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02-12-2013, 07:53 AM   #1
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Serious front focus on Bower 85 1.4!!

Hi guys
Posted this question on the "other forum" also ;-)

Got my self a Spyderlenscal a few months back, to test my lenses with.

Because of work I did not have time to do any testing until this week, my lenses are all about spot on, of my Pentax glass only Pentax DA#55 1.4 needed a bit correction, also my Sigma 17-50 2.8 needed a bit back focus correction.

I waited with my Bower 85 1.4 until last because I knew I had a problem there, focusing has always been hit and miss with this lens.

Unfortunately the problem is way bigger than my K5 can handle, at least front focus by -15 and the K5 only can handle -10..... also an other problem is that because the lens is manual I can not make changes to only that lens, I have to change al!......

I try selecting USER, but it still did not work.

Do guys have any helpful advise, should I send the lens back to B&H Photo?

problem is I bought it over a year ago!

Also would they need the K5 too?.

I live in Faroe Islands, so maybe I could send it to Pentax scandinavia, but I don't think they would touch a Bower lens

Is there a way to save only the Bower lens setting, with out overriding the other 2 lenses?

-10 would be better than notting.

Have a nice day.

02-12-2013, 07:59 AM   #2
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Isn't that a manual focus lens?
02-12-2013, 08:08 AM   #3
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QuoteOriginally posted by VisualDarkness Quote
Isn't that a manual focus lens?
Yes it is, i focus manually and it looks spot on when taken the picture, but when reviewing the picture, it is way front focus... the camera tells when one optaines focus.
02-12-2013, 08:09 AM   #4
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You could set the global adjustment to -10, with every other lens to +10, which would get them back to zero.

I suggest experimenting more to see how predictable the focus reading is. Try minimum focus, 3 meters, and infinity; try wide open and stopped down. It could be that the calibration system, while accurate, isn't representative of how you actually use the lens.

02-12-2013, 08:09 AM   #5
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QuoteOriginally posted by VisualDarkness Quote
Isn't that a manual focus lens?
I'd like to hear the response to that one
02-12-2013, 08:11 AM   #6
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QuoteOriginally posted by gryphongryph Quote
Yes it is, i focus manually and it looks spot on when taken the picture, but when reviewing the picture, it is way front focus... the camera tells when one optaines focus.
Can you do a test - focus until you get the confirmation, and then go straight into live view? On a tripod, of course.

This way you can check if it's the lens front-focusing, or if it is focus shifting during aperture change. If going straight to live view is in focus, then it must be shifting when the camera closes the aperture for the shot.
02-12-2013, 08:13 AM   #7
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QuoteOriginally posted by JinDesu Quote
Can you do a test - focus until you get the confirmation, and then go straight into live view? On a tripod, of course.

This way you can check if it's the lens front-focusing, or if it is focus shifting during aperture change. If going straight to live view is in focus, then it must be shifting when the camera closes the aperture for the shot.
A well thought-out response.
02-12-2013, 08:14 AM   #8
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QuoteOriginally posted by gryphongryph Quote
Hi guys
Posted this question on the "other forum" also ;-)

Got my self a Spyderlenscal a few months back, to test my lenses with.

Because of work I did not have time to do any testing until this week, my lenses are all about spot on, of my Pentax glass only Pentax DA#55 1.4 needed a bit correction, also my Sigma 17-50 2.8 needed a bit back focus correction.

I waited with my Bower 85 1.4 until last because I knew I had a problem there, focusing has always been hit and miss with this lens.

Unfortunately the problem is way bigger than my K5 can handle, at least front focus by -15 and the K5 only can handle -10..... also an other problem is that because the lens is manual I can not make changes to only that lens, I have to change al!......

I try selecting USER, but it still did not work.

Do guys have any helpful advise, should I send the lens back to B&H Photo?

problem is I bought it over a year ago!

Also would they need the K5 too?.

I live in Faroe Islands, so maybe I could send it to Pentax scandinavia, but I don't think they would touch a Bower lens

Is there a way to save only the Bower lens setting, with out overriding the other 2 lenses?

-10 would be better than notting.

Have a nice day.
If I were you, I would get in touch with B&H and see what they are saying. If you are still under warranty, I am sure it shouldn't be any problems - I doubt they will give you a refund after so many months though ... maybe a replacement.
I doubt they will need you to send the K-5. If the lens is defective, will be defective on all the cameras.

As far as I know, there is no way to save a specific profile for manual/non-pentax lenses ... but I will stand corrected if there is a such a way.
I also think (could be wrong again), there was some sort of a hack that was allowing you to change the correction value to be bigger than 10 ... can't remember where I've read that ...

And here is a crazy question ... have you changed your focus screen by any chance!?

QuoteOriginally posted by VisualDarkness Quote
Isn't that a manual focus lens?
Hi Captain Obvious ... how's it going!?

02-12-2013, 08:16 AM   #9
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QuoteOriginally posted by JinDesu Quote
Can you do a test - focus until you get the confirmation, and then go straight into live view? On a tripod, of course.

This way you can check if it's the lens front-focusing, or if it is focus shifting during aperture change. If going straight to live view is in focus, then it must be shifting when the camera closes the aperture for the shot.
Yep. if it's spot on in liveview but front-focused when you check the pic afterwards the problem won't be solved with focus calibration as it got nothing to do with the phase-detection AF.
02-12-2013, 08:19 AM   #10
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QuoteOriginally posted by mrNewt Quote
Hi Captain Obvious ... how's it going!?
Focus calibration with a manual lens made my head spin.
02-12-2013, 08:35 AM   #11
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QuoteOriginally posted by mrNewt Quote
If I were you, I would get in touch with B&H and see what they are saying. If you are still under warranty, I am sure it shouldn't be any problems - I doubt they will give you a refund after so many months though ... maybe a replacement.
I doubt they will need you to send the K-5. If the lens is defective, will be defective on all the cameras.

As far as I know, there is no way to save a specific profile for manual/non-pentax lenses ... but I will stand corrected if there is a such a way.
I also think (could be wrong again), there was some sort of a hack that was allowing you to change the correction value to be bigger than 10 ... can't remember where I've read that ...

And here is a crazy question ... have you changed your focus screen by any chance!?



Hi Captain Obvious ... how's it going!?
Hi, yes you are right I changed my focuses screen to a Canon S-type a year ago, which is great by the way, you think it could be a problem?
I think the lens was the same before, but to be true I don't use it that much, like my DA 55 better.
02-12-2013, 08:39 AM   #12
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QuoteOriginally posted by gryphongryph Quote
Hi, yes you are right I changed my focuses screen to a Canon S-type a year ago, which is great by the way, you think it could be a problem?
I think the lens was the same before, but to be true I don't use it that much, like my DA 55 better.
BINGO .... did you changed your shims for the focus screen to correct the focus? If not, that is your problem my dear friend.

You need to change the shims ... and you need to find the correct one ...
Depending on where you are located, you have to get in touch with your "local" Pentax and order a set of focus-screen shims for your K-5
02-12-2013, 08:43 AM   #13
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QuoteOriginally posted by VisualDarkness Quote
Yep. if it's spot on in liveview but front-focused when you check the pic afterwards the problem won't be solved with focus calibration as it got nothing to do with the phase-detection AF.
Thanks a lot for your input, did the to focus with live view, this time, only using my tired eyes and you are spot on, the live view is in focus, but not when iI use the view finder and the confirmation bib, from the camera!!!
02-12-2013, 08:44 AM   #14
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QuoteOriginally posted by mrNewt Quote
BINGO .... did you changed your shims for the focus screen to correct the focus? If not, that is your problem my dear friend.

You need to change the shims ... and you need to find the correct one ...
Depending on where you are located, you have to get in touch with your "local" Pentax and order a set of focus-screen shims for your K-5
But all the other fast glass I have is spot on? well very close too
02-12-2013, 08:47 AM   #15
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QuoteOriginally posted by gryphongryph Quote
But all the other fast glass I have is spot on? well very close too
Are those AF or MF!?

Rule of thumb ... if you change your focus screen you have to change the shims to correct for focus.
If you do not do that, what you see in the viewfinder is not what you get in the picture. And on the K-5 it will tend to front-focus like you have.

I have a K-5 and I have a focus screen as well - I had to install new shim for the focus screen.
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