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03-03-2011, 09:55 AM   #46
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QuoteOriginally posted by Parallax Quote
Here it is after using Focus Magic. OOF blur 1pxl radius, 75%
I could live with that.....the Focus Magic, that is, Mrs Rupert would frown on any other interpretation.
While we all want a Fix, and hopefully will get one, many of our shots, or at least mine, just have to be acceptable to the target audience, not those here that have more experienced eyes.

Focus Magic is a great tool......Jim, have you ever used the "motion blur function"? I seldom do, but used it here to good advantage, again, for the target audience, which was to stick on the wall at the SAK where I eat lunch.
Best Regards
Rupert

Original -just downsized
[IMG] [/IMG]

Focus Magic- Motion blur action.....I did this very quickly and then sharpened it, so a better job could have been done, no doubt, but you get the idea.
[IMG] [/IMG]

If you take a little time, are not in need of a perfect shot, just usable, Focus Magic is a very handy tool.....Squirrels swear by it!

03-03-2011, 11:55 AM   #47
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f1.4?

QuoteOriginally posted by awaldram Quote
Follow the door fame down to the floor and then use the floor line to keep you straight the door handle you mention bisects the ladies feet and is roughly in line with her knees.

She is stood stooped slightly backwards.

The shot is taken from 4-5ft and @f1.4 DoF is just under 1 inch !!
Even slight decentering in the lens would produce and image that looks like this.


I was being polite to the ladies dignity it is obvious on what the camera was focussed (look straight up from the agreed focal plane )

He didn't it happens to be the same distance from the lens as her feet,knees and other appendages.


You can always tell if and image is focussed or just blurred.

Yes the sharpening was overdone as I used my normal profile for raw conversion and I always shoot low light with strong post NR so additional sharpening is required.

Yep it look terrible (especially the left one) but does show where the focal plane of the lens was and I see no FF in either image.

I could make comment on the IQ of the lens (left) but the is obvius to see and well know the fa50 doesn't cut it at f1.4 for short range portraits f5.6 or f8 would have been appropriate here.

I could not find where the OP stated he shot these at f1.4. Maybe I missed that?

He did say he used the 18-55 and it was somewhat better than the Sigma 50 f1.4 and the Tammy 28-75 f2.8, but I do not see the specific shooting conditions listed and the files did not have the EXIF intact as far as I could tell.

Ddin't he say that the two images were from the Sigma and the Tammy? That would make one of them no more than f2.8, but either way, we do not know and it seems that you are assuming the f stop with no way to know if you are correct.

At the end of the day, it seems that it has been proven beyond the slightest doubt that the K5 has a FF issue in some conditions. It also seems to me that someone like the OP who describes himself as reasonably knowledgeable about photography (and we have no cause to doubt him) should be able to pick up a K5, bolt on any of the lenses he mentioned, attach the flash, select P or green or any other mode, and get images like this that are in reasonable focus and decently exposed.

Post after post from all over the world showing badly focused K5 images by all sorts of users tell the story very clearly as far as I am concerned. Using extra sharpening and focus magic and other tricks should not be necessary in all but a very few special circumstances.

I still wonder what all of the folks that deny this problem are going to do if Pentax issues a fix? Are they going to claim Pentax is wrong and not install the fix on the camera they own?

Time will tell, I suppose.

Ray
03-04-2011, 04:19 AM   #48
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Still don't know why EXIF data not showing...

...but:

1st shot: Sigma 50mm f1.4 lens, shot at 1/100, f2.8, ISO 400
2nd shot: Tamron 28-75 f2.8 lens, shot at 75mm, 1/125, f4, ISO 400

DOFMaster tells me that:

for 50mm lens, at a shooting distance of 4m, Near and Far Focus Distances are 3.83m and 4.18m respectively - a 35cm (13.8 in).

for 75mm lens, at a shooting distance of 4m, Near and Far Focus Distances are 3.89m and 4.11m respectively - a 22cm (8.7 in).

I must admit to being guilty of largely ignoring the difference between 35mm (FF) and cropped sensor DOFs, having worked with the former for so long and getting away with somewhat sloppy focusing for mere quick snapshots. I've been focusing on the desired area, then recomposing. And yes, I do understand the geometry that makes this technique imprecise, but I've been relying on DOF to mask the error. I can see now that I have to be more careful with this technique, given the relatively shallow DOF on cropped sensors. Could be a factor in some of the crap I've been producing lately.
03-04-2011, 04:40 AM   #49
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QuoteOriginally posted by bxf Quote
I can see now that I have to be more careful with this technique, given the relatively shallow DOF on cropped sensors. Could be a factor in some of the crap I've been producing lately.
But isn't it the other way around, you have more DOF with a smaller sensor.

03-04-2011, 05:05 AM   #50
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QuoteOriginally posted by Gimbal Quote
But isn't it the other way around, you have more DOF with a smaller sensor.
Only for the same focal length, as DoF is related to CoC (circle of confusion) then DoF will be smaller for the same lens used .

i.e 35mm film (55m@f4 from 4metres)
Depth of field 1.28 m
K5 (55mm@f4 from 4metres)
Depth of field 0.84 m

Last edited by awaldram; 03-04-2011 at 05:15 AM.
03-04-2011, 08:11 AM   #51
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Thanks

QuoteOriginally posted by bxf Quote
...but:

1st shot: Sigma 50mm f1.4 lens, shot at 1/100, f2.8, ISO 400
2nd shot: Tamron 28-75 f2.8 lens, shot at 75mm, 1/125, f4, ISO 400

DOFMaster tells me that:

for 50mm lens, at a shooting distance of 4m, Near and Far Focus Distances are 3.83m and 4.18m respectively - a 35cm (13.8 in).

for 75mm lens, at a shooting distance of 4m, Near and Far Focus Distances are 3.89m and 4.11m respectively - a 22cm (8.7 in).

I must admit to being guilty of largely ignoring the difference between 35mm (FF) and cropped sensor DOFs, having worked with the former for so long and getting away with somewhat sloppy focusing for mere quick snapshots. I've been focusing on the desired area, then recomposing. And yes, I do understand the geometry that makes this technique imprecise, but I've been relying on DOF to mask the error. I can see now that I have to be more careful with this technique, given the relatively shallow DOF on cropped sensors. Could be a factor in some of the crap I've been producing lately.
Thanks for the data.

This confirms the most likely explanataon (which is also pretty clear in your first image) that the camera FF to a degree that the subject is just beyond the rear of the DOF at your f stop.

BTW, I focus/re-compose with my K20 all the time and this technique works just fine at reasonable apertures.

Had the camera focused correctly, the DOF would have covered most of the depth of the body of the subject. The door handle might still have barely been within the DOF, but at the front of the DOF, not the rear as appears here.

So far, the only work arounds are:

Live view focusing

Manual focusing

Set your lens AF adjustment all of the way to -10 when shooting in conditions like these. You will need to dial it back out when shooting brighter scenes or you might get BF.

Good luck and let's hope Pentax sorts this out soon.

Ray
03-04-2011, 08:40 AM   #52
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QuoteOriginally posted by Parallax Quote
Here it is after using Focus Magic. OOF blur 1pxl radius, 75%
Nicely done, and it makes Jodi stand out better, but it doesn't change the fact that the original is pretty $hitty. Thanks for the effort.
03-04-2011, 08:47 AM   #53
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QuoteOriginally posted by Ray Pulley Quote
Thanks for the data.

...

So far, the only work arounds are:

Live view focusing

Manual focusing

Set your lens AF adjustment all of the way to -10 when shooting in conditions like these. You will need to dial it back out when shooting brighter scenes or you might get BF.

Good luck and let's hope Pentax sorts this out soon.

Ray
Thanks for all your input. I have tried LiveView in a few recent shots, but have yet to evaluate the results. I have run into some problems with LV, where it refuses to focus on occasions - lens just hunts and then stops out of focus. I think I may try the RESET process and see if that helps any.

I've also tried the -10 AF adjustment, with noticeable, though not absolute improvement, so it may be fair to conclude that there's nothing dramatically wrong (i.e. unknown problems) with my K5.

03-04-2011, 08:47 AM   #54
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QuoteOriginally posted by bxf Quote
..........but it doesn't change the fact that the original is pretty $hitty........
No, and in wasn't intended to diminish the importance of the the issue. It is a great tool though to correct the oops shots that we all encounter once in a while.
As seen above, they even happen to Rubert, of all people!
03-04-2011, 09:56 AM   #55
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If you insist

QuoteOriginally posted by Stratman Quote
I think what you need to do is this...Take a LOT more photos of her, and post them here so we can all try to figure out what the problem is........
Just to show that with my K20D, I didn't have the type of problems I'm having with the K5. Also, since I recall some post not long ago stating that the poster was tired of the images being posted and asking for something a bit more anatomical, these should provide some relief
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03-04-2011, 09:58 AM   #56
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QuoteOriginally posted by bxf Quote
................ these should provide some relief
Interesting choice of words.
03-04-2011, 10:12 AM   #57
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I could understand if there where focusing problems here...
03-04-2011, 01:34 PM   #58
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QuoteOriginally posted by Gimbal Quote
I could understand if there where focusing problems here...
03-04-2011, 02:16 PM   #59
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QuoteOriginally posted by bxf Quote
Just to show that with my K20D, I didn't have the type of problems I'm having with the K5. Also, since I recall some post not long ago stating that the poster was tired of the images being posted and asking for something a bit more anatomical, these should provide some relief
I think that this pretty well proves that your issue with the K-5 is an obvious case of user error.
03-04-2011, 04:16 PM   #60
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I'm going to see if I can get my K20D to replicate your results........can you forward the phone number I need to get in contact with the lovely model?
Best Regards!
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