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
Forums  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear
Guest
Forums  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear
Register to forums    Log in

 
FORUMS Cameras, Lenses & Accessories Canon Lenses 
Thread started 28 Oct 2007 (Sunday) 02:57
Search threadPrev/next
sponsored links (only for non-logged)

Is my 70-200mm F2.8 L back focusing?

 
MannP
Senior Member
Avatar
430 posts
Joined Apr 2007
Location: Sydney, Australia
     
Oct 28, 2007 02:57 |  #1

I did some tests. The focus chart and real world ones. Can you help me check?

Center crops:

1. Focus on the guy's head. Camera focuses on the tree on the right

IMAGE: http://img.photobucket.com/albums/v648/mannanddulchtwo/Miscellaneous/_MG_6333.jpg

2. Focus on first N on the donut king box. Camera focuses on the king part
IMAGE: http://img.photobucket.com/albums/v648/mannanddulchtwo/Miscellaneous/_MG_6351.jpg

3. Focus on the number 14 on the measuring cup. Camera focuses on the pizza carton on the left
IMAGE: http://img.photobucket.com/albums/v648/mannanddulchtwo/Miscellaneous/_MG_6354.jpg

Returning it to the store tomorrow :(

https://photography-on-the.net/forum/showthre​ad.php?t=463218

  
  LOG IN TO REPLY
kevin_c
Cream of the Crop
5,745 posts
Likes: 4
Joined Mar 2005
Location: Devon, England
     
Oct 28, 2007 06:26 |  #2

Did you use a tripod? (I somehow doubt it) - When holding a lens at a wide aperture it is quite easy to move a fraction after locking focus, you have a very limited DOF.

You really need to do something more controlled using a tripod IMO.

You may be right, it may be in need of adjustment, but using fast lenses wide open at long focal lengths does take a bit of practice.


-- K e v i n --

Nikon D700, 17-35mm, 28-105mm, 70-200mmVR, 50mm f/1.4
Canon EOS 3, 24-105L, 135L

  
  LOG IN TO REPLY
ashdavid
Osteoglossum bicirrhosum
Avatar
986 posts
Joined Aug 2006
Location: Japan
     
Oct 28, 2007 06:44 as a reply to  @ kevin_c's post |  #3

I don't know ,it is not looking good to me.


1Ds MKIII, 5D, 30D, EF 50mm f/1.2L , EF 85mm f/1.2L , EF 24-70mm f/2.8L , EF 80-200mm f2.8L, EF 70-200mm f/2.8L IS , EF 300mm f/2.8L , EF 400mm f2.8L IS, EF 800mm f5.6L IS EF 180mm f/3.5L Macro , EF 100mm f/2.8 Macro ..... Speedlite 580EX II x 4, Speedlite 430EX x 1, ST-E2 , Remote Switch,

  
  LOG IN TO REPLY
rodal126
Senior Member
Avatar
392 posts
Joined May 2007
Location: Southern California
     
Oct 28, 2007 12:29 |  #4

to ensure if the camera was focused on the items you mentioned, look at the pics using Canon's Zoombrowser EX. There is a view that you can use to see what the camera focused on, similar to the AF points in the viewfinder. That way you can confirm that you focused on exactly what you wanted.


beauty & fashion photographer
facebook (external link) :: website (external link)



  
  LOG IN TO REPLY
transcend
Goldmember
Avatar
1,461 posts
Joined Oct 2004
Location: Squamish, BC
     
Oct 28, 2007 13:50 |  #5

rodal126 wrote in post #4206555 (external link)
to ensure if the camera was focused on the items you mentioned, look at the pics using Canon's Zoombrowser EX. There is a view that you can use to see what the camera focused on, similar to the AF points in the viewfinder. That way you can confirm that you focused on exactly what you wanted.

If he focused and recomposed or moved slightly, this will do him no good. It only shows which focal point was activated at the time of the shot. If he locked focus elsewhere, then it is useless.


http://www.fraserbritt​on.com (external link)

  
  LOG IN TO REPLY
rodal126
Senior Member
Avatar
392 posts
Joined May 2007
Location: Southern California
     
Oct 28, 2007 14:05 |  #6

transcend wrote in post #4206821 (external link)
If he focused and recomposed or moved slightly, this will do him no good. It only shows which focal point was activated at the time of the shot. If he locked focus elsewhere, then it is useless.

True. Let me add that this method would be more accurate if used with a tripod (and the shot was not recomposed);)


beauty & fashion photographer
facebook (external link) :: website (external link)



  
  LOG IN TO REPLY
Glenn ­ NK
Goldmember
Avatar
4,630 posts
Likes: 3
Joined Oct 2006
Location: Victoria, BC
     
Oct 28, 2007 14:13 |  #7

Without a controlled test, it's a waste of time:

1. Tripod is essential,

2. For longer focal length, mirror lockup and remote release essential,

3. Use the standard chart (with horizontal lines perpendicular to line of site) shot at 45 degree angle.

4. Focus/recompose is looking for trouble and can be misleading.


When did voluptuous become voluminous?

  
  LOG IN TO REPLY
MannP
THREAD ­ STARTER
Senior Member
Avatar
430 posts
Joined Apr 2007
Location: Sydney, Australia
     
Oct 28, 2007 18:09 |  #8

Thanks for the replies. I used a tripod on the 2nd and 3rd pic. Mirror lockup and remote shutter. As for the focus points, I used the center focus point and remember very well which point I aimed at.

However, this morning I tried again. I don't know what I did other than switch the focus distance switch on the lens. Forgive me if I seem dumb. I haven't read the manual yet because I left the box at a friend's house.

F/4, iso400, 1/25 sec, tripod, mirror lockup, remote

IMAGE: http://img.photobucket.com/albums/v648/mannanddulchtwo/Miscellaneous/_MG_6360.jpg

https://photography-on-the.net/forum/showthre​ad.php?t=463218

  
  LOG IN TO REPLY
silvex
Cream of the Crop
Avatar
7,313 posts
Gallery: 21 photos
Likes: 55
Joined Sep 2006
Location: Southern California, USA
     
Oct 28, 2007 18:13 |  #9

was it at 70? 200? try about 10ft away and put the batteries appart about 2ft-3ft. I use hard cover books for my "in-house" focusing tests.


.
-Ed
CPS Platinum Member.
Canon Gear
SilvexPhoto.comexternal link

  
  LOG IN TO REPLY
MannP
THREAD ­ STARTER
Senior Member
Avatar
430 posts
Joined Apr 2007
Location: Sydney, Australia
     
Oct 28, 2007 18:18 as a reply to  @ Glenn NK's post |  #10

Another one:

Circled area is the point of focus. Though this doesn't show much, it just seems to me that the focused area is sharp.

IMAGE: http://img.photobucket.com/albums/v648/mannanddulchtwo/Miscellaneous/_MG_6364.jpg

https://photography-on-the.net/forum/showthre​ad.php?t=463218

  
  LOG IN TO REPLY
MannP
THREAD ­ STARTER
Senior Member
Avatar
430 posts
Joined Apr 2007
Location: Sydney, Australia
     
Oct 28, 2007 18:21 |  #11

silvex wrote in post #4207806 (external link)
was it at 70? 200? try about 10ft away and put the batteries appart about 2ft-3ft. I use hard cover books for my "in-house" focusing tests.


200mm. I was 7 feet away. Ok, I'll try your method now. Got no books here though.


https://photography-on-the.net/forum/showthre​ad.php?t=463218

  
  LOG IN TO REPLY
silvex
Cream of the Crop
Avatar
7,313 posts
Gallery: 21 photos
Likes: 55
Joined Sep 2006
Location: Southern California, USA
     
Oct 28, 2007 18:27 |  #12

MannP wrote in post #4207845 (external link)
200mm. I was 7 feet away. Ok, I'll try your method now. Got no books here though.


Shoot two shots f2.8 iso100 the f4 iso100 on a tripod as perpendicular and level a s possible to the subject. Like put objects on a dining table one on each end staggered. then put the lens height about 3'6" (on tripod ) 10feet way and shoot on the fist object at f2.8 the at f4 Av mode on tripod an remote switch or cameras timer.

then open it and sharpen both shots ONLY no noise or levels etc etc.


.
-Ed
CPS Platinum Member.
Canon Gear
SilvexPhoto.comexternal link

  
  LOG IN TO REPLY
MannP
THREAD ­ STARTER
Senior Member
Avatar
430 posts
Joined Apr 2007
Location: Sydney, Australia
     
Oct 28, 2007 18:39 |  #13

How about this? 10 ft away, camera raised to your specified height. But iso is at 200 and F/4.

IMAGE: http://img.photobucket.com/albums/v648/mannanddulchtwo/Miscellaneous/_MG_6379.jpg

https://photography-on-the.net/forum/showthre​ad.php?t=463218

  
  LOG IN TO REPLY
silvex
Cream of the Crop
Avatar
7,313 posts
Gallery: 21 photos
Likes: 55
Joined Sep 2006
Location: Southern California, USA
     
Oct 28, 2007 18:41 |  #14

Looking good...at F4, but try BOTH f2.8 and f4 at 70 then at 200. four shots. BTW the camera does not look THAT level with the surface the batteries are at. check this thread...

https://photography-on-the.net/forum/showthre​ad.php?t=398587

see how my camera was "kind of level with kitchen counter...

try like three boxes with letters on ( cereal, sugar, bounty etc etc)


.
-Ed
CPS Platinum Member.
Canon Gear
SilvexPhoto.comexternal link

  
  LOG IN TO REPLY
silvex
Cream of the Crop
Avatar
7,313 posts
Gallery: 21 photos
Likes: 55
Joined Sep 2006
Location: Southern California, USA
     
Oct 28, 2007 18:50 |  #15

I forgot about this link...

http://www.pbase.com/i​mage/40706398 (external link)


.
-Ed
CPS Platinum Member.
Canon Gear
SilvexPhoto.comexternal link

  
  LOG IN TO REPLY
sponsored links (only for non-logged)

2,241 views & 0 likes for this thread, 7 members have posted to it.
Is my 70-200mm F2.8 L back focusing?
FORUMS Cameras, Lenses & Accessories Canon Lenses 
AAA
x 1600
y 1600

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

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 2.58forum software
version 2.58 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is SteveeY
1688 guests, 167 members online
Simultaneous users record so far is 15,144, 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.