What's up with focusing my 85mm f1.4?

[DogShot]

A couple of months ago I checked the focus of my 85mm f1.4 from about 6ft from the subject (often my working distance), using the centre and outer focus points on my D3. No problems, focus was great on all points. However, I did not check the upper & lower focus points.

I could use some help trying to figure out what might be going on here. This photo is taken from about 12ft away. Does his face look in focus here? To me it looks like his hair caught the back end of the area in focus. The second photo shows where the focus point was set, etc.





Same setup and session, but no problem here:





or here:





Any ideas?

Mark

 

[maxz]

the focus is right-on (yes including the 1st shot). You just demonstrated the importance of choosing the best area for AF.

Max

A couple of months ago I checked the focus of my 85mm f1.4 from about
6ft from the subject (often my working distance), using the centre
and outer focus points on my D3. No problems, focus was great on all
points. However, I did not check the upper & lower focus points.

I could use some help trying to figure out what might be going on
here. This photo is taken from about 12ft away. Does his face look
in focus here? To me it looks like his hair caught the back end of
the area in focus. The second photo shows where the focus point was
set, etc.

 

[DogShot]

the focus is right-on (yes including the 1st shot). You just
demonstrated the importance of choosing the best area for AF.

Max

Can you explain what you mean by "the importance of choosing the best area for AF"?

Mark

 

[msweston]

The line in the first shot made by the boy's cheek and his shirt is further back than the features on his face- by a few inches. That is enough to rob you of sharpness where it matters most. His cheek is sharp, though!

 

[ddt332]

Looks all soft to me. Especially first one. Are you sure the focus is locked ?

 

[DogShot]

Looks all soft to me. Especially first one. Are you sure the focus is
locked ?
--

Yes - I don't think that CNX will show the focus point if one was not locked. What you may be noticing is how poor Apple's web galleries are for hosting photos. When posting from Aperture to a web gallery, there is some 'invisible' process that resizes photos. It also makes them appear much less sharp.

Mark

 

[ddt332]

I meant to ask what focus mode you used: S, C, or M? in C mode, you can easily get a lot of unlocked shots while still show the "red box".

 

[Fella]

One thing to pay particular attention to is focus lock. I've noticed some focus issues with my 85 f1.4 that I've not nailed down yet, the latset thing I've noticed is with AF-C mode sometimes I'm taking the shot when the little green circle focus indicator and green arrows are flashing - so the focus is at this point effectively hunting - although in my previous non scientific tests there seemed to be a consistent back focus issues with outer sensor when using AF-C (but good focus when using AF-S and the outer sensors) and it seemed to change to front focus with AF-S and center focus point (but good focus with AF-C and center focus points)

I've only just started paying closer attention to what the incamera focus indicator is saying so I dont have much of a conclusin other than to say the focus results seem more accurate when I only take a photo when focus is indicated - I'm usually tresting with stationary subjects, random items around the house which wont necessarily be the best choices.
--
Martin
http://www.martwilliams.co.uk

 

[DogShot]

I see what you are both saying. My subjects are usually moving around, so I keep the camera in C mode (release priority). There is clearly no reason to use this mode when shooting a static subject at apertures larger than f2.8.

Next time I try this, I will switch into S mode and focus priority to see if it makes a difference.

Thanks for the suggestions - good ideas, and I would not have thought of them.

Mark

 

[Busterman]

I'll have a go. Firstly, I don't think it is the lens but it could be one or a combination of what I have tried to set out below.

I would humbly suggest that having the camera in continuous autofocus mode (as you have done) does not help with this kind of shot. Even the slightest movement could result in a slight shift in focus. You need to set it on AFS and use the appropriate focus point to focus on the eye. You seem to be taking the shot from perhaps a prone position on the floor, not the easiest way to hold the camera steady.

The D3 is not the best at dealing with forward movement of the subject and although you have the camera set at AFC it simply does not respond as quickly as we might like. In your first shot therefore, with the subject moving forward to throw the toy, he has moved out of the focal plain. Also the shutter speed at 100th of a second will not freeze movement.

I notice you have the Picture control set at Portrait and even though you have altered the sharpening from the default 2 to 4, Portrait also uses less contrast which softens the shot considerably.

I would also suggest you check to see if the camera is set up with focus priority or shutter priority. If set to focus priority the camera will not fire if the focus is not locked or if the subject moves out of focal range.

If you did focus on the cheek as in the first photograph the camera will not achieve focus correctly as the cheek is a smooth low contrast area. Best to set the camera on AFS and select the most suitable focus point.

Finally, the subject's face does not seem lit well enough to enable clear focus. I know the D3 is very good in low light but perhaps a better illumination of the subject may give the camera a better chance at locking focus. I note you have the camera set to Commander mode and therefore you may have used off-camera flash? I would suggest to aid focussing in low light perhaps using the flash on camera and its focus assist lamp could get you the better focus.

Finally, finally, the softness we are seeing on the web could be down to the method used for resampling for the web? Perhaps the originals are not as soft as you might think.

Now absolutely really finally, if the originals were shot in NEF Raw, have you tried altering the Picture Controls in post production or changing the tone curves manually and adjusting the exposure and finally adding a litle sharpening to the eyes? I'm sure there is so much more than can be done to bring these shots into acceptable apparent focus.

--
Busterman

 

[DogShot]

Thanks for your thoughts. We must have posted at roughly the same time, as we have come to a few similar conclusions.

Yes, I was balancing the ambient light with some fill shot through an umbrella. The first shot is at a shutter speed of 1/320, so I'm not sure where you saw the 1/100. I did not post any that I shot at that shutter speed (I did, however shoot a few with a lower shutter speed to increase the amount of flash compared to ambient light, and they came out nicely).

I did shoot raw (I do my adjustments in Aperture, and only used CNX to show the focus points), and while the top shot it acceptable and prints nicely, I would like to be in better control of my focus.

I don't think the ambient light was low enough to affect auto focus in this situation, but switching modes to focus priority and AF-S seems like the solution for my problem.

Mark

 

[Busterman]

My apologies. It was the second shot I read as 1/100th. On closer inspection I see it was 1/180th. That'll teach me to look at DP Review on a 13 inch laptop screen.

Glad to hear we came to similar conclusions anyway. It all helps us get better at photography when someone asks us to think a bit.

---
Busterman

 

[DogShot]

I tried implementing the suggestions made on this thread. I used a very shallow DoF to judge the focus accuracy, and I am very happy with the results.

I used a fairly static subject again, and put the camera in AF-S with focus priority, and did not lose a shot from focus problems.









Thanks to all for the help! I will be making more use of focusing options from now on. I had incorrectly assumed that the most dynamic mode would be suitable for any type of subject.

Mark

 

[jlf]

Focus looks OK. I do see motion blur in the hair and face.

j.

--
'The soul never thinks without an image.' - Aristotle