FOV comparison DA21 on APS-C vs FA31 on K-1/FF

dtra · 11-23-2016, 09:26 PM

Hi all

I have both lenses but only one body (trusty old K-5), I haven't got around to trying to fix my DA21 focusing issues yet so I've been using primarily the FA31 recently, I do miss the FOV the DA gives though. Now I'm not about to get the K-1, and I'm not sure when I will get the full frame Pentax (I will eventually), but out of curiosity was wondering if the FOV for these two lenses on the respective bodies is similar or not?
David

**clackers** · 11-23-2016, 09:29 PM

They are, David.

bertwert · 11-23-2016, 09:33 PM

Close enough you wouldn't notice any difference.

dtra · 11-23-2016, 09:48 PM

Ah thanks, just need to find some time to try and fix this DA then, or save some money to get the FF

Kozlok · 11-23-2016, 09:54 PM

Originally posted by dtra

Ah thanks, just need to find some time to try and fix this DA then, or save some money to get the FF

What's wrong with your DA21? I've had mine apart (screws came loose and it self-disassembled).

More info in this thread: HERE

dtra · 11-24-2016, 09:35 PM

Originally posted by Kozlok

What's wrong with your DA21? I've had mine apart (screws came loose and it self-disassembled).

More info in this thread: HERE

I'm pretty sure I have this issue: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/121842-prob...-infinity.html

Kozlok · 11-27-2016, 08:43 PM - **1 Like**

Originally posted by dtra

I'm pretty sure I have this issue: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/121842-prob...-infinity.html

This is the first stage of the problem I had. If the screws are loose, the focus can become off. If they loosen up all the way, the lens separates. Those 3 screws connect the front element to the focusing mechanism and set infinity focus. When they get out of alignment, the focusing will stop before the lens reaches infinity (or can go the other way).

You need to remove the front covers (the first two are held by sticky tape, then the third cover has 3 tiny screws). Don't remove anything on the mount side. If any of the screws is completely out, put it in right away, but not too tight. You may also need to loosen the screws up a little more, but in any case get all three in and a little loose, and then rotate the front element relative to the focus mechanism (I did it by pushing on the screws in the direction of rotation). You should see marks where the screws belong. Once it's back in the right place, tighten up the screws, check for infinity focus. You may need to adjust a little bit one way or the other to get it in the right place.

Once you get infinity back on the mark, remove the screws one at a time and put a drop of thread locker on them, then tighten. It sounds scary, but it's really a very easy repair.

dtra · 11-27-2016, 09:58 PM

Originally posted by Kozlok

This is the first stage of the problem I had. If the screws are loose, the focus can become off. If they loosen up all the way, the lens separates. Those 3 screws connect the front element to the focusing mechanism and set infinity focus. When they get out of alignment, the focusing will stop before the lens reaches infinity (or can go the other way).

You need to remove the front covers (the first two are held by sticky tape, then the third cover has 3 tiny screws). Don't remove anything on the mount side. If any of the screws is completely out, put it in right away, but not too tight. You may also need to loosen the screws up a little more, but in any case get all three in and a little loose, and then rotate the front element relative to the focus mechanism (I did it by pushing on the screws in the direction of rotation). You should see marks where the screws belong. Once it's back in the right place, tighten up the screws, check for infinity focus. You may need to adjust a little bit one way or the other to get it in the right place.

Once you get infinity back on the mark, remove the screws one at a time and put a drop of thread locker on them, then tighten. It sounds scary, but it's really a very easy repair.

Thanks for the details, I need to get the right screwdrivers for the job, what kind of tape would you recommend to stick the plates back on with?

Kozlok · 11-30-2016, 08:02 PM

Originally posted by dtra

Thanks for the details, I need to get the right screwdrivers for the job, what kind of tape would you recommend to stick the plates back on with?

I just stored them carefully so no dirt or hair attached to the tape that was already there, and just re-used it.

11-23-2016, 09:26 PM	#1
dtra Senior Member Join Date: Sep 2007 Location: melbourne, au Photos: Gallery Posts: 158	FOV comparison DA21 on APS-C vs FA31 on K-1/FF Hi all I have both lenses but only one body (trusty old K-5), I haven't got around to trying to fix my DA21 focusing issues yet so I've been using primarily the FA31 recently, I do miss the FOV the DA gives though. Now I'm not about to get the K-1, and I'm not sure when I will get the full frame Pentax (I will eventually), but out of curiosity was wondering if the FOV for these two lenses on the respective bodies is similar or not? David

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11-23-2016, 09:29 PM	#2
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	They are, David.

11-23-2016, 09:33 PM	#3
bertwert Veteran Member Join Date: Jun 2015 Location: Golden, BC Posts: 15,172	Close enough you wouldn't notice any difference.

11-23-2016, 09:48 PM	#4
dtra Senior Member Join Date: Sep 2007 Location: melbourne, au Photos: Gallery Posts: 158 Original Poster	Ah thanks, just need to find some time to try and fix this DA then, or save some money to get the FF

11-23-2016, 09:54 PM	#5
Kozlok Pentaxian Join Date: Jun 2012 Location: Albuquerque Photos: Gallery Posts: 3,148	Originally posted by dtra Ah thanks, just need to find some time to try and fix this DA then, or save some money to get the FF What's wrong with your DA21? I've had mine apart (screws came loose and it self-disassembled). More info in this thread: HERE

11-24-2016, 09:35 PM	#6
dtra Senior Member Join Date: Sep 2007 Location: melbourne, au Photos: Gallery Posts: 158 Original Poster	Originally posted by Kozlok What's wrong with your DA21? I've had mine apart (screws came loose and it self-disassembled). More info in this thread: HERE I'm pretty sure I have this issue: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/121842-prob...-infinity.html

11-27-2016, 08:43 PM - 1 Like	#7
Kozlok Pentaxian Join Date: Jun 2012 Location: Albuquerque Photos: Gallery Posts: 3,148	Originally posted by dtra I'm pretty sure I have this issue: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/121842-prob...-infinity.html This is the first stage of the problem I had. If the screws are loose, the focus can become off. If they loosen up all the way, the lens separates. Those 3 screws connect the front element to the focusing mechanism and set infinity focus. When they get out of alignment, the focusing will stop before the lens reaches infinity (or can go the other way). You need to remove the front covers (the first two are held by sticky tape, then the third cover has 3 tiny screws). Don't remove anything on the mount side. If any of the screws is completely out, put it in right away, but not too tight. You may also need to loosen the screws up a little more, but in any case get all three in and a little loose, and then rotate the front element relative to the focus mechanism (I did it by pushing on the screws in the direction of rotation). You should see marks where the screws belong. Once it's back in the right place, tighten up the screws, check for infinity focus. You may need to adjust a little bit one way or the other to get it in the right place. Once you get infinity back on the mark, remove the screws one at a time and put a drop of thread locker on them, then tighten. It sounds scary, but it's really a very easy repair.

11-27-2016, 09:58 PM	#8
dtra Senior Member Join Date: Sep 2007 Location: melbourne, au Photos: Gallery Posts: 158 Original Poster	Originally posted by Kozlok This is the first stage of the problem I had. If the screws are loose, the focus can become off. If they loosen up all the way, the lens separates. Those 3 screws connect the front element to the focusing mechanism and set infinity focus. When they get out of alignment, the focusing will stop before the lens reaches infinity (or can go the other way). You need to remove the front covers (the first two are held by sticky tape, then the third cover has 3 tiny screws). Don't remove anything on the mount side. If any of the screws is completely out, put it in right away, but not too tight. You may also need to loosen the screws up a little more, but in any case get all three in and a little loose, and then rotate the front element relative to the focus mechanism (I did it by pushing on the screws in the direction of rotation). You should see marks where the screws belong. Once it's back in the right place, tighten up the screws, check for infinity focus. You may need to adjust a little bit one way or the other to get it in the right place. Once you get infinity back on the mark, remove the screws one at a time and put a drop of thread locker on them, then tighten. It sounds scary, but it's really a very easy repair. Thanks for the details, I need to get the right screwdrivers for the job, what kind of tape would you recommend to stick the plates back on with?

11-30-2016, 08:02 PM	#9
Kozlok Pentaxian Join Date: Jun 2012 Location: Albuquerque Photos: Gallery Posts: 3,148	Originally posted by dtra Thanks for the details, I need to get the right screwdrivers for the job, what kind of tape would you recommend to stick the plates back on with? I just stored them carefully so no dirt or hair attached to the tape that was already there, and just re-used it.