I don't test my new lenses by any other method than taking lots of shots and then seeing the results.

Sometimes a check on perhaps a newspaper page can be useful in comparing the sharpness of two lenses, but the real world photos should normally suffice.

If you want to test in a more scientific way then very precise technique is needed.

How about cloning out the offending areas, or copying some similar part that isn't burnt out?

It would be easier to be specific if we had sight of the image.

Totally correct, these lenses have no focusing mounts of their own so the bellows is used to focus.

Looks like the 1:1 version, but in a Medical kit. Pentax also did a Dental version of the 100mm f4. The last Pentax dental kit came with the MZ-6 and the terrific SMC Pentax-FA 100mm f2.8 Macro lens. The best bit though was the fantastic case it came in. Really wanted that!

The Elicar has a very fine reputation. Do you have the 1:1 version or the greater-than-life-size 2.5:1 version?

A bit late for the discussion thread in the forum, but here it is anyway!

Quite a challenging subject this time, but a good one I think. Some very interesting shots already.

IMHO an out of date camera is only one that can't be used any more, for example, if the film type is no longer available.

Even that is often not insurmountable though, although electronic cameras do become defunct when the batteries or electronics are no longer replaceable.

Pentax currently offer three DSLRs, all of which are perfectly well useable and "up to date" compared with offerings from their competitors. There isn't anything in terms of photography that you can't do with them, so how much more do we need them to be?

If the lens has an "A" setting on the aperture ring, set it to that and control the aperture from the camera body. All should then be fine.

If it doesn't then you will need to go into the custom functions and select "Using Aperture Ring" setting it to "Permitted" - then you can use stop down metering via the green button in Manual and Aperture Priority. This is somewhat less convenient, but it does work.

I have spoken to John Hannavy at camera fairs from time to time, but can't say I know him as such.

John was another of the good writers from Photo Technique.

Without making my head hurt too much, I think the reason for the aperture is to make sure there is enough DOF to avoid strange OOF effects. Most stereo images have incredible depth so wide apertures would be a bit odd perhaps.

As for digital, the 1.5x crop factor may be a problem, but, as I said, without making my head hurt too much I'm not totally sure about that.

Best thing is to try it and see what happens!

BTW, we have some nice old stereo card sets at ADAPS, along with a wooden viewer that holds them at the right distance and separates the images optically. It works very well.