d750 nikon af fine tune: Just started getting acquainted with my new D750 (second 750) setting it up the same as the first. af-on button is fn button etc . First 750 needs +6 fine tune...

mikeysaling Loc: essex uk

Just started getting acquainted with my new D750 (second 750) setting it up the same as the first. af-on button is fn button etc . First 750 needs +6 fine tune - new one needs +4 - is this normal as I always thought most adjustments were for back focus -ie minus correction. what correction do you have for a d750 ?

martinfisherphoto Loc: Lake Placid Florida

Your fine tune is for Each individual lens, not normally across the board. Each lens and camera come off the assembly line with in a specific tolerance range. Tis the reason for the fine tune so you can Individually adjust/fine tune your focus for each lens.

CO

I do AF fine tuning with my D7000 cameras. Generally, I have to set in a little minus fine tuning around minus 3. If you have to use a large amount of fine tuning I would exchange that lens. Nikon says that entering large amounts of fine tuning can interfere with the autofocus. I use the DataColor SpyderLensCal for checking for front/back focusing.

zigipha Loc: north nj

Can someone explain why af fine tuning is needed?

if the sensor used for focusing was different from the sensor used for light capture, I can see the need to adjust for differences in how they are mechanically aligned.

but my understanding is that the same sensor is used for focusing and light capture.

So what is being compensated for?

mrtobin Loc: North East Ohio

zigipha wrote:

Can someone explain why af fine tuning is needed?

if the sensor used for focusing was different from the sensor used for light capture, I can see the need to adjust for differences in how they are mechanically aligned.

but my understanding is that the same sensor is used for focusing and light capture.

So what is being compensated for?

The same sensor is NOT used for focusing and light capture ( unless perhaps only in "live" view.)

With a SLR camera the sensor is blocked by the "reflex" mirror. The focusing and metering is done on an other "sensor" that is located in front of the mirror, in that pentaprism area.

CO

zigipha wrote:

Can someone explain why af fine tuning is needed?

if the sensor used for focusing was different from the sensor used for light capture, I can see the need to adjust for differences in how they are mechanically aligned.

but my understanding is that the same sensor is used for focusing and light capture.

So what is being compensated for?

When using the viewfinder, the camera is using its phase detection autofocus. A small portion of the light entering the lens is split into two beams and directed to the sensors located near the bottom of the camera. All of the components need to be very precisely aligned to be accurate. Also, because of manufacturing tolerances you can get lens and camera combinations that will back focus or front focus. Af fine tuning will compensate for these inaccuracies.

When in live view mode the camera is using its contrast detection autofocus. There are no AF errors when using contrast detection because the camera adjusts the focus until it achieves the highest contrast at the sensor.

Tracyv Loc: Del Mar, Ca

They received mine on 03-02-2016 yesterday I received a letter and email it was being repaired at no charge. That's good but really missing my camera.

zigipha Loc: north nj

So dlsrs might need af tuning..but can you say that mirrorless cameras would not?

CO

zigipha wrote:

So dlsrs might need af tuning..but can you say that mirrorless cameras would not?

Mirrorless cameras use contrast detection autofocus so they wouldn't need fine tuning. I was reading that Fuji developed a phase detection autofocus system for some of their mirrorless cameras. It doesn't work the same way as the phase detection autofocus in DSLR cameras.

Snappin053 Loc: Southern Vermont

Information please. I just purchased a Nikkor 200-500f/5.6 lens to be paired with a D600. I did some basic shooting this past afternoon, but not critical. How do I accomplish fine tuning this lens?

speters Loc: Grangeville/Idaho

mikeysaling wrote:

Just started getting acquainted with my new D750 (second 750) setting it up the same as the first. af-on button is fn button etc . First 750 needs +6 fine tune - new one needs +4 - is this normal as I always thought most adjustments were for back focus -ie minus correction. what correction do you have for a d750 ?

It should never be the body that needs AF fine tuning, but the lenses in use!

CO

Snappin053 wrote:

Information please. I just purchased a Nikkor 200-500f/5.6 lens to be paired with a D600. I did some basic shooting this past afternoon, but not critical. How do I accomplish fine tuning this lens?

The Photography Life website has a method for fine tuning that compares photos taken with live view mode (contrast detection autofocus) and when using the viewfinder (phase detection autofocus). There are links to two targets that are used for the test. Here is the website:
http://photographylife.com/how-to-quickly-test-your-dslr-for-autofocus-issues

I use the DataColor SpyderLensCal to check my camera and lens combinations. I was testing my Tamron 45mm f/1.8 lens at f/2.2 in this shot. I have -3 fine tuning set for this lens.

(Download)

pmackd Loc: Alameda CA

Snappin053 wrote:

Information please. I just purchased a Nikkor 200-500f/5.6 lens to be paired with a D600. I did some basic shooting this past afternoon, but not critical. How do I accomplish fine tuning this lens?

Before worrying about fine tuning the lens I would do a lot more shooting and look carefully at what you are getting at various focal lengths and distances. Are you able to get tack sharp shots? Try stopping down from f5.6 to f6.3 and f8. Your shots should be a little sharper.

You can fine tune most simply (although not necessarily most accurately) by choosing a target, adjusting the AF fine tune values from -20 to +20 and seeing which values give you the best result. However this needs to be done separately at different focal lengths and focal distances. For many lenses, fine tuning at one focal distance will mean you are way off at another very different distance. The D600, and most other Nikons will not allow you to store AF fine tune values for multiple focal lengths or distances. However, the new D500 boasts the ability to fine tune automatically.

I've been very happy with my 200-500 on a D7100 and have seen no reason to bother with AF Fine tuning, at least not yet. Seriously, have fun with your new lens first!

mikeysaling Loc: essex uk

speters wrote:

It should never be the body that needs AF fine tuning, but the lenses in use!

Yes agree with that and I have several years experience with Nikon - but I have found that once you tune one lens (probably your favourite) other lenses will generally follow very closely to that first one. I.E. the camera mirror sensor adjustment is slightly out but within Nikon tolerance. So I am talking about the 'default' value which I have found to be very near the value for most Nikon lenses I have . What I am asking is what 'default' value others have found with their cameras.

zigipha Loc: north nj

CO wrote:

Mirrorless cameras use contrast detection autofocus so they wouldn't need fine tuning. I was reading that Fuji developed a phase detection autofocus system for some of their mirrorless cameras. It doesn't work the same way as the phase detection autofocus in DSLR cameras.

ty!