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Lens calibration
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Jun 18, 2019 12:44:24   #
photogeneralist Loc: Lopez Island Washington State
 
I have a Sigma 17-70 that had variable focus errors. Similar symptoms on both my camera bodies (front focus one time then back focus another) I couldn't standardize on an in-camera adjustment for that lens. After consultation with Sigma, I sent them my lens and my main camera body. When it and the camera came back, it focused beautifully on the main camera body and happily also on my spare camera body. The autofocus with my other lenses was not effected. They did something to the lens itself, not just adjusted the camera body to compensate for the lens errors. I don't know what the technicians did inside the lens but I like the results. Their response to my direct question as to how they accomplished the improvement was offputting "That technician is now on vacation so we cannot ask him". I guess the method they used is irrelevant as long as the results are so good.

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Jun 18, 2019 12:55:37   #
billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
 
TriX wrote:
What way is that? With all due respect, have you looked at the link? Are you willing to consider actual tested facts or just rely on unsubstantiated opinion? If you can demonstrate that the test is wrong, or if you have tested and found different results, please post them.

Cheers


So sorry. U are wrong.

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Jun 18, 2019 13:49:30   #
abc1234 Loc: Elk Grove Village, Illinois
 
Strodav wrote:
Live View (LV) uses Contrast Detection Auto Focus (CDAF) and AF uses Phase Detection Auto Focus (PDAF). LV will give you the sharpest result your camera and lens are capable of as long as you are using GOOD TECHNIQUE and LV is more consistent than PDAF. So, set up a resolution target, like a newsprint page at a 30 to 45 degree angle, with a good focus point and take some LV and AF shots. IF the LV and AF shots are equally sharp, no need to do anything. If the LV shots are sharper, then you might benefit from tuning. If the AF shot is sharper than the LV shot, something is wrong. Further, because your target is at an angle, you should be able to see if your AF shots are front or back focused.
Live View (LV) uses Contrast Detection Auto Focus ... (show quote)


That works for me.

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Jun 18, 2019 14:49:42   #
TriX Loc: Raleigh, NC
 
billnikon wrote:
So sorry. U are wrong.


Please share your reasons and your evidence if you have any. I am sorry, but otherwise your statement is not convincing.

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Jun 18, 2019 14:55:53   #
billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
 
TriX wrote:
Please share your reasons and your evidence if you have any. I am sorry, but otherwise your statement is not convincing.


None of my 350 Brides asked me if my lenses were calibrated. My award winning photo judges never asked if my lenses were calibrated. My more than 20 AF n Nikon lenses never needed calibration to produce tack sharp 20X30 images.

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Jun 18, 2019 14:56:26   #
abc1234 Loc: Elk Grove Village, Illinois
 
TriX wrote:
Please share your reasons and your evidence if you have any. I am sorry, but otherwise your statement is not convincing.


Anecdotes and poor methods are not substitutes for good evidence. Photography is part science and part art. You are entitled to your opinions about the art but let us stick to data for the science.

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Jun 18, 2019 15:04:28   #
abc1234 Loc: Elk Grove Village, Illinois
 
billnikon wrote:
None of my 350 Brides asked me if my lenses were calibrated. My award winning photo judges never asked if my lenses were calibrated. My more than 20 AF n Nikon lenses never needed calibration to produce tack sharp 20X30 images.


Bill, I do not doubt any of that. However, I still side with TriX. The issue is how do you really know. How about telling us how you determined your lens are "dead on"?

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Jun 18, 2019 16:54:47   #
ken_stern Loc: Yorba Linda, Ca
 
When I 1st became aware of recalibration my initial reaction was my lenses were just fine & frankly I just didn't want to spend any time doing it - Then I started feeling all kinds of guilty for not doing it -- Sooo I went ahead bought the Spyder & printed out the Canon AF Microadjustment Guidebook -- Spent the greater part of a morning doing & doing & re-doing it --- Out of my 6 lenses two needed additional adjustment --- How did I know 2 lenses needed adjustment -- I could damn well see it! -- Over & over again testing/retesting -- Same goes for the 4 that needed no adjustment -- Think Trix is on to something regarding the higher need for Portrait vs Landscape.

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Jun 18, 2019 18:50:28   #
TriX Loc: Raleigh, NC
 
billnikon wrote:
None of my 350 Brides asked me if my lenses were calibrated. My award winning photo judges never asked if my lenses were calibrated. My more than 20 AF n Nikon lenses never needed calibration to produce tack sharp 20X30 images.


Bill, what you are saying is that your work is sharp enough. What you are not saying (and have yet to demonstrate) is that it couldn’t be sharper with proper calibration.

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Jun 18, 2019 19:09:26   #
crazydaddio Loc: Toronto Ontario Canada
 
2mishka wrote:
On kits or digital software to calibrate my camera and lens. Any suggestions?


I always need to calibrate any lens below 2.8.
...if you care about pin-sharp during portraits with just the eye in focus.

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Jun 18, 2019 22:54:09   #
Doc Barry Loc: Huntsville, Alabama USA
 
billnikon wrote:
Agreed. Many many folks just don't get it. Lens calibration is good for only one distance
Regardless of whatever folks have to say here. And many folks screw it up and lens ends up worse than when they started.


Actually, you are not quite on the mark stating calibration is good for only one distance. Nikon lenses are designed to maintain the same bfl as you change the focus. Their zoom lenses have a correction equation in them that hopefully maintains the bfl for changes in focal length and focus. At the factory, each lens is calibrated to take out build variations. Nevertheless, it isn't perfect so there may be a residual error in the final bfl. The AF fine tune is there to "fix" this residual error. Also, different camera bodies can have slight variations in the flange to sensor distance. By bfl, I am using this term to mean the distance from the lens flange to the sensor. Nikon is rather confident that they only need a single AF fine tune value for each lens-camera combination. Canon I understand has three AF fine tune values per lens-camera combination which I guess means Canon is trying to provide even better compensation or they aren't as confident in the build of their lenses. I just saying and not intending to have a debate.

I have a variety of calibration means and have found that the new version (just released) of FoCal is by far the best, but you have to carefully do the setup, follow instructions (always the hard part for many of us), and invest significant time. My experience calibrating my dozen or so Nikon pro-glass lenses and my Tamron 150-600 G2 is that all but one lens required more than +/-2 of correction (in general, this is "okay"). The Tamron required 18 different range and focal length combinations. Was the effort worth it? You bet. I have over $20,000 invested in my camera equipment and saying that "out of the box is good enough" isn't good enough for me. I want my equipment to be spot on. I am a shooter too. Would any rationale person take an AR-15, slap a scope on it, and enter a competition without sighting in the scope? I don't think so. Same goes for quality camera equipment INHO.

Doc Barry

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Jun 18, 2019 23:20:47   #
frankraney Loc: Clovis, Ca.
 
2mishka wrote:
On kits or digital software to calibrate my camera and lens. Any suggestions?


The above statement is hard to understand........but, it sounds like you want to calibrate a lens to the camera?

1) which camera and lens? It does make a difference. Some you can not calibrate. Check your manual.
2) fixed (prime) or zoom lens

Some have already told you not to waste your time, it is not worth it. They are wrong (IMHO).

It is a fairly simple thing to do but can take some time. IT can cost some money but not if you do it my way. I use batteries, 5 of them, (photo attached) lined up about 30-45 degrees. I like the smaller angle, as long as you see each battery in full. You can also print out a sheet of paper with printed lines the full length. Focus on the dead center of the middle battery. As you can see in the photo, the center battery was mostly in focus and part of the one after (depth of field). the front part of the middle battery was a little off, the center was on, and the next one was a little off. I made no adjustments to the camera and accepted my test as GOOD. I probably could have more light.....I did not use a flash.

as you see in my photo (this is just one of many in the test), Mine was real close I made no adjustments. Some say 4-5 feet away, some say minimum focus distance for the lens, some say the distance you normally shoot.

The camera on a tripod, and level with the subject. Do not shoot down or up. You can try different apertures or just test where you normally shoot.

I was 4 feet away at F5, 35mm (prime) lens...

For zoom lenses, it is a little more time-consuming, and more distance to subject.....this stuff is not hard to do, just takes time. On a zoom lens, I would pick either mid-range or where you would normally shoot at. The procedure is the same, shoot at different apertures and compare. Follow the manual for your camera to make adjustments and store them (if your camera allows fine tuning). You do not store or make any changes to the lens.

Here is a good write up... https://photographylife.com/how-to-calibrate-lenses

IT IS WORTH THE TIME, especially if you are having problems with focus.

This method is good for checking, but as some have mentioned, FoCal is not so expensive....


(Download)

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Jun 18, 2019 23:28:46   #
Strodav Loc: Houston, Tx
 
Doc Barry wrote:
Actually, you are not quite on the mark stating calibration is good for only one distance. Nikon lenses are designed to maintain the same bfl as you change the focus. Their zoom lenses have a correction equation in them that hopefully maintains the bfl for changes in focal length and focus. At the factory, each lens is calibrated to take out build variations. Nevertheless, it isn't perfect so there may be a residual error in the final bfl. The AF fine tune is there to "fix" this residual error. Also, different camera bodies can have slight variations in the flange to sensor distance. By bfl, I am using this term to mean the distance from the lens flange to the sensor. Nikon is rather confident that they only need a single AF fine tune value for each lens-camera combination. Canon I understand has three AF fine tune values per lens-camera combination which I guess means Canon is trying to provide even better compensation or they aren't as confident in the build of their lenses. I just saying and not intending to have a debate.

I have a variety of calibration means and have found that the new version (just released) of FoCal is by far the best, but you have to carefully do the setup, follow instructions (always the hard part for many of us), and invest significant time. My experience calibrating my dozen or so Nikon pro-glass lenses and my Tamron 150-600 G2 is that all but one lens required more than +/-2 of correction (in general, this is "okay"). The Tamron required 18 different range and focal length combinations. Was the effort worth it? You bet. I have over $20,000 invested in my camera equipment and saying that "out of the box is good enough" isn't good enough for me. I want my equipment to be spot on. I am a shooter too. Would any rationale person take an AR-15, slap a scope on it, and enter a competition without sighting in the scope? I don't think so. Same goes for quality camera equipment INHO.

Doc Barry
Actually, you are not quite on the mark stating ca... (show quote)


Well said Doc although I'm only in for about $15k of Nikon gear. My experience, especially with the Tamron 150-600mm G2 is very similar to yours. Also own a Nikon 200-500mm f/5.6 and the two have virtually identical IQ at 500mm on a DX body, but only after the G2 was tuned. The Nikon is a better in the corners on an FX body.

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Jun 18, 2019 23:33:28   #
Doc Barry Loc: Huntsville, Alabama USA
 
Strodav wrote:
Well said Doc although I'm only in for about $15k of Nikon gear. My experience, especially with the Tamron 150-600mm G2 is very similar to yours. Also own a Nikon 200-500mm f/5.6 and the two have virtually identical IQ at 500mm on a DX body, but only after the G2 was tuned. The Nikon is a better in the corners on an FX body.


Thanks Strodav, but don't let my wife know how much I have invested in my camera gear. It will be another visit to the jewelry store.

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Jun 19, 2019 08:01:36   #
TriX Loc: Raleigh, NC
 
Doc Barry wrote:
Actually, you are not quite on the mark stating calibration is good for only one distance. Nikon lenses are designed to maintain the same bfl as you change the focus. Their zoom lenses have a correction equation in them that hopefully maintains the bfl for changes in focal length and focus. At the factory, each lens is calibrated to take out build variations. Nevertheless, it isn't perfect so there may be a residual error in the final bfl. The AF fine tune is there to "fix" this residual error. Also, different camera bodies can have slight variations in the flange to sensor distance. By bfl, I am using this term to mean the distance from the lens flange to the sensor. Nikon is rather confident that they only need a single AF fine tune value for each lens-camera combination. Canon I understand has three AF fine tune values per lens-camera combination which I guess means Canon is trying to provide even better compensation or they aren't as confident in the build of their lenses. I just saying and not intending to have a debate.

I have a variety of calibration means and have found that the new version (just released) of FoCal is by far the best, but you have to carefully do the setup, follow instructions (always the hard part for many of us), and invest significant time. My experience calibrating my dozen or so Nikon pro-glass lenses and my Tamron 150-600 G2 is that all but one lens required more than +/-2 of correction (in general, this is "okay"). The Tamron required 18 different range and focal length combinations. Was the effort worth it? You bet. I have over $20,000 invested in my camera equipment and saying that "out of the box is good enough" isn't good enough for me. I want my equipment to be spot on. I am a shooter too. Would any rationale person take an AR-15, slap a scope on it, and enter a competition without sighting in the scope? I don't think so. Same goes for quality camera equipment INHO.

Doc Barry
Actually, you are not quite on the mark stating ca... (show quote)


😎😎 Spot on. Why invest thousands of $ in lenses and balk at <$100 to calibrate them all to make sure you get all the performance yo paid for? It’s called attention to detail, and it’s the difference between 90% performance and 100%.

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