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07-21-2011, 02:49 AM   #1
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Catch in Focus in Question

I recently read somewhere in the internet that the guy was trying to use catch in focus and ended up with multiple shots and in those resultant pictures, only one was sharper than the rest. The message he was trying to give was there is scope of ending with multiple focus quality levels - but I am not sure whether that was true as I don't have a manual lens yet to try this feature.

I only suspect in largest DOF maybe you get varying degrees of sharpness with varying focal planes but don't know if this is correct.

My next question is: As I understand that to make the DAs to work with catch in focus, I need to disable the AF functionality by a switch which I cannot see in DA 35 f2.4 which means I am presuming this feature will not be available with the DA ALs?


Last edited by sany; 07-21-2011 at 07:12 AM.
07-21-2011, 07:10 AM   #2
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No, DALs do not have that option because they don't have the so called quick shift button. However, if you use aluminum foil in one the the contacts (I think it is the second from the bottom) you can use CIF (catch in focus) with your DAL lenses. It works with my K-X and the 18-55 and the 55-300.
07-21-2011, 07:13 AM   #3
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I for got to mention that some people argue that you can enable catch in focus if you press the release button (the one to remove the lens) while you take the picture... that never worked for me though.
07-21-2011, 09:15 AM   #4
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Try twisting the lens off very very slightly (just enough to misalign the contacts, so no signal passes). You'll know when it's right when you turn the camera on and get the 'input focal length' screen.

07-21-2011, 09:19 AM   #5
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mmm, that makes sense. I will try it when I go back home. Thanks Joe
07-21-2011, 10:41 AM   #6
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will these contacts not create any electrical circuit problems later on!!?
07-21-2011, 10:45 AM   #7
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never heard of it...the contacts basically "talk" to the camera, but there is no risk.
07-21-2011, 10:48 AM   #8
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QuoteOriginally posted by sergysergy Quote
never heard of it...the contacts basically "talk" to the camera, but there is no risk.
I must be wrong, just thinking if the communication happens with the help of some electrical power then it ought to make some issues - again it is just guessing by me.

07-21-2011, 11:12 AM   #9
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QuoteOriginally posted by sany Quote
will these contacts not create any electrical circuit problems later on!!?
Hi sany,

You'd short the "Data" pin with foil or metal tape to fool the body into thinking that an AF lens is an MF lens.

This cannot possibly do any damage to the body since this pin is shorted any time you attach a MF lens with a metal mount anyway since only AF lenses have a data pin. Fully manual lenses (K & M) don't have any pins and short all of the contacts, but do no damage to the body's electrics.

A pretty complete mapping of the contact locations/functions can be found here:

http://www.robertstech.com/matrix.htm

Scott
07-23-2011, 11:29 PM   #10
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QuoteOriginally posted by snostorm Quote
Hi sany,

You'd short the "Data" pin with foil or metal tape to fool the body into thinking that an AF lens is an MF lens.

This cannot possibly do any damage to the body since this pin is shorted any time you attach a MF lens with a metal mount anyway since only AF lenses have a data pin. Fully manual lenses (K & M) don't have any pins and short all of the contacts, but do no damage to the body's electrics.

A pretty complete mapping of the contact locations/functions can be found here:

http://www.robertstech.com/matrix.htm

Scott
there you go, you have a point.
that gives more courage!

thanks
07-24-2011, 06:48 AM   #11
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QuoteOriginally posted by sany Quote
will these contacts not create any electrical circuit problems later on!!?
The electrical contacts are designed to tolerate shorting because older K-mount lens cause them to short circuit. Being short circuited is a normal condition for the contacts.

Some Pentax cameras give better exposure settings with manual lenses if some of those pins are short circuited (in my experience the data pin - the lower most contact is the one to short circuit.)

If you can also short circuit the slightly recessed pin (the A pin) the camera will think all lenses are A type.
07-24-2011, 10:36 PM   #12
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QuoteOriginally posted by newarts Quote
<br />
...Some Pentax cameras give better exposure settings with manual lenses if some of those pins are short circuited (in my experience the data pin - the lower most contact is the one to short circuit.)<br />
<br />
If you can also short circuit the slightly recessed pin (the A pin) the camera will think all lenses are A type.
<br />
<br />
Wow, something of interest to me there! can you elaborate on the above two please, by better exposure do you say the green button will do the metering for me still? or what is the process to get the better exposure after disabling that button?<br />
Secondly, what is the advantage of making the camera think all lenses are 'A'? can it still do catch-in focus?
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