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06-15-2016, 04:38 AM   #16
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QuoteOriginally posted by Lowell Goudge Quote

I do not discuunt also the possibility of missed focus also being part of the culprit and this can happen when you have the edge of a subject with a good contrast pattern behind it. It may have focused on the tree not the bird,
Yep, Bob, which AF point went red?

06-15-2016, 05:08 AM   #17
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QuoteOriginally posted by clackers Quote
Yep, Bob, which AF point went red?
He mentioned center point and recompose...
06-15-2016, 05:16 AM   #18
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QuoteOriginally posted by UncleVanya Quote
He mentioned center point and recompose...
Oh, yeah, thanks for pointing that out!

I would have done the same, so have nothing to add.
06-15-2016, 01:39 PM   #19
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On the 20d, was the focusing screen changed?

06-15-2016, 01:48 PM   #20
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QuoteOriginally posted by denik Quote
On the 20d, was the focusing screen changed?
It makes no difference to focusing with an AF lens.
06-15-2016, 02:14 PM   #21
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The hexagon is a bit useless for manual focus, but it can be useful for knowing that the AF has locked on.

A couple things I'll note from my own experiences:

1. Each time I've gotten a new dSLR body, it has taken me about a month and a lot of shooting to get the practice necessary to be comfortable and consistent results. I was shocked, even when I upgraded from the old K10d to the K5 to the K3. The changes would seem subtle, but I always struggled on initial uses to get sharp focus on shots. Practice is necessary.

2. Some of the cheaper zoom lenses tend to be soft at the extreme telephoto end. I never had the lens you are using, but I did have the 55-300, and it is almost impossible to get a sharp image at the 300 end. The lenses are cheap and performance is not equal across the zoom range. With the 55-300, I was having to limit myself to about 250 mm for good shots. As a result I picked up the 60-250, which is more costly and sharp out to the full 250.

3. Practicing on static and fixed subjects is quite useful. I usually shoot photos along a fence or wall outside my house to (a) check that what I think I have focused on is in focus and observe the depth of field and (2) to practice getting an idea of what shutter speeds I can use reliably hand-held. If there are focus issues, having the fence also allows me to make adjustments to the lens using the camera's micro-adjustments.

4. Using a tripod can also help to eliminate any issues with camera shake, at least while you trouble shoot.

I'll admit that I am not much of a tripod user when I am out and about. I feel too constrained. I only typically use them for long exposures. As a result, I loved it once I got to the K5 (now K3). I can shoot at ISO settings to 6400 (adequate for a snapshot photographer, which I typically am like you stated you were). At ISO 6400, I can almost always shoot at a sufficient shutter speed to keep shake from being an issue.

All that being said, I agree that your sample doesn't show signs of camera shake being an issue. The exposure does look a little dark, and the focus looks like it was nailed on the tree. Pentax has always had issues getting focus where you want, especially when you are dealing with smaller subjects. The K5 and K3 show some improvements, but I suspect you'd need a K1 to get that part perfect.
06-18-2016, 09:33 AM   #22
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Mystery solved (not resolved... Yet!)

Thanks for everyone who posted and all the advice...
As I said before, I was going to go out and do some accuracy testing on my camera to see if it was me, the lenses or the auto focus feature of my K-20D.
The Results are in...
There is definitely an issue with the Pentax DA zoom lenses that I have.
Let me first apologize for not including the lens data in my first post.
The lens I was using and that I use when I am out field shooting is an SMC Pentax DAL 1:4-5.6 50-200mm Zoom ED. (Purchased on Ebay...)
When trying to focus at full focal length, (200mm) it is okay, at close range, but not great.
After that, the lens will focus a few inches/ up to a foot beyond where the camera says it is in focus. At close focus the lens will focus within an inch of the subject so using a higher ISO and smaller aperture corrects that...
In my examples below you will see the comparison between the DA and my SMC Pentax 200M (The DA used an auto exposure of 1/500 @f8.0 the SMC 200M used a manual setting of 1/350 @ f8)
As you can see there is a world of difference...
Pentax DAL 200 Auto The focus here was supposed to be on the first red mark...



SMC 200 M 1/350 @f8



Thanks again for all the help!


Cheers
Bob
06-18-2016, 10:19 AM   #23
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Bob, you may want to look at the Pentax AF fine tune menu and experiment a little to correct what appears to be back focus with this lens.

I would also add that the rule trick can confuse AF as there is not a solid enough line to concentrate on - perhaps better to mark the timber with a felt tip to be used as an exact FP?

The problem may be if corrected at 200mm it may throw out 50mm but IMHO worth a try at your most common FL

Rather than invest in focus charts I would suggest looking at Bart Van Der Wolfs excellent method using moire pattern to confirm focus points
AF microadjustment for the 1Ds mark III, 1D Mk3, 5D Mk2, 7D, 1D X

06-18-2016, 10:21 AM - 1 Like   #24
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See also: PENTAX DSLRs: PART-1. Autofocus Adjustment charts for front and back focusing problems. Good for Pentax, Canon and Nikon.
06-18-2016, 06:10 PM   #25
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QuoteOriginally posted by emalvick Quote
I did have the 55-300, and it is almost impossible to get a sharp image at the 300 end.
Assuming the copy of the lens is OK, with a little practice it is possible.


---------- Post added 06-19-16 at 11:28 AM ----------

With telephoto lenses the depth of field is quite short, so stopping down gives more margin for acceptable focus. Also, with consumer zooms like the 55-300, sharpness generally improves one or two stops down from wide open. So with the 55-300, I try to get f7.1-f11 whenever the conditions allow.
06-18-2016, 07:01 PM - 1 Like   #26
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A box of matches (or something) as the focus target on the wood next to the tape measure may help.
06-19-2016, 03:30 AM - 1 Like   #27
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I have used the K20D with the DAL50-200 for many years and have not had the issues as noticeably as in the image you posted. Given your experience with SLRs and the examinations you have made to all aspects to this point I think some focusing adjustment to the lens is needed for you to resolve the issue.

Attached is a picture that was taken in shade with similar subject matter over similar distance with the same lens and camera.
1/60sec, F8 and ISO200



And this one on the same shoot at 1/50 sec



Good luck with solving this dilemma.
06-20-2016, 09:02 PM   #28
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Emalvick says "The hexagon is a bit useless for manual focus, but it can be useful for knowing that the AF has locked on".

On the contrary, the green hexagon focus indicator applies equally to manual lenses. From personal use ( I use it all the time) and page 116 of Pentax K5 II operating manual.


06-20-2016, 11:55 PM   #29
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QuoteOriginally posted by beachboy2 Quote
Emalvick says "The hexagon is a bit useless for manual focus, but it can be useful for knowing that the AF has locked on".

On the contrary, the green hexagon focus indicator applies equally to manual lenses. From personal use (I use it all the time) and page 116 of Pentax K5 II operating manual.

Seconded. Focus confirmation is wonderful.
06-21-2016, 07:09 AM   #30
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Focus confirmation is ok with slower lenses. With faster aperture lenses it is hit or miss. Also this method relies on fine AF tuning which can't be setup on a per lens basis for most manual focus lenses.
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