Autofocus problems (my technique, NOT the camera)

Specifically: D500, Sigma 150-600 C @600mm. I'm photographing sandhill cranes, early morning with the sun behind me so I have good light... I'm shooting from a beanbag so the camera is very stable, though my panning is ALWAYS suspect...

I'm getting a LOT (a HUGE percentage) of shots where the birds are in front of trees where the TREES are in focus. I'm having trouble keeping focus ON THE BIRDS. I'm not sure if the camera just reacts faster than I'm used to when my focus point loses the bird, or if I should be using different settings...

AF-C - always
153 points, 3D
I don't have the camera inside with me, but my recollection is there are 2 settings for the AF lock-on. One for how long the lock-on should last, the other for erratic subject motion... I believe I've left these at the defaults which were "2" and "center"...

I'm using the center focus point as the starting focus for any focus tracking...

Here's a shot from the middle of a series of shots... The one before this (a TENTH of a second ago) is much SHARPER. This one, in my opinion, has refocused on the trees behind the bird. This is what I keep seeing. The bird is large enough that I should have a reasonably good target for focusing, I even tried Nikon View NX to see if it would show me where the focus point was, but they don't show up on any of my RAW images with this camera...



The shutter speed is lower than I'd like, but I'm trying to keep the ISO at a reasonable level.

I have several HUNDRED of these from today at various times.

I don't think it's a camera or lens problem - I THINK it's a photographer problem - do I need a DIFFERENT autofocus setting? Auto area? No 3D? Is it the lock-on? Something I haven't thought of yet?

Thoughts?

just to rule it out, you are allowing it time to focus? i have had shots with the focus point bang center of the bird but its still off because i fired before it was ready, i only use bbf, single focus point and af_c.

GracieAllen said:

Specifically: D500, Sigma 150-600 C @600mm. I'm photographing sandhill cranes, early morning with the sun behind me so I have good light... I'm shooting from a beanbag so the camera is very stable, though my panning is ALWAYS suspect...

I'm getting a LOT (a HUGE percentage) of shots where the birds are in front of trees where the TREES are in focus. I'm having trouble keeping focus ON THE BIRDS. I'm not sure if the camera just reacts faster than I'm used to when my focus point loses the bird, or if I should be using different settings...

AF-C - always
153 points, 3D
I don't have the camera inside with me, but my recollection is there are 2 settings for the AF lock-on. One for how long the lock-on should last, the other for erratic subject motion... I believe I've left these at the defaults which were "2" and "center"...

I'm using the center focus point as the starting focus for any focus tracking...

Here's a shot from the middle of a series of shots... The one before this (a TENTH of a second ago) is much SHARPER. This one, in my opinion, has refocused on the trees behind the bird. This is what I keep seeing. The bird is large enough that I should have a reasonably good target for focusing, I even tried Nikon View NX to see if it would show me where the focus point was, but they don't show up on any of my RAW images with this camera...

View attachment 234696

The shutter speed is lower than I'd like, but I'm trying to keep the ISO at a reasonable level.

I have several HUNDRED of these from today at various times.

I don't think it's a camera or lens problem - I THINK it's a photographer problem - do I need a DIFFERENT autofocus setting? Auto area? No 3D? Is it the lock-on? Something I haven't thought of yet?

Thoughts?

Click to expand...

Right click on the image in View NX ( I have View NX2 so it might be different) and select "show focus point"

Tracking birds needs lots of practice. Even large birds. The key is, not to take your eyes off the view finder. If you lose your subject, keep your eye in the viewfinder and zoom out. Once you locate the subject, then zoom in again.

I spent a lot of time practicing zooming in and out while keeping my eye on the viewfinder. With lots of practice you will get the hang of it. Small birds are tougher. You almost need to get lucky , especially when they are not in really close.

As for settings, I found that for me AF-C with single point works the best acquiring and keeping focus .

ALSO! I just noticed in your EXIF data, that the shutterspeed was 1/400th of a second. Way too slow for BIF. With large and slower birds you could get away with a 1/1000th shutterspeed, but I really would recommend an even faster shutter, like 1/1500th of a second.

Roy1961 said:

just to rule it out, you are allowing it time to focus? i have had shots with the focus point bang center of the bird but its still off because i fired before it was ready, i only use bbf, single focus point and af_c.

Click to expand...

Do you have your focus priority set to focus release or shutter release?

Blacktop said:

Do you have your focus priority set to focus release or shutter release?

Click to expand...

???

i will look in the morning.:very_drunk::very_drunk:

A shutter speed of 1/400 is way too slow for the 600mm focal length used in that shot. Shutter speed needs to be at least 1.5 times the focal length so at 600mm you shouldn't be shooting any slower than 1/1000 and, considering you're panning/shooting a moving subject, 1/1500 would probably be better, if not actually essential, for sharp focus.

I've currently got the body set in Focus+release, so in THEORY, it should be in focus before it takes the first shot, so I don't THINK it's a "not enough time to focus" problem.

The shot above isn't the first one in the series, it's probably 3rd or 4th.

What SEEMS to be happening is that as the bird moves off the "current" focus point, it refocuses very quickly - in the shot above, it's not bird motion despite the "low" shutter speed, it's refocused on the trees in the background. Again, in theory as I understand it, in 3D, the camera should switch focus points as necessary as the subject moves. This is what the D300 always did and I've photographed a lot of birds in flight with it.

As for View NX - yes, I know HOW to display a focus point, it doesn't display on any of the images taken with the D500.

Anyhow, yesterday morning I tried some other focus modes to see if they'd work any better, AFC with 153 points, grp AF, even auto AF. I haven't had time to go through the images, but I'll see if one of the other focus modes will work better. I had decent light, but the reality is that at 7 a.m., unless I"m willing to shoot at ISO 3200 or HIGHER, I'm NOT gonna get 1.5X the focal length. the optical stabilization helps, and I'm shooting on a beanbag so my platform is stable. I'm pretty sure it's just something basic I'm doing poorly or sloppily, so I'll just keep workingon it with this combination.

I"m through two days of images (about 2500) and I've concluded what I'm seeing is pretty specific. When the birds are against the sky there's no problem. I can focus and follow with no problem. Saturday I shot at ISO 800 most of the time, which is still slow for birds in flight (the sort-of "rule of thumb" I've always used is 1/1000 for perched birds and 1/2000 for bif), but other than some motion blur on the wings, they're pretty good. On the other hand, when the birds are in front of trees and such, I have a lot more trouble keeping them sharp. First, there's not as much light, so shutter speed is often 1/400 or so, and I believe when my 3D focus point moves off the bird it instantly refocuses on the trees. PREVIOUSLY, on the D300 and the D810 I've always turned up the focus lock-on value so it DIDN'T refocus so quickly. I'll have to figure out exactly what the equivalent is for the D500.

I'll have to look at the Sunday images, when I used AFC 153, 3D, grp, and auto focusing to see if any of the other modes worked any better.....

BTW: I haven't been able to install Capture NX on the desktop 'cause it has some kind of seizure every time I try and insist there's an old version on, and it HAS to remove it, and it can't find it, which causes it to puke all over it's feet... I'll have to see if I can find out how to get it installed so I can see the focus points...

Just curious, but why are you afraid to go to a higher ISO? That camera should hit 3200 with no issues. Might be a little noise but I would put money that it is very minimal in a physical print.

I'm not super familiar with the 3D focus but you are relying on the camera a lot with it. Why not use a single focus point or maybe 9 or 21 group focus points? Should be easier to keep focus when panning.

I would also check you auto focus delay time. It is it set higher it might have a little lag time before it re-focuses. Set it low and it should start to focus right away.

Blacktop said:

Do you have your focus priority set to focus release or shutter release?

Click to expand...

it's set to Focus release

I'm about halfway through the 2K+ images from Sunday (I"m up to about 7:15 a.m.)...

I'm not new to shooting birds in flight. I've routinely photographed trumpeter and tundra swans, egrets, herons, hawks, owls and so on for years. I've shot trumpeters at 1/60-1/100 specifically to get the blurred background with sharp heads and bodies and wing movement..... So, this isn't my first rodeo... BUT, my past experience was with a D300 (or D810) on a very stable tripod and a Nikon 500/f4 with a 1.4X TC on a full gimbal mount.

This IS my first experience doing a similar thing with a D500, Sigma 150-600C, and a beanbag in the truck window... I BELIEVE there are a couple things that led to what I"m seeing:

• The D500 is VERY, VERY fast at picking up a change in distance to where the focus point is and refocuses very quickly.
• I had the Sigma in the "more precise" focusing mode... This provides a more accurate focus but at the EXPENSE OF TIME... It (the lens) doesn't refocus as fast - it's not HORRIBLY slower, but it's perceptibly slower as it focuses more accurately. I neglected to switch it to the "very fast, but POSSIBLY less accurate" focus mode - another stupid human trick.
• I was shooting from a beanbag instead of my gimbal. It's convenient, but I noticed on several occasions that I could FEEL the lack of smoothness as I attempted to rotate the camera through a series of shots of a landing crane...
• Once I had good light, I had marginally adequate shutter speeds, but certainly not in the 1/2000 range. I tested the D500 beforehand and decided I was comfortable at ISO 800, OK at 1600, and acceptable at 3200. BUT, I personally find ISO 3200 "noisy", though I can minimize the noise at what I consider to be perceptible loss of sharpness. So, I tried hard to stay at ISO 800 when I could and 1600 when I needed it.
• The very early morning shots where pretty much guaranteed to be unusable since my shutter speeds at ISO 1600 were in the 1/15 - 1/60 range with the aperture wide open at 6.3. I'm not good enough to track flying cranes in those conditions.

I largely use the 153 point 3D focusing when shooting bif, and when they're against SKY, it works quite well. When there is dense woods, marsh, prairie grass all around them, not so well. I selected the center focus point as the base and tried to keep that on the bird. The 3D APPEARED to be doing a reasonable job of selecting other points as the bird moved, but now that I have View NX back on the desktop and can SEE what focus point it chose, they're FAR different than what I THOUGHT I was seeing. I have images where the bird has moved left, completely off the center point, and the focus point has moved far right to try to focus on some tree in the background. And not getting there...

I did have a couple runs of 10-15 images when using the group autofocus where I stayed close enough on the bird for at least one of the focus points to be on, and those are nice and sharp. Shutter speed was also 1/1000, slow for flying, but much better than what I'd had earlier.

SO, I believe it was a combination of bad choices and bad technique. I got a number of good images, but I could have done better. One thing I need to go and do is learn a lot more about the autofocus modes on the D500 'cause I've never had to use them before. On the D300 I just put it on the 3D focus tracking, slowed down the "refocus" one notch and it worked very well. I never messed with the group autofocus or the auto autofocus or any of that. Same thing on the D810, which has a frame rate half that of the D500 so perhaps had more time to get the focus right? In any case, I still don't believe it is the body or the lens or the light or the phase of the moon or whatever. I need to work on the photographer.

I truly believe the 3D mode is your issue. I've been shooting a ton with the D500 and my Sigma 150-600 Sport and I almost never use 3D mode because I find it extremely unreliable, particularly in situations like your shot above. I will generally use AF-C with 153 dynamic point AF when trying to track birds like this. It allows me to lock focus initially and then it will track throughout the 153 point band across the center of the frame (which is so sweet on the D500) attempting to maintain a lock on the object under the initial point throughout. Unless the movement is almost exclusively towards/away from you and you are able to keep the focus point directly on your subject (something that takes a lot of work with that lens and a flying bird) 3D will, in general, quickly find something else to focus on. I also use Release mode with AF-C. You may also want to play with your Focus Tracking setting (Custom Menu a3) with I generally have a the most delayed setting.

Steve Perry is a wonderful wildlife photographer and D500 user and my settings come from a lot of trial and error after watching his videos and reading a lot of his D500 posts on the Fred Miranda forum. It's important to understand precisely how each of Nikon focus modes work and what other settings can impact how focus locks and for how long. This is a video he did prior to the release of the D500 but everything in it is perfectly valid in the post-D500 world. You can also venture over the FM forum and peaking the Nikon subforum for his various D500 posts, most in reply to questions like yours (sorry for sending folks elsewhere, but if there's meat someone and the person's hungry...)

Thanks for the reply. I'm gonna have to do some more research on what the different focus modes can do. Clearly, the D500 is a very different animal than the D300 or even the D810 when it comes to chasing things that won't sit still!

I originally had the camera set to release instead of focus. I'll switch it back.

I haven't tried the dynamic focus mode, though I did try the group mode which seemed to work better than the 3D.

Sounds like I've got some settings to change and some work to do... Thanks again.

i had mine set to focus, trying release tomorrow, turned the 3 sec focus delay off also, we will see how it works.