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02-26-2013, 07:39 AM   #1
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K-r or...

I've posted a few other threads regarding the issues I've been having with my K-r over the last 1-1.5 months now. Long story short, it seems to have developed the inaccurate focusing under tungsten lighting problem. I've got a few questions regarding that and switching from a K-r to a K-30 or 5-II.

1. Is the tungsten lighting issue able to be addressed by C.R.I.S and fixed? Or is it just an issue with the camera that some copies have?
2. Will using an off-camera flash auto-focus assist light help with this auto focus problem?
3. I've found myself longing for something more from my camera over the last month or so. I'm starting to get a bit more business for engagements/senior portraits and have also been doing quite a bit more for the school with event photography. I'm wanting a body that has a bit better low-light focusing capability and better high-iso noise. From looking at the K-30 sample pictures in the thread "My experience with the Pentax k-30 @ B&H (BIG PICTURES)", the K-30 has almost no noise or IQ reduction up until about 6,400 or so. Would the K-30 fix my auto-focus/high ISO worries?
4. While I'm saving up to possibly switch to a K-30 or 5-II, what would be a good full-manual, affordable, flash to invest in for the mean time? Do they all contain an AF assist light, or is that only on the newer models? I have experience using flashes when working with a wedding photographer I assist on occasion, but have never looked into buying one of my own.

02-26-2013, 08:32 AM   #2
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You can get a cheap K-01, it has a great sensor (better than K-r, the same one as K-5 and K-30) and it AF is always equally accurate, because it is contrast detect. With the newest firmware, its even reasonably fast.
I'm not sure a flash assist light will help you. I think what helps is the newest firmware and setting the WB to tungsten. You can also try live view focusing in conditions where you know PD AF will fail. Can't help you more than that, I have a K-r and it doesn't have this problem.
02-26-2013, 08:36 AM   #3
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I'm not sure about the 1st two questions. But dpreview.com has a pretty great studio comparison tool that is useful for comparing noise at both the raw and jpeg level:
Studio shot comparison: Digital Photography Review

To me it looks like there isn't much difference between the cameras, at least at the RAW level. They all do pretty well. The jpegs do look a little better from the newer cams though.

As to #4, I own the K-5 IIs, and can state that it does have an AF assist light. The really great thing about the newer cameras though is that they really don't need the AF assist lamp. My camera will focus in VERY low light, with or without the assist lamp due to the newer AF system. It's pretty impressive, and is the only place the AF system matches or betters the AF systems from the competition.

Hope that little bit helps!
02-26-2013, 08:43 AM   #4
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QuoteOriginally posted by Na Horuk Quote
You can get a cheap K-01, it has a great sensor (better than K-r, the same one as K-5 and K-30) and it AF is always equally accurate, because it is contrast detect. With the newest firmware, its even reasonably fast.
I'm not sure a flash assist light will help you. I think what helps is the newest firmware and setting the WB to tungsten. You can also try live view focusing in conditions where you know PD AF will fail. Can't help you more than that, I have a K-r and it doesn't have this problem.
I also recently bought the K-01 and would recommend if you can still get one.
The newest firmware seems to help on my K-r but I need to do more shooting.

02-26-2013, 08:45 AM   #5
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Thanks for the suggestions. I'd rather just stick with a DSLR instead of grabbing a K-01. Just a personal preference. I've updated the firmware on my K-r and use a tungsten WB, but it still has trouble unfortunately. Any more opinions on if a flash AF assist light would help at all?
02-26-2013, 09:07 AM   #6
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What kind of exposures are you typically seeing under tungsten light (ISO/shutter/aperture)? If these could be considered low light levels, some kind of AF assist light might help.

Have you checked your camera's AF Fine Adjustment (Menu #21 - C3) under both daylight and tungsten lighting? You might want to use the charts at this web site. Use a cheap clamp light on the target switching between a daylight (6500K) fluorescent bulb and a tungsten flood lamp. If the only difference is the lighting type, it would be easy to dial in the difference prior to a photo shoot.

I love my K-r. At the same time, I'd really like a K-5IIs. The world hasn't changed. In 1981 I drooled over the Pentax LX, but settled for a Super Program. I expect my wallet will have similar behavior this time around.
02-26-2013, 09:16 AM   #7
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QuoteOriginally posted by JimJohnson Quote
In 1981 I drooled over the Pentax LX, but settled for a Super Program. I expect my wallet will have similar behavior this time around.
I wish my wallet had a similar behavior... I can't keep the damned thing closed!

02-26-2013, 09:36 AM   #8
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When under tungsten lighting (Mostly for school based events in seminars), I'm usually shooting anywhere from 1600-6400 ISO, 1/10-1/60 shutter and 2.8-4 aperture. It's always pretty dim in the rooms. I always try to talk to the lighting guys to see if they can help me out at all, but it's always the same answer. "Sorry, its all the lights or nothing." I've played with my AF fine adjustment a bit, but haven't had a chance to dial it in super sharp. I've been meaning to take a weekend to play with it.

I'm just wondering how much an AF assist light on a flash would really help my AF in low-light conditions. I could pick up a Sunpak for like 30 bucks, but they don't have an AF light, IIRC. At least then if that light would help, I could drop $75-100 right now and semi-fix my problem, and then save up for a K-30 at a later date. I'm wanting to wait until April when the K-3 is rumored to be announced and go from there. Prices may drop a bit more!
02-28-2013, 03:45 AM   #9
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I shoot frequenly under low kelvin light or mixed light and the K-r is a disater for such situations with very strong front focus. You can use live view and this will help if there isn't a lot of movement it might be a work around for you.
But honestly it's a flawed AF module that Pentax knowingly used and did not offer a fix for customers so the only solution is to do what I did, get rid of the K-r.
Could have been a great camera but they messed up here big time

I've shot with many cameras since and this one is not in any way reliable in this type of lighting.
Not sure about the K-30 I have to try one but one would hope the issue is resolved

The AF assist light is next to useless on the K-r it hardly ever comes on bar ultra dark conditions, and it's too annoying to use in some shooting situations.
02-28-2013, 08:14 AM   #10
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Would the AF be a bit more accurate with even faster glass? Currently the fastest I have is the Tamron 17-50/2.8.
03-02-2013, 08:04 PM   #11
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Bump!

Does anyone have any insight on if my autofocus may be a bit more accurate with faster lenses? I'm trying to decide if I should just stick with my K-r for now and continue improving the lenses I have available to use, or if I should snag a K-30 or K-5 instead.
03-03-2013, 03:11 AM   #12
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With my K-r, it was when I bought a fast lens (FA50 f/1.4) and started using it near wide-open in low light that I noticed the camera was front focusing, and was outside the range of the AF adjustment. On testing, the front focus also showed up when I used the kit lenses on this camera, but it was rarely a problem with the slower lenses due to their greater DOF.

The DOF gets much narrower at f/1.4 or f/2.0 than at f/2.8 or smaller, so assuming the AF errors are at all related to calibration of the AF sensor vs image sensor, you might find it hard to make use of the extra speed without AF errors becoming more of a problem than with your F/2.8.
03-03-2013, 06:08 AM   #13
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QuoteOriginally posted by jbuck92 Quote
Bump!

Does anyone have any insight on if my autofocus may be a bit more accurate with faster lenses? I'm trying to decide if I should just stick with my K-r for now and continue improving the lenses I have available to use, or if I should snag a K-30 or K-5 instead.
Very doubtful you can "fix" this on a K-r. The problem is reported to be related to light wavelength, not intensity, so a faster lens wouldn't affect it. Not a problem on a K-30 if you're looking to go that route.
03-03-2013, 06:17 AM   #14
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Thanks everyone! That answered my question. Time to save for a new camera body instead. It's not a problem with the k-5 or K-5ii either, right?
03-03-2013, 08:55 AM   #15
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It is a problem with the K-5, the K-5 II we hope has fixed this.
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