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07-04-2015, 02:39 AM   #1
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focus issue canon and pentax lenses

As noted in the thread title i have noticed an issue with my pentax lenses mounted on my canon 60d. my pentax lenses are all m42 screwmount . When i go pixel peeping after using my pentax lenses they appear out of focus a little when i use the focus point. I do have a katzeye screen in my canon and i have taken images with the kit lens i have and there is no problem there.I thought perhaps it may have been the screen at first however i am confident that i have eliminated that aspect. i get acceptable images when i use the micro prism to focus its only when i use the actual focus point square for focus confirmation that the images are out. Am i correct this is back focus or front focus ? i have done some test shots and i'm pretty sure that if i'm focused at 2 meters say. Then to correct it i have to turn it from 2 m towards 1.5 m (clockwise a tiny amount as viewed standing behind the camera). i am wondering what my options are ? i was thinking if it is back focusing then screwing the lens out 1/2 a turn or so in the adapter aught to fix it correct ? or is my thinking flawed ? if that's the fix then i would buy a few more cheap adapters and glue or shim the lenses into each adapter after doing tests for each lens.if its front focusing then i 'm stuffed for an easy fix i think as the only option would be to remove material of the face of the adapter right ? or does the camera need a return to a sevice department for correction ?
i seem to use the focus point 70 % the other 30% is under live view. thanks in advance for any ideas or suggestions

07-04-2015, 03:07 AM   #2
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I think this is just the AF system tolerance, which is something I believe you have to live with when using AF confirmation with manual lenses. One simple remedy would be to stop down a bit more. A global AF adjustment might help reduce the tolerance when focusing from one side (i.e. either when going from infinity to minimum, or the other way around), but FF/BF really only applies to AF lenses.

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07-04-2015, 04:28 PM   #3
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QuoteOriginally posted by chardie Quote
if that's the fix then i would buy a few more cheap adapters and glue or shim the lenses into each adapter after doing tests for each lens.if its front focusing then i 'm stuffed for an easy fix i think as the only option would be to remove material of the face of the adapter right ? i seem to use the focus point 70 % the other 30% is under live view.
what adam said...

in the world of mirrorless liveview, hard focus stops on lenses are obsolete, because cheap adapters always allow the lens to manually focus past infinity, which gives you plenty of room for getting perfect infinity focus... normally there is never any need to machine or shim an adapter.

if the hard stop on the lens is off with a dslr, your only recourse is to adjust the lens... ala the korean 14/2.8 wide primes... you should be able pixel-peep your shots to confirm that the lens is never reaching perfect infinity focus.

doesn't dslr focus confirm use the mirror, just like af autofocus does? if so, won't it have the same problems with ff/bf? liveview with a dslr is with the mirror up, so there can't be any ff/bf issues?
07-05-2015, 04:13 AM   #4
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perhaps i am a little needy i like to hear the beep and know that's it take the shot. i may need to adjust my style perhaps. care to elaborate on the korean primes ? i am guessing you mean samyang ? i have seen some good reviews on the 85mm 1.4 which i have been tempted to get. i would like to get a pentax 85mm 1.8 in m42 however the prices are a little high for my taste i may as well buy new i figure . i did just have a play with the canon under live view there appears to be no focus confirm with live view unless i have turned a setting off somewhere but i doubt that has happened.

07-05-2015, 11:28 AM   #5
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beep won't help if the focus confirm isn't accurate.

try adjusting the level of focus peaking that's being displayed in live view, you want it to be just barely visible.

07-06-2015, 01:02 AM   #6
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yes your right ! beep doesn't help when when focus is out that is why i am here asking for advice. i have looked on the net and it seems the the canon model below and the model above have some sort of software that can be altered to fix the issue in camera however the 60 d doesn't have that. At the moment my options are either use it in live view and zoom in (my eyes aren't what they used to be ) or use the microprism screen and trust my eyes and ignore the focus confirmation. While playing with settings in the camera i did manage to change something that caused the mirror to lock up for every shot except in liveview that took 24 hours to solve which meant i had to depress the shutter button twice per image. Thought i'd really stuffed it up for awhile there . Being currently unemployed i cant afford to send it to canon for adjustment at this point and i'd want more info about what is possible and what is not before i did that anyway. That's the other reason i'm in the forum looking for a bit of self help lol
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i have been thinking of getting the version 3 confirm chip for a couple of adapters. These apparently allow the aperture to be programmed in so to speak. i'm guessing that its rather inconvenient to do that for every shot. Still it would be nicer to have the the base aperture programmed in (i think) rather than have every shot fixed at 1.4 no matter what lens is mounted. fromr my searches the price of these gen 3 chips is close to 3 times the price of the cheap confirm chips which is why i'm a bit hesitant to commit at the moment. has anyone had much experience which these chips and is it an easy enough process to perform ? thanks again in advance for any advice.

Last edited by chardie; 07-06-2015 at 01:08 AM.
07-06-2015, 06:21 PM   #7
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unfortunately the 60d doesn't appear to have a microfocus adjustment... i would want to see if that helped the focus confirm problem.

07-07-2015, 10:56 AM   #8
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Chardie, I use numerous Pentax lenses on Canon bodies including 60D and 6D. The 60D does not have in-body focus adjustment, so you cannot do it that way. You can however accomplish this through use a a chipped adapter that supports focus adjustment. You program the chip with the focus adjustment. This is precisely what you want. Not all chips support this, so choose carefully when shopping.

P,S. I have some spare chips of the type you are looking for. They also support aperture and focal length programming. PM me if you like to buy any.
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