d850 fine tune

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david dono

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I was fine tuning my 500pf with 1.4 TC in camera(d850) using live view and was getting consistent results but -6 if zoomed in most of the way but -13 zoomed all way in. Without TC it was at -6. What figure should I use. Not had chance to field test yet.
 
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Zoomed in? On a 500pf. Or do you mean focused at minimum distance and then at infinity?

1. Keep the number for the distance you most commonly shoot at.
2. Split the difference, set it at -9/-10.
3. Re-set the tuning depending on the distance.

But — focus tuning should not be needed in live view!
 
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I'm not following I guess. Using LV for auto AFFT is correct, but I don't get why zoomed in or out would make any difference. If it's focused properly, it's focused properly. The system actually doesn't look at the LV screen at all - we simply use it to show the camera the correct distance for the lens to be sharp. The camera then used PDAF to determine if it would set the lens at the same focus distance you did. If so, you get a value of zero. If not, the camera corrects itself. So, I'm a little fuzzy (get it, pun intended) on what's going on.

Also, did you notice front focusing in the field? I don't tend to tune anymore unless I actually see an issue.
 
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Steve said:
I'm not following I guess. Using LV for auto AFFT is correct, but I don't get why zoomed in or out would make any difference. If it's focused properly, it's focused properly. The system actually doesn't look at the LV screen at all - we simply use it to show the camera the correct distance for the lens to be sharp. The camera then used PDAF to determine if it would set the lens at the same focus distance you did. If so, you get a value of zero. If not, the camera corrects itself. So, I'm a little fuzzy (get it, pun intended) on what's going on.

Also, did you notice front focusing in the field? I don't tend to tune anymore unless I actually see an issue.
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Thanks-not sure why the difference either , hence the question :) .Seemed to be pretty consistent. I turned on live view then used the"+" to zoom in for live view , de-focused and then focused . Did the test outside (Australian summer so quite bright)-maybe the heat haze thing??? but you would think it would still be same.
And yes I don't think I need -13!.
Interesting you do not fine tune now.Suppose everyone blames equipment rather than themselves...
 
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david dono said:
Thanks-not sure why the difference either , hence the question :) .Seemed to be pretty consistent. I turned on live view then used the"+" to zoom in for live view , de-focused and then focused . Did the test outside (Australian summer so quite bright)-maybe the heat haze thing??? but you would think it would still be same.
And yes I don't think I need -13!.
Interesting you do not fine tune now.Suppose everyone blames equipment rather than themselves...
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It's not that I don't fine-tune, it's just that I check first :) I tend to get pretty close to my critters and coupled with wide open shooting, I can tell in a hurry if there's an issue. Between you, me and the wall (and everyone reading this I guess), I sometimes will just take new gear out for a test run and check the LCD in the field. If I see front / back focus, I'll just adjust on the spot and try again. Most of the time, I can get it as good as I can with any other method. Although, I have been doing it for awhile LOL!

Outside + sun is also a potential problem - if there's any sun hitting the ground between you and the target, the results are suspect. Heat haze is far more prevalent than most people think. I'd try it on a cloudy day for sure and see if there's a difference.
 
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Steve said:
It's not that I don't fine-tune, it's just that I check first :) I tend to get pretty close to my critters and coupled with wide open shooting, I can tell in a hurry if there's an issue. Between you, me and the wall (and everyone reading this I guess), I sometimes will just take new gear out for a test run and check the LCD in the field. If I see front / back focus, I'll just adjust on the spot and try again. Most of the time, I can get it as good as I can with any other method. Although, I have been doing it for awhile LOL!

Outside + sun is also a potential problem - if there's any sun hitting the ground between you and the target, the results are suspect. Heat haze is far more prevalent than most people think. I'd try it on a cloudy day for sure and see if there's a difference.
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Yes definite sun hitting ground ++ between me and target. Really need a good inside set up to take away those variables, but as you suggest you cannot beat experience.
 
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Sounds like you are not doing the proceedure right. You let the camera do its own focus thing in live view before you push the two buttons etc. Dont try to focus the lens yourself. If the focus motor has to move then the display gives you the amount it moves so you can adjust for non live view focusing.
Put your target at about 60 yards and use that figure .
 
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Pistnbroke said:
Sounds like you are not doing the proceedure right. You let the camera do its own focus thing in live view before you push the two buttons etc. Dont try to focus the lens yourself. If the focus motor has to move then the display gives you the amount it moves so you can adjust for non live view focusing.
Put your target at about 60 yards and use that figure .
Click to expand...
thanks ,was doing it exactly as you outlined, sorry if not clear on this..
 
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It actually doesn't matter how you focus, as long as the image on the LCD is as sharp as you can make it. Most of the time LV is the best bet, but sometimes manually focusing with magnification works better. The trick is that you're trying to show the camera what the target looks like at maximum sharpness when you activate auto AFFT.
 
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Do the testing early in the morning. If you want to know if there is heat distortion put the D850 in slo mo video mode and then look at a short clip. You can easily see the air cooking. Also try to avoid a breezy day. I was focus checking my 400/2.8 with 1.4TCIII on my back deck. Live view zoomed 100% and the shot was pulsing up and down. Stepped back a few feet and it stopped. I realized it was my own pulse coming through the bottom of my shoes next to the tripod feet. Once I stepped backward onto a different joist it stopped. So concrete/solid ground is a better platform than even indoor wood framed flooring. Do not underestimate how much outside factors will effect a long lens. I use a $100 US bill and view the threads or other safety feature edges for sharpness. I suppose the Aussie dollar has the same features.
 
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