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06-13-2016, 12:59 PM   #1
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How commonly is AF fine adjustment needed with lenses?

[The following post was moved from another thread - @gatorguy had stated that he hasn't yet found the need to fine adjust the AF for his lenses]

QuoteOriginally posted by BigMackCam Quote
We're going off-topic here, but I'll just briefly comment on this... The need to fine adjust lenses is, in my view, very much down to an individual's expectations / tolerance, the subjects and distances they shoot at, the apertures they typically shoot at and what size they view the final images at. It's quite possible for a lens that appears to be spot-on to reveal, under focus chart testing, slight front or back focus that the individual has never noticed in real world use (within their typical shooting conditions).

Apologies to the OP for going off-topic. Might be worth starting a separate thread for this?
Yup a separate thread would be appropriate. Feel free to move this and make it the first post.


Last edited by BigMackCam; 06-13-2016 at 01:10 PM.
06-13-2016, 01:32 PM   #2
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Just to add to what I'd already said in my last post... My DA Limiteds required no fine adjustment on my K3 - not one of them. My Tamron 28-75 f/2.8, if I remember correctly, needed -7 adjustment, but the focusing inaccuracy was only really noticeable with wider apertures than f/5.6, at the longer end, when shooting fairly close subjects (hence shallow depth of field). My Sigma 17-50 f/2.8 required either -5 or +5 adjustment (can't remember which), and this was even less noticeable than the Tamron... I shot with it happily for several days before I had even the slightest concern...
06-13-2016, 01:35 PM   #3
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I think I would in general agree with @bigmackcam it is not an automatic that a new (to you) lens should need an adjustment. That said, I always test a new lens (or new to me old one) just to be sure. And your style of shooting and the maximum aperture of a particular lens also have an impact.

Would I check and carefully adjust a 50mm f/1.4? Yes. No question. Would I do the same to an 18-55 kit lens? probably not, the maximum aperture tends to hide any front/back focus anyway.
But checking a lens to make sure it is within my tolerance is just part of getting a new lens IMHO. You might have a dud, or a lens just might not work on your camera. So I always check.

On my k-5 almost all of my lenses needed adjustments. On my k-3 none of them needed any adjustment. On the k-1 a few do, most don't. So I check.
06-13-2016, 01:40 PM   #4
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I've ended up doing microadjustments on all my Pentax lenses. Of my 6 DA(L) lenses, I need +1 to +7 on my K-30. I'm wondering if the adjustment is a factor of the camera and/or of the lens.

06-13-2016, 01:41 PM - 1 Like   #5
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if you want the AF to be accurate, expect to fine adjust every lens you have.

---------- Post added 06-13-2016 at 01:43 PM ----------

QuoteOriginally posted by mgvh Quote
I've ended up doing microadjustments on all my Pentax lenses. Of my 6 DA(L) lenses, I need +1 to +7 on my K-30. I'm wondering if the adjustment is a factor of the camera and/or of the lens.
it is probably simply a reflection of compounding tolerances combined with your own personal threshold for acceptable precision. Some folks may be fine ignoring this fine tuning and others not so much.
06-13-2016, 01:52 PM   #6
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QuoteOriginally posted by mikeSF Quote
if you want the AF to be accurate, expect to fine adjust every lens you have.
Well, I'd say expect to *test* every lens... not necessarily *adjust* every one of them. I test all of my lenses with a Spyder LensCal. I say again, with my K3, every single one of my DA Limited lenses is spot on at their widest aperture with zero adjustment. I could just have been very lucky, or maybe those six Limited lenses received more precise calibration in the factory than, say, a run-of-the-mill Sigma or Tamron...
06-13-2016, 01:58 PM   #7
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Seems to be luck of the draw. My Sigma 30mm 1.4 needed adjustment, but my Sigma 85mm 1.4 was dead-on perfect out of the box, and that is one of the most demanding lenses you could find when it comes to AF accuracy due to the extremely thin DOF.

And my first, older, Sigma 100-300mm f4 needed some adjustment, but my newer one did not.

Nikon is touting a new automatic AF fine-tune feature on their newest high-end body, so it's definitely not just a Pentax thing or a 3rd-party thing (as a lot of people on here like to think). It's a DSLR thing, and even the most expensive professional bodies and lenses are not exempt.

Last edited by Edgar_in_Indy; 06-13-2016 at 04:19 PM.
06-13-2016, 02:00 PM   #8
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QuoteOriginally posted by mgvh Quote
I'm wondering if the adjustment is a factor of the camera and/or of the lens.
Camera *and* lens. The AF fine adjustment is there to cater for tolerances in manufacture / calibration of both the body and lenses.

06-13-2016, 02:09 PM   #9
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Well I'm a bonafide pixel peeper. Before I take any time to work with any of my RAW files I've previewed them in the Bridge browser using the magnifying tool. If the focus isn't darn close I don't waste time with it.

It's not unusual for me to take just one or two shots of something so if the focus is off it's a lost opportunity but much more often than not they're good. Perhaps as with BigMackCam it's because I generally shoot better quality glass? I dunno, But being the pixel-peeper I am if there was a fine focus issue I think I would have seen it. So far so good, tho I will mention that my HD DA55-300 might be a little suspect as my keeper rate is lower with it in really fairly limited use. With the DA*200, DFA 100WR, Sigma 17-50 and even the cheap Bower 85mm I just got there's no question in my mind that fine focus is really good as is.

But I'll admit that I could still be missing even better focus success so I might move the LensCal from the wishlist to the cart. Perhaps a small investment in tools and time might have benefits. You guys have a whole lot more experience with it than I do.
06-13-2016, 02:17 PM   #10
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QuoteOriginally posted by gatorguy Quote
Well I'm a bonafide pixel peeper. Before I take any time to work with any of my RAW files I've previewed them in the Bridge browser using the magnifying tool. If the focus isn't darn close I don't waste time with it.

It's not unusual for me to take just one or two shots of something so if the focus is off it's a lost opportunity but much more often than not they're good. Perhaps as with BigMackCam it's because I generally shoot better quality glass? I dunno, But being the pixel-peeper I am if there was a fine focus issue I think I would have seen it. So far so good, tho I will mention that my HD DA55-300 might be a little suspect as my keeper rate is lower with it in really fairly limited use. With the DA*200, DFA 100WR, Sigma 17-50 and even the cheap Bower 85mm I just got there's no question in my mind that fine focus is really good as is.

But I'll admit that I could still be missing even better focus success so I might move the LensCal from the wishlist to the cart. Perhaps a small investment in tools and time might have benefits. You guys have a whole lot more experience with it than I do.
From what you're saying, it does sound like you'd know if you weren't getting good AF accuracy. Very glad to hear you're getting the results you are - long may it continue

Interestingly, my HD DA55-300 needed some small tweaking, too.

One of the reasons I like using the LensCal is it helps to reassure me that when I do get a missed focus shot, it's not due to poor calibration and is more likely (a) the AF system getting confused or making a bad decision (no AF system is perfect), or (b) my own failure in nailing the focus point
06-13-2016, 02:18 PM   #11
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It depends on the camera too. With my K-5 my Sigma 100-300 f4 needed more than 10. With my K3 no adjustment was necessary.
06-13-2016, 02:44 PM   #12
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I found all of mine needed some adjustment. Surprisingly the Pentaxes needed most...with the 35mm on +9...

By the way, those looking to buy a lenscal should look up GhettoCal - there is a DIY kit you can print, mount and cut out to make your own. Took me 10 fun mins and saved cash!
06-13-2016, 03:09 PM   #13
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QuoteOriginally posted by victormeldrew Quote
I found all of mine needed some adjustment. Surprisingly the Pentaxes needed most...with the 35mm on +9...

By the way, those looking to buy a lenscal should look up GhettoCal - there is a DIY kit you can print, mount and cut out to make your own. Took me 10 fun mins and saved cash!
I've seen the homemade instructions posted here someplace before. Maybe one of the mods can look it up and link it. 20 years ago I would have made my own too, but when you get my age you never know how much time you have left. I'll let someone else's time go towards it thank you.
06-13-2016, 03:19 PM   #14
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Quick question: Which is easier/quicker to use, LensAlign MkII or Spyder LensCal? Both are highly rated.
06-13-2016, 03:26 PM   #15
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One of our users, Yvon Bourque, kindly produced a free ebook with this printable auto-focus adjustment chart.

I like working with the LensCal, though, as it's easy to set it up on a tripod and it's a good, fairly solid bit of kit that should last a long time...
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