Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and our Privacy Policy.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Guest
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Nikon Cameras, Lenses & Accessories Nikon Cameras 
Thread started 26 Feb 2015 (Thursday) 19:12
Search threadPrev/next
sponsored links
(this ad will go away when you log in as a registered member)

Newer DX sensor Focus woes

 
Pagman
I just hold the thing :-)
Avatar
8,497 posts
Gallery: 1800 photos
Likes: 7762
Joined Dec 2011
     
Feb 26, 2015 19:12 |  #1

I have been reading about all the focus issues with the D7000 over the past 4 years or so, and wondered if these or similar could be also affecting the D7100? there have been many owners of the d7000 talking about focus issues some fixable by micro focus adjustment and some not so easy, have these two particular cameras been rushed into production with AF problems that where either not picked up at the factory or just kept quiet?

Any thought folks...

P.


Some stuff.

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)
smythie
I wasn't even trying
3,680 posts
Gallery: 30 photos
Likes: 617
Joined Jun 2009
Location: Sydney - Australia
     
Feb 27, 2015 04:34 |  #2

I can't remember any focus issues with my D7000. It's been nearly 2 years since I parted with it but whether panning MotoGP or tracking them coming head on it didn't have issue that wasn't operator error - and that was using a Sigma 120-400 (probably not the best telephoto AF lens on the market).


Gear List

  
  LOG IN TO REPLY
Pagman
THREAD ­ STARTER
I just hold the thing :-)
Avatar
8,497 posts
Gallery: 1800 photos
Likes: 7762
Joined Dec 2011
     
Feb 27, 2015 18:48 |  #3

Here is something i didn't know till i researched it - in the D7100 and possibly others ? the focus points that surround the center cross type f8 one, are only cross types at f5.6 or larger, smaller than this and they resort to line type, this would make a difference with focus accuracy in dynamic mode if the subject moves away even slightly from the center, esp with more complex subjects or poor lighting.

P.


Some stuff.

  
  LOG IN TO REPLY
sandpiper
Cream of the Crop
Avatar
7,171 posts
Gallery: 1 photo
Likes: 50
Joined Aug 2006
Location: Merseyside, England
Post edited over 4 years ago by sandpiper. (2 edits in all)
     
Feb 27, 2015 19:18 |  #4

Pagman wrote in post #17452954 (external link)
Here is something i didn't know till i researched it - in the D7100 and possibly others ? the focus points that surround the center cross type f8 one, are only cross types at f5.6 or larger, smaller than this and they resort to line type, this would make a difference with focus accuracy in dynamic mode if the subject moves away even slightly from the center, esp with more complex subjects or poor lighting.

P.

That is pretty normal, most cameras (certainly most, if not all, Canon ones) are f/5.6 or faster on all points but the centre point (and most still require f/5.6 on the centre as well). So, are you using a TC for these shots? Maybe there is an issue with that on the 55-300?

Also, are you sure about them resorting to line type with apertures smaller than f/5.6? Most cameras can't AF at all past f/5.6, especially away from centre point. Often, they are line type at f/5.6 or larger and the cross type may only kick in with f/2.8, or f/4 maybe.

[EDITED TO ADD]: I have just looked up the d7100 AF system and the cross type points are always cross type as far as I can see. The centre cross point works at f/8 or faster, the other cross points work at f/5.6 or faster, as cross types. Smaller than f/5.6 and they don't work at all, it isn't a matter of resorting to line type. The other outer points are always line type only, and are again f/5.6 or faster.




  
  LOG IN TO REPLY
Pagman
THREAD ­ STARTER
I just hold the thing :-)
Avatar
8,497 posts
Gallery: 1800 photos
Likes: 7762
Joined Dec 2011
     
Feb 27, 2015 20:17 |  #5

sandpiper wrote in post #17452990 (external link)
That is pretty normal, most cameras (certainly most, if not all, Canon ones) are f/5.6 or faster on all points but the centre point (and most still require f/5.6 on the centre as well). So, are you using a TC for these shots? Maybe there is an issue with that on the 55-300?

Also, are you sure about them resorting to line type with apertures smaller than f/5.6? Most cameras can't AF at all past f/5.6, especially away from centre point. Often, they are line type at f/5.6 or larger and the cross type may only kick in with f/2.8, or f/4 maybe.

[EDITED TO ADD]: I have just looked up the d7100 AF system and the cross type points are always cross type as far as I can see. The centre cross point works at f/8 or faster, the other cross points work at f/5.6 or faster, as cross types. Smaller than f/5.6 and they don't work at all, it isn't a matter of resorting to line type. The other outer points are always line type only, and are again f/5.6 or faster.


I was getting a bit confused to be honest as one thing i did not realize was that focusing is done wide open and not stopped down, so adjusting my exposure ap is not necessary, and with the focus sensors in mine - the center is f8 cross and as long as the lens is f5.6 or faster, then the surrounding 14 sensors are also cross type, adjusting the aperture for exposure makes no difference to focusing?

P.


Some stuff.

  
  LOG IN TO REPLY
sandpiper
Cream of the Crop
Avatar
7,171 posts
Gallery: 1 photo
Likes: 50
Joined Aug 2006
Location: Merseyside, England
     
Feb 27, 2015 20:32 |  #6

Pagman wrote in post #17453048 (external link)
I was getting a bit confused to be honest as one thing i did not realize was that focusing is done wide open and not stopped down, so adjusting my exposure ap is not necessary, and with the focus sensors in mine - the center is f8 cross and as long as the lens is f5.6 or faster, then the surrounding 14 sensors are also cross type, adjusting the aperture for exposure makes no difference to focusing?

P.

Yes, that's correct. All focusing is done wide open and the lens is only stopped down as you take the shot (otherwise the viewfinder would get very dark if you were shooting at small apertures). So your 55-300 will always take advantage of the cross-type points, as it is f/5.6 at the long end. Put a 1.4x TC on it though, thus making it an f/8, it will only focus (at all) with the centre point, and a 2x TC will mean no AF as none of the AF points will work at f/11.




  
  LOG IN TO REPLY
Pagman
THREAD ­ STARTER
I just hold the thing :-)
Avatar
8,497 posts
Gallery: 1800 photos
Likes: 7762
Joined Dec 2011
     
Feb 27, 2015 20:47 |  #7

Is there any difference in focus accuracy if following and focusing and object that is moving diagonally, if you are keeping your camera at a diagonal to the subject, would this impact predictive focus tracking in any way?

P.


Some stuff.

  
  LOG IN TO REPLY
sandpiper
Cream of the Crop
Avatar
7,171 posts
Gallery: 1 photo
Likes: 50
Joined Aug 2006
Location: Merseyside, England
     
Feb 28, 2015 09:41 |  #8

Pagman wrote in post #17453071 (external link)
Is there any difference in focus accuracy if following and focusing and object that is moving diagonally, if you are keeping your camera at a diagonal to the subject, would this impact predictive focus tracking in any way?

P.

No, that shouldn't matter at all. The only time camera orientation, relative to the subject, should make a difference is when using a single line AF point and lining it up the same way as the contrast line. That is to say pointing an AF point that is only sensitive to vertical lines at something which only has horizontal lines. That is why you need to be aware of which way your points are oriented, some single line sensors are horizontal and others vertical and many cameras have a mix, so you should be aware which are which and use them as appropriate.

But a diagonal line should be readable by either a horizontal or vertical sensitive AF point, and certainly by a cross type point.




  
  LOG IN TO REPLY
Pagman
THREAD ­ STARTER
I just hold the thing :-)
Avatar
8,497 posts
Gallery: 1800 photos
Likes: 7762
Joined Dec 2011
Post edited over 4 years ago by Pagman.
     
Feb 28, 2015 18:24 |  #9

sandpiper wrote in post #17453661 (external link)
No, that shouldn't matter at all. The only time camera orientation, relative to the subject, should make a difference is when using a single line AF point and lining it up the same way as the contrast line. That is to say pointing an AF point that is only sensitive to vertical lines at something which only has horizontal lines. That is why you need to be aware of which way your points are oriented, some single line sensors are horizontal and others vertical and many cameras have a mix, so you should be aware which are which and use them as appropriate.

But a diagonal line should be readable by either a horizontal or vertical sensitive AF point, and certainly by a cross type point.


Thanks for that mate as i do struggle with focus with predictive tracking of my metallic birds in flight ;-)a i get a series of shots all at the same time -same settings, and same conditions and they are - one in focus, one out, one in, one out and on and on etc no pattern to it but like when you have a bad signal on the tv where it is perfect one minute then gone off the next.
I am sure it is not user error or conditions, if it was the pictures that are pin sharp under the same conditions would be off.

P.


Some stuff.

  
  LOG IN TO REPLY
slickaj115
Member
142 posts
Likes: 20
Joined Aug 2013
Location: Oregon
     
Apr 30, 2015 14:52 |  #10

Pag -

I just sold my D7000 because every photo was every so slightly out of focus, or soft, with every lens I used on it. Even after microadjusts...some lenses needed to be maxed at +20, and it still wasn't enough. I recently picked up a 2nd D300 body and just use those two. I love my D300's...probably will use both until they go "tits up".

So far, both D300 bodies only require adjustments of +5-10 for backfocusing, on all my Nikon lenses. My recently acquired 50mm 1.8G is in fact SO sharp on them I am in love with the outcomes.


Nikon D300 / Nikon D70 / Nikon 18-70 3.5-4.5 / Nikon 35mm f1.8G / Nikon 50mm f1.8G / Nikon 70-210 f4 AF / Yongnuo 468ii
Previously had Canon 5dc / Canon 40d / Canon 60d / Canon 7d

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)

2,408 views & 1 like for this thread
Newer DX sensor Focus woes
FORUMS Nikon Cameras, Lenses & Accessories Nikon Cameras 
AAA
x 1600
y 1600

Jump to forum...   •  Rules   •  Index   •  New posts   •  RTAT   •  'Best of'   •  Gallery   •  Gear   •  Reviews   •  Member list   •  Polls   •  Image rules   •  Search   •  Password reset

Not a member yet?
Register to forums
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!


COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and to our privacy policy.
Privacy policy and cookie usage info.


POWERED BY AMASS forum software 2.1forum software
version 2.1 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is dtjones1987
1336 guests, 334 members online
Simultaneous users record so far is 15144, that happened on Nov 22, 2018

Photography-on-the.net Digital Photography Forums is the website for photographers and all who love great photos, camera and post processing techniques, gear talk, discussion and sharing. Professionals, hobbyists, newbies and those who don't even own a camera -- all are welcome regardless of skill, favourite brand, gear, gender or age. Registering and usage is free.