Cause(s) of soft images

blackstar

blackstar

Senior Member
Recently, I practiced a lot with z6ii + sigma 200-600mm + gimbal tripod for small birds. Most images I got look soft (like the sample below). Just wonder what is (are) the cause(s): lens, camera body, settings, scene issue (background/foreground interference), lighting issue, or my technical skills? Appreciate your opinion and input.

2023-02-15_16-53-35 (2)gimps.jpg
 
Clovishound

Clovishound

Senior Member
It looks to me like the branch behind the bird is sharp. That would indicate a focusing issue. I believe the Z6 has a menu option for dialing in focus for your individual lens. I have heard this is more often needed on 3rd market lenses. You might want to enlarge the original full size image and make sure. Your shutter speed was 1/2000 sec, so it's unlikely to be subject movement, or camera movement.
 
Clovishound

Clovishound

Senior Member
I'm not knowledgeable on the process involved, just aware it is there. On my Z5 it is under the "wrench" menu and is called "AF fine-tuning options". It should be the same or similar on your Z6. There is an option for "fine tune and save lens".

Did a quick search on Youtube, and there are several videos that document how to use this feature. Here is a short one (I didn't watch it, but thought I'd at least point you towards one.) I looked at the accuracy of my Nikon 200-500 mounted to the Z5 with an FTZ and found mine to be pretty much spot on, so I haven't investigated this option. I can't be sure this is your problem, but it is worth investigating if you are having consistent focus issues with this lens.

Youtube
 
Fred Kingston

Fred Kingston

Senior Member
Google "lens calibration"... Basically... cameras and lenses are manufactured to within specific tolerances...with a plus or minus percentage for error...the theory being that when combined, the error tolerances cancel each other out giving a perfect calibration... REALITY deviates from theory... hence the reason for the menu option on Nikon cameras for "AF-Fine Tuning"... It can be as simple as a few test shots at a target that you can print off the internet, or as complex as specialized software that takes control of your camera and lenses and automatically makes those adjustments and calibrates the lens and camera... I like Focal from Reikan because it's considered one of the best.
 
Peter7100

Peter7100

Senior Member
You can also buy folding Calibration charts which can be found on Amazon and ebay, but the printable ones from the internet do the same job but you just need to balance them properly at the correct angles.
 
hark

hark

Administrator
Staff member
Super Mod
When I did my AF calibration, I printed out Steve Perry's chart. The chart is in this link.

backcountrygallery.com

Get The Most From Nikon's Auto AF Fine Tune System - Backcountry Gallery

Do you have a Nikon camera that features Auto AF Fine Tune? If so, then this video is just what you need to get the most from it! When Auto AF Fine Tune first came it, it was pretty exciting – In fact, I think we all had visions of never going through a tedious lens […]
backcountrygallery.com backcountrygallery.com
 
blackstar

blackstar

Senior Member
Thank you everyone for the suggested cause of needing AF calibration and the info on implementing such calibration. Studied the subject a little but after a field test (not calibration) of shooting wild birds, I had a different thought about the cause of soft images. I am leaning toward the cause of the camera setting on the "focus area" mode. I set "auto AF area" and activate "object tracking" when firing shots. I found this often leads the camera to focus on a sub-object that is covered inside the focus area "square" and likely has more contrast than the main object. And this is due to the camera, not the camera user, being able to choose any object in the "square" under the auto AF area mode (according to the Manual). So if the subject situates near a background full of sub-objects (tree branches, plants, etc.), under auto AF area mode the camera may likely pick up something more contrasty in the back or foreground to focus on and render the main subject soft... see pic1 and pic2.

Interestingly, this also has an effect on focusing distance: the auto AF area square keeps its size unchanged when the focusing distance changes. When the subject is close to the lens, it is displayed in VF or LV in a larger size that may equate to or even cover the "square". So no sub-object is to be chosen to focus on by the camera but the main subject. The result will be in focus most of the time. see pic3 (I had six bursts all successful)

Another thought: contrast is a very significant factor when considering sharp focus. see pic4 (no background interference) and pic5 (background interference)

My theory may be faulty, please bring out and correct any. (all examples are 100% crop, no pp)

pic1
2023-02-20_15-12-12s.jpg

pic2
2023-02-20_15-14-54s.jpg

pic3
2023-02-20_16-44-37 (2)s.jpg

pic4
2023-02-20_16-31-50 (2)s.jpg

pic5
2023-02-20_16-41-28s.jpg
 
Clovishound

Clovishound

Senior Member
When shooting relatively static subjects, which I would consider all the pictures you posted as such, I normally use the small AF area. Anything else risks the camera grabbing something other than the intended subject. The only issue I have with that is that the little joystick that moves the focus area around the frame is very easy to unintentionally be manipulated. I can't tell you how many times I've put my camera to eye, and the little red box is in a corner. I've learned to live with that. Fortunately, someone had the sense to put a little button in the middle that, when pressed, returns the focus area to dead center of the frame.
 
Fred Kingston

Fred Kingston

Senior Member
You might want to review Steve Perry's excellent videos and eBooks on the Nikon focus systems, and their intended purposes... I just saw an email where he updated something in the Z systems recommendations...Regardless of which "auto-focus" system you use, you need to really calibrate the lens with the camera first... If you don't have a baseline to work from, anything you do with regard to focus is just wasting time...
 
blackstar

blackstar

Senior Member
Fred Kingston said:
You might want to review Steve Perry's excellent videos and eBooks on the Nikon focus systems, and their intended purposes... I just saw an email where he updated something in the Z systems recommendations...Regardless of which "auto-focus" system you use, you need to really calibrate the lens with the camera first... If you don't have a baseline to work from, anything you do with regard to focus is just wasting time...
Click to expand...
Thanks, Fred. I'll dig into this. Making baseline is hard with no joy, but critical work to move ahead though. Like my past scientific works, the starting baseline (fundamental things) is boring but essential. Good reminder!
 
blackstar

blackstar

Senior Member
Clovishound said:
When shooting relatively static subjects, which I would consider all the pictures you posted as such, I normally use the small AF area. Anything else risks the camera grabbing something other than the intended subject. The only issue I have with that is that the little joystick that moves the focus area around the frame is very easy to unintentionally be manipulated. I can't tell you how many times I've put my camera to eye, and the little red box is in a corner. I've learned to live with that. Fortunately, someone had the sense to put a little button in the middle that, when pressed, returns the focus area to dead center of the frame.
Click to expand...
Actually, all subjects in my example photos were active at the time, some moved slowly (swimming ducks) some fast and abruptly (birds in pic1, 2, 3). I used "large AF area" before but wanted to try "object track". I had thought about "small AF area" but the next day I went back to the area for some pano for the weekly challenge, and all those small birds were gone (moved to some other area I think). No testing opportunity. Will try some other time.
 
Clovishound

Clovishound

Senior Member
I probably should have said I use the small area for all but the faster moving subjects. Birds in flight and such. Obviously, if you can't maintain the subject in the focus area, you probably need a different setting. Most of the birds I shoot are not moving that quickly, unless in the air. I am using the gimbal mount on a tripod for almost all my bird pictures these days as well. That makes keeping them in frame easier for me than handheld with a long, heavy lens. I have been experimenting with other focus area settings, but haven't settled on a different strategy. I find that the focus tracking on my Z5 works well once it has locked on something. The issue I have is sometimes it is difficult to get that initial lock.
 
hark

hark

Administrator
Staff member
Super Mod
I don't have that body, but on my DSLR's, there is an option for the focus point to be illuminated during playback. If you have that option, consider turning it on. I've been surprised with my own where I put a point directly on a face only to have the dot display next to the face on the brush in the background. The dot won't show up once the files are transferred to my computer.
 
blackstar

blackstar

Senior Member
hark said:
I don't have that body, but on my DSLR's, there is an option for the focus point to be illuminated during playback. If you have that option, consider turning it on. I've been surprised with my own where I put a point directly on a face only to have the dot display next to the face on the brush in the background. The dot won't show up once the files are transferred to my computer.
Click to expand...
I may have already set it up, but not sure, will check it again. BTW, does "playback" means replaying the images you have caught, not refreshing the image after clicking the shutter button? Also, I remember having a setting on d3500 that makes all images downloaded to computer display focus square in the small preview picture. But now I don't remember how to set it on z6ii. Any tip? Thanks
 
hark

hark

Administrator
Staff member
Super Mod
blackstar said:
I may have already set it up, but not sure, will check it again. BTW, does "playback" means replaying the images you have caught, not refreshing the image after clicking the shutter button? Also, I remember having a setting on d3500 that makes all images downloaded to computer display focus square in the small preview picture. But now I don't remember how to set it on z6ii. Any tip? Thanks
Click to expand...
When you view the images on the back of the screen after taking them, a red square will show the focus point. The square will still be there even if you take a number of pics and go back through them.
 
blackstar

blackstar

Senior Member
hark said:
When you view the images on the back of the screen after taking them, a red square will show the focus point. The square will still be there even if you take a number of pics and go back through them.
Click to expand...
Thanks. I now confirm seeing red square both after shot and playback. Still don't see it on my mac's Finder preview like old D3500 images. May need to set up somewhere on my computer...
 
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