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10-01-2021, 01:32 PM   #31
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QuoteOriginally posted by psoo Quote
Jatrax said above that to fine tune his lenses it takes at least half an hour to to fine tune. In the K50 manual the fine tuning procedure seems to be a quick one that one can used. However, the manual states that one should "Be sure to use fine adjustment only when necessary. Care should be taken as adjusting the auto focus may make it difficult to capture images with the appropriate focus" whatever that means. I did attempt to follow the quick Pentax procedure. with my K50 and a Pentax 18-135 mm lens and saw no sharpening of the image, but maybe I didn't carry out the procedure correctly. In any case, the warning given in the manual was enough to discourage me from fiddling with fine adjustment.
It's good to hear your perspective on this subject.

I would agree about the "fiddling." I have a technical background and years of experience in lab-based research and development. You'd think I'd be delighted to spend time 'calibrating' my lenses...nope. I have developed a good procedure, but it's tedious to calibrate a dozen lenses. Like @Jatrax, it takes me about 30 minutes per lens, sometimes longer. I manage to fine-tune each lens precisely, but it takes time and ambition.

If you're happy with your images, then maybe nothing more is required.

- Craig


Last edited by c.a.m; 10-01-2021 at 01:42 PM.
10-01-2021, 01:32 PM - 1 Like   #32
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QuoteOriginally posted by psoo Quote
and saw no sharpening of the image
I will repeat what I said to a previous poster to this thread.

AF/FA is not about sharpness. It is about getting the plane of focus exactly where you want it.
10-01-2021, 02:22 PM   #33
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QuoteOriginally posted by pschlute Quote
I will repeat what I said to a previous poster to this thread.

AF/FA is not about sharpness. It is about getting the plane of focus exactly where you want it.
So you would recommend using Live View as much as possible?
10-01-2021, 03:09 PM - 2 Likes   #34
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I intend to purchase a bottle of red wine tomorrow to facilitate the fine tuning of my lenses, having tried other methods with indifferent success. I look forward to revealing the results of my investigations. I may even mention how I get on with the lenses.

10-01-2021, 03:14 PM - 2 Likes   #35
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QuoteOriginally posted by 35mmfilmfan Quote
I intend to purchase a bottle of red wine tomorrow to facilitate the fine tuning of my lenses, having tried other methods with indifferent success. I look forward to revealing the results of my investigations. I may even mention how I get on with the lenses.
I think it's supposed to be one bottle per lens, no?
10-01-2021, 06:17 PM   #36
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QuoteOriginally posted by psoo Quote
So you would recommend using Live View as much as possible?
No I don't. Although I will say that if I am using a tripod for a static scene shot I do focus using Live View, but I focus manually.
10-02-2021, 05:22 AM   #37
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QuoteOriginally posted by mikeavison Quote
PSchlute thanks for the reminder. Pretty stupid of me I should have thought of that, since similar thinking is required with film cameras if you wanted a leaf shutter and interchangeable lenses - you can't have TTL viewing (unless you want to go through a slow process of opening the lens, viewing, closing the lens, taking a picture with mirror synced to the lens). I guess this may be one reason why rangefinder cameras and TLRs have enduring appeal. You get the lower latency, quieter operation and (relevant with vintage cameras) longer reliability of a leaf shutter compared with a blind shutter. But I digress horribly - sorry.

Hassleblad? Pentax 645 and 6x7? There are many TTL cameras with leaf shutter lenses available.

10-02-2021, 08:07 AM   #38
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QuoteOriginally posted by 35mmfilmfan Quote
I intend to purchase a bottle of red wine tomorrow to facilitate the fine tuning of my lenses, having tried other methods with indifferent success. I look forward to revealing the results of my investigations. I may even mention how I get on with the lenses.
With all the interest being expressed in my "wine bottle autofocus tuning method" I thought I would give a pictorial demonstration of it's capabilities.

These two pictures were taken with the K1 + DFA* 85mm at f1.4 from a distance of about 4 feet. Central single AF point used centred on the B of Beaujeu. The first was shot with the calibrated +7 I have set up for this lens. The second taken with the AF/FA turned off.

You can see the backfocus evident without any adjustment. If I was taking a close portrait shot at wide aperture the difference is glaring and would ruin the shot.

Because I know my K1 has backfocus without adjustment, this quick and easy method of using such a wine bottle label works well for me, especially as I always have a steady supply of wine bottles to hand although I have to go to the store to get one
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10-02-2021, 02:13 PM - 1 Like   #39
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QuoteOriginally posted by c.a.m Quote
I think it's supposed to be one bottle per lens, no?
I was thinking more along the lines of one bottle per day, actually.
10-04-2021, 07:36 PM - 1 Like   #40
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QuoteOriginally posted by 35mmfilmfan Quote
I was thinking more along the lines of one bottle per day, actually.
That'll work- just do one lens per day! You can then calibrate, then celebrate!

---------- Post added 10-04-21 at 07:39 PM ----------

QuoteOriginally posted by pschlute Quote
With all the interest being expressed in my "wine bottle autofocus tuning method" I thought I would give a pictorial demonstration of it's capabilities.

These two pictures were taken with the K1 + DFA* 85mm at f1.4 from a distance of about 4 feet. Central single AF point used centred on the B of Beaujeu. The first was shot with the calibrated +7 I have set up for this lens. The second taken with the AF/FA turned off.

You can see the backfocus evident without any adjustment. If I was taking a close portrait shot at wide aperture the difference is glaring and would ruin the shot.

Because I know my K1 has backfocus without adjustment, this quick and easy method of using such a wine bottle label works well for me, especially as I always have a steady supply of wine bottles to hand although I have to go to the store to get one
This is a great illustration of the effectiveness of this type of test. I have often used this or a similar setup.

Last edited by mikesbike; 10-04-2021 at 07:44 PM.
12-17-2021, 04:05 PM   #41
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QuoteOriginally posted by UncleVanya Quote
My own relationship to this topic is complex. I have tried and NEVER gotten the same results from fine focus testing even with a costly test target system. I haven’t tried DOT TUNE methods yet but they look promising.Sometimes if critical focus is needed I resort to CDAF live view or magnified live view and manual focus.
Just curious, is there a DOT TUNE method for Pentax bodies documented somewhere ? I can only find ols threads for CanNikoNy at the moment...

Last edited by Weevil; 12-17-2021 at 04:15 PM.
12-17-2021, 04:15 PM   #42
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QuoteOriginally posted by Weevil Quote
Just curious, is there a DOT TUNE method for Pentax bodies documented somewhere ?
I don't believe that there is a specific procedure for Pentax cameras. Have you seen the video linked at this post: Dot Focus microfocus adjustment - PentaxForums.com

The procedure is similar for various brands of cameras. Basically, the AF Fine Adjustment setting is stepped up and down until the focus confirmation indicator (Green Hexagon) does not illuminate immediately. Pentax cameras do not have the right and left directional symbols in the viewfinder, but it's not essential.

That thread also has a post that describes my recent experience in comparing the Dot-Tune method to my own detailed quantitative method: Dot Focus microfocus adjustment - Page 3 - PentaxForums.com

- Craig


- Craig
12-17-2021, 05:10 PM   #43
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QuoteOriginally posted by Weevil Quote
Just curious, is there a DOT TUNE method for Pentax bodies documented somewhere ? I can only find ols threads for CanNikoNy at the moment...
https://youtu.be/7zE50jCUPhM
I recently used the dot tune method but I can’t fully say it’s exactly the same as the videos.
12-18-2021, 05:33 AM   #44
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QuoteOriginally posted by c.a.m Quote
I don't believe that there is a specific procedure for Pentax cameras. Have you seen the video linked at this post: Dot Focus microfocus adjustment - PentaxForums.com

The procedure is similar for various brands of cameras. Basically, the AF Fine Adjustment setting is stepped up and down until the focus confirmation indicator (Green Hexagon) does not illuminate immediately. Pentax cameras do not have the right and left directional symbols in the viewfinder, but it's not essential.

That thread also has a post that describes my recent experience in comparing the Dot-Tune method to my own detailed quantitative method: Dot Focus microfocus adjustment - Page 3 - PentaxForums.com

- Craig
Ok, great, i'll have a look! TFS!
02-25-2022, 12:46 PM   #45
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Can focus adjustment be made to a SMC-A manual focus lens?
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