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10-07-2010, 06:18 PM   #1
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Lens Correction: Good or Bad Idea?

The menu item that corrects for chromatic aberration and the resulting fringing... How well does it work, is it a good idea, or is there a piper to pay?

(I have a K-x with 18-55 and 50-200mm lenses btw)

10-07-2010, 06:43 PM   #2
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I'd use it. That's one thing I'd love to have.

In some newer cameras like the micro 4/3 line, you don't even have the option of using it or not
10-07-2010, 06:54 PM   #3
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I don't use those settings. Normally the Chromatic Aberration on modern lenses is so low it never shows up on prints, plus it slows down writing of shots to your card.

On my K-7, it's out of commission for at least 2 seconds after I take a shot so it can process the image and take out CA.

Like I said, the level of CA in modern lenses is so low it's a non-issue. And if it is an issue in say one out of 100 shots, it's trivial to take out in Photoshop or Lightroom in PP. Like I said, although a review of a lens may say it has CA, when you actually print the image I'd bet you a nickel you won't see it.
10-07-2010, 07:02 PM   #4
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I don't know about the CA but the distortion correction works. anyway I prefer messing with that after the fact

10-07-2010, 07:57 PM   #5
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The only CA I experience with any of my lenses is with my DA* 200mm, but only at f2.8. As mentioned, it doesn't print, and the only way I can see it is by pixel peeping. As others have mentioned, with modern DA lenses, it's really not an issue, and if what you occasionally find while pixel peeping at over 100 percent bothers you, it can be fixed in PP.
10-07-2010, 08:01 PM   #6
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QuoteOriginally posted by bigdave56 Quote
The menu item that corrects for chromatic aberration and the resulting fringing... How well does it work, is it a good idea, or is there a piper to pay?

(I have a K-x with 18-55 and 50-200mm lenses btw)
I've enabled it when using native P.brand lenses (although I mostly use generics, so no help there), but I don't think I understand enough to know how much I don't know about what it really does, or doesn't.

The worrying thing I believe is that it's another Big Brother control by mfgrs in the market trend to using inbuilt firmware to manage and manipulate the resultant output of cameras to mainstream "We know what's best for you" level.

That's not really a bad thing in one sense, for the needs and convenience of the masses. But surely it does pose a potential problem, or conundrum, in that exactly how many cameras and at what price will end up being available to not just the pro but dedicated hobbyists and serious tech-oriented enthusiasts who seek and need less 'adulterated' and manual control.

Even now, we have to buy in the mid to high DSLR bracket because lower end models are increasingly rapidly becoming glorified P&Ss - and cumbersome interchangeable lens Videocams.

Scary future for sure. Sorry I don't have crystal balls. (Oops, don't read that as a double entrendre will you

.R.
10-07-2010, 08:04 PM   #7
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The DA L 18-55mm has substantial distortion/CA at the 18mm end. It's a good idea to have the corrections enabled when you use it. For the other focal lengths is not necessary, although if the lag of image processing doesn't hurt your shooting (aprox. 2 seconds), you can prefer keep it enabled.
10-07-2010, 08:31 PM   #8
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I enable lens corrections with the 16-45mm, 18-55 and 18-250mm. Not with my other lenses, 55-300 and primes, as it isn't needed or worthwhile.

10-07-2010, 08:53 PM   #9
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QuoteOriginally posted by audiobomber Quote
I enable lens corrections with the 16-45mm, 18-55 and 18-250mm. Not with my other lenses, 55-300 and primes, as it isn't needed or worthwhile.
Now that's an interesting point you bring up.
Surely such a mundane extra thing to have to remember though, most would prefer to attend to all the usual other pic-taking setting variances we have to alter to suit the circumstances at the moment.

But I vaguely recall reading a post on another forum that alluded to the camera (Nikon in this case, IIRC), being able to auto-sense and configure it's settings to a user preset (saved) 'profile' for each of their given lenses.

Is this reality or was it just something I ate on the day, and more important, do any Pentax cameras support that autoconfig~userprofiles capability that would hands-off cope with audiobomber's lens' range needs above?

.R.
10-07-2010, 09:06 PM   #10
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QuoteOriginally posted by brofkand Quote
the level of CA in modern lenses is so low it's a non-issue.
but for those of us shooting with not so modern lenses it might be helpful.
10-07-2010, 09:28 PM   #11
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QuoteOriginally posted by Hypocorism Quote
Now that's an interesting point you bring up.
Surely such a mundane extra thing to have to remember though, most would prefer to attend to all the usual other pic-taking setting variances we have to alter to suit the circumstances at the moment.

But I vaguely recall reading a post on another forum that alluded to the camera (Nikon in this case, IIRC), being able to auto-sense and configure it's settings to a user preset (saved) 'profile' for each of their given lenses.

Is this reality or was it just something I ate on the day, and more important, do any Pentax cameras support that autoconfig~userprofiles capability that would hands-off cope with audiobomber's lens' range needs above?

.R.
Yes, some Nikon bodies support user configurable profiles for saving settings.

It's not so hard to enable/disable CA though, you can change it under the INFO menu with no more than a dial flip. I find K-x menus very usable, specially the STATUS and INFO ones. Sometimes you want it on, but sometimes when speed is critical you might want off. Thank God Pentax made it user-configurable.

Last edited by hcarvalhoalves; 10-07-2010 at 09:39 PM.
10-07-2010, 11:07 PM   #12
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The lens distortion correction is available on the newest Pentax dSLR with Pentax lenses. The feature does not work with non-Pentax lens. You receive already some comment. let me share my own experience with my DA18-250mm, a zoom lens with which the lens distortion can be sizeable.

- I do not enable the in-camera lens distortion correction; partly because it requires some camera CPU time an slow down the camera;

- typically, I PP the photographs and I use the lens distortion correction in PDCU;

- when I need some accurate distortion correction (eg for an engineering job), I prefer to use the software PTLens; this software is very powerful and excellent value.

Hope that the comment may help...
10-08-2010, 05:24 AM   #13
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Thanks, all.
The processing time is not much of an issue for me most of the time.
Think I'll do some A-B shots and see what I see...
Thinking about the 17-70 at some point; expect that to be a better performer and the extra reach at the long end would be nice.
10-08-2010, 05:46 AM   #14
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In my opinion, unless you are really serious about using JPEGs right out of the camera for very large prints, this is better left in the PP phase.

the down side of processig demands to do this in camera are too great at present.

Additionally, the possibility exists for doing corrections with more than pentax lenses in PP.

What would be "nice" would be to have a tool, supplied by pentax, but that runs on your PC, where you could make corrections to distortion, and perform some analysis of CA etc, on screen, to generate correction files for non pentax lenses.

I would think shots against some form of test target could be analyzed to measure distortion and CA to do this.
10-08-2010, 07:07 AM   #15
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I never use the CA correction, it's something that I attend in post=processing if desired. I only use the in-camera lenscorrection in the K-7 for my DA14mm/f2.8 lens and wich is the only lens that I shoot RAW+Jpeg as standerd.

This is picture of my street, from a 14 m high crane (there are no high buildings nearby).

No lens correction:


Lens correction:

You can see the difference when you use a messuring-item

My place under the photoshop sun:


The DA14mm is an excellant lense on it's own to me.
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