AF-Fine Tune: You Don't Need It

Ade

Not to defend KR (who oversimplifies explanations to the point they are incorrect) -- but did you know that AF calibration depends on factors like temperature, humidity, etc.?

So if you calibrated your lenses indoors (maybe in your home during this past winter) and now shoot outdoors on a hot humid day, then all of those AF Fine Tune settings might be wrong. In fact, depending on the direction of the adjustment, the AF Fine Tune changes might have made calibration worse than the default settings for the new shooting conditions.

But how many of us re-calibrate AF Fine Tune when shooting outdoors, then re-calibrate it again when moving to an air conditioned room? Not very practical for most photographers (especially those poor wedding photographers.) Maybe not practical for anyone except the odd Aviation photographer who calibrates at zero meters MSL to 15 degrees Celcius and 1013.25 hPa.

Golf007sd

@Ade: Where did you read or come about this knowledge? Hence, " AF calibration depends on factors like temperature, humidity, etc?" And what is "etc" exactly?

If temperature and humidity affect the internal components of the glasses within a lens then by that assertion ALL lenses are miss calibrated...AF Fine tuning or not.

Ironheart

Well, all materials expand and contract as temp and pressure change (not sure how humidity factors in) to a greater or lesser degree. Since glass, metal and plastic all have a different coefficient of expansion, things will go slightly out of tolerance as the environment changes.
Nothing is ever perfect from an absolute perspective. You can be within the Circle of Confusion and be good enough, but perfect? Doesn't exist.
In other types of products, Rolex as an example, they have designed temperature compensating components to keep the time accurate over a wide range of temperature. Nikon doesn't do this AFAICT. This is probably one reason why the clock in a digital camera is so wildly inaccurate.

Golf007sd

Have a look at this video at 1:30. I'm sure Nikon does the same level of testing to make sure their Pro lenses perform as they should.

Ade

@Golf007sd

Zeiss lenses are manual focus only on Nikons so they do not need to solve the phase detect calibration problem.

Most equipment will be calibrated to "standard conditions" and yes that means they may be out of calibration for other conditions. I have no idea what reference standard condition Nikon uses. The ones I jokingly listed above for the Aviation photographer is the International Standard Atmosphere (ISA) conditions used by pilots. When flying in non-ISA conditions (pretty much always), an adjustment factor must be made.

Thom Hogan explains factors and issues affecting AF Fine Tune in his guidebooks.

chrisjakes

IMO he sounds a lot like a car salesman.

I have read alot of reviews on lenses on his website just to see what he says. yes he contradicts himself A LOT but before coming to this group i visited his site the most for tips and reviews. Bc of his site i bought the 35mm 1.8 DX lens for my camera and its a good lens that i have used a lot. So its not all bad. Its unfortunate that he isnt truthful or is misleading sometimes.

Elvishefer

He does recommend good sources for equipment, i.e., Adorama, B & H, etc.

He recommends any company/product for which he has affiliate links.

brownie314

I used to read KR when I first was getting into photography. I now know that a lot of his "you don't need this gear to get that picture" talk is directed towards gear heads that collect thousands of dollars in lenses to shoot test charts and b*tch about it on the internet. But one thing I appreciate about KR is that he is a good resource and source of information for old manual Nikon lenses. I got an old manual focus 80-200 f4 ais on his advice and have not regretted it at all. It cost me $86 plus shipping and it might be the sharpest zoom I have. Of course he always says "manual focus lenses on modern autofocus cameras is a stupid idea" - but I really like the feel of this old lens and I don't mind manual focus, manual aperture.

Photophun

Just wondering but if you have a 24-70 2.8 and a 50 1.4 and they are both Fine Tune adjusted to say -9, does that through a wrench in where your infinity mark is?

I have had to adjust both my lenses and am wondering if I need to undo the setting when shooting at infinity for night time moon/sky/landscape shots?

Ironheart

It could. If you adjust the lens for a close focus, it may not be the same for infinity. However setting it to zero is no guarantee either. I always manually focus for nighttime sky and landscape. Usually zoom the live view to max and set it that way.

TaoTeJared

Just wondering but if you have a 24-70 2.8 and a 50 1.4 and they are both Fine Tune adjusted to say -9, does that through a wrench in where your infinity mark is?

I have had to adjust both my lenses and am wondering if I need to undo the setting when shooting at infinity for night time moon/sky/landscape shots?

Simple answer is NO. At infinity everything (for what you suggested) is in focus and is beyond what effect any AF tuning has. Anything beyond 20ft (50mm @1.4) the focus area (DOF) is 4ft and just expands with distance. At that point it would be hard to see any AF adjustments.

Golf007sd

For those that are interested in doing AF Fine Tuning.

How to Calculate AF Fine-Tune for Nikon Cameras

Photobug

Original question: I like Ken Rockwell for many things he does, and one of them is that he's so bold with his statements. It's just that when he's in error, it can be quite an issue for beginners who just don't know better.

What do you think?

I use to enjoy reading KR web site until I started finding statements that were WRONG. When people at work started coming to see me asking for clarification on something they read on KR's site. I don't put much trust in his recommendations and bold comments. I seldom check his site anymore.

When I take photographs I try to create the image that I saw. His "VIVID" setting and over sharpening of images is NOT natural. If your trying to be creative, that is fine but all those family pictures are over saturated. And yes his frequent references to iPhone pictures is ridicules. To the point I wonder if Apple is paying him to write about his experience using the camera option on their phones.

I do check for new lens reviews but don't put a lot of weight in his final comments.

Guys thanks for the references to other web sites for reviews.

tc88

Just wondering but if you have a 24-70 2.8 and a 50 1.4 and they are both Fine Tune adjusted to say -9, does that through a wrench in where your infinity mark is?

YES. Here is what Nikon has to say. "The camera my be unable to focus at minimum range or at infinity when AF tuning is applied." Note it says that you may not even be able to focus at infinity at all regardless the mark.

Basically to account for back or front focus using AFMA, the camera will try to purposely focus to some distance in front or behind. So in a front focus situation, to focus at infinity at the imaging plane, the lens is focused beyond that at the AF sensor plane. Now if one plays with the focus ring, there is sometimes room past infinity. I don't know what focus range that corresponds to, (beyond infinity?), but that indicates there is some margin built in to account for such adjustments. So as long as you don't need to adjust too much, the lens should be able to focus at infinity though at a slightly different mark location.

roombarobot

In addition to the quotes above, I find it odd/hilarious that KR seems to be afraid of using disk space. He seems to always recommend shooting in Basic JPEG, medium or less size. Why buy a D800 then?

Fred_B

There are a couple of situations that I can think of where AF fine tune is useful.

First is the possible gap between the AF sensor measurement and the sensor position. This can be seen as a focus error in all of the lenses. I half remember a global setting on the D800 fine tune that applies to all attached lenses.

Second is a slight lens mount position error. This is lens specific and caused by the mount being slightly long or short. This offset goes under the lens specific data.

AF fine tune will do nothing for a zoom calibration issue. If you have good focus at the short end and an error at the long end you'll need to send it in. I saw this on an old 80-200 but not on my other zooms. Point being you should check the focus at several different distances to see if there is a lens issue.

I think KR would have a much easier time if he would be more specific. A novice with a slow kit lens probably doesn't need to mess with the focus adjustment. A professional or more experienced shooter probably will need to check and understand the adjustments. He could avoid a lot of internet jabs if he would direct his statements at a specific audience.

haroldp

Internet Jabs are the core of KR's business model.

Given the quality / composition of the photos KR posts on his site, it probably doesn't matter what he uses (or how).

KR is often technically correct and provides some useful info, the problem is when he goes beyond that and assumes that his priorities (which change daily) are the same as the readers.

.... H

ecanedo

Hi everybody!
I can resist adding my own dart on poor KR. He hates China (even more than he hates Plastic, another boogeyman): to be “made in China” is the ultimate derogatory statement, to the point that “made in Thailand” looks like compliment now... As many of you already pointed out, he likes these generalized and unsubstantiated (that you call “bold”) statements. Lenses made in China may be worse (or may by not) than lenses made in Thailand or Japan. But you would never know if and why that’s so by reading KR comments...
Now, speaking on AF fine tuning. I never did. And probably will not, as I haven’t felt the need. But, have somebody read the “white papers” and test results in www.falklumo.com/lumolabs/index.html ? If you did, what do you think of it?

kyoshinikon

Ren Crockwell not only over generalizes ut has been on the megapixel traiup to the 5Dmk3. He thought the mk2 was the best pro camera out there...

Msmoto

I thought we had a Ren Crockwell thread somewhere.....LOL

runbei

AF Fine Tune - you DO need it. My 35/1.8 on a new D7000 body backfocuses like crazy.

Pistnbroke

If you think you dont need it then you dont understand it..re check occasionally as a new lens runs in

Msmoto

Actually one only needs the AF Fine Tune if sharp images are desired. If folks always shoot at f/8 or smaller, and use focal lengths less than 50mm, maybe AF Fine Tune is superfluous. But, at 800mm, f/5.6 subject at 200 feet, the DOF is about 24 inches and an error in AF Fine Tune drops the important part of one's subject out of focus rather quickly.

Pistnbroke

I think its a bad concept Msmoto to suggest that depth of field will compensate for the focus being out ...If I focus on an object I don't expect the true focus point to be 4 inches behind that point

WestEndFoto

I think its a bad concept Msmoto to suggest that depth of field will compensate for the focus being out ...If I focus on an object I don't expect the true focus point to be 4 inches behind that point

It is a bad concept (lazy?, poor discipline?), but MSMOTO is right.