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02-13-2011, 03:20 PM   #16
JGB
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Sorry, the second is outside, that's the front patio, with flash, but underexposed a bit intentionally to show that it was night.

I'm finding it way too consistent, even with flash, the subject is always slightly out of focus, and the background(if it is within a foot) is always in focus.

Thanks, that was why I tested the LV vs AF points first, to see if it was an issue with my lens(it wasn't)
I get slightly better results with the kit 18-55 lens, I've just started shooting with flash and f 5.6 or smaller, good enough for the internet, but not crisp and nice like I was getting earlier on. This is an example of focus I'm pretty happy with considering it was a quick snap while in the middle of eating and him throwing something at me, but same kind of distance and lighting now even on a tripod with flash, and a still subject and I get blurry faces, despite doing everything the same, or more carefully, it just isn't turning out. I can post this older one, because it was already uploaded to my gallery.



My most recent examples(I'm having trouble uploading again, the joys of cell phone based internet) are a boy sitting 1' in front of a wall with texture, center focus right between the eyes from 5' away, bright overhead lights and flash at 1/180. The wall is again clearer than the subject, the eyes are showing obvious signs of lack of focus especially(no eyelashes visible)
If I shoot at a 45 degree angle to a wall(highly patterned, easy to focus on) at F 2.8 I can clearly see the focus plane is not where I focused.

I'm going to try and set up my tripod and do some testing, but first I have to find someone with a printer to print a test sheet, a bit tricky where I am right now.

02-13-2011, 03:58 PM   #17
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I think you need a calibration. You should be getting better results with that combo. I rarely used LV on the K7.



02-14-2011, 01:34 AM   #18
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QuoteOriginally posted by JGB Quote
I'm finding it way too consistent, even with flash, the subject is always slightly out of focus, and the background(if it is within a foot) is always in focus.
JGB, you are describing a typical case of back focus.
The bad news is that your camera needs calibration, the good news is that you can do it yourself.
It is done in the last user setting menu, look it up in the manual.
It is not hard to do at all.

You can calibrate the camera for each lens and/or for all lenses.
Just follow the procedure here: Lens Calibrating A DSLR Is Easy and Fun - Don't Be A Chicken - Just DO IT - Peter Gregg | Pro Photo Home

There are many other descriptions like that on the Internet.

Cheers, Bert
02-15-2011, 02:03 PM   #19
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QuoteOriginally posted by bymy141 Quote
JGB, you are describing a typical case of back focus.
The bad news is that your camera needs calibration, the good news is that you can do it yourself.
It is done in the last user setting menu, look it up in the manual.
It is not hard to do at all.

You can calibrate the camera for each lens and/or for all lenses.
Just follow the procedure here: Lens Calibrating A DSLR Is Easy and Fun - Don't Be A Chicken - Just DO IT - Peter Gregg | Pro Photo Home

There are many other descriptions like that on the Internet.

Cheers, Bert

Thanks! When you input the one lens setting, does it remember it for each individual lens?(I'm assuming it won't remember for old manual lenses?)
I'm ready to do it(tripod etc all ready), I just have to find someone with a printer now.

I've never used live view before, even shooting while wearing a helmet I find it more pain than it's worth.
Even using the standard AF though, the camera has real trouble focusing on anything as I move which is a pity. I tried it with a 5dmk2 and had good luck, but with the 35mm ltd I'm always waiting for it to cycle the lens. I'm thinking of figuring out the hyperfocal distance, and taping the lens focus ring there so I can shoot while I ride.

02-15-2011, 02:33 PM   #20
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JGB, I disagree with much of the advice so far, the first thing to rule out is too slow of a shutter speed because the images you have posted are absolutely consistant with this problem.

As I said before pic#1 is entirely consistant with camera shake caused by too slow shutter speed (<1/60?), not back focus. Pic #2 is consistant with subject movement caused by too slow shutter speed (<1/100?), not necessarily back focus.

It is possible that your lenses are also backfocussing but that is less likely to be the cause of blurriness in the first 2 pics you posted.

What shutter speed are your blurry photos? Pentax DSLR's have a know "feature" when usnig flash of using too slow of a shutter speed to freeze movement.

Unfortuantely your photos do not have EXIF attached
02-15-2011, 03:40 PM   #21
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QuoteOriginally posted by JGB Quote
When you input the one lens setting, does it remember it for each individual lens?(I'm assuming it won't remember for old manual lenses?)
I'm ready to do it(tripod etc all ready), I just have to find someone with a printer now.
Yes, I believe up to 15 different lenses.
And yes, the old manual lenses will not be recognized, however, if you would set AF for all and for specific lenses, all manual lenses will be treated with the generic compensation.

You don't need a printer. Focusing on a large size ruler works also great.

QuoteOriginally posted by twitch Quote
JGB, I disagree with much of the advice so far, the first thing to rule out is too slow of a shutter speed because the images you have posted are absolutely consistant with this problem.
If JGB does the lens calibration and she finds that the lenses do not need calibration, then yes motion blur could be the problem.
However, since she indicated that all her photos are back focused, some parts of these images are sharp, which would not have been the case if she was suffering of motion blur.

- Bert
02-15-2011, 09:40 PM   #22
JGB
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QuoteOriginally posted by bymy141 Quote
Yes, I believe up to 15 different lenses.
And yes, the old manual lenses will not be recognized, however, if you would set AF for all and for specific lenses, all manual lenses will be treated with the generic compensation.

You don't need a printer. Focusing on a large size ruler works also great.



If JGB does the lens calibration and she finds that the lenses do not need calibration, then yes motion blur could be the problem.
However, since she indicated that all her photos are back focused, some parts of these images are sharp, which would not have been the case if she was suffering of motion blur.

- Bert
LOL I'm a guy.

I have an example of it clearly showing out of focus face(can't even see the eyelashes) while center focused on it with flash at 1/180, but so far I've been hotlinking images from my gallery, the connection here is being a pain about uploading the new one at a decent resolution.
If I move the aperture to F 5.6, I can see eyelashes.
02-16-2011, 01:02 AM   #23
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QuoteOriginally posted by JGB Quote
LOL I'm a guy.

I have an example of it clearly showing out of focus face(can't even see the eyelashes) while center focused on it with flash at 1/180, but so far I've been hotlinking images from my gallery, the connection here is being a pain about uploading the new one at a decent resolution.
If I move the aperture to F 5.6, I can see eyelashes.

Oops... sorry, sorry.

Do the calibration.

- Bert

02-16-2011, 04:56 PM   #24
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HAHAHAHA!!!!
At least we're not in a bar!
02-18-2011, 03:02 PM   #25
JGB
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No worries.



Here's the chart I was thinking of, haven't a clue where I'd get a garden thermometer...

PENTAX DSLRs: PART-1. Free Autofocus Adjustment charts for front and back focusing problems. Good for Pentax, Canon and Nikon.
02-19-2011, 04:50 PM   #26
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Thanks for the link, I finally found someone with a printer, but it didn't work after 2 hours of fiddling!
I tried the garden thermometer trick, but with a 3 edged ruler instead. I decided on +5, though 0 wasn't bad either some of the time(I noticed about 1/3 shots wouldn't be focused correctly with adjustment turned off, and the camera set to focus on exactly the same spot(I'd move the lens a bit to force the camera to refocus each time) and occasionally it would get the focus spot on. A bit strange considering I was on a tripod, with the ruler well lit, SR turned off, etc.
02-20-2011, 01:39 PM   #27
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QuoteOriginally posted by JGB Quote
Thanks for the link, I finally found someone with a printer, but it didn't work after 2 hours of fiddling!
If you follow the link I provided in post #7, you won't need to print anything. The method described in the link works beautifully.
11-18-2011, 09:35 PM   #28
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I hope you have sorted out your AF woes by now, but just in case you still have issues: Please forget garden thermometers or rulers. They are not reliable tools for checking AF precision, let alone performing AF adjustment.

The issue is that the so-called "AF points" are not points at all, but "AF areas". The AF areas are much bigger than the small red AF indicators in the viewfinder indicate. You may think you are targeting a particular line on a ruler, but the camera has its own idea where to focus within the AF area.

For a good AF micro calibration, you need a precise target that provides no ambiguity for the camera whatsoever. You may find my Autofocus Adjustment Hints helpful. They assume that you know the general approach (setting up a target and measuring the AF error) and elaborate on the pitfalls and useful things to know.

Last edited by Class A; 11-20-2011 at 01:40 PM.
11-19-2011, 09:52 AM   #29
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There is absolutely no reason at all - not even the slightest - to suspect your AF system needs calibration based on any of those pictures. The sort of errors that can result from poorly calibrated AF are measured in millimeters, not feet. When you are seeing a post that is a foot behind your subject in focus, there is no possible way that could due to poorly calibrated AF. It is one thing and one thing only - the camera choosing to focus on the background for whatever reason. As noted above, the focus "points" are anything but, so even though you may be putting the focus "point" on your subject, the background is generally still in range and will occasionally seem a better target to the camera (if it is higher contrast, not moving, etc).
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