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09-21-2009, 02:25 PM   #1
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K20D ignorance...

I asked for some help last week with the selection of an additional body (I'd reference the thread, but I'm typing on my phone and don't think I could pull that off!). Many suggested the K20D, and initially I shot that down. However after reading so many praise it's performance, I want to take a second look at the camera. Specifically can the focus adjust help overcome the front focus under tungsten light? That is about my only complaint with the K200D (present body) and something that seems much improved on the K7. I realize the focus adjust is up to 20 lenses individually or as a 'whole'. Can you use it selectively? Say when shooting in those situations where it is more pronounced as way to overcome the issue?

How do users over come this when shooting with a shallow depth of field? I mean, it is apparent to me on my K200D and I can only imagine it is more pronounced on sensor that has a higher resolving power.


Last edited by joeyc; 09-21-2009 at 02:37 PM.
09-21-2009, 03:15 PM   #2
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I don't know the answer to your question because I don't use the focus-adjust for my lenses and I almost never shoot under tungsten.

I don't want to hijack your thread - I think this question is related: Why don't camera manufacturers link their focus systems to the WB settings??
09-21-2009, 03:18 PM   #3
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QuoteOriginally posted by joeyc Quote
I asked for some help last week with the selection of an additional body (I'd reference the thread, but I'm typing on my phone and don't think I could pull that off!). Many suggested the K20D, and initially I shot that down. However after reading so many praise it's performance, I want to take a second look at the camera. Specifically can the focus adjust help overcome the front focus under tungsten light? That is about my only complaint with the K200D (present body) and something that seems much improved on the K7. I realize the focus adjust is up to 20 lenses individually or as a 'whole'. Can you use it selectively? Say when shooting in those situations where it is more pronounced as way to overcome the issue?

How do users over come this when shooting with a shallow depth of field? I mean, it is apparent to me on my K200D and I can only imagine it is more pronounced on sensor that has a higher resolving power.
Not in they way you are hoping. You could, conceivably, dedicate a specific lens, or lenses, for tungsten and adjust focus for those lenses under tungsten light, but they would be off under daylight. Now, having said that, fuggetaboutit. The difference is minimal and you have to do some serious pixel peeping to see it.
09-21-2009, 03:27 PM   #4
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I've never had front-focus issues under tungsten (or indeed at all) with any of my lenses on my K20D.

09-21-2009, 03:29 PM   #5
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With most lenses it's not a big issue. It IS a big issue with my FA 50mm f/1.4 -- much bigger than pixel-peeping-scale, I'm afraid.

But unfortunately, there's no easy way to switch back and forth between focus-adjust settings. Here's what I do:

I usually leave the global setting alone.

For the FA 50, I leave the lens-specific setting at zero most of the time (it's dead-on in sunlight).

If I'm going to be shooting at wide apertures (f/1.4 to 2.0) indoors in bad lighting, I'll go into the focus adjust menu and dial in a -9 for that specific lens. That's the setting that works for me.

After I'm done, I TRY TO REMEMBER to set it back to zero. I don't always. And sometimes I'll switch lenses while shooting indoors, and you can't change the FA 50 setting unless that specific lens is mounted. So next time I mount the lens, I need to remember to check the focus setting.

This is one of my (few) peeves with K20D usability. I'm more or less in the habit now of checking the focus adjustment settings every time I mount the FA 50. Usually.
09-21-2009, 03:31 PM   #6
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QuoteOriginally posted by Frank Fletcher Quote
I don't know the answer to your question because I don't use the focus-adjust for my lenses and I almost never shoot under tungsten.

I don't want to hijack your thread - I think this question is related: Why don't camera manufacturers link their focus systems to the WB settings??
I had the same idea when I did some thinking about this topic when I first got my K200D.

QuoteOriginally posted by Parallax Quote
Not in they way you are hoping. You could, conceivably, dedicate a specific lens, or lenses, for tungsten and adjust focus for those lenses under tungsten light, but they would be off under daylight. Now, having said that, fuggetaboutit. The difference is minimal and you have to do some serious pixel peeping to see it.
I appreciate the response. I realize it is not relevant most of the time, but I have noticed this with close-up work quite often when using available/ambient light in a room, etc. In normal shooting it is usually not an issue. I do recall reading K20D users experiencing this from time to time, much like some of the other Pentax bodies.

QuoteOriginally posted by deadwolfbones Quote
I've never had front-focus issues under tungsten (or indeed at all) with any of my lenses on my K20D.
Good to know! Do you ever do any shallow depth of field work under tungsten light (or any artificial light for that matter)?
09-21-2009, 03:33 PM   #7
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Thanks for the great response. This is exactly what I was looking for. In some situations I like to use my 50mm 1.7 without flash @ 1.7 and have a pronounced front focus issue.

So it seems it would have to be a situational type of use.

QuoteOriginally posted by Quicksand Quote
With most lenses it's not a big issue. It IS a big issue with my FA 50mm f/1.4 -- much bigger than pixel-peeping-scale, I'm afraid.

But unfortunately, there's no easy way to switch back and forth between focus-adjust settings. Here's what I do:

I usually leave the global setting alone.

For the FA 50, I leave the lens-specific setting at zero most of the time (it's dead-on in sunlight).

If I'm going to be shooting at wide apertures (f/1.4 to 2.0) indoors in bad lighting, I'll go into the focus adjust menu and dial in a -9 for that specific lens. That's the setting that works for me.

After I'm done, I TRY TO REMEMBER to set it back to zero. I don't always. And sometimes I'll switch lenses while shooting indoors, and you can't change the FA 50 setting unless that specific lens is mounted. So next time I mount the lens, I need to remember to check the focus setting.

This is one of my (few) peeves with K20D usability. I'm more or less in the habit now of checking the focus adjustment settings every time I mount the FA 50. Usually.
09-21-2009, 03:36 PM   #8
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QuoteOriginally posted by joeyc Quote
Good to know! Do you ever do any shallow depth of field work under tungsten light (or any artificial light for that matter)?
Not a ton, but I've shot my fair share.

09-21-2009, 10:31 PM   #9
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Like a lot of others I was initially concerned about the tungston AF problem but in real life (mine) it has not turned out to be an issue at all. When the lighting is typically close to 100% tungsten and I am using shallow DOF, its always a Pentax-A 50mm f1.4 and I have the focus control needed. When using my DA lenses under tungsten I usually am using a bounce flash anyway and even when not have stopped thinking about the issue which must mean I don't actually notice a real life difference as the keepers seem to number the same.

your mileage may vary.
09-21-2009, 11:56 PM   #10
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Well, I made some tests about this very problem two days ago, and I found that for my main lenses (FA50 and Tamron 28-75), the amount of front-focusing under tungsten is about the same (-9)...

So, when shooting tungsten, I dial a -9 general adj., and I remove it once done... This is far easier than adjusting individual lenses, and you can see at a glance what your current setting is... That's "Menu-left-up-up-up-ok" for the AF Adj menu...

But, I still don't understand why they didn't link the WB and focus adj...
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