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12-18-2016, 12:38 PM   #1
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Pentax K-70 and Tamron not liking each other?

Well, i have Tamron 18-200 lens that is left from my K-30. On K-30 it works very well, but on K-70 the focus is only in the middle of the picture and i cannot help myself to enter into menu for LENS CORRECTION (it's all greyed out).
I don't know why but on K-30 is working Ok, on K-70 is out of focus
Maybe i can help myself if i manually enter focal length of for the lens (currently is 55). Is there a better option for this?
Need a help..thank you!



12-18-2016, 01:40 PM   #2
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QuoteOriginally posted by yoko666 Quote
but on K-70 the focus is only in the middle of the picture
Please elaborate. Are you saying that this lens on your K-70 is never in focus in the edges/corner or are you saying that you cannot use other than the center AF point? Something else?

QuoteOriginally posted by yoko666 Quote
and i cannot help myself to enter into menu for LENS CORRECTION (it's all greyed out).
As with your K-30, lens correction is not available for non-Pentax brand lenses.

QuoteOriginally posted by yoko666 Quote
Maybe i can help myself if i manually enter focal length of for the lens (currently is 55).
If you are allowed to enter focal length, the camera is not detecting your lens as being auto-focus. This is usually caused by poor connection at the data contact on the mount. You may want to consider lightly buffing the mount contacts on both body and lens with a microfiber cloth to remove any contamination.

Is this the only lens where you are having problems on the K-70?


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12-18-2016, 02:57 PM   #3
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Yes, lens correction works with a database inside of the camera. This database only includes Pentax lenses, so lens correction functions are not available with Tamron, Sigma, Samyang, and other non-Pentax lenses.
I suggest you clean the lens and camera mount, make sure they are free of grime and damage. Now when you mount the lens, make sure it clicks into place. Sometimes a brand new mount might be a little tight at first, but the lens has to go all the way and then click into place.
If this doesn't solve the problems, then please elaborate about the AF settings. Can you achieve good, sharp photos with manual focus?
12-18-2016, 03:47 PM   #4
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Tamron are reverse engineered, or at least that has been said, so specs could be off a little.. I sent my K-30 to Tamron with my Tamron 70-200 because it was not lining up correctly, they adjusted it and it works perfect, as it also does with my K50 and a friend's K-50 too. I doubt they would do that for an older lens (unless you bought it new). Just make sure the contacts are very clean, you can use a little alcohol on that microfiber cloth that Steve suggested.

12-19-2016, 12:08 AM   #5
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I am saying that pictures are not in focus at the edges (corners). It's more likely like the center-circle is focused but edges are a bit blurry. I've tried with stock Pentax DA 18-55 mounted and all ok.
Now, i've cleaned all the contacts (both the camera and a lens) and the camera doesn't ask me at the start for the focal length. All working OK with the lens, AF..etc but only pictures are rather not focused at the edges. I will try later today to add some picture for you to see it. And i say it doesn't happen with K-30
12-19-2016, 07:25 AM   #6
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Here are 2 pictures on same K-70
1. Shot with Pentax lens 18-55

2. Shot with Tamron 18-200


You can notice out of focus blur that isn't on 1st picture. On K-30 both lenses act same..perfect. What can i do to prevent this?
12-19-2016, 07:59 AM   #7
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QuoteOriginally posted by yoko666 Quote
Here are 2 pictures on same K-70
1. Shot with Pentax lens 18-55

2. Shot with Tamron 18-200


You can notice out of focus blur that isn't on 1st picture. On K-30 both lenses act same..perfect. What can i do to prevent this?
Could this simply be the extra resolution plus some minor autofocus fine adjustment needed?

Can you try manually focusing or focusing in live view to see if the differences are decreased?

12-19-2016, 08:53 AM   #8
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QuoteOriginally posted by UncleVanya Quote
Could this simply be the extra resolution plus some minor autofocus fine adjustment needed?
Can you tell me how to do that please? Thank you!

EDIT: Not so noticable in with LV and M ...

Last edited by yoko666; 12-19-2016 at 08:58 AM.
12-19-2016, 11:13 AM   #9
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QuoteOriginally posted by UncleVanya Quote
Could this simply be the extra resolution plus some minor autofocus fine adjustment needed?
Good point! What passes muster at 16 Mpx will often not be good enough at 24 Mpx.


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12-19-2016, 11:32 AM   #10
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But can you please someone explain how to do fine AF tuning?
And also on 14mp (this is the first option below 24mpx) the lens doesn't work OK
12-19-2016, 12:22 PM   #11
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QuoteOriginally posted by yoko666 Quote
But can you please someone explain how to do fine AF tuning?
And also on 14mp (this is the first option below 24mpx) the lens doesn't work OK
I have zero knowledge of the K-70 beyond the common features that it has with the K-50 and K-3.

Here's an article (I think written before the K-70 was released) that should give the basic info:
Fixing Front and Back Focus - The Remedy - In-Depth Articles

The reason you may see this on the K-70 and not the K-30 is that there is a tolerance for minor differences of mount distances. If the mount of the 18-55 is a little short and the mount of the Tamron is a little long and the mount on the K-30 is perfect and the mount on the K-70 is short or long (or vice versa) - then on one camera the two might work without adjustment and be OK - while on another camera one of these may fall out of the range of acceptable. This is worse with higher resolution which is why I suggested that might be involved.

Try the fine tuning first and then see if you have issues. If LV and Manual focus work reasonably well that suggests that the PDAF calibration is the issue. This calibration is what you adjust in fine focus adjustments.
12-19-2016, 12:28 PM   #12
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QuoteOriginally posted by yoko666 Quote

EDIT: Not so noticable in with LV and M ...
Yep, as others have indicated, you're actually missing PDAF focus consistently.

On consumer level Nikons there's nothing you can do, with all Pentaxes you can micro adjust.
12-19-2016, 12:37 PM   #13
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Ok, i'll try tomorrow and will provide a results. The only thing that bothers me is that i am able already in a ViewFinder to see those mild unfocused edges..
12-19-2016, 12:43 PM   #14
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QuoteOriginally posted by yoko666 Quote
Ok, i'll try tomorrow and will provide a results. The only thing that bothers me is that i am able already in a ViewFinder to see those mild unfocused edges..
Sorry but there may be a small language issue here.

Are you saying you see this focus problem in the viewfinder? If so be aware that the viewfinder focus and the actual focus DO NOT use the same calibration. The viewfinder is calibrated via shims and only affects how this looks to you. Make sure you adjust your diopter as well for sharp viewing of the data in the viewfinder not to the image itself and that should clearly show if the viewfinder is properly shimmed. There is no way to adjust the viewfinder to reflect lens differences - but normally the viewfinder is so sloppy in terms of precision of focus that it doesn't show these af fine focus differences. Essentially once you have the viewfinder as close to perfectly at the same distance from the lens as the sensor that's the best you can do. But the sloppy nature of the focusing screen makes it hard to get exactly perfect and so I'm surprised you are seeing any differences at all.


If you manually focus while using the viewfinder and that looks acceptable, or use live view and then switch back to the viewfinder (on a tripod) and that looks right then it's likely that AF fine tuning is all you need. If the viewfinder looks wrong even when the LV is in focus I'm not sure what is going on if the diopter is adjusted correctly.

Let me know if I am misunderstanding you.
12-19-2016, 01:01 PM   #15
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What are the apertures set to ? I.E. Are both shots taken at f/5.6 ?
While I haven't used the Tamron 18-200, I do have the Pentax 18-55 and a Sigma 18-200.
The 'superzooms' such as the 18-200 typically suffer more outside of the center as they have to be able to function as both a wide (18mm), normal (55mm) and zoom (+135mm).
Even the decent Pentax 18-135mm has been critiqued on this 'issue' (Yes, I have one as well).
As a result, my 18-200mm was retired for my 18-135mm, which is my 'all in one' walkabout lens.
If/when I'm somewhat serious, I have a Sigma f/2.8 28mm, a Pentax f/1.4 M 50 (and f/1.8 DA) as well as a Rokinon f/1.4 85mm and a Pentax f/4 M 200mm.

In general, zooms with 3x or less are ideal for quality across the frame and at various focal lengths and aperture settings.
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