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Old Nov 12, 2010, 9:53 PM   #1
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Default Does anyone know about the k-r front focusing problesms?

Hi, i have been researching for a while trying to decide which dslr to get. I was leaning toward the k-r due to the improved AF, and higher fps but have found some complaints about front focusing specially under tugsteng light and also some people report having metering issues?
Do you have any experience with these? Are they common problems?
What would you do? Would you still get it?
Thank you
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Old Nov 12, 2010, 11:22 PM   #2
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I have seen this discussed in a number of places and it seems that most Pentaxes going back many years all have this 'issue'. If I remember correctly though there is a specific, logical, reason for it. Many Pentax lenses are now adjusted in camera so for those it isn't a problem anyway. As I remember it's not only Pentax cameras that front focus.

There are other posters on here more knowledgable on the front focusing question. I'm sure they'll bring us up to speed by commenting.
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Old Nov 13, 2010, 11:20 AM   #3
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Hi marubex,

My personal feeling is that this is one of those issues that is overblown in photo fora. Just about all DSLRs front focus to some extent in tungsten light due to the difference in color temperature differences between tungsten and daylight -- and always have. The more discriminating viewfinders of 135mm format cameras make this more apparent, but APS-C VFs make it harder to see and correct for manually. A few models, like the Pentax K-7 and K-5 have an extra focusing sensor and automatically correct for this. The fact that this more sophisticated AF system has not been demanded by a the great majority of DSLR shooters points to the fact that it's not a problem for most people.

This is really only an issue for the most discriminating photographers using very wide aperture lenses at relatively close distances where Depth of Field is very shallow and precise focus is very critical. 135mm format cameras have shallower DOF and make this more critical, but the natural added DOF of the "crop" sensored cameras generally cover this flaw well enough that it's not even noticed by the great majority of the population.

If you plan to shoot very fast lenses at close to their minimum focusing distance, and shoot wide open to gain the shallowest possible DOF, then you might want to spend more money and get a more sophisticated body if you need to rely on AF -- most who are this critical about focusing will manually focus anyway. If you're like over 90% of the people who shoot DSLRs just for their own satisfaction, and probably won't be getting into relatively exotic lenses, then this probably won't even be an issue.

Regardless, the Kr is probably the only sub semi-pro level body from any mfg that has a global focus correction capability, and if you plan to shoot a lot in tungsten lighting, you can do focus testing under the specific lighting that you'll be shooting under and set the focus correction for that setup. Turn it on when you need it, and turn it off when you're shooting in daylight. It also is a very capable high ISO camera, so the necessity of shooting wide open, even in very low light, is minimized so most would tend to shoot stopped down to get better sharpness and resolution under these conditions anyway -- increasing DOF and making small focus errors less critical.

Scott

Last edited by snostorm; Nov 13, 2010 at 11:24 AM.
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Old Nov 13, 2010, 6:49 PM   #4
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Thak you both frogfish and snostorm. Snostorm that was really informative. Thank you
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Old Dec 12, 2010, 3:44 PM   #5
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I asked Pentax support about the focussing problems K-r cameras have. They told me, that this is a known problem and they want to solve it with a firmware update. The front focus happens with all AF lenses I tried and is clearly visible at indoor lighting. Focussing via live view in the same situation will give correct focus.

I can't really imagine nor understand, that such a clearly visible bug was overlooked - I mean, testing accurate focus is a basic test, the more as SAFOX IX(+) was included in the K-r and K5 and this is one of the key improvements.

That's why I also asked, if the missing "+" might be the reason for the K-r behaving that way. Answer: no.

The focus correction function will NOT solve that problem.

At the moment taking well-focussed indoor shots with artificial lighting is a challenge, I try to use a single focus point, lock at a point well behind my inteded target and cross fingers. Another workaround: use a high aperture, which is a good idea with the kit-lens anyway. F/8..F/11 is a good starting point.

I don't really know, if I should wait for that promised firmware update, which MIGHT solve the problem or if I should call that a clear malfunction and send the camera back. The support guys couldn't give a date for the release of that firmware update. Shameful, if you ask me.

What's your opinion - what would you do? (Reminder: this is a confirmed software bug, not a hardware/mechanical thingie).

Th.
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Old Dec 12, 2010, 11:56 PM   #6
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having the kr for about a month, I have not had any front focusing problems.
The only thing that has really bugged me is the shooting mode fiasco: using the timer/remote in conjunction with HDR... i wish that could be solved with a firmware update!
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Old Dec 13, 2010, 1:50 AM   #7
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Quote:
Originally Posted by ewheeler20 View Post
having the kr for about a month, I have not had any front focusing problems.
Did you change any camera settings?

Can you try a simple focus test indoor with not too bright artificial/tungsten light? (use a fast lens, look about 45 down on a newspaper etc. - middle/center focus point only, aim at a certain line and let the camera find focus. Repeat like 4-5 times and watch results)

For me the focus sits like 1-1,5cm in front of the focus point, with a f/3.5 lens the targetted line is barely in focus.

Regards,
Th.
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Old Dec 13, 2010, 12:28 PM   #8
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I would say that 85% of the time, i am in aperture priority mode, 10% in shutter priority, and 5% in manual. Nothing else. I did do the focus test, with the whole 45 degree thing with a template i found online. I did this when i bought my sigma 30mm 1.4 to test its front focusing problem. I ended up returning the lens because it was really front focusing. I tried my other lenses (4 others at the time) and had no problems with any of those.
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Old Dec 13, 2010, 12:43 PM   #9
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I see. Well - I did the test with a Pentax-A 50/1.7 at f/2. The lens works well on my *istDL2 by the way. And my *istDL2 was with heavy front-focussing problems at the support just some weeks after purchase.

For me the test looks like this and I call this a serious problem. #1 is indoors, #2 outside/daylight. Almost identical results which shouldn't be the case if it is an indoor/dim light software thingie, right?

I already contacted Pentax support and showed these images, let's see what they say. Looks like the story repeats here...

Regards,
Th.
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Old Dec 13, 2010, 7:19 PM   #10
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Quote:
Originally Posted by thkn777 View Post
The support guys couldn't give a date for the release of that firmware update. Shameful, if you ask me.


Th.


Well i would go easy on them, thats definitely not the department who would work on such a thing, and if pentax is anything like the big company i work for, nothing is ever communicated like such. I believe if they had a planned release date, it would be all over the net or should i say: If they knew how to fix it, it'd be rolled out already.

I am sure it will be fixed with firmware but i would exude patience. They dont want to advertise they are working to 'fix' anything im sure, as that kind of statement would slow sales and create bad press. Problem ? What problem? Of course when you call them out on it they cant insult your intelligence and have you think you just bought a crappy camera, yes of course theres something wrong with it, but it will be fixed dont worry. Its the same way in the business I am in.

My .02

Last edited by NMRecording; Dec 13, 2010 at 7:44 PM.
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