I am interested about a feature for fine tune autofocus
I would like to solicit responses from users that have fine tuned their lens and what the end results were.
85 1.4 needed to +3 at 10ft
50 1.8 needed to -8 at 5 feet
I am somewhat confused on how to use this fine tuning with a zoom lens however. does it matter what length you choose? a 70-200 is it best to fine tune at 70 or at 200?
and last, does it matter what distance your target is set at or aperature?
I assume you use manual focus...
all help is appreciated
Thanks for sharing,
#1. "RE: lens fine tuning" | In response to Reply # 0evytubb Registered since 09th Dec 2006Wed 31-Dec-08 09:56 PM | edited Wed 31-Dec-08 10:29 PM by evytubb
Good question - was just looking for an answer to that. Just acquired Thom Hogan's D700 manual - perhaps the answer is there, I will look.
I have just read that part in Thom's book. Basically, if you calibrate a zoom lens at either ends of its length, it can throw off the other end noticeably. Thom suggests calibrating the lens at the most often used distance. He also has several suggestions regarding how to correctly shoot the included calibration target.
His manual is very good if you are looking for a lot of info on the D700 and using its features. I certainly have a lot to learn!
#2. "RE: lens fine tuning" | In response to Reply # 0ACSwash Registered since 05th Oct 2007Thu 01-Jan-09 02:45 PM
I tried using the fine tuning option but I found it hard to objectively judge what was happening - so I have just bought the new LensAlign product - not yet delivered.
You can find out about it here
This site also has several reviews of the LensAlign product which includes information about the general technical side of lens tuning.
#4. "RE: lens fine tuning" | In response to Reply # 2Thu 01-Jan-09 08:21 PM
>You can find out about it here http://www.rawworkflow.com/lensalign/
I have reservations about this particular expensive product.
As the Nikonians pod cast points out if you do not get your test target exactly parallel etc you can drive yourself nuts with misleading results.
Although the $138 product in the link avoids the pitfall of focusing on a target at 45 degrees to the sensor the "inventor" seems to have gone out of his/her way to use focus targets that do not meet several of Nikon's requirements for avoiding camera AF mis focus.
Camera AF mis focus (when the AF misreads the AF target) is not the same as front or back focus - Nikon give guidance on when it may happen on page 70 of the D300 instructions and page 82 of the D3 instructions,
I suggest anybody getting a front or back focus indication with this device adds a further test target ABCDEFGH printed a little larger than the AF viewfinder mark to help separate failure to read the target 100% accurate from front or back focus.
Photography is a bit like archery. A technically better camera, lens or arrow may not hit the target as often as it could if the photographer or archer does not practice enough.
#5. "RE: lens fine tuning" | In response to Reply # 4TomCurious Registered since 03rd Jan 2007Thu 01-Jan-09 08:30 PM
This is a good idea Len! So one could just tape a piece of paper with letters printed onto the front plate of the lensalign product for a better AF target. From what I have seen, the product should work fine in every other respect. So this would be a very simple fix.
I have not bought one though. It should be quite easy to build one of these myself.
Bay Area Nikonian
#8. "RE: lens fine tuning" | In response to Reply # 4MichaelT Registered since 04th Nov 2008Thu 01-Jan-09 10:48 PM
Thanks for your thoughts.
>>You can find out about it here
>I have reservations about this particular expensive product.
Happy to listen and discuss.
>As the Nikonians pod cast points out if you do not get your
>test target exactly parallel etc you can drive yourself nuts
>with misleading results.
Yes, the PRO version of LA has 3 different Camera-to-target alignment methods, ranging from very fast to perfect accuracy. Which you use will be personal preference, available time, distance and lens, etc.
>Although the $138 product in the link avoids the pitfall of
>focusing on a target at 45 degrees to the sensor the
>"inventor" seems to have gone out of his/her way to
>use focus targets that do not meet several of Nikon's
>requirements for avoiding camera AF mis focus.
I am the inventor of LA. I am not sure why "inventor" is in quotes, sounds like a negative inference to me, but not important. FYI, I consider LA an invention, and it is subject to multiple patent claims which of course in of itself means nothing unless they are granted. Obviously I did not invent the overall concept of focusing on a parallel focus target and reading the DOF results on a slanted "display", but LA incorporates many "inventions" that allow it to achieve very accurate and repeatable results quickly. All feedback from beta testers and owners has been virtually 100% positive. However, we want to improve LA in any way we can along the way. There are some options that will be announced soon that will add to its versatility. And the concept of different focus targets, and/or ruler displays is incorporated into the current design.
>Camera AF mis focus (when the AF misreads the AF target) is
>not the same as front or back focus
>Nikon give guidance on
>when it may happen on page 70 of the D300 instructions and
>page 82 of the D3 instructions.
The LensAlign development project took place over about a years time. I showed the initial concept to a few camera makers (I was not able to get with Nikon at the trade shows where my "meetings" occurred, however), as well as various pro photographers, and other respected industry professionals. We discussed concepts and I took their feedback into account as the design evolved. Several physical prototypes were made along the way and they were tested with several of these industry pros.
I had been a Canon shooter since going digital, but based on my involvements with Capture One DSLR, and RawShooter, I brought almost every Nikon DSLR in house as either a loan or purchase. I would say that equal amounts of LA development testing was done on Canon and Nikon equipment. In the interim I have decided to use Nikon equipment as my main system. I currently own the following Nikon bodies: D40, D90, D300, D700, D3 and several lenses. I have also rented long and fast Nikon glass to test with LA, and have just purchased the 500mm f4 for my own photography and LA customer support and continuing development and product documentation.
Specifically regarding the focus "warnings" that Nikon discusses in their manual, I do not find a conflict in the LA focus target design, not have I had problems in my personal tests. The 2 of 6 items that are listed that might raise eyebrows (and I assume which concern you) are #3 ("dominated by regular geometric pattens), and #4 (areas of sharply contrasting brightness).
I interpret #3 to reference repeating objects such that the focus point can be "inside" of, as shown with the drawing of the "skyscraper" windows. I believe that the Siemens star pattern that we use is in compliance with this potential problem.
I feel the same way about the contrast issue, in that I do not see the difference between black type on white having any different contrast "advantage" over the focus target that we use in LA.
Having said that, type *is* a good focus target, but I have not seen so far any issues with the LA focus target in regards to mis-focus where type would be a clear advantage. But I am open to possibility that something was missed. No one or product is perfect. So I welcome the discussion.
>I suggest anybody getting a front or back focus indication
>with this device adds a further test target ABCDEFGH printed a
>little larger than the AF viewfinder mark to help separate
>failure to read the target 100% accurate from front or back
While I do not see the need for your concern, the suggestion of using the "type" target taped onto the LA target will not impede any of the functionality of LA, so I have no problem with it.
As I stated above, one of the design features of LA is repeatability. That is why in all 3 "alignment methods" (we call it sighting) we specifically have the focus point of the camera be aimed specifically at the sighting hole area that was used in the alignment. This allows the distance from the LA focus target point to the DOF display ruler to be consistent for a given sighting point (we provide 5).
One of the industry professionals that I contacted during the LA development was Thom Hogan. Thom declined my invitation/request to look at a prototype or the design concept and opted to wait for a production unit. He will be receiving one shortly.
Sorry about the rambling post...hope it was helpful, and look forward to continued discussion.
#10. "RE: lens fine tuning" | In response to Reply # 8walkerr Nikonian since 05th May 2002Fri 02-Jan-09 12:33 PM
I ordered one of these products (and produced the podcast mentioned elsewhere in this thread) and found it works quite well. As with other approaches, you have to be meticulous, but I'm finding it confirms my previous settings. Having the 45 degree scale to visually check whether you're focusing in front or behind the target is a big help and speeds up what can be a fairly manual process.
As mentioned in the Luminous Landscape article, it's not uncommon to find errors that benefit from an AF fine tune adjustment. I think Michael Reichmann noted that about 50% of the lenses he tested benefited from an adjustment, and my numbers (and Jason Odell's, who does the podcast with me) were in the same ballpark. Most of the lenses I tested were fast primes like the 85mm 1.4, 105mm 2.0, 135mm 2.0, 180mm 2.8, etc.
In a future podcast, we'll talk about the product. I'm loaning it to Jason to play with while I'm on vacation.
#3. "RE: lens fine tuning" | In response to Reply # 0
Hi Jeff, here is a link to an image doctors podcast on the Af fine tune.
From my understanding, you shoot wide open, manually throw the lens out of focus, then re-focus using the AF.
#6. "RE: lens fine tuning" | In response to Reply # 0
>85 1.4 needed to +3 at 10ft
>50 1.8 needed to -8 at 5 feet
All my lenses focus fine with good AF targets, quite often focus well with poor AF targets, and sometimes wrongly focus (not the same as front or back focus as your camera instructions point out) with poor AF targets.
I have found no need of fine tune with over 20 Nikon lenses - in line with Nikon saying fine tune is rarely needed.
A picture of your test target might help as -8 is significant.
The attached images show the significant difference between nil with a good AF target and -10.
If I had a lens that needed -10 I would not fine tune it - I would exchange it for one that was clearly not defective
Attachment#1 (jpg file)
Attachment#2 (jpg file)
#7. "RE: lens fine tuning" | In response to Reply # 6Max Power Registered since 13th Jan 2006Thu 01-Jan-09 10:37 PM | edited Thu 01-Jan-09 10:38 PM by Max Power
I have printed the chart from this website here:
Seems all well and good, but it also seems to me that if you are trying to determine front and back focus, having the camera at exactly 45 degrees would be important. How exactly does one do that?
It's not an optical illusion. It just looks like one.
#11. "RE: lens fine tuning" | In response to Reply # 7JerryPH Registered since 04th Jul 2007Tue 13-Jan-09 01:06 PM | edited Tue 13-Jan-09 01:24 PM by JerryPH
>Seems all well and good, but it also seems to me that if you
>are trying to determine front and back focus, having the
>camera at exactly 45 degrees would be important. How exactly
>does one do that?
- I have a water level that is 10 inches long with an integrated 0-15-30-45 (etc...) degree markings and the water level portion is adjustable. I set the water level mark so that when the level is at 45 degrees, the bubble is centered.
- I then used the best straight edge on the camera, the lens, and adjusted the camera so it is pointing at a 45 degree angle.
- I then set the camera to use ONLY the center of the screen as the focus point.
- After that, I adjust the height of the camera so that the focus chart properly fills the screen. Since you cannot change camera angle, you will be forced to center the page by moving it either closer or further away from the camera so that the proper portion of the page is centered right on the center of the camera's focus point.
- Make sure lens is at it's widest possible aperture
- Either focus manually or automatically so that the center focus point is the SHARPEST part of the picture. Once that is done, set focus to manual and don't change anything in the focus department anymore.
Phase one of adjusting your focus - General focus:
- Take the shots with the fine tune focus settings at -20, -10, 0, +10, +20
- Look at the results on screen and localize which pictures were the sharpest. For the sake of the post, lets say -10 to 0 was the sharpest area... so we move on to find the next smallest jumps.
Phase two of adjusting your focus - lightly more concentrated focus:
- Take the shots with the fine tune focus settings at -10, -8, -6, -4, -2, 0
- Look at the results on screen and localize which pictures were the sharpest. For the sake of the post, lets say -4 to 2 was the sharpest area... so we move on to find the next smallest jumps.
Phase two of adjusting your focus - concentrated focus:
- Take the shots with the fine tune focus settings at -4, -3 -2
- Look at the results on screen and localize which picture was the sharpest. For the sake of the post, lets say -3 ... thats where you set it and where it stays for this lens.
You can do it in 2 phases or you can do it in 10 phases, just keep doing it until you are satisfied that you are getting the sharpest results you can see.
Big question: Primes are a no brainer, but what if the lens is a zoom? Divide the test up into 3 sections:
- closest range
- middle range
- farthest range
... do the same tests three times and look at the results. If there are large differences between the closest and farthest settings, place your emphasis on the areas of the zoom that you use the most or average it out in the middle if you are at a loss to make the choice.
Rinse and repeat with all the other lenses you own.
The procedure above is if you are using the focus test chart. However you do not need to have the camera at 45 degree angle for focus testing. You can just as easily use a clean white page with paragraphs of text on it, and tape it to your wall. In this scenario, you make sure that the camera is at 90 degrees and that the center of the page is the same height as the lens and exactly 90 degrees between the wall (side to side) and your camera lens center. Move the camera closer or further from the wall to properly fill the viewfinder. I especially like that idea of using the rear of a cereal box because they are a pretty easy source to find and use to spot focus differences... that or some other crisply printed out source that would aid you in displaying focus accuracy... thin lines or designs are the best, IMHO.
Walk in the park!
Just your average enthusiastic Nikonian from Montreal, Quebec, Canada!
#12. "RE: lens fine tuning" | In response to Reply # 11Tue 13-Jan-09 08:08 PM
>- I then used the best straight edge on the camera, the lens, and adjusted the camera so it is pointing at a 45 degree angle.
Slow down - and perhaps reconsider.
Your target will result in objects being at different distances along the AF detection lines.
Nikon have said in every DSLR and SLR camera instruction book issued in the last decade objects at different distances may not (not the same as will not) cause AF to be unreliable.
AF not being able to read the target well and stopping the lens at the wrong focus distance is not the same as a lens front or back focusing.
When mis focus happens Nikon advise either finding a better AF target or - for sharp focus where you want it - switching to manual focus.
I suggest if you find a reasonable target (see my earlier post) and line up the camera back parallel to the target there is a very high probability nil will be sharper than 8.
If so your lens does not need fine tune
#9. "RE: lens fine tuning" | In response to Reply # 0
I was bored today and tried to adjust my 500 f4 with a 14tc on my d300
I used a sea gull which was 100ft away and found that I didnt need any major adjustment. possibly could have adjusted -2 or -1 but left it alone.
this is a interesting feature but I hope I dont ever need to use it.
Thanks for sharing,