Focus problems - DPChallenge Forums

08/11/2008 08:46:19 AM · #1

Hi
Need some advice I have the Nikon D700 with 24-70 lens and 50mm 1.8 lens.
I'm new to the new focus system on the D700 and all my photographs that contain more than one person are out of focus
ie: 2 persons standing next to each other one person will be sharp and the other soft and slightly out of focus.

I have tried other settings and still the same, any advice please

thanks
John

08/11/2008 08:51:52 AM · #2

What lens are you using when this happens? What is your aperature setting?

Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II

08/11/2008 09:02:56 AM · #3

Hi
It started on the 24-70 and as I had just purchased it I thought it needed calibrating, however I tried the 50mm lens and it happens with this.
Both persons standing together neither in front or behind.
I didn't have this problem with the D2xs, the aperture has been different in every picture but still happening.
I am attempting to place a few pictures on this thread, but not sure how to do it

MattO

Nikon D4

08/11/2008 09:04:28 AM · #4

If you are used to a crop factor camera then go to a full frame, you will have to realize that your dof at f2.8 on ff is alot shallower then it will be at f2.8 on a 1.5x crop camera. To get the same dof you must stop down a bit.

Matt

08/11/2008 09:08:32 AM · #5

ok i'll give it a go

Canon EF 24-70mm f/2.8L USM

08/11/2008 09:10:22 AM · #6

I was shootin Woodies the other day @ F2.8 on a 70-200. One Woody was about 1 inch or so closer to the camera than the other a about 6-8ft distance and the closer one was OOF bad.

Telehubbie

Canon EOS-40D

08/11/2008 09:45:30 AM · #7

I had the same thing happen to me with my 24-70 in landscape-oriented group shots. The people to the far left would be softer than the people on the right, same distance from the camera so not a DOF thing. I found this happened more at the wide angle of the zoom range on that particular lens at mostly any aperture. I did a some simple tests at home which confirmed it. Ended up sending the lens and camera to Canon for calibration, nothing major. As a side note, I tend to shoot events with the autofocus point set to one of the 3 right points so that when I flip to portrait oriented, it's right about where their faces are. When I switched the A/F point to the far left horizontal it helped a little bit, but still not quite right. Call Nikon and ask, they probably want you to send the camera and lens in together. BTW, it was free... at least with Canon, not sure about Nikon.

one2one

Olympus E-5

Olympus 7-14mm f/4.0 Zuiko Digital Zoom

08/11/2008 10:54:03 AM · #8

Dumb question maybe but are you parallel to the line of focus that your subjects are on? Or should I say perpendicular to your subjects.

08/12/2008 09:58:22 AM · #9

//i278.photobucket.com/albums/kk88/foldcroft/DSC_0282.jpg

This is one of the pictures

Sony 24-70mm F4 Vario-Tessar T* FE OSS

08/12/2008 09:59:04 AM · #10

//i278.photobucket.com/albums/kk88/foldcroft/DSC_0282.jpg

Message edited by Manic - please keep images under 500px and 30kb, or post links or thumbs instead.

Bear_Music

Samsung Galaxy S24 Ultra

08/12/2008 10:13:56 AM · #11

Originally posted by MattO:

That's not really true. Assuming the same lens both bodies, the DOF is exactly the same. If you switch lenses to get the same angular coverage on the FF camera, then you'll be using a longer focal length lens and at the same nominal aperture (f/2.8) you'll have less DOF. But if you use the same PHYSICAL aperture (which would be a smaller nominal aperture on the longer lens) the DOF would be the same.

DOF is a function of the physical diameter of the aperture.

R.

Bear_Music

Samsung Galaxy S24 Ultra

Sony 24-70mm F4 Vario-Tessar T* FE OSS

08/12/2008 10:18:28 AM · #12

Jarjar,

Your sample photo shows natural progression of DOF in a wider-aperture situation. If you're shooting at f/1.8 or close to it, that's all you're gonna get. Look closely at the alignment of everything and you'll see that you're not quite "square" to your subjects; the guy to the right is further from the camera by a few inches at least than the guy to the left.

R.

MattO

Nikon D4

Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II

08/12/2008 10:42:32 AM · #13

The photo he posted is shot @ 5.6 that should easily get his DOF correct for the shot posted. If
is sure that the left side of the photo isnt hampered by motion blur as it was shot at 1/60th then I'd
say there is a problem with sensor alignment as it happens with more then one lens. I'd say the lens isnt parallel to the focal plane.

Bear at the moment I dont have time to discuss this, however I will refer you to this online source for discussion at a later time. I have discussed
this many times with alot of people. And I can use FF sensor, 1.3X sensor, and 1.6X sensor and back
up the findings of the site.

Matt

08/12/2008 10:45:52 AM · #14

//i278.photobucket.com/albums/kk88/foldcroft/JT.jpg

jut taken no movement by subjects
f10
1/60
iso 200
with sb800

Message edited by Manic - please keep images under 500px and 30kb, or post links or thumbs instead.

08/12/2008 10:49:59 AM · #15

I don't see anything wrong with last one you posted. The 1st I was also gonna attribute some blurr to motion as the kid looks to be making jestures with his hands. Peoples heads tend to move with their hands.

08/12/2008 10:53:05 AM · #16

if you zoom in the boy is not sharp where the girl is...........IS IT ME

Canon EF 24-70mm f/2.8L USM

08/12/2008 10:57:42 AM · #17

[thumb]709971[/thumb]

With sharpening applied per Canon recommendation (300,.3,3) in post it comes out fine. Are you shooting RAW or the Nikon equivalent? If so they will look a bit soft until you sharpen them.

Message edited by author 2008-08-12 10:59:47.

violinist123

Canon EOS-6D

08/12/2008 10:57:42 AM · #18

I'd like to see the same shot with you focusing on the tip of the boys nose and
DONT move the camera at all after doing so, just trip the shutter.

Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II

08/12/2008 11:59:12 AM · #19

//i278.photobucket.com/albums/kk88/foldcroft/DSC_0359.jpg

Focus point was moved to boys face
f10
1/60
iso 200
sb800

Message edited by Manic - please keep images under 500px and 30kb, or post links or thumbs instead.

MattO

Nikon D4

08/12/2008 12:14:03 PM · #20

There is no need to shoot @F10 to get that in focus, that should easily be done at F5.6.

Just curious why are you locked in at 1/60th shutter speed?

Matt

violinist123

Canon EOS-6D

Canon EF 24-70mm f/2.8L USM

08/12/2008 12:17:51 PM · #21

Other than a bit of motion blur from the slow shutter, focus looks fine. Could be you are recomposing after focusing at wide apertures if you are seeing issues at 2.8, 1.4, whatever, etc.

spiritualspatula

Panasonic LUMIX DMC-LX100

08/13/2008 12:26:25 AM · #22

I think the answer here is
VERY OBVIOUS.

08/13/2008 04:12:14 PM · #23

very funny

FireBird

08/13/2008 08:03:18 PM · #24

Originally posted by MattO:

There is no need to shoot @F10 to get that in focus, that should easily be done at F5.6.

Just curious why are you locked in at 1/60th shutter speed?

Matt

Probably because he's using the flash. Which should eliminate any talk of motion blur in this discussion. I think jarjar should take a test image of newspaper print at about six feet making sure the camera is as close to perpendicular to the print as possible. It could be he has a camera problem.
The camera should be on a firm surface or tripod. But..... none of the shots looked in exact focus to me. I wonder if the crops he's posting are the full frame he took or only a portion of the frame.