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09-13-2011, 11:06 PM   #1
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AF adjustment..can you tell me...?

Is the AF lens adjustment on the K-5 reductive or additive? For instance, if my lens is front focussing I assume
I would initially head into the minus direction...yes? Appreciate any feedback. Thanks, Nogster.

09-14-2011, 01:39 AM - 1 Like   #2
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I have just stumbled over this which I will try later today -

AF microadjustment for the 1Ds mark III, 1D Mk3, 5D Mk2, 7D
09-14-2011, 04:20 AM   #3
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Try reading page 126 of the K-5 user manual, near the bottom of the page.

That's how I tend to adjust AF these days and it works quite well and is relatively quick too; saves having to print out a AF target, taking shots at an angle, etc
09-14-2011, 08:26 PM   #4
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Good link. Tried it, but still have this strange anomaly...

That was an excellent link guys. Been experimenting with it right now. Other than the distance required to set up the camera - 15 metres for my Sigma APO 70-300 - it seems relatively
straight forward. (How do folks with small rooms and long lenses accomplish this I wonder?) Anyway, my lens seems spot on at 300mm with a +5 adjustment. Still doesn't explain why
I'm getting more bird tails than eyes in focus... no matter how careful I am. One anomaly I noticed was that at 70mm, the AF point was quite noticeably out. What does one do about that?
Any views on this? Thanks for the excellent reference BTW. Appreciate it. Nogster

09-25-2011, 02:44 PM   #5
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AF not locking on slow-moving subject (or ANYTHING) in frame

I was photographing runners at a Half Marathon event Sunday morning, and anticipated getting some great, sharp images of them with my new Pentax K-5 and DA* 16-50!
Well, I have a MAJOR issue that I need to resolve ASAP…Please see attached images from this morning’s shoot. The Mustang statue was shot moments before the Race Finish images of my son, and as you can see, there is a vast difference in sharpness (using same lens, same ISO, and tripod-mounted. The only differences are that in the race shots, I used High-speed drive mode, and exposure settings of something like f/4.5 at 1/250 sec. These images should be tack sharp, but they arequiteout of focus, which obviously really frustrated me! Apparently, the system did not lock focus on the runner (or apparently on anything in the frame) prior to shooting a burst of about 8 frames!
I have the camera set to “Focus-Priority” for all settings (AF.S and AF.C), Catch-in-Focus Off, Auto AF Point Setting “Auto 11”, Shake Reduction “Off” (when on a tripod).

This K-5 (and all my Pentax lenses) are obviously capable of extreme sharpness and detail rendering, as shown by the other attached image. But when I had the AF Point set on the runner, and fired off a burst of 7 or 8 images at relatively high shutter speed in daylight at ISO 100, I expect to get tack-sharp images! In a few weeks,we're to run a full marathon, and obviously cannot “wonder” if those irreplaceable shots will be sharp! I should just know that they are sharpat the moment of exposure.

Unfortunately, I don’t have the luxury of sending all my equipment to Pentax for pro calibration, so must do this myself.
So assuming I use good technique (tripod/monopod, low ISO, high-shutter speed, bracketing, etc.), what can I do (via in-camera settings) to ensure that I will get sharp results??
As an aside, I’ve been into photography for 35 years, having using many systems, from Polaroid to 35mm to micro 4/3 to large format. The Pentax System is my very first DSLR system, and I have been very pleased with the image quality I get, that is, when the images are properly focused! However, this is also the first system in which I’ve had to make so many “AF Adjustments” for various lenses, AND am still not absolutely confident that my next image will have the biting sharpness that Pentax lenses are known for. Why is that I am only now experiencing “Back or Front focusing” issues? Perhaps I am missing a crucial in-camera setting, as this is my second K-5 body.
Why is it that a much less capable camera/sensor such as the Panasonic G2 (also with interchangeable lenses) never had a focus issue, and I could count on every image at least being recorded sharply, regardless of which lens is used? (I know…smaller sensor yields greater depth of field, etc., but I’m talking purely about sharpness at the point of focus, not overall image sharpnessper se.)
Bottom line…Assuming good light and good technique, how can I guarantee sharpness at the point of focus with this K-5?
Thank you all for any insight you might provide.
Regards,
Stevelink
Steve@totalqualityphoto.com
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09-25-2011, 03:08 PM   #6
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QuoteOriginally posted by stevelink Quote
I have the camera set to “Focus-Priority” for all settings (AF.S and AF.C), Catch-in-Focus Off, Auto AF Point Setting “Auto 11”, Shake Reduction “Off” (when on a tripod).
Here are some tips I could suggest

1) Switch to Auto 5
Since your subject is in the middle of the frame, it would be better to limit the AF points used so the camera doesn't have to guess as much

2) Switch to single-point AF/center-point AF
Using Auto AF point might confuse the camera and it could choose to focus on the background or the high-contrast things in the background such as the tree or the banner or the sign. Use a single-point and track the subject with it. Unfortunately the K-5's AF system isn't that great compared to Nikon's 51-point with 3D-tracking. I've found that the Auto AF hasn't worked out for me too well so far.

3) Prefocus
Since you seem to be shooting runners crossing the finish line, you could pre-focus there, choose a smaller aperture to increase DOF and shoot as they enter this zone. The AF-C might be ruining the shot as the camera keeps alternating between runner and background. I'd use AF-C only for shots where I'm more zoomed in or if the background wasn't so cluttered, so there's less confusion (for the camera) about what I'm focusing on.
09-25-2011, 03:17 PM   #7
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I'm interested very much in this thread and look forward to hearing from some of you experienced folks. No matter what I do I just cannot seem to get sharp photos with my DA 70mm limited. At this point I'm getting sharper images with my kit lens than the limited (very upsetting). Since I'm an absolute newbie to photography I realize there is a large learning curve here but seriously, my kit lens is sharper than my limited and I can get very good detail with it (kit lens). Not so with my Limited! One problem that concerns me is that it is not constant, I have gotten some seriously sharp photos from the limited, they are just very few and far between. May be just all technique but I'm starting to doubt it.
09-25-2011, 03:33 PM   #8
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I'm not to demanding on the AF, so can't really advise much, other than to say I adjusted my Bigma to +3 and got pretty good results.I just took it outside and shot a while using different adjustments on a stationary object at my most usual range.

I almost exclusively use center spot focus, and it also works best for me......otherwise, I find the camera may pick up something I was not intending to focus on. A shallow DOF often plays havoc with me.....and it is often a toss up as to whether it was me or the camera.

Horses at Los Colinas? I always did love those!

Regards!

09-26-2011, 02:26 AM   #9
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QuoteOriginally posted by stevelink Quote
using same lens, same ISO, and tripod-mounted. The only differences are that in the race shots, I used High-speed drive mode, and exposure settings of something like f/4.5 at 1/250 sec. These images should be tack sharp, but they arequiteout of focus, which obviously really frustrated me! Apparently, the system did not lock focus on the runner (or apparently on anything in the frame) prior to shooting a burst of about 8 frames!

I have the camera set to “Focus-Priority” for all settings (AF.S and AF.C), Catch-in-Focus Off, Auto AF Point Setting “Auto 11”, Shake Reduction “Off” (when on a tripod).
Tripod you say? Does that mean you're not panning to follow your subject? You must pan to make AF.C work. And you must pan smoothly and carefully to keep the same focus point on the same spot on your subject.

Auto 11 is not a good idea either. The Pentax AF system always picks the center point if there's reasonable contrast there. I suggest you try the center point setting or the "select a point" setting. Don't use auto5 or auto11.

Re. your example shot of the finish line, it's the spectator dead center in the background that has focus. I suspect the camera picked the center focus point. You can use the free "PhotoME" tool to see which focus point the camera picked.

QuoteOriginally posted by stevelink Quote
So assuming I use good technique (tripod/monopod, low ISO, high-shutter speed, bracketing, etc.), what can I do (via in-camera settings) to ensure that I will get sharp results??

Don't use Auto11 or Auto5, use center or select focus point.

Technique: smooth panning that follows your subject. Keep the selected focus point on the same spot on your subject. Pick a contrasty spot on your subject, such as the number on the chest. As the subject is approaching in the distance, half-press the shutter for a second or two while panning, to give the AF system a good chance of acquiring the subject. Fully depress the shutter button when the subject is about to fill the frame as you want it.

Still, there's no insurance. I suggest you practice the technique a few times before the important day.

Good luck with the shoot.

Sincerely,
--Anders.
09-27-2011, 06:16 AM   #10
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K-5 AF and general settings

Greetings, All.
Thank you for your expert feedback! Anders, to clarify, I did use a tripod (SR Off), but did not truly pan, as my subject was running almost "towards" me, rather than across the frame. I use AF.S (with "Focus-Priority"), Single Center AF Focus Point, and as soon as I saw my subject, locked focus on his bib (number), and fired off about 7-8 frames to get the most shots of him as he crossed the Finish Line. I don't see how the camera could have locked on another person in this scenario, unless I mistakenly locked focus on the wrong subject.
One other question if I may...I use "Natural" Mode with all settings (Saturation, Contrast, etc.) set to "0". However, I wonder if the Sharpness setting set to "Fine" would lose any detail (or add subtle noise), rather than make the image actually a bit sharper coming out of the camera. (I usually use Photoshop to post process, which is why I like to keep any camera influence off. I guess I'll just experiment with this. Thanks again for all the much needed and appreciated advice!
09-27-2011, 06:46 AM   #11
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Steve:

I use AF-C/focus priority pretty much all of the time for BIF (Birds in flight) with the K5 + a DA*300/4, handheld.
Shooting mode on "Hi".
Spot AF. TAv mode: I try to stay at a minimum of 1/1000s and usually between F4 to F8.
Of course, this will crank up the ISO but the K5 is quite capable in that department.
SR "ON"
Spot metering.
I shoot RAW.
But, as I say, this is for BIF. On the other, being similar in the type of subjects: they move!

While I cannot really compare the type of shots you are taking vs. mine here (I have not posted BIF shots here for the past couple of years at least), I can nevertheless say that moving subjects toward the camera are "toughies" but attainable.
I must remind myself to get some of those shots here.

Looking at your shot of the runners, it looks that they are coming toward the finish line at an angle rather than "almost" directly toward you.
I would agree with Anders with the panning method for that reason.

Another point would be the lens which you are using ... you have to get pretty close to the moving subject(s) with a maximum focal length of 50mm. ... but that may not be a reason for "out of focus" moving subjects.
Or perhaps it would be a good idea to use a faster shutter speed? Especially for runners. Again, this is only an opinion.

So, best of luck with your next assignment!

Cheers.

JP
09-27-2011, 07:18 AM   #12
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This is what happen to me: https://www.pentaxforums.com/forums/pentax-k-5-forum/142620-de-pentax-schwere...ml#post1660990
09-27-2011, 11:31 AM   #13
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Steve...I'm going to go out on a limb here and suggest that you simply might have moved as you anticipated and then executed the shot. I'm not saying you're a poor photographer - the shot of the Mustang looks tack sharp and areas around the finish line look sharp as well, just not the area most important to you. I've been shooting a fair amount of XC races of late and am still in experimentation mode. I've found that sometimes, while anticipating and getting set for a shot, I move a bit while executing. After kicking myself, I try to disassociate my emotions from the race and just shoot. I'm also learning: 1) To echo a comment made above, pre-focusing and then turning AF to M gives me the best oppt to capture a sharp image. I often set focus to an area on the ground where I know a runner will pass and then lock it by switching to manual focus; after this, I let high-speed shutter take over. 2) I've also found that 1/400 or faster works better. and 3) With the K-5, I'll offer that ISO 400 is the new ISO 100. I shoot at 400 A LOT and noise is not an issue. If I do see any, I simply pull up NR in LR3 and away it goes.

The image posted w/this thread was shot at ISO400 f/9 1/500 with my DA*60-250 (at 250mm), handheld and a slight pan due to the runners running across the frame. #111 was my target.

Good luck with the marathon pics and look forward to seeing the results!
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Last edited by AlphaGAK20D; 09-27-2011 at 11:43 AM.
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