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01-08-2012, 04:44 AM   #1
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Focus confirmation with manual lenses

I recently acquired a k135mm f2.5 lens and I have discovered that the green hexagon focus confirmation indicator is not accurate and is confirming focus just before sharp focus. Which means catch in focus is useless. Is there an adjustment in the camera body on the K5?

Thanks

01-08-2012, 04:59 AM - 1 Like   #2
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The "Apply all" AF fine adjustment applies to all manual lenses (or, actually, to all lenses without a specifc setting).
01-08-2012, 05:21 AM   #3
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Thanks for the quick response. So, just to confirm. If I fit the manual lens and make adjustments under the apply all setting this will not affect the individual settings for my af lenses?
01-08-2012, 05:40 AM   #4
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QuoteOriginally posted by everydaylife Quote
Thanks for the quick response. So, just to confirm. If I fit the manual lens and make adjustments under the apply all setting this will not affect the individual settings for my af lenses?
It will affect all lenses, but what you could do is simply use it for the manual lens, then revert to the individual lens setting for the others.

I can't say I've ever checked, but I'm reasonably sure that the settings in 'Apply One' aren't lost when switching to 'Apply All'.

You are using the Centre AF point aren't you?


Last edited by JohnX; 01-08-2012 at 05:46 AM.
01-08-2012, 05:41 AM   #5
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QuoteOriginally posted by everydaylife Quote
Thanks for the quick response. So, just to confirm. If I fit the manual lens and make adjustments under the apply all setting this will not affect the individual settings for my af lenses?
Right. (assuming individual setting = "apply one" setting, also it is worth noting that the "apply all" and "apply one" settings are not cumulative)
01-08-2012, 06:26 AM   #6
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QuoteOriginally posted by JohnX Quote
It will affect all lenses, but what you could do is simply use it for the manual lens, then revert to the individual lens setting for the others.



You are using the Centre AF point aren't you?
Yes I am using centre point but the indicator , red square, is switched of when I use manual lenses as it irritatingly obstructs the view for manual focus

So I just have to remember to uncheck the all lenses setting when using AF.

Thanks for the info
01-08-2012, 06:48 AM   #7
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QuoteOriginally posted by everydaylife Quote
...
So I just have to remember to uncheck the all lenses setting when using AF.
Actually, assuming that you have an "apply one" setting for each AF lens (this can be zero) there is no need to change anything if the one shared setting (= "apply all") is (more or less) ok with all the MF lenses. (Of course, if it turns out that different settings are needed for different MF lenses you'd need to dial the specific setting in when you change the lens. The underlying thing here is that the camera body cannot tell the older lenses apart, the newer ones provide a lens id via their data pin).
01-08-2012, 08:40 AM   #8
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QuoteOriginally posted by jolepp Quote
also it is worth noting that the "apply all" and "apply one" settings are not cumulative)
When I received my K5 I spent several hours calibrating all my AF lenses, one by one, and saving the settings using "apply one" to each. All were mid to high in the + scale (+5 to +10). Worked like champs after that.

The next day I thought of and calibrated all my MF lenses. They were in the -5 to -8 range, and I chose to "apply all" at -5 which was the value for my most used and most critical MF lens. Once I did that I found that my AF lenses didn't focus as well once again, so I repeated the long task of calibrating them all. They had all shifted downward by 5, so they are now set in the 0 to +5 range, except the one that was at +10, it is at +6 now.

I note this because I checked the forum at the time and most people who claimed that the settings weren't cumulative just quoted the manual or repeated what they read or heard from someone else. The others didn't specify that they, themselves, had actually used both the "apply one" and apply "all settings," nor did anyone say which setting they had used first.

Obviously, if they are cumulative and you set the "apply all" setting first, then you'd never realize that the "apply one" settings were affected by it.

My experience is that they are cumulative, unless that has changed with firmware versions or I just totally screwed something up while calibrating (but in a way very consistent with them being cumulative).

01-08-2012, 12:32 PM   #9
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QuoteOriginally posted by KyPainter Quote
My experience is that they are cumulative, unless that has changed with firmware versions or I just totally screwed something up while calibrating (but in a way very consistent with them being cumulative).
I had the same experience with my K20D; setting AF adjust for individual AF lenses first, then doing an "apply all" for MF lenses - then having to redo the AF lenses. Sure enough, no one here could say for certain whether they were supposed to be cumulative or not, but I saw a cumulative result, so I stopped asking.

Haven't done an "apply all" to my K-5, so no idea if it's a firmware or even camera version thing or not...
01-08-2012, 01:22 PM   #10
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Well, I just upgraded to the latest firmware. I already had 1.11, but I downloaded and installed again, and it accepted it, so I assume there was some minor revision slipstreamed in recently like some have said.

Anyway, after doing this I tried changing the "apply all" setting between -10, 0, and +10, with several lenses that had apply one settings made. In no instance did it seem to affect the focus adjustment this time. I did, however, notice that my lenses were in need of adjustment again. Perhaps some firmware change, perhaps not, but I decided to reset everything and try adjusting them all again.

Now, I am entirely confused. Adjusting the apply all setting has zero effect on any lens. I have tried 4 fast MF "A" lenses, and 3 AF lenses, and I can change the "apply all" setting to -10, 0, or +10 and see absolutely no movement in the focus plane except for one lens - an A50 1.7. Also, trying to adjust the "apply one" setting to my AF lenses, seems to have zero effect except for on my Sigma 18-50 F2.8. No visible change with 3 Tamron lenses across the full range.

I have the exact same setup I have used before, both with the K-5 and a K-10, and am following the exact same procedure. I'm not sure what to make of it.
01-08-2012, 02:06 PM   #11
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QuoteOriginally posted by KyPainter Quote
I have tried 4 fast MF "A" lenses, and 3 AF lenses, and I can change the "apply all" setting to -10, 0, or +10 and see absolutely no movement in the focus plane except for one lens - an A50 1.7. Also, trying to adjust the "apply one" setting to my AF lenses, seems to have zero effect except for on my Sigma 18-50 F2.8. No visible change with 3 Tamron lenses across the full range.
When you test the focus are you defocusing the lens in between each test? If you leave it in focus the general inaccuracy of the phase AF sensor will usually just give confirmation again even if you have changed the adjustment.

I normally put a piece of masking tape on the focus ring and mark the exact focus point established with magnified Live View. Then defocus. Then try again with the focus ring (or phase AF if an AF lens) until the green hexagon shows. If it doesn't line up with the marker then adjust, defocus, try again until focus confirmation (or AF focus) occurs on that marked point on the ring.
01-08-2012, 02:27 PM   #12
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QuoteOriginally posted by karma mechanic Quote
When you test the focus are you defocusing the lens in between each test?
Yep, I am defocusing between each test, and I made sure that I always focused from the same side/direction. I even tried turning the camera off and back on and defocusing between each test.
01-08-2012, 09:03 PM   #13
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So if it is cumulative then whatever adjustment I make in the apply all setting if I adjust for that in the apply one setting I should be ok?

I recently sent my K5 body and FA lens to Pentax because there wasn’t enough adjustment for my FA77. Since having it returned, luckily, no adjustment has been necessary for my FA lenses. So this should mean that if for example I have to adjust plus 5 for my manual lens in apply all then I would have to adjust minus 5 for my FA lenses in apply one?

I may not even bother because I had such problems before! Also when manual focusing at f2.5 with my 135 lens I doubt if it will be much help.
01-09-2012, 11:04 AM   #14
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This discussion got me thinking...

Seems to me there are probably three methods of achieving in focusing manual lenses...

1. Sharpness of the subject in the viewfinder.
2. AF adjustments made to the Pentax AF system
3. As determined by high contrast in the Live view system.

In 1, exact focus will be dependent on placing the camera's focus screen in the correct position. There are various thickness of shims to set this value correctly.

In 2., the camera can be calibrated by setting offsets in the K5 AF Adjustment settings. This will determine when to turn on the green hexagon indicating the lens is focused. In my experience there seems to be quite a bit of hysteresis in rocking the lens barrel for exact focus...

In 3. Focus accuracy as determined by highest contrast on the sensor appears to be the highest probability of getting a sharp image. This method does not depend on a calibrated AF system or focus screen position. The final result should match the exact focus precisely. But this method is slower, and not feasible for fast moving subjects.

After installing a Katz Eye focus screen on my K20d, I found a discrepancy between focus methods 1 and 2. The split image of the Katz Eye clearly shows incorrect focus. The adjusted AF focus point did not match the visible focus point in the viewfinder. I then discovered that the Katz Eye screen was a tiny amount thicker than the Pentax screen, and I had to change the shim in the viewfinder to match. After that proper focus in both methods were identical.

After reading the thread on capture in focus:

https://www.pentaxforums.com/forums/pentax-k-5-forum/170765-catch-focus-accuracy-solved.html

I was also surprised to learn that the AF adjustments that would trigger the shutter when doing capture in focus did not seem to change the focus point. I only tried +/- 5 settings from both directions, but the focus point on my focus chart did not seem to move. I suspect that is probably attributable to the hysteresis I referred to above.

I love my manual focus lenses, and they provide an affordable way to hand held low light photography. I look forward to reading more about the experience of others in achieving sharp focus.

Dick
01-12-2012, 03:13 AM   #15
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Friends, change the focusing screen. Place the screen with wedges and Dodena microprisms, and increases the eyecup. Then you focus confirmation does not need.
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