I am unfamiliar with this concept. Can someone please explain the procedures for this fine tuning? (Thanks in advance)
Some lens you can tune them for your camera to there most efficient focusing with that camera , some new ones come with a Turner
For $65 or more , Sigma is one that comes to mind , some camera stores will do it for a price ,
When using the viewfinder, your camera is using its phase detection autofocus. Phase detection autofocus is error prone. The AF sensors in the camera body must be very precisely aligned. Also, due to manufacturing tolerances, you can have camera and lens combinations that will front focus or back focus. I use the DataColor SpyderLensCal to calibrate mine. Many people use Reikan FoCal 2 software.
When your camera is in live view mode, it's using its contrast detection autofocus. There are no errors when using contrast detection autofocus. The camera adjusts the focus until it achieves the highest contrast at the sensor.
Nikon D7000 AF fine tuning menu
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Download)
DataColor SpyderLensCal
TriX
Loc: Raleigh, NC
CO wrote:
When using the viewfinder, your camera is using its phase detection autofocus. Phase detection autofocus is error prone. The AF sensors in the camera body must be very precisely aligned. Also, due to manufacturing tolerances, you can have camera and lens combinations that will front focus or back focus. I use the DataColor SpyderLensCal to calibrate mine. Many people use Reikan FoCal 2 software.
When your camera is in live view mode, it's using its contrast detection autofocus. There are no errors when using contrast detection autofocus. The camera adjusts the focus until it achieves the highest contrast at the sensor.
When using the viewfinder, your camera is using it... (
show quote)
Good comprehensive response.
Gene51
Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
CO wrote:
When using the viewfinder, your camera is using its phase detection autofocus. Phase detection autofocus is error prone. The AF sensors in the camera body must be very precisely aligned. Also, due to manufacturing tolerances, you can have camera and lens combinations that will front focus or back focus. I use the DataColor SpyderLensCal to calibrate mine. Many people use Reikan FoCal 2 software.
When your camera is in live view mode, it's using its contrast detection autofocus. There are no errors when using contrast detection autofocus. The camera adjusts the focus until it achieves the highest contrast at the sensor.
When using the viewfinder, your camera is using it... (
show quote)
The first line in your screen shot from the manual says it all - AF tuning is not recommended in most situations and may interfere with normal focus; use only when required."
Phase Detection involves correct mirror alignment (two different mirrors). The AF sensor position is not adjustable, at least in the D800. Not sure about other cameras. However, the calibration software can write focus point values in a manner similar to AF Tune, but it does a broad range of focus points, and in the case of a zoom, at different focal lengths. Using the very coarse, single or dual point adjustment of AF Tune in the camera is not going to fix a front or rear focusing lens, without adversely affecting other focus points. If you are in the field, and you drop your camera but not enough to break it, but the focus seems off, yes, AF Tune is a good idea, as long as you bring it to the manufacturer's repair facility so they can assess, repair and adjust the system correctly and completely.
Here is a good explanation with pictures and diagrams that should help.
https://photographylife.com/how-phase-detection-autofocus-works/
Gene51 wrote:
The first line in your screen shot from the manual says it all - AF tuning is not recommended in most situations and may interfere with normal focus; use only when required."
Phase Detection involves correct mirror alignment (two different mirrors). The AF sensor position is not adjustable, at least in the D800. Not sure about other cameras. However, the calibration software can write focus point values in a manner similar to AF Tune, but it does a broad range of focus points, and in the case of a zoom, at different focal lengths. Using the very coarse, single or dual point adjustment of AF Tune in the camera is not going to fix a front or rear focusing lens, without adversely affecting other focus points. If you are in the field, and you drop your camera but not enough to break it, but the focus seems off, yes, AF Tune is a good idea, as long as you bring it to the manufacturer's repair facility so they can assess, repair and adjust the system correctly and completely.
Here is a good explanation with pictures and diagrams that should help.
https://photographylife.com/how-phase-detection-autofocus-works/The first line in your screen shot from the manual... (
show quote)
Why are you responding to my post? I think the OP wants information about AF fine tuning. I know all about how phase detection works. I've read a lot of the articles on Photography Life including the one you provided a link for. Nasim Mansurov is very knowledgeable.
TriX
Loc: Raleigh, NC
Really!!?? You bought your equipment to test it or to photograph? Quit beong a lab tech and go photograph. How sharp arr your eyes anyway?
r
It usually isn't brought up in these discussions but it seems to me that using hyperfocal distance techniques would eliminate most problems with lens focal point issues with respect to subject and composition.
TriX
Loc: Raleigh, NC
gvarner wrote:
It usually isn't brought up in these discussions but it seems to me that using hyperfocal distance techniques would eliminate most problems with lens focal point issues with respect to subject and composition.
Depends on the conditions. Let me suggest a scenario. you're shooting a portrait at a distance of 10' with a 135mm f2 lens wide open. The DOF is about 2" and you focus on the eyes. If your camera/lens combination focus is off by 2" (which is not a lot) and front focuses. the eyes will be out of focus. Now if you don't care about the bokeh (and have the light) and shoot at f5.6, you probably would never notice it.
gvarner wrote:
It usually isn't brought up in these discussions but it seems to me that using hyperfocal distance techniques would eliminate most problems with lens focal point issues with respect to subject and composition.
It usually isn't brought up in these discussions because, with the exception of ultra wide panoramic landscapes, it's seldom desirable to have everything in the frame in sharp focus, and all the money spent on f/1.4, f/2.8 and f/4 lenses would be wasted. Bokeh anyone?
OddJobber wrote:
It usually isn't brought up in these discussions because, with the exception of ultra wide panoramic landscapes, it's seldom desirable to have everything in the frame in sharp focus, and all the money spent on f/1.4, f/2.8 and f/4 lenses would be wasted. Bokeh anyone?
I said "most". Didn't I say "most"? Well by golly I just read it again and I did say "most". The technique has application not only with wide angle shots but in many other situations where depth of focus is important. Being aware of where the Bokey begins is important.
I'm still no wiser as to what to do. It appears that having bought expensive lenses ,I then have to adjust them to focus correctly. No wonder us amateurs are seeking better photographs thinking that better cameras and lenses will solve the problem.
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