[Excalibor]

Hi, all:

I have had to fine-tune several of my lenses because the ratio of out-of-focus pictures was extremely high. My 18-55mm DA-L WR kit lens is working perfectly now, but I have some older KAF and KAF2 lenses plus a manual 50mm from times yonder.

In the users' manual, it is stated that manual lenses will have to use the global AF correction, while modern lenses can have a personalized value for themselves. My doubt it: in which number do I have to leave the C setting for all lenses to work? In 3 (AF tune one lens) and the camera uses the AF correction for all, or should I have to change it when I change lenses?

I'm asking this because sometimes I cannot get a sharp image from the other lenses: maybe they aren't that sharp, but I am suspicious and think some out-of-focus might be crawling around.

Thanks in advance!

[BigMackCam]

Yes, if you use an AF fine correction "for all" to adjust focus confirmation for a manual lens, you'll need to go back to "3" when you switch over to one of your modern lenses. Plus, as I'm sure you realise, you need to fine tune the AF for each lens that you use...

I'd recommend that you carry out AF fine tuning in natural light, using a proper focus test target. And bear in mind, even with the fine tuning carried out perfectly, you will get some AF misses, depending on the individual target you're focusing on. The camera is only so clever...

[Ole]

Correct me if I'm wrong, but the KAF and KAF2 lenses are not manual lenses and you should be able to dial in correction for each lens.

[mikesbike]

A better trained eye is a big help too. When you use your manual focus lens, don't always rely on only your camera's focus indicator. It is one advantage for an OVF. You are seeing exactly what the lens is doing in its relationship to a real object. In fact, it is a good thing to practice- disregard the indicator and focus manually by just using your vision. It will take some time, but you will improve, and you'll be better able to spot AF focus problems as they occur.

The kit lens is good, especially for its price, but is not among the best for AF accuracy.

[stevebrot]

In the users' manual, it is stated that manual lenses will have to use the global AF correction, while modern lenses can have a personalized value for themselves. My doubt it: in which number do I have to leave the C setting for all lenses to work? In 3 (AF tune one lens) and the camera uses the AF correction for all, or should I have to change it when I change lenses?

I am not sure what the "C" setting is, but I can provide some guidance regarding AF fine adjustment and manual focus lenses. The basics go something like this:

1. Don't do fine adjustment unless you are sure that the problem in front or back focus. Having a lot of soft of out-of-focus results may have other causes that adjustment will not help.
2. Most front/back focus problems are lens-caused and needed correction would be related to the lens being used. Only very rarely is a global adjustment indicated and then that need may be best addressed by a service center.
3. The "Apply One" option is only available for auto focus lenses*
4. According to the user guide, the "Global" option applies to all lenses. However, a mix of "global" and "apply one" adjustments may have unexpected results. I personally, do not recommend combining the two. There is nothing about the global option that is specific to focus confirmation with manual focus lenses and nothing in the English version of the manual(s) that suggests such. Other language versions may read differently, however.
5. Adjustments should not be made on the basis of one focus attempt. Likewise, confirmation of adjustment should not be made on one attempt
6. Attempting the adjustment may be frustrating and may not fix the problem at all focus distances and/or focal lengths.

Point #4 above may generate some controversy and heated comments in regards to the "Global" option. The manual is explicit that changes there apply to all lenses, though attempts to set +10 global in conjunction with +5 "apply one" expecting a +15 result fail. In addition, some users have seen unexpected and unpredictable changes to existing existing "apply one" adjustments when a global setting was made or changed. I did a small study in response to a user help request a month or so ago using my K-3 (firmware v1.30) and various combinations of global and per lens adjustments. It appeared to make a difference whether a global change is applied before or after "apply one" settings are made. Existing settings did not work and a new adjustment attempt resulted in far different fine adjust values. I have not yet confirmed the detailed behavior since doing so requires recording and erasing my existing tunings to be re-entered afterwards. It is enough to say that I don't recommend using the "Global" option if per lens adjustments are also being used and suggest that use of the "Global" option has extremely limited application and should probably not be used at all.

If one is having problems with a manual focus lens and out-of-focus results, my recommendation is to use magnified live view as an alternative to the "focus confirm" feature or ioptical focus using the stock focus screen. Live view shows the actual focus on the sensor and is extremely accurate.


Steve

* A few Irix-brand manual focus lenses may also be used with fine adjustment, but I am unaware of any successful user attempts.

[BigMackCam]

Very interesting, @stevebrot - that wasn't my understanding, but you have more than enough credibility in my eyes for me to believe your findings...

[stevebrot]

Very interesting, @stevebrot - that wasn't my understanding, but you have more than enough credibility in my eyes for me to believe your findings...

It was not my understanding either until I actually did some experimentation. At present, I am not willing to suggest that cameras other than the K-3 with v1.30 firmware behave that way. I did not make detailed notes, but the experiment went something like this:

• Erase all adjustments
• Set an appropriate fine adjustment for a particular lens (say +3) using "adjust one"
• Confirm the fine adjustment as good
• Make a significant global adjustment (say -10)
• Check the AF for lens above again and note that it is no longer good
• Redo the fine adjustment for the lens and note that the number is quite different than before, but not obviously based on the global setting

I did enough fiddling around involving multiple resets and different order of global vs. per lens to come to the conclusion that the global feature is not stable on my camera and that I would not recommend its use. Of course, this topic requires a thread of its own, but I am not prepared to do that without doing a complete set of test cases.

I hope this is not too much of a thread hijack, but given that it appeared that making global adjustments were being considered, I figured it was worth the risk.


Steve

* A prevalent view on this site is that global and per lens adjustments are independent.

[BigMackCam]

Thanks, Steve - this is very useful information, even in its formative stages...

I did enough fiddling around involving multiple resets and different order of global vs. per lens to come to the conclusion that the global feature is not stable on my camera and that I would not recommend its use.

If pressed at this point, would you say that the global feature is not stable, or that global + individual lens is not stable, on your camera (with the installed firmware)?

Of course, this topic requires a thread of its own, but I am not prepared to do that without doing a complete set of test cases.

It definitely deserves a thread of its own. If you're able to continue with your tests, then whenever you're able and ready to create that thread, I'll be one of the first readers!

I hope this is not too much of a thread hijack, but given that it appeared that making global adjustments were being considered, I figured it was worth the risk.

In the circumstances, it absolutely was worth mentioning. Thanks again

[stevebrot]

If pressed at this stage, would you say that the global feature is not stable, or global + individual lens is not stable, on your camera (with the installed firmware)?

Unless one is sure the per lens option will never be used, I consider the feature to be unstable. There may be a logic hole somewhere. The unfortunate thing is that most users on this site would likely not be keen to erase or put at risk existing settings. After all, who writes these things down, right? I am not sure I want to do so, but since I have a limited number of lenses with fine adjustments, I will make the sacrifice...in a couple of weeks...


Steve

[BigMackCam]

Unless one is sure the per lens option will never be used, I consider the feature to be unstable. There may be a logic hole somewhere. The unfortunate thing is that most users on this site would likely not be keen to erase or put at risk existing settings. After all, who writes these things down, right? I am not sure I want to do so, but since I have a limited number of lenses with fine adjustments, I will make the sacrifice...in a couple of weeks...

Thanks, Steve. If you're happy to lead the tests but want some help with that, let me know... I have all my fine adjustment settings for each camera and lens combo in a spreadsheet, so I can sacrifice those stored in my K-3 (or a different camera) if necessary

[Excalibor]

A better trained eye is a big help too. When you use your manual focus lens, don't always rely on only your camera's focus indicator. It is one advantage for an OVF. You are seeing exactly what the lens is doing in its relationship to a real object. In fact, it is a good thing to practice- disregard the indicator and focus manually by just using your vision. It will take some time, but you will improve, and you'll be better able to spot AF focus problems as they occur.

The kit lens is good, especially for its price, but is not among the best for AF accuracy.

I do try and focus by eye, but it was easier in film days because we had these split circles and prisms to focus with that really nailed the pictures. I love it on my Ricoh K10x, and I am very used to shooting with the 50mm f/1.7 with it. Moving to the digital world with manual focus lenses, where there's advanced AF, is proving a bit challenging. I will have to train myself not to press the AF button with my thumb and rely on the instincts, as you say... Thanks for the advice, it's always good to be reminded of the basic stuff like "use your eyes"! :-)

---------- Post added 07-18-18 at 11:49 PM ----------

Correct me if I'm wrong, but the KAF and KAF2 lenses are not manual lenses and you should be able to dial in correction for each lens.

Yes, both are (noisy) autofocus and can, indeed, have individual settings. But as I have some manual lenses to throw in the mix, I am always doubting which and when it works, thus my question... It's better to ask :-)

---------- Post added 07-19-18 at 12:12 AM ----------

(...)

I hope this is not too much of a thread hijack, but given that it appeared that making global adjustments were being considered, I figured it was worth the risk.

(...)

No hijacking at all! It's been some really interesting interventions, and you have certainly answered my doubts and nailed some points (like fine AF tuning is hard to do, boring and prone to error).

The "C" settings tab is the last one in the Settings menu, where the AF tuning lives on (in number 26): following advice from other threads, I tinkered in some AF options in this menu and now I am much more confident in my shooting skills. So, I will follow your advice and not make corrections at all. If I find a consistently miss AF lens, I might think about trying to A tune it. And the manual lens, I will use "by eye" or live-view to focus with, this battery holds very well.

Thanks for your help and advice, it's much appreciated!