Custom Setting Menu - A Autofocus A7

06Honda

Senior Member
Under A7 you have a choice between 11 or 51 points, any big difference which one to use for shooting in P Mode for birding. Maybe a quick explanation on it would be helpful as the manual doesn't have much other than a brief note.
 

Danno

Senior Member
I used 51 focus points on my D7200. I wanted to be certain I always have the max number of focus points.
 

hark

Administrator
Staff member
Super Mod
Contributor
Steve Perry from Backcountry Gallery has a video that explains some of the differences. Here is the link to his article, and at the end I will post the video from that article.

https://backcountrygallery.com/understanding-nikon-af-modes/

There is something important to remember. The Nikon 51-point AF system is designed to fully work with lenses that are f/5.6 or faster. If you are using a Sigma or Tamron variable aperture zoom such as the Sigma 150-600mm f/5-6.3 DG OS HSM lens where the lens is zoomed out to the tele end, the largest aperture you can use is f/6.3 when shot wide open. That throws a caveat into the equation. To simplify - you will no longer have all 51 points available to you.

If you advance the video to 1:30, that's where Steve shows examples of 51 points vs. 11. I can't remember if he mentions not being able to use all the points with lenses that are slower than f/5.6 though.

 

hark

Administrator
Staff member
Super Mod
Contributor
I just found this Nikon article which hopefully will provide you with a little more info than what's available in the camera's User Manual. Choosing a lower number of points (such as 11) will make the focus point jump from one point to another thereby skipping some of the in between points.

https://www.nikonusa.com/en/learn-a...and-innovation/51-point-autofocus-system.html

Here is a quote from the Nikon article which contains helpful information:

"The 51-point AF system positions 51 points of focus within the frame to allow photographers to choose a variety of focus configurations to suit the shooting situation.

Available in selected Nikon D-SLRs, the 51-point AF system positions 51 points of focus within the frame to allow photographers to choose a variety of focus configurations to suit the shooting situation.

The 51-area grid forms a wide rectangle across the frame, with minimal spacing between each AF area. The system keeps even quick-moving subjects in focus across a wide extent of the frame. The 15 points of the three center rows of focus points employ cross-type sensors for powerful focus detection.

Nikon’s latest Flagship D-SLR, the Nikon D4s uses Nikon’s Advanced Multi-CAM 3500FX AF sensor module to provide photographers with even more refined focus point capabilities.

You can choose to use a single AF point to hone in on an exact spot on your subject in which to focus on, or use all 51 AF points working together to capture moving subjects. Using the Dynamic-area AF and you’ve also got the choice between 11, 9 or 21 AF points.

Using an AF NiKKOR lens with an f/5.6 or faster aperture, you can use all 51 AF points for fast and accurate AF detection up to an impressive -2 EV (ISO 100, 20 degrees C), which is approximately the physical limit of the eye to see through an optical viewfinder. What this will provide you with is the ability to shoot more smoothly in low light situations.

Most Nikon D-SLRs that utilize the 51-point AF system have the 15 points of the three center rows employ cross-type sensors for added focus detection; detecting contrast in both vertical and horizontal lines. Each cross-type sensor performs at full capacity with any AF NIKKOR lens, f/5.6 or faster."
 

hark

Administrator
Staff member
Super Mod
Contributor
If you or anyone is shooting wildlife, Nikon bodies have some AF points that are called cross type AF points. They are more advanced AF points than the others. Since that is really getting out of my realm of knowledge, hopefully some of the members who are more familiar with how those operate can weigh in with their thoughts. Maybe @BackdoorArts @Woodyg3 @nickt @FredKingston or @Danno might be able to offer a good explanation of how those work. Of course, anyone who can explain cross type AF points and where they are located is most certainly welcome to offer input! :encouragement:
 

BackdoorArts

Senior Member
This is a pretty good article explaining what they are. How many you get and where they are located varies by camera body. Essentially they are faster and more accurate points.

This is what you have with the D500 (cross-type in red):

Nikon-D500-Viewfinder-Coverage.jpg


https://digital-photography-school.com/understanding-normal-and-cross-type-focusing-points/

 
Last edited:

nickt

Senior Member
I had the same article Jake posted book marked to explain crosspoints.

But to answer @06Honda 's question... Menu A7 on the d7200 only selects how many points you see in the viewfinder for the purpose of jogging around the the initial focus point.

"Choose the number of manual focus points available for manual focus-point selection in the viewfinder."

In other words, it cuts down the viewfinder clutter and lets you more quickly get the initial focus point to the top, bottom or sides of the viewfinder.
This will limit you if you are using single point focus- what you see is what you get. But for the other focus modes, it just gives you a lower selection of starting points to more quickly jump around. The camera should still be able to use the number of points as determined by your focus mode setting. So if you have d51 selected with the focus mode button but your a7 is set to 11, you still have 51 points available but only 11 choices to choose from as a starting point in the viewfinder. The d500 has similar under a6. The choices are 55 or 15 points.
 
Last edited:

06Honda

Senior Member
Great help and info with all the posts. The video was a good learning tool for me. I shot these 2 pics of a Barred Owl today handheld with 11 Focus Points set on AF-S, I think I am getting the handle on flight shots finally. Just uploaded some smaller pics around 800 x 600 approx.

50870999953_7376a033bb_c.jpg

50871806947_edfa729e65_c.jpg
 

hark

Administrator
Staff member
Super Mod
Contributor
Great help and info with all the posts. The video was a good learning tool for me. I shot these 2 pics of a Barred Owl today handheld with 11 Focus Points set on AF-S, I think I am getting the handle on flight shots finally. Just uploaded some smaller pics around 800 x 600 approx.

View attachment 351541

View attachment 351542

These are great! I've enjoyed your previous owl images, too! Honestly I felt a little guilty adding several posts to your thread but wanted to make sure you had all the important info in one place rather than just getting your initial question answered. Looking forward to seeing more owls in flight. :encouragement:
 
Top