catch in focus


redbusa99

Link Posted 05/03/2017 - 00:44
having trouble getting this to work with a reversing ring, which is anodised black, the shutter releases when out of focus. do i need to scrape the coating off the ring to short certain contacts out to get it to work? it works fine with the lens attached (M 28mm f3.5) but this has a chrome mating face. any help much appreciated
K3 II and the odd lens or 2

Flickr

redbusa99

Link Posted 05/03/2017 - 08:26
answered my own question and just purchased a genuine Pentax one in chrome, this will short out all contacts as the lens mount does.
K3 II and the odd lens or 2

Flickr
Last Edited by redbusa99 on 05/03/2017 - 08:27

McBrian

Link Posted 05/03/2017 - 08:28
No, you shouldn't have to do that.

CIF won't work if you have focusing set to the back button only, the camera has to set to focus with half press of the shutter button.
Cheers
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.

McBrian

Link Posted 05/03/2017 - 08:29
redbusa99 wrote:
answered my own question and just purchased a genuine Pentax one in chrome, this will short out all contacts as the lens mount does.

I didn't know that
Cheers
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.

stu62

Link Posted 05/03/2017 - 09:15
Stupid moment

Why would you want to short out contacts it's electrical you short out any power circuit it wil cause damage

screwdriver222

Link Posted 05/03/2017 - 09:43
Quote:
Why would you want to short out contacts it's electrical you short out any power circuit it wil cause damage

With a manual lens such as an M series for example that has no contact,s it would short out contacts on the camera body, that in turn would tell the camera that a manual lens is fitted. I think its only 2 pins that have to be shorted and if a reversing ring extension tube or a lens has a painted or anodised mount then the camera will not recognise that a lens is fitted.
Flickr link

pschlute

Link Posted 05/03/2017 - 10:07
stu62 wrote:
Stupid moment

Why would you want to short out contacts it's electrical you short out any power circuit it wil cause damage

By "short out" we mean that bare metal (not a lens connector) touches the cameras connectors. We don't mean sparks, smell of burning, "OMG what have I done" moments
Peter



My Flickr page

petrochemist

Link Posted 05/03/2017 - 11:12
stu62 wrote:
Stupid moment

Why would you want to short out contacts it's electrical you short out any power circuit it wil cause damage

The aperture contacts on a lens/mount are not 'power circuits' they are low voltage data connectors which are read by whether or not they are earthed. This is very common in binary data systems The usual implementation is 5V is 1 & 0V is 0. The cable release on Pentax (& Canon) cameras uses the same system of forcing contacts low to activate.
Mike
.
Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.

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Last Edited by petrochemist on 05/03/2017 - 11:16

redbusa99

Link Posted 06/03/2017 - 08:10
thanks people, i did have shutter release set to AF as i use CIF quite a bit with macro but it still kept firing even when out of focus. it took a while for my old brain to twig the coating on the ring could be the problem
K3 II and the odd lens or 2

Flickr
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