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07-03-2008, 06:05 AM   #1
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FA 50 Focus Adjustment

Hi,

I just purchased a FA 50 1.4 from another pentaxforums member. It arrived today and I tried a few test shots. Despite the AF locking on quickly, I felt the images looked out of focus. I've taken a few focus test shots to check for FF & BF using the - 3 batteries on a 45 degree angle method and would like your opinion on the results.

All images taken wide open as suggested @ 1.4 at just over minimum focus distance. Using Av, center focus, SR off, all focus points the same and camera sitting flat on a table.

1st image with no focus adjustment - focus point the top of the middle battery at the letter R
Attachment 14842

2nd image with -5 adjustment - same focus
Attachment 14843

3rd image with -10 adjustment - same focus
Attachment 14844

From what I can see, the FA 50 needs to be at -10 focus adjustment...actually to me it looks like -12 would be best, but that's not possible!

Appreciate your feedback

Daz


Last edited by dazman; 07-22-2008 at 12:11 AM.
07-03-2008, 06:28 AM   #2
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-10 focus, how are you ding this, I cannot find such an adjutemtn on my K100d?
07-03-2008, 06:33 AM   #3
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Focus adjustment was added in the K20D. Our K100D cameras do not have this feature.
07-03-2008, 06:53 AM   #4
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QuoteOriginally posted by MrApollinax Quote
Focus adjustment was added in the K20D. Our K100D cameras do not have this feature.
Darn, that would have been useful!
Oh well thanks anyway!


07-03-2008, 07:08 AM   #5
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I have the same problem with my K20. The assembly of the camera is so bad that I can't bring a couple of lenses into spec.
07-03-2008, 07:22 AM   #6
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Just thought I'd add that my Sigma 17-70 was prefect with no adjustment under the same testing.
07-03-2008, 11:29 AM   #7
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QuoteOriginally posted by dazman Quote
From what I can see, the FA 50 needs to be at -10 focus adjustment...actually to me it looks like -12 would be best, but that's not possible!
Daz
Yes, adjustments over 10 are possible, just not at one time. If you exit the adjustment screen and then go back in, the camera is still set at -10 and you can then dial in another -10, or whatever number you need.
Give it a try.

Last edited by felix68; 07-03-2008 at 11:30 AM. Reason: Cut too much of the quote out.
07-03-2008, 11:33 AM   #8
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Not True.

QuoteOriginally posted by MrApollinax Quote
Focus adjustment was added in the K20D. Our K100D cameras do not have this feature.
This is not true. While there is no menu selection to adjust focus like the K20D, with the K100D you can go into a service menu and make an adjustment. Do a search on this forum and you will find instructions on how to get your camera into the focus adjustment screen.

07-03-2008, 02:28 PM   #9
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Welcome to the club!

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/30117-help-fa-...us-issues.html

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/26337-50mm-f-1...us-issues.html

If there's a good and permanent solution to this I'd love to hear it. But one thing to try before you do anything (or end up using that lens in manual-focus mode as I do now) is to try again, under bright natural sunlight, and see what happens. My results are better there.
07-04-2008, 02:21 AM   #10
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Hi Quicksand,

Thanks for letting me join "The Club". Woohoo! Yeah...I read through those topics before my post, was just hoping someone new could help further. It's very likely that the newbie behind the camera (who ME!?) was at fault and it will take time to master the FA 50. I still did some more testing today in natural light and the focus was perfect at -10 & 0...go figure, so I'll leave it on 0 unless I'm shooting in low light/indoor situations, which I'll change to -10 for the best results when using AF. Most of the time I'll use manual focus...less of a headache. It's a tricky little lens, but I'm loving the results when you get it right.
Living & Learning
Daz
08-16-2009, 10:27 PM   #11
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QuoteOriginally posted by Marilith Quote
Darn, that would have been useful!
You can make AF focus adjustments on the K100D as well using a debug menu. That's only one adjustment for all lenses, but you can change it each time you change a lens.

If you have the "K100D super" the key sequence won't work but if you really want it you may be successful with another approach using a special MODSET file.

In any event, you may find these Autofocus Adjustment Hints useful.
08-16-2009, 11:36 PM   #12
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The links don't seem to work, but I can tell you that 99% of all focus tests performed without the aid of an actual well-designed focus test chart are worthless - it's far too easy to setup a test in a way that invalidates the results (eg, putting more than object object within range of the AF sensor). Repeat the test using a known good test chart and post those results.
08-17-2009, 03:34 PM   #13
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QuoteOriginally posted by MrApollinax Quote
Focus adjustment was added in the K20D. Our K100D cameras do not have this feature.
The K10D also has it but only for a couple of lenses and you have to do a hack or revert to one previous firmware to be able to do it.
08-20-2009, 10:05 PM   #14
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FA50 Focus Adjustment

Hi dazman, I recently tried out an FA50 from a forum member in Perth and it back-focused badly on my K10d. Disappointed as it was in perfect condition and a reasonable price. I figured it was just the combination of my specific body and that lens.

Note, while I agree in general with Marc's comment above, I've got a pretty good idea of how great DOF is at f2.8 with a 50mm lens, and I've also had plenty of MF experience on this particular body. None of my AF or MF lenses BF or FF to any noticible degree that can't be blamed on poor technique.

I find a good quick focus test is to shoot an object filling at least half the frame on a uniform surface (like grass) with central AF point. For the FA 50 I tried a number shots framing a stationary seagull at about 3m. At ~f2 the images were consistently soft, at 2.8 the grass is consistently in focus behind the bird. By f5.6 the image was OK but I wouldn't say it was particularly sharp, compared to the A 50/1.7 or the FA35/2 for instance. Same technique using a Tamron 90 (the pre-DG AF model) at least has some of the bird in sharp focus, even if is just some part of the body or legs!

So I wouldn't chalk this up to your poor technique just yet!

-Steve
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