[deanklim]

Looked but didn't see any threads about this, but might of over looked one, if I did please direct me to it.

Picked up a used K-3 a while back as a backup to my K-1 and to use the K-3 more for birding. I've tried the camera on several occasions and really haven't been impressed with it. All my images seem to be out of focus and blurry. Today I got a new to me Tamron 90 2.8 and I wanted to check the sharpness of the lens. I set up my lens align tool and was trying to get it in perfect alignment with the tool. I took about a half a dozen shots on a tripod, f8.0, 2 second delay to minimize movement and everyone of them were blurry. Wondering if my eyes in the view finder might be deceiving me I switched over to life view, didn't change any other settings, took a shot and it was sharp! Took it off live view and went back to live view and it was blurry again. Put it back on live view and it was sharp. All settings should be the same in both live and viewfinder. What am I missing on being able to get really sharp images through the viewfinder??

Thanks for any and all suggestions and help

[pschlute]

Have you tried AF/FA ? (Autofocus-FineAdjustment) With my K1 I need to use +8 on average with my lenses to calibrate perfect focus.

If your second image was with viewfinder AF it looks like you have front-focus issues. Use single centre AF only and shoot wide open, not at f8. Do 10 tests each time making the camera/lens focus from infinity/shortest focus distance each time.

[deanklim]

I was thinking AF FA too. Lens Align said to use f8 to make sure everything was in line. And make adjustments as needed. Then do my test shots wide open. Using the viewfinder my pictures were to blurry to align everything. In live view it’s much sharper. I guess my question should be is why is there such a difference in AF in live view and view finder?

[Wingincamera]

Using the VF maybe it needs Doppler adjustment for focusing. I think that is the correct name for it. It has nothing to do with the lens, just adjusting the VF to your eyes, can be different for every person, like wearing glasses.

[deanklim]

Does the Doppler adjustment affect the auto focus function? I always thought it might look a little blurry to me but the final photo should be sharp.

Using the VF maybe it needs Doppler adjustment for focusing. I think that is the correct name for it. It has nothing to do with the lens, just adjusting the VF to your eyes, can be different for every person, like wearing glasses.

I think you have to adjust the diopter setting as Wingincamera suggests. You wrote that you have blurry vision in VF, that means the diopter is not adjusted to your eye. There is a procedure here on Pentaxforums that describes how to adjust this. You do this with no lens on the camera against a well lit background as I recall. The diopter adjuster is situated at the right side of the VF.

[stevebrot]

I've tried the camera on several occasions and really haven't been impressed with it. All my images seem to be out of focus and blurry.

OK

Today I got a new to me Tamron 90 2.8 and I wanted to check the sharpness of the lens. I set up my lens align tool and was trying to get it in perfect alignment with the tool. I took about a half a dozen shots on a tripod, f8.0, 2 second delay to minimize movement and everyone of them were blurry.

OK

I switched over to life view, didn't change any other settings, took a shot and it was sharp!

OK

Quick question...are you saying that you turned AF off before switching to live view?

Took it off live view and went back to live view and it was blurry again. Put it back on live view and it was sharp.

You lost me here...

Quick question...Do you see the same behavior with the Tamron on your K-1 or with other lenses on the K-3?

Another quick question...Is the Tamron an auto-focus version of the 90/2.8? (Just to make sure we are on the same page.)

I guess my question should be is why is there such a difference in AF in live view and view finder?

The two views used two different AF systems, PDAF for viewfinder (AF sensor in floor of mirror box) and CDAF for live view (main image sensor used for focusing). PDAF is faster and more sensitive than CDA, but may be have a lapse of accuracy caused by quirks in lens internal alignment and/or issues of manufacturing or wear. Front/Back focus is the result. CDAF does not have this weakness. The AF fine adjustment feature is provided to help compensate for the PDAF issue, but does not apply to CDAF. As a result, it is not unexpected to CDAF (live view) be sharp while PDAF is providing poor results.


Steve

[Just1MoreDave]

Diopter, not doppler. There's a sliding adjustment on the top edge of the viewfinder. The rubber eyecup conceals it. If you slide the eyecup up, you can see the adjuster and its +/- marks. Slide this back and forth until the numbers in the viewfinder status line look sharpest.

The focus screen might not be perfectly positioned. The viewfinder image comes through the lens, hits the mirror and is projected up onto the focus screen. Then it gets bounced around a few more times by the pentaprism before you see it. Live view is much simpler; the mirror is up, the shutter is open and the image goes right from lens to sensor. The focus screen has to be the right distance away from the mirror for both focus types (live view and viewfinder) to be the same. That is adjusted by placing shims in the focus screen tray to get it to rest at the right distance. The previous ownrer might have had another screen installed and forgot to change the shims.

[Not a Number]

Adjust the viewfinder diopter until the etch markings on the viewfinder screen are as sharp as you can get them.

You may want to check to see if the viewfinder screen is seated properly in the holder too. Search for posts on how to change/replace the screen.

[stevebrot]

I think you have to adjust the diopter setting as Wingincamera suggests. You wrote that you have blurry vision in VF, that means the diopter is not adjusted to your eye. There is a procedure here on Pentaxforums that describes how to adjust this. You do this with no lens on the camera against a well lit background as I recall. The diopter adjuster is situated at the right side of the VF.

Adjusting the diopter may be done with lens on or lens off, but is easiest with a a fully blank frame in the viewfinder. On the K-3 and the K-1, there is a small thumbwheel to the right of the eyepiece. Turn this wheel while looking through the viewfinder until the AF area lines appear sharp. Although useful for manual focus, it does not affect auto-focus operation.


Steve

[stevebrot]

Does the Doppler diopter adjustment affect the auto focus function?

No, it adjusts for your eyes only.


Steve

[stevebrot]

The focus screen might not be perfectly positioned.

This is the part that is not clear, whether the issue is with auto focus or with attempts to manual focus.


Steve

[deanklim]

Diopter, not doppler. There's a sliding adjustment on the top edge of the viewfinder. The rubber eyecup conceals it. If you slide the eyecup up, you can see the adjuster and its +/- marks. Slide this back and forth until the numbers in the viewfinder status line look sharpest.

The focus screen might not be perfectly positioned. The viewfinder image comes through the lens, hits the mirror and is projected up onto the focus screen. Then it gets bounced around a few more times by the pentaprism before you see it. Live view is much simpler; the mirror is up, the shutter is open and the image goes right from lens to sensor. The focus screen has to be the right distance away from the mirror for both focus types (live view and viewfinder) to be the same. That is adjusted by placing shims in the focus screen tray to get it to rest at the right distance. The previous ownrer might have had another screen installed and forgot to change the shims.

That makes sense. I’ve tried multiple lenses on it and 75%+ seem soft me. On my K-1 the ones that aren’t sharp are user error. Might have to send it off and get it realigned

---------- Post added 05-11-20 at 04:16 PM ----------

This is the part that is not clear, whether the issue is with auto focus or with attempts to manual focus.


Steve

Auto focus only.

[stevebrot]

That makes sense. I’ve tried multiple lenses on it and 75%+ seem soft me. On my K-1 the ones that aren’t sharp are user error. Might have to send it off and get it realigned

---------- Post added 05-11-20 at 04:16 PM ----------


Auto focus only.

Then having the focus screen adjusted will make no difference.

Since more than one lens is effected, it might be worth using your LensAlign to evaluate each for front/back focus. If present and if the amount is the similar between lenses, doing a AF fine adjust for "all" might be the cure. (Do the alignment step in Live View using that AF system.)

If general front/back focus is not the problem, something else might be amiss. Possible PDAF problems that cause general issues of missed focus might include:

• Main mirror misalignment
• Dirty or damaged secondary mirror

A camera repair facility should be able to help determine if those are at fault.


Steve

[rogerstg]

Might have to send it off and get it realigned

Before you do that, try the simple fix first. Set the AF fine adjustment to -10 and see if that improves/changes it. If so, you can simply spend a bit more time to dial in the optimum fine adjustment.

(BTW, it's possible that I have the direction of adjustment wrong. If so, use +10)