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01-19-2011, 07:59 AM   #16
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QuoteOriginally posted by peterh337 Quote
It would be pretty interesting to do any tests in both normal and live-view modes because they use completely different methods for detecting the optimum focus point.
I have seen tests that show live-view focus hits focus right on and the normal focus method has FF (both under the same EV2-3 lowlight conditions of course).

01-19-2011, 08:02 AM   #17
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QuoteOriginally posted by Michaelina2 Quote
So... how is this a Pentax issue and NOT a non-branded lens issue?

All you seem to be saying is... if a non-branded lens (in this case, Tamron) is paired to a K-5 expect results like yours.

Is it possible your results simply reflect the 'no longer being good enough' generic design of this particular non-brand lens?

Just curious... M
As contrast AF works pretty well overall there seems to be no particular reason why this lens + body combination could/should not work with phase AF as well. Also, with led light (different color temperature) the combination actually works nicely enough. Of course, testing one particular lens + body only goes so far; it would be nice to see results from others.

I guess the Tamron seemed more relevant for me (than the Pentax DFA 100mm 1:2.8 which would be my other reasonably fast AF lens): I have actually ran into AF accuracy problems with that when trying to take normal pictures inside in artificial light while there was no apparent problem in similar circumstances with that and the k-x (on its way back from warranty repair).
01-19-2011, 08:24 AM   #18
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QuoteOriginally posted by peterh337 Quote
...
It would be pretty interesting to do any tests in both normal and live-view modes because they use completely different methods for detecting the optimum focus point.
Clarification: above "contrast AF" = live-view AF.
01-19-2011, 09:14 AM   #19
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QuoteOriginally posted by peterh337 Quote
Does a K5 focus differently according to which lens is attached to it?

I would have thought the AF was a closed-loop system where the camera is using the sensors to detect the focus and drives the focus actuator to achieve it. In live view, the camera will be using a max-contrast AF method and that does the same thing.

If a lens achieves good focus at say F8 but not at say F4 the cause of that must be something fairly subtle.

It would be pretty interesting to do any tests in both normal and live-view modes because they use completely different methods for detecting the optimum focus point.
Live view ( contrast ) focussing works fine in low light, while the regular focussing does not.

01-19-2011, 09:40 AM   #20
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I am following all of these threads closely, wanting to hit "Buy Now" as soon as possible, but not wanting problems or the hassles of returns or waiting for a repair that may never come.
Will someone just answer this for me to the best of their abilities......Here is a shot I took with the K20D DA*50-135 in poor light from a tungsten porch light about 25 ft away from the subject. I have been thinking that the K5 would get this shot at a better resolution at the same settings, but if focus under this circumstance is not possible, where is my gain?
1/30 F 2.8 115 mm about 8 ft away ISO 6400


I'm not much on technicalities or testing figures, but if you can use this to give me an answer it will be of great help.
Best Regards!
01-19-2011, 10:15 AM   #21
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Those who thinks we are just whining will tell you to stop down a few stops and be done with it. Not a solution in my opinion.

Last edited by Gimbal; 01-19-2011 at 10:30 AM.
01-19-2011, 10:20 AM   #22
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QuoteOriginally posted by Michaelina2 Quote
So... how is this a Pentax issue and NOT a non-branded lens issue?

All you seem to be saying is... if a non-branded lens (in this case, Tamron) is paired to a K-5 expect results like yours.

Is it possible your results simply reflect the 'no longer being good enough' generic design of this particular non-brand lens?

Just curious... M

I tested my Pentax DA 18-55 kit lens that came with my k10 and it to suffers from FF so it "works" with Pentax lenses as well.

First picture with ceiling lamp lit, second picture with only ambient lamps lit. All tungsten. jpegs straight from the camera, only cropped to 100%, Phase focus in both pictures. 18mm, distance 2,2m, f3,5.





The focus scale on the lens changes from 2m to approximately 1,2m at a certain light level. Quite a change.
01-19-2011, 11:10 AM   #23
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QuoteOriginally posted by Rupert Quote
I am following all of these threads closely, wanting to hit "Buy Now" as soon as possible, but not wanting problems or the hassles of returns or waiting for a repair that may never come.
I am in the same position. I really want to get the K-5 as a upgrade to my K-7 but the focus issue and B&H not having it in stock is keeping me from buying one. Hopefully it is a problem that a FW update can fix. Then again it could be like the K-10D where the early ones didn't focus as fast as the later models. The only way I found that out was that I had the sensor go out after 11 months of use and the repaired K-10D focused a lot faster.

01-19-2011, 12:29 PM   #24
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Apparently, there is a late firmware fix for the K5 low light focusing problem, as described in this thread:

https://www.pentaxforums.com/forums/pentax-k-5-forum/128562-relevant-news-re-...-light-10.html

Post number 138

Has anyone tried this firmware "fix" and done further AF tests?

JP
01-19-2011, 04:11 PM   #25
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I too would like to hear from those with the update....and I would still like an answer to my Raccoon question? We are getting a lot of talk here, but I am not sure we are getting a lot of answers regarding "Relevant to the FF Problem"? I would love to see more of those and less of the other stuff.....just saying......
Regards!
01-19-2011, 04:48 PM   #26
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QuoteOriginally posted by jpzk Quote
Apparently, there is a late firmware fix for the K5 low light focusing problem, as described in this thread:

https://www.pentaxforums.com/forums/pentax-k-5-forum/128562-relevant-news-re-...-light-10.html

Post number 138

Has anyone tried this firmware "fix" and done further AF tests?

JP
I am just about to. I'll let you know as soon as I've had a chance to see if there's any improvement.
01-19-2011, 05:12 PM   #27
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Ok, just tried the silent 1.02 firmware update. It has NOT cure the low light FF problem on my K-5. I did exactly the same focus tests with my K20D to compare and it focussed spot on everytime.
01-19-2011, 08:41 PM   #28
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Rats!

Someone actually mentioned that it had fixed his/her FF problem, so I was mistaken.

This may sound redundant but from what I gather from other threads relating to the low light FF issues, I would make a wild guess and assume, maybe wrongly, that this is a firmware fixable problem.
That's what I am hoping, and not a harware thing.

Thanks for the quick test with the "silent" firmware.

JP
01-19-2011, 11:13 PM   #29
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I tried the latest and greatest too; the AF problem was not affected. I assume the poster in the "news" thread was referring to some other issue that this in fact had fixed.

How does one see the complete firmware version info btw? Holding <MENU> while powering up just reports "1.02".
01-20-2011, 12:39 AM   #30
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DA(L) 18-55 @50mm, tungsten/led @5EV

I gave the 18-55 kit lens (from the k-x kit) a try @50mm. For this I moved the eneloops a bit closer (30 cm from sensor plane) for less DOF. Spacing in "depth" is still 14mm ("width" increased to 14mm as well, but should be of no consequence). For tungsten light I used two 40W spots and one 28W halogen fist reflected off the white ceiling to avoid reflections from the battery surfaces (these could interfere with AF?). Led light is still the bicycle light.

#1 : tungsten : contrast (LV) AF : baseline : camera WB 3156K
#2 : tungsten : phase (VF) AF : FF in comparison to #2 : camera WB 3156K
#3 : led : contrast (LV) AF : baseline : camera WB 6970K
#4 : led : phase (VF) AF : very slight FF in comparison to #3 : camera WB 6989 K

Last edited by jolepp; 03-03-2017 at 02:41 AM.
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