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02-05-2011, 02:51 PM   #346
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QuoteOriginally posted by betaPhoto Quote
What kind of test lists a less than 1 sec. and a greater than 2 secs. exposure only?

Without ISO and f-stop, how would one determine if you were shooting in EV1 to EV4 (where the problems are reported). Furthermore, what kind of lighting source are you in, as tungsten light is thought to either cause or increase the problem.
It was ISO 100. The camera is mounted on a tripod, with 2 sec shutter delay to eliminate mirror blur. SR was turned off.

If you read my earlier post, I did say I was using the 43mm limited at f1.9. I also mentioned it was dimmed halogen lighting.

There were no other sources of lighting. This is our home theatre room with a projector, so perfect darkness can be achieved at any time of the day.

I don't have an EV meter, so I haven't quoted EV numbers. But since I have given some indication of exposure time and lens used, I am sure you can work out the approximate EV.

Let me repeat - the only conditions under which I can get the K-5 to FF were the same conditions that the EOS-1D will not lock focus at all. It is near dark and my eyes can't even focus properly under those conditions.

Under conditions where the Canon was able to lock focus, the K-5 did not exhibit FF. These are still pretty dim conditions with the lights mostly dimmed - I would not be able to read a book.

Once again, my apologies for not giving the EV numbers that you require since I don't have a meter.

Again I stress, the results are for my K-5 (on one lens) and I can't speak for other K-5s out there (or even other lenses). Based on the results, I don't believe a fix is required for my K-5 - I can't say for certain whether that is true for all K-5s.


Last edited by Christine Tham; 02-05-2011 at 02:57 PM.
02-05-2011, 02:58 PM   #347
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QuoteOriginally posted by bikecoboss Quote
She said she thinks that if all K-5's are like hers, there's nothing to fix. She carefully qualified her conclusions, I'm sorry if you can't or won't understand that.
I fully understand what both you and Christine said, but I don't believe you understand what I've said.

Her test results don't mean anything, because no one knows (not even her) if her test is even in the EV 1-4 range of the reported problem. We only know she really likes her K-5 and doesn't see any problems with it. If I owned a K-5 I think I would like it also (there appears to be a lot to like, that's why I'm interested in one).

But from the evidence I've seen reported so far, I definitely will not buy a K-5 until the front focus problem is shown conclusively to not exist and/or be fixed. Christine's tests do not show this!

Last edited by betaPhoto; 02-05-2011 at 05:42 PM.
02-05-2011, 03:08 PM   #348
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Oh, another one who has never used the camera!
QuoteOriginally posted by betaPhoto Quote
I definitely will not buy a K-5 until the front focus problem is show conclusively to not exist and/or be fixed.
So someone has to prove a negative before you'll be happy?
02-05-2011, 03:08 PM   #349
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QuoteOriginally posted by betaPhoto Quote
We only know she really likes her K-5 and doesn't see any problems with it.
Minor correction - I have never said I "really like" my K-5, merely that I do not believe the focus needs fixing.

I am reserving judgement on the K-5 until I have a chance to take it out for a real shoot (hopefully today).

My initial thoughts are that it does NOT appear to be as easy to use as my K10D, but then I have not finished reading the manual.

I have done some test high ISO shots, yes they are impressive but not as impressive as I have been led to believe by some of the comments in this forum. My K10D with noise processing in Lightroom can achieve reasonable results to ISO800, but the K-5 obviously can do better, but I would hesitate to shoot at very high ISO anyway (I am a big fan of ISO100).

Auto focus speed - I haven't noticed much of a difference from K10D to be honest. But I will find out today.


Last edited by Christine Tham; 02-05-2011 at 03:45 PM. Reason: Sorry - forgot the NOT in the easy to use paragraph
02-05-2011, 03:12 PM   #350
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QuoteOriginally posted by betaPhoto Quote
But from the evidence I've seen reported so far, I definitely will not buy a K-5 until the front focus problem is show conclusively to not exist and/or be fixed. Christine's tests do not show this!
Thats great! You don't even own the camera??? What a great contribution to a threat titled "Relevant news..."
02-05-2011, 03:14 PM   #351
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QuoteOriginally posted by Ivor K Ecks Quote
Oh, Christine....

Recant your faith in the god Pentax and his son K5 before the inquisition find you
QuoteOriginally posted by betaPhoto Quote


Am I supposed to respect this type of analysis and believe many other posters are wrong or got bad K-5's
QuoteOriginally posted by Smeggypants Quote
I've never heard such utter rubbish.
QuoteOriginally posted by betaPhoto Quote
Christine Tham's results don't mean anything, because we have no idea what they are. The only thing we know for sure is that she is happy with her K-5. That' great.

But to say there isn't a problem without any respectable test, and to further say Pentax has nothing to fix because of her tests is ridiculous!
OOOPS..........Too late
02-05-2011, 03:15 PM   #352
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QuoteOriginally posted by Christine Tham Quote
It was ISO 100. The camera is mounted on a tripod, with 2 sec shutter delay to eliminate mirror blur. SR was turned off.

If you read my earlier post, I did say I was using the 43mm limited at f1.9. I also mentioned it was dimmed halogen lighting.
...
I don't have an EV meter, so I haven't quoted EV numbers. But since I have given some indication of exposure time and lens used, I am sure you can work out the approximate EV.
...
f=1.9 t=1s : EV 1.85
f=1.9 t=2s : EV 0.85

(EV = log2(f^2/t) for ISO 100).
02-05-2011, 03:16 PM   #353
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QuoteOriginally posted by volley Quote
Why don't you just go out and have some fun taking pictures with the great cameras you have??
Oh I do. I've taken many thousands of pics with my K-5. And I workaround the FF problem.

You were saying?

02-05-2011, 03:21 PM   #354
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QuoteOriginally posted by volley Quote
Thats great! You don't even own the camera??? What a great contribution to a threat titled "Relevant news..."
To say I can't refute bad methodology without owning the camera is bad logic.
02-05-2011, 03:48 PM   #355
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QuoteOriginally posted by jolepp Quote
f=1.9 t=1s : EV 1.85
f=1.9 t=2s : EV 0.85

(EV = log2(f^2/t) for ISO 100).
Thanks for doing the calculation, jolepp!

Sounds like the camera does indeed perform to specification, but gives a false positive below 1EV.
02-05-2011, 03:55 PM   #356
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QuoteOriginally posted by volley Quote
What a great contribution to a threat titled "Relevant news..."
LOL!

I know it was a spelling mistake, but did I laugh ever!
02-05-2011, 05:29 PM   #357
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QuoteOriginally posted by Christine Tham Quote
It was ISO 100. The camera is mounted on a tripod, with 2 sec shutter delay to eliminate mirror blur. SR was turned off.

If you read my earlier post, I did say I was using the 43mm limited at f1.9. I also mentioned it was dimmed halogen lighting.
.

Christine

as Jolepp has given us the relevant EV for your test, the only remaining factor is distance to the test subject from the focal plane...could you please give us those parameters of your test...

if your too far away the increase in DOF can mask the FF...
02-05-2011, 05:33 PM   #358
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QuoteOriginally posted by Gimbal Quote
It is indeed dependent on the lens used, try a normal zoom lens at the wide end on normal indoor distance around 2m. The scene could be a typical dinner, my k5 will lock instantly but will FF with around 0,5m. And it is not pitch dark but around EV 4. Easily hand holdable at iso 1600.

Add a little more light and it's suddenly spot on. This is what I'm complaining about, not a few mm in total darkness.

your K5 and the one other thats been reported , is not typical of the FF suffered by the rest of us..Id suggest that you and the other PF member who has this issue, have a body that's is failing else where to have FF that severe
02-05-2011, 09:26 PM   #359
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QuoteOriginally posted by Tommot1965 Quote
Christine

as Jolepp has given us the relevant EV for your test, the only remaining factor is distance to the test subject from the focal plane...could you please give us those parameters of your test...

if your too far away the increase in DOF can mask the FF...
Can't give you exact distance, but it's not too much further than minimum focus distance for the 43mm Limited lens.

Basically I positioned the batteries at minimum focus distance, then moved the batteries a little bit back to give some headroom for the autofocus mechanism to work - check that there was enough for the motor to play with, and did the test.
02-05-2011, 11:45 PM   #360
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QuoteOriginally posted by Christine Tham Quote
Can't give you exact distance, but it's not too much further than minimum focus distance for the 43mm Limited lens.

Basically I positioned the batteries at minimum focus distance, then moved the batteries a little bit back to give some headroom for the autofocus mechanism to work - check that there was enough for the motor to play with, and did the test.

no worries..that's well within the parameters of a FF test.....do you mind telling us the build date of your K5...".photo me" will be able to give you this info...just open up a image taken with your K5..then go to manufacturer's notes...


any chance you could post the test images that you took?

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