[dlacouture]

you are not supposed to use any tungsten bulbs in EU !

No, we are not allowed to buy tungsten bulbs anymore, but those already installed are still running...

But note that I have not said it was under tungsten lighting... Come to think of it, it was actually fluorescent bulbs, with a greenish tinge, so maybe that's why proper focus could be attained.

[jolepp]

Tungsten bulbs: being phased out >= 100W not sold any more, >=60W this year, >7W next year (some countries have a faster schedule), however halogen replacements are to stick around until 2016, these are a more efficient version of tungsten filament bulbs where the filament operates at a higher temperature made practical by a bit of halogen, the latter are apparently as bad as basic tungsten (using a dimmer can make them worse). Besides, the effective color temperature of some (most?) of CFL and LED replacements is similar to tungsten (but spectrum non-continuous).

[Christine Tham]

And Pentax may still not understand this. Or otherwise speaking, why did they hack some special (yet to be identified) cases in the v1.03 firmware without addressing the above root cause? Of course, the other option is I made some errors in my analysis (or my K-5 is different) and Pentax did what was possible. Both is likely.

If you recall, I suggested some time ago that there were two distinct front focus issues - one I referred to as a "micro" issue and other a "macro" issue. I proposed that because I believe you have quantified the "micro" issue but some people on the forum were actually reporting the "macro" issue.

Initially I can only observe the "micro" issue on my camera but I accidentally discovered the "macro" issue (that was the photo I posted of the camera misfocusing on a tungsten flashlight even in quite bright conditions).

For me, the "macro" issue disappeared once I disabled the camera AF fine adjustment.

My guess is that Pentax has addressed the "macro" issue but the "micro" issue remains. On firmware 1.03, re-enabling AF fine adjustment on my camera still results in a focused photo of the flashlight so I can confirm Pentax has fixed at least one specific issue in my camera.

However, on my camera, as on yours, the "micro" issue remains.

The hypothesis that there are two separate issues would explain why many people are reporting that 1.03 fixes the focus problem for them.

As for your speculation that in the conditions that the K-5 has a "false" focus lock, I can confirm that the Canon EOS-1D refuses to lock focus in situations where my K-5 exhibits the "micro" FF. I also agree with you that refusing to lock focus is actually more reliable than a false lock.

[Class A]

Class A : having owned a K7 for a full year before the K5, and shooting my kids in relatively unchanging environments, the K5's FF problem leaped at me, so I'd say there is definitively a gap in the K5 low-light AF capabilities compared to the K7...

Thanks, dlacouture, that's useful to know. Too bad that you are observing inconsistent behaviour (which rhymes with what other posters report).

The circumstances under which it will FF seems to be a bit unpredictable. If I knew exactly where it would fail I could work around it.

...I can confirm that the Canon EOS-1D refuses to lock focus in situations where my K-5 exhibits the "micro" FF.

In all of them? How systematically did you verify this statement? What exact model of the 1D do you own?

I'd be more than happy to learn that the K-5 doesn't have a real issue (except from demanding the photog to know in which situations it will produce a false lock), but, unfortunately, I'm not yet convinced that this is the whole picture.

[Christine Tham]

In all of them? How systematically did you verify this statement? What exact model of the 1D do you own?

Not sure what you mean by "all of them", but generally my K-5 has a slight FF in EV 0-2 under yellowish light, and in these conditions the EOS 1D Mk III does not lock focus. When it does lock focus though, it's perfect.

I did not conduct systematic tests a la Falk, so it's just an observation. I was progressively increasing/decreasing the dimmer, and had 3 cameras with me (K10D, K-5, 1DMkIII) so were taking pictures on all three cameras in exactly the same conditions. Obviously I am not using the same lens for the Canon as for the two Pentax bodies (it was f2 rather than f1.9).

For the record, my K10D was also misfocusing under roughly the same conditions as the K-5. But it took a lot longer to lock focus.

[falconeye]

If you recall, I suggested some time ago that there were two distinct front focus issues - one I referred to as a "micro" issue and other a "macro" issue. I proposed that because I believe you have quantified the "micro" issue but some people on the forum were actually reporting the "macro" issue.
[...]
My guess is that Pentax has addressed the "macro" issue but the "micro" issue remains.

Christine, your theory is a good one. I recall you (and some others) making the distinction.

I introduced the idea that both issues are actually the same, but the micro issue becomes a macro issue with dark backgrounds. The difference between micro and macro issue would be the EV value where the issue happens, not its magnitude.

The point is I never actually conducted systematic tests with a dark background and therefore, I cannot compare for this situation. My bad.

[Smeggypants]

Morning folks

I got my replacement K-5 yesterday. it was a 4xxxxxx serial number copy and was manufactured in Janurary.

It came with V1.01 isntalled and exhibited Front Focus problems in low light btu niot so much as my previous copy.

After installing 1.03 I got success in focussing at EV2 most of the time. V1.03 gives inconsistent focussing. it focusses accurately at EV2 say 8 times out of 10. V1.01 and 1.02 front focussed consistently EVERY TIME!!!

With my old K-5 V1.01, 1.02 and 1.03 front focussed consistently EVERY TIME!!!

Proof that not all K-5s are equal hardware wise.


Today I have purchased a 2nf K-5 and will reci9eve it on thursday. It will be interesting to compare.

[Catalana]

I will be receiving a new K-5 shortly; if it is at firmware version 1.01, I'll leave it there for a while and see what I can document as I go up the firmware ladder.
Unfortunately I don't have version 1.02. Maybe I should skip 1.02 and make the jump to 1.03.

[Ash]

Smeggy and Christine, I agree that there are bigger and smaller issues within this FF monkey that just won't be resolved, and that each K-5 behaves differently, even if subtly. I am finding that there are situations where I can get my own K-5 to FF, and others where I find it back-focusing; and then there's the bounce flash overexposure issue. There are a few plagues to work out on the K-5, but I too am hopeful it can be more definitively rectified in future firmware updates.

[the swede]

Why does the cameras behave differently? Isnt they made of same parts, same software and so on...?

Is the problem so "subtle" and depending on different lenses? And the fact that its very hard to test this without a lab of somekind, to get consistent results.

Consistent results are needed, otherwise all cameras behave different.

Falk, cant you test all cameras

only joking, but it would be interesting if you wanted or had the ability to test 3-4 K-5's at the same time.

I imagine though that you'd rather be out taking pictures like the rest of us

[Smeggypants]

My experience today ( from my K20/K-5 test thread )

Now I've noticed a strange behaviour with my replacement K-5. I put my sigma 30/1.4 on it and it focussed spot on in daylight without any AF fine tuning. Cool! - it also focussed spot on at EV2 ( most of the time ) - Also cool.

today, after making the SmegAlign I decided to calibrate my lenses. I put my FA50/1.4 on and that needed no adjustment either. Cool!

I then put another lens on which did need some adjustment. so after turning on AF adjustment and calibrating this lens, I then put the Sigma 30/1.4 back on and it was really back focussing. It needed a +5 to calibrated it again. The same happened with the FA50/1.4 which needed -10 to calibrate it.

A bit flabbergasted by this I reset the AF fine tuning and turned it off. Both the Sigma 30/1.4 and the FA 50/1.5 showed back focus and front focus respectively and the need the +5 and -10 to correct them


So it seems that simply turning the AF Fine tuning on does something permanent to the AF system, which even a reset won't cure.

I'm taking delivery of my 2nd K-5 tomorrow so I'll be sure to test this again with the new camera.

note: this was all in daylight and was nothing to do with any front focussing in low light. In fact the front focussing behaviour with the replacement K-5 is working fine ( most of the time ) with the sigma in daylight and EV2. AFing with 103 in low light is still inconsistent.

[deejjjaaaa]

Besides, the effective color temperature of some (most?) of CFL and LED replacements is similar to tungsten

even close (and including) IR part ?

[jolepp]

even close (and including) IR part ?

AFAIK the energy savings of both fluorescent and LED lights is because they emit a mix of visible wavelengths instead of the continuous black body spectrum of a hot filament including IR (and UV).

[jstevewhite]

AFAIK the energy savings of both fluorescent and LED lights is because they emit a mix of visible wavelengths instead of the continuous black body spectrum of a hot filament including IR (and UV).

Yep. CFLs - most fluorescents - emit a discontinuous spectrum, but the magic of our visual system renders stuff reasonably well. A filament emits a continuous spectrum. CFLs have gotten really good at putting in lots of spikes to balance out color rendering, though.

[Ray Pulley]

Yep. CFLs - most fluorescents - emit a discontinuous spectrum, but the magic of our visual system renders stuff reasonably well. A filament emits a continuous spectrum. CFLs have gotten really good at putting in lots of spikes to balance out color rendering, though.

This is indeed true, but the magic of the DSLR isn't nearly as magic as our eyes and brains and often results in issues with taking images in lighting that has spikes or peaks that our visual system accounts for (mainly) but the camera does not.

This will be a photographic challenge for quite some time to come methinks.

Ray