a description of these lenses). When I get home tomorrow I'll check and see if these two behave the same.


John, I am very grateful to you for pointing out that you can use DOF preview to get a real meter readout, but it gives the same result either way (though the DOF preview makes compensating for it less painful!)

I wouldn't mind so much if it would at least meter correctly wide open so you can guestimate the rest for yourself.

I was just thinking the same thing. Ben seems to think it's altered the metering but I don't think he's tried it with non-A lenses

yes, but if we knew that some K10D's exhibit this fault and some don't then we COULD exchange them

the issue doesn't effect the *istDS or any other *ist body, it is limited to the K10D

my DL2 also starts to underexpose in extreme low light, the stop down meter never picks anything slower than 0.5s. However it is much more generally accurate than my 10D.

One thing I have noticed is that spot metering seems to be more accurate than centre weighted.

My experience is exactly the same as Chris's, with 50mm F2, 200mm F4 and Zeiss Flektogon 35mm.

It's very disapointing as all these lenses worked great with the DL2.

just a thought, haven't tried it so don't know if it would work, but you can get refill kits for most inkjet carts these days. How about refilling the tri colour cart with black ink in all three tanks?

sorry I can't help with spares dealers, just wanted to say hope you came out of the hedge in better shape than your lens hood!