catch in focus

Absolutely, Chris, except for the last sentence (which might often be true, but isn't invariably) .

The only AF lens I have with an AF/MF switch is an F* 300m, and CIF doesn't work with it either, in any combination of modes.

I suspect the switches on more modern lenses may work differently.

G

That's very interesting.

In the manual for the K-5 (which has a specific CIF setting), it's quite explicit - manual focus lenses, and DA or FA ones.

Not F, so you're probably right.

What happens when you try it with the F*? Does the shutter just not release, or does it release immediately whether in focus or not?

If AF is set on the camera, and MF on the lens, the camera tries to focus, but can't. Every time you try to turn the focus ring, the camera tries to join in.

It's very odd. It seems that the AF/MF switch on the lens (set to manual) does not disable the focus screw, but something stops the body from being able to turn it, despite it trying to.

In AF mode (on the lens), the focus ring is locked and disconnected from the focussing mechanism.

What all this means is that for manual focus, both body and lens have to be set to MF, and the reverse for auto-focussing.

With a normal FA lens (having no AF/MF switch), you can manually focus with the body set to AF mode, but you are turning the focus motor when you do. With a DA lens, the focus screw is disconnected when you move the focus ring. I no longer have a DA* lens with a switch, and I don't recall how they work.

G

The only lens that I have which works with CIF is an old Pentax M 1:1.7 50mm.

The only lens I have which has a A/M option is a Tamron 90mm 1:2.8 and this doesn't do CIF no matter how I try.


Bernard

You could, of course, do what Charlotte has helpfully suggested to me for the exact same problem with my new Vivitar AF macro with no MF switch and put a small extension tube on the camera first to disable the contacts.

Presumably it would mean manual only and would limit the focus range, but it does work. I can now use an AF lens with no MF/AF switch with the camera body set to AF and CIF works perfectly.

The 18-55 kit lens is a DA but as it doesn't have AF/MF I won't get it to CIF so the following looked a wayout :-

That looked like a good idea but with contacted tubes its no go, the lens acts as normal; with plain contactless tubes the focus drive is running all the time, but does CIF.

My smallest tube is 12mm so that limits the kit 55mm lens to 307mm maximum. Probably acceptable for macro, but.....


Benard

I should have said contactless tubes, sorry.

Certainly works with my Vivitar macro, but obviously fully manual and would limit things outside of macro. No problems with the focus drive running here, so lenses obviously differ.

What about some tape over the contacts?

My contactless tubes present a plain epoxy coated finish to the camera. Isolating the lens and AF, so I can't see it being variations in the lens.

Masking tape over contacts just stops the AF but still takes blurred pics. Removing the tape removed a lot of grot as well - magic!

Bernard

I disagree. There's no logical reason why the camera can't be programmed for CIF to work when the camera is set to MF whatsoever ...

... and in fact expecting it to work when the camera is set to MF is perfectly sensible IMO. Because this would mean that AF lenses with no quick shift could be used to manually set a focus distance and have CIF trigger the shutter when the AF Detection triggers.

It's only a matter of programming. Pentax have for some restrictive reason chosen otherwise.

You're missing the point. The camera only detects the point of focus when its AF system is switched on. Switch it off and you can only use MF, obviously.

Well of course that's true. You can always argue for an alternative design.

It should be programmable, to allow CIF with the camera set to MF - if there was an option in MF to prevent shutter release when not focused, just as there's an option in AF to permit it, I imagine it would all just work.

But a lot of people seem genuinely confused about how it currently works, and seem therefore surprised when they get one behaviour or another.

Well, this is misleading.

You still get focus confirmation when the camera is set to MF, so the AF system is still on and working.

The point is whether it lets you release the shutter when it's not focused.

Things have become a little blurred with the K-5, with its additional options, but the point remains.

Interesting that F*300 doesn't work with CIF. I wouldn't have expected that at all. The only F lens I have left in the house is the 70-210 and that has no MF switch.

Virtually any lens without contacts is going to work with CIF, so my K lens and adapted to PK Zeiss, Cosina and Voigtander lenses work perfectly, as does my DA*300 and

The Tamron 90 di doesn't because the AF/MF sleeve is basically just a quick-shift by another name and doesn't actually disengage the screw drive as it does with those with dedicated AF/MF switches.

BTW for the Tamron 90 and any other lens not working with CIF, including all AF lenses without an MF/AF switch, you can force CIF to work by depressing the lens lock with one finger and holding down the shutter with another as you manually focus the lens. The AF screw drive will turn but as the screw can't engage the lens' focus mechanism, only when achieve focus manually will the shutter trip. Just don't let the lens fall off !

If you have a lens with contacts that doesn't work with CIF then I believe (but haven't had the need to do this myself) that you need to short out one of the contacts by scrapping the paint off it so it's bare metal (sometimes this is a problem with M42 - PK adapters whereby you need to do the same thing).
To make sure that the lens body does short the contacts you can either 1) remove the paint on the lens body over the relevant contact or 2) place some aluminium foil or metal tape between the lens and the body when you attach the lens. You can then use your lens with CIF. Theoretically this should also work with the F*300 as it effectively makes the lens an MF lens no different to a K.

Isn't it much easier to just follow the instructions? I know some love to make things work where they "shouldn't" work, but for the majority of users that isn't really relevant.

It's a useful, but minor, feature that's available on all the Pentax DSLRs I've used, and it's a consequence of how things work, rather than the raison d'etre.

Thank god heavens there are people that aren't content to just put up with the status quo.

On the contrary. It's an extremely useful feature, that Pentax have explicitly recognised with a dedicated option in the K-5 menu.

It wouldn't surprise me in the least, if, eventually, they further recognise its limitations and add more options to remove them.

It would surprise me, however, if they did it soon, or without a lot of haranguing.

I'm sorry John but that doesn't make any sense to me at all ! If a feature is provided in camera or in-lens then why not make use of the possibilities ? Pentax made it possible and it's a wonderful function that makes manual focusing (and catching movement with MF lenses) a lot easier for many folks so why deny them that pleasure. The addition of a tiny piece of silver paper or metal tape is all that is required. for non-compliant lenses.