[pentaxfall]

Is it possible to conduct a lens calibration test and share your results?

Typically, lens calibration is conducted by being a certain distance away from the calibration target: focal length * n (n is typically a value between 25-50). Since you have a 560mm, I would not expect for you to stand 90 feet away from a target. Instead, I would just choose a 'working' distance. I selected 40 feet when I calibrated my 500mm.

Some additional tips:
- lens on a tripod
- target must be well lit
- turn OFF image stabilization
- shoot at the widest aperture available (in your case, 5.6)
- shoot at a lower ISO (I would aim for 800 or lower)
- shoot with a shutter speed equal to or GREATER than the max focal length to mitigate shake and increase sharpness
- use single point focus

The printout target should be fine, but I would find an image that has a ruler positioned next to the center target. The ruler is used to show degrees of front or back focus.
...

So, I manufactured a calibration tool of sorts, and took about sixty shots, varying the fine adjustment number every three shots or so, using only "live view" autofocus. Distance, about 41'. Results were all over the place. Extremely inconsistent. Finally got the best one I could get with that method (by the way, I was shooting with the camera sideways, and didn't bother to realign the image because the ruler's easier to read that way - the 24" mark is exactly even with the point of focus, and the 2x4 stud, 45 degrees off from plane of target, is eight feet long with approximately one inch increments). (I repeated some sets of test shots because the images were wildly inconsistent. I came to the conclusion that there's something wrong with the autofocus gizmo in the lens, because I tried the same thing with a 70-200 zoom (which tested perfectly at zero adj. value) and with both a K-1 and K-50 with similar results. I did get one sharper image with manual focus but still no comparison to the pictures posted on this thread. By the way, I've never messed with AF calibration before, had it turned off, because no other lens has caused any problems with autofocus.
This w/LV-AF is using an adjustment value of +4:

[sutherland]

So, I manufactured a calibration tool of sorts, and took about sixty shots, varying the fine adjustment number every three shots or so, using only "live view" autofocus. Distance, about 41'. Results were all over the place. Extremely inconsistent. Finally got the best one I could get with that method (by the way, I was shooting with the camera sideways, and didn't bother to realign the image because the ruler's easier to read that way - the 24" mark is exactly even with the point of focus, and the 2x4 stud is eight feet long with approximately one inch increments).
The first of these is with manual focus (generally my preferred method), and the second w/LV-AF is using an adjustment value of +4:

That calibration tool should work just fine. One suggestion: shift the ruler down so that the middle of the rule lines up with center point of one of those circle targets. The aim of this is that when you shoot, you can validate the following:
- if the number (on the ruler) directly inline with the target is the sharpest, then no adjustment is necessary
- if the number (on the ruler) directly inline with the target is blurry and a number above it is sharper, that would mean the lens/body combo has back focusing
- if the number (on the ruler) directly inline with the target is blurry and a number below it is sharper, that would mean the lens/body combo has front focusing

I would not use liveview. I would use your viewfinder and center point to target. I would also use your camera's Auto Focus as that is the mechanism you are trying to resolve, not the manual focus.

Review on screen to confirm front or rear focus, then take multiple shots at different AF adjustment points (remember the order in which these are performed). Review on screen to find the best value.

[Des]

Little Wattlebird sunbathing. K-3 + FA*300 f4.5


I used a little fill flash in each of the next three.

A vocal Lewin's Honeyeater. K-S2 + DA 55-300 PLM at 300mm


More contemplative this time. K-3 + FA*300 f4.5.


Laughing Kookaburra. K-3 + FA*300.

[Mike L]

Note the claws, just what a roo needs when attacked by drop bears



---------- Post added 15th Mar 2019 at 10:34 AM ----------

This goanna was a small one at about 1 metres long



His big cousin though was closer to 2 metres

[redpit]

Little Wattlebird sunbathing. K-3 + FA*300 f4.5
I used a little fill flash in each of the next three.
A vocal Lewin's Honeyeater. K-S2 + DA 55-300 PLM at 300mm
More contemplative this time. K-3 + FA*300 f4.5.
Laughing Kookaburra. K-3 + FA*300.

Note the claws, just what a roo needs when attacked by drop bears
This goanna was a small one at about 1 metres long
His big cousin though was closer to 2 metres

Great images, congratulations to both! Thank you for sharing. I love images of the fauna/flora of the other side of our planet (for me) because its both different and familiar at the same time!

[Des]

Great images, congratulations to both! Thank you for sharing. I love images of the fauna/flora of the other side of our planet (for me) because its both different and familiar at the same time!

Thanks very much. Yes we are blessed with an abundance of wildlife here.

[alfa75ts]

So, I manufactured a calibration tool of sorts, and took about sixty shots, varying the fine adjustment number every three shots or so, using only "live view" autofocus. Distance, about 41'. Results were all over the place. Extremely inconsistent. Finally got the best one I could get with that method (by the way, I was shooting with the camera sideways, and didn't bother to realign the image because the ruler's easier to read that way - the 24" mark is exactly even with the point of focus, and the 2x4 stud, 45 degrees off from plane of target, is eight feet long with approximately one inch increments). (I repeated some sets of test shots because the images were wildly inconsistent. I came to the conclusion that there's something wrong with the autofocus gizmo in the lens, because I tried the same thing with a 70-200 zoom (which tested perfectly at zero adj. value) and with both a K-1 and K-50 with similar results. I did get one sharper image with manual focus but still no comparison to the pictures posted on this thread. By the way, I've never messed with AF calibration before, had it turned off, because no other lens has caused any problems with autofocus.
This w/LV-AF is using an adjustment value of +4:

G'day Dan,

Unless you have a filter on the front of the lens or a fingerprint/smudge on the internal filter it does sound like a problem with the lens.

At 41' you would have a depth of field of about 6 inches and in the image you posted roughly the middle third of the ruler was in better focus but not as sharp as it should be. That shows that the issue is not front/back focus and must be something else.

[alfa75ts]

Golden-headed Cisticola (Sis-tic-oh-la):

[zzeitg]

DA560

[Mike L]

No trouble filling the frame with these guys

[sutherland]

[aslyfox]

trumpeter swan ( only captive bird )
hen wood duck
drake mallards

K 3 + HD PENTAX-DA 55-300mm F4.5-6.3 ED PLM WR RE

[aslyfox]

another set of three species

Trumpeter Swan

Hen Wood Duck

Turtle


K 3 + HD PENTAX-DA 55-300mm F4.5-6.3 ED PLM WR RE

[swip]

No trouble filling the frame with these guys

A very nice pair.

---------- Post added 03-16-19 at 11:55 PM ----------

A snowy owl that I came across on my way home yesterday.