Go to a  "printer friendly" view of this message which allow an easy print Printer-friendly copy Go to the page which allows you to send this topic link and a message to a friend Email this topic to a friend
Forums Lobby GET TO KNOW YOUR CAMERA & MASTER IT Nikon D90/D80/D70 (Public) topic #250623
View in linear mode

Subject: "Auto fail at wide angles" Previous topic | Next topic
Omaha Registered since 07th Jan 2012Sat 04-Feb-12 04:34 AM
461 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
"Auto fail at wide angles"


Omaha, US
          

Something I've noticed...

I have a D70 with the included 18-70 lens.

The auto focus works great IF the lens is set to around 25mm or greater. Choke it all the way down to 18mm, and the AF really struggles (often refusing to get a focus lock at all).

Took me a while to figure that out. Its an easy thing to work around, but it has me wondering.

Is this normal behavior?

Visit my Nikonians gallery
Most of my Nikon photos end up here.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Replies to this topic
Subject Author Message Date ID
Reply message RE: Auto fail at wide angles
elec164 Silver Member
04th Feb 2012
1
Reply message RE: Auto fail at wide angles
OldCodger
04th Feb 2012
3
Reply message RE: Auto fail at wide angles
CharlieS Silver Member
04th Feb 2012
2
Reply message RE: Auto fail at wide angles
Omaha
04th Feb 2012
4
     Reply message RE: Auto fail at wide angles
elec164 Silver Member
04th Feb 2012
5
          Reply message RE: Auto fail at wide angles
OldCodger
04th Feb 2012
6
               Reply message RE: Auto fail at wide angles
Omaha
04th Feb 2012
7
                    Reply message RE: Auto fail at wide angles
ShrimpBoy Silver Member
05th Feb 2012
8
Reply message RE: Auto fail at wide angles
Covey22 Moderator
06th Feb 2012
9
Reply message RE: Auto fail at wide angles
Omaha
07th Feb 2012
10
Reply message RE: Auto fail at wide angles
avm247 Moderator
08th Feb 2012
11
Reply message RE: Auto fail at wide angles
profpb Gold Member
13th Feb 2012
12
     Reply message RE: Auto fail at wide angles
Omaha
13th Feb 2012
13
          Reply message RE: Auto fail at wide angles
OldCodger
13th Feb 2012
14
               Reply message RE: Auto fail at wide angles
Omaha
13th Feb 2012
15

elec164 Silver Member Nikonian since 15th Jan 2009Sat 04-Feb-12 01:29 PM
1897 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#1. "RE: Auto fail at wide angles"
In response to Reply # 0


US
          

Hard to say without specific information and sample images, but it very well could be normal.

The problem with wide angle lenses arises because generally we use them for landscape shots at a distance. In that circumstance the subject matter is relatively small in the frame, and occupies a small segment of the AF sensor. That may make it difficult for the system to lock focus. There can also be multiple low contrast targets at varying distances on the same AF sensor which could also cause problems and a miss-focus.

Also with shorter focal lengths, the harder it is to correct aberrations which could affect AF performance, especially in zoom lenses which are often optimized for a specific focal range at the expense of the others.

Then again, it could be a malfunction in the lens that occurs only at the wide end.

So for me at least, you need to provide a bit more information.

Pete

Visit my Nikonians gallery.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
OldCodger Registered since 15th Oct 2011Sat 04-Feb-12 03:34 PM
481 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#3. "RE: Auto fail at wide angles"
In response to Reply # 1


Sawbridgeworth Hertfordshire, GB
          

Pete,
Your explanation gels with me, I was musing on this topic while you were writing. Unless the subject is something very large and dominating with no visual depth it is going to be very hard to decide how to achieve automatic focus. Perhaps a large well lit factory wall would be about the only practical object to fill the sensor?
I am sure that subjects that fooled automatic sensors used to result in what was once known as subject failure, e.g. snow that appeared too white and slewed the 18% grey issue, black cats in coal mines, etc. Does anyone else remember that term?

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

CharlieS Silver Member Nikonian since 29th Aug 2007Sat 04-Feb-12 03:31 PM
1729 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#2. "RE: Auto fail at wide angles"
In response to Reply # 0


US
          

A sample shot or two would help.
If you know someone with another compatible Nikon, or your local camera store, try your lens on another body and another fairly wide lens on your body, and see if the same issue occurs under similar conditions.
Lack of contrast is a major culprit in autofocus issues and not confined to wide by any means. Pick a good contrasty target, a dark building against a bright sky for example, aim so half your focus point is in the light and half in the dark areas and test the focus ability on a variety of subjects in this manner.
The 18-70 being an F3.5/4.5 lens looses about 2/3 of a stop of light over an f2.8 lens so light transition through the lens as a focus aid is a little more limited.
In low light/poor contrast situations all Nikon models can have AF issues. Think driving down a road on a foggy day. The details you need for safe driving are harder to acquire. Under less than ideal conditions AF struggles more to acquire a good focus lock.

____________________________________________________________________
When no one is looking, Pigs can walk on they're hind legs

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
Omaha Registered since 07th Jan 2012Sat 04-Feb-12 04:42 PM
461 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#4. "RE: Auto fail at wide angles"
In response to Reply # 2


Omaha, US
          

Here's an example...

Say I'm sitting in my easy chair, fiddling with the camera. I have a fireplace/bookcase thing on the wall on the other side of the room. Its filled with lots of good contrasty lines and shapes and stuff...the sort of stuff that AF can grab instantly.

I set the lens to 18mm...point and click...and "whirrr....whirrr...." camera hunts for focus from end to end and gives up. Won't fire.

I set the lens to 25mm...point and click...and "POP!" Instant focus lock and exposure.

This is with my AF point set to the center, and with the little center block on the viewfinder positioned right over some good high-contrast (easy to AF) stuff.

Visit my Nikonians gallery
Most of my Nikon photos end up here.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

        
elec164 Silver Member Nikonian since 15th Jan 2009Sat 04-Feb-12 05:00 PM
1897 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#5. "RE: Auto fail at wide angles"
In response to Reply # 4


US
          

>Here's an example...
>
>Say I'm sitting in my easy chair,

It’s nice having a specific scenario, but sample images would be better.

In your scenario, what appears bright and contrasty to you might not be so bright and contrasty to the AF sensor. How far is the bookcase, and how magnified are the subjects?

There is just too many variables involved, and without specific sample images to say “OK this shot the AF failed, and this shot it could AF” we’re just going to go round and round in an academic exercise, not a determination and solution.

Perhaps use a wide angle setting that AF fails on, use manual focus to take the shot then provide us with that sample. We could then determine if there may be a lens malfunction when set to the wide end. That will at least help eliminate one of the variables.

Pete

Visit my Nikonians gallery.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

            
OldCodger Registered since 15th Oct 2011Sat 04-Feb-12 05:34 PM
481 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#6. "RE: Auto fail at wide angles"
In response to Reply # 5


Sawbridgeworth Hertfordshire, GB
          

If it is a bookcase across the room then I am going to guess it is illuminated only with normal internal light and is likely to be a challenging condition. I think Pete is right that an example shot of the scene would be 'worth a thousand words'.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                
Omaha Registered since 07th Jan 2012Sat 04-Feb-12 09:28 PM
461 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#7. "RE: Auto fail at wide angles"
In response to Reply # 6


Omaha, US
          

I should be more clear.

This isn't about my bookcase. Its ANYTHING. Any subject, any distance, any light, it doesn't matter.

At 18mm, the lens/camera will focus lock maybe 5% or 10% of the time at most.

At 25mm (and longer), the lens/camera will focus lock virtually 100% of the time, subject to the normal limitations that have been discussed.

Visit my Nikonians gallery
Most of my Nikon photos end up here.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                    
ShrimpBoy Silver Member Nikonian since 08th Jan 2006Sun 05-Feb-12 03:35 AM
882 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#8. "RE: Auto fail at wide angles"
In response to Reply # 7


Brighton and Hove, GB
          

Your lens or your camera is faulty. My D70 and 18-70 combo works perfectly at any focal length unless there is some egregious issue with the subject such as others have already described. Since that lens is variable-aperture, it ought to focus most reliably at 18mm because that focal length gives the AF sensor the most light to work with.

Gary
"Yea, Sussex by the sea!" - Rudyard Kipling

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Covey22 Moderator Expert in various fields including aviation photography Awarded for his contributions to the Resources and The Nikonian eZine Charter MemberMon 06-Feb-12 01:35 PM
10410 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#9. "RE: Auto fail at wide angles"
In response to Reply # 0


US
          

My first reaction to this post is to ask exactly what your Autofocus settings are. You're dealing with a lot of variables, so let's eliminate the ones that can be easily and clearly quantified. Specifically - AF-Area Mode, Servo Mode, frame advance and which sensor in the array are you relying on? All the other factors would rely on the situational environment (lighting, subject, etc)

"Toodle-loo from Covey22!"

-Armando
Nikonians Team
Nikonians News - Fresh Everyday!

The Covey Blog!

My Plan:

Get out of the car.
Get closer to the subject.
Pick the right mid-tone this time.

See My Nikonians Gallery

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
Omaha Registered since 07th Jan 2012Tue 07-Feb-12 11:13 PM
461 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#10. "RE: Auto fail at wide angles"
In response to Reply # 9


Omaha, US
          

I just bought a new lens (different specs than the 18-70) off of eBay. I'll be interested to see how it behaves.

Visit my Nikonians gallery
Most of my Nikon photos end up here.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

avm247 Moderator Awarded for high skills in documentary architecture and aviation photography Charter MemberWed 08-Feb-12 12:18 AM
18153 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#11. "RE: Auto fail at wide angles"
In response to Reply # 0


Rancho Cordova, US
          

The auto focus works great IF the lens is set to around 25mm or greater. Choke it all the way down to 18mm, and the AF really struggles (often refusing to get a focus lock at all).

I have not had this issue with the D70s and 18-70mm lens that I have at work and many of my images are shot at 18mm.

Anthony

The Moderator Page and My Gallery
The important things in life are simple; the simple things are hard.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
profpb Gold Member Nikonian since 28th Oct 2010Mon 13-Feb-12 01:02 AM
85 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#12. "RE: Auto fail at wide angles"
In response to Reply # 11


Venice, US
          

Not to pile it on, but my Life pixel converted D70 with the same 18-70mm lens does not have problems focusing at 18 mm through out the f/range.


Dr. Buick

Visit my Nikonians gallery.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

        
Omaha Registered since 07th Jan 2012Mon 13-Feb-12 01:11 AM
461 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#13. "RE: Auto fail at wide angles"
In response to Reply # 12


Omaha, US
          

I think it was the original kit lens.

I bought an 18-200 VR off of ebay, and it works much better. Even allowing a moment for the VR to dial in, its much quicker than the old 18-70, and has no problems finding focus lock at 18mm.

And it seems sharper too.

So, all's well that ends well.

Visit my Nikonians gallery
Most of my Nikon photos end up here.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

            
OldCodger Registered since 15th Oct 2011Mon 13-Feb-12 03:38 PM
481 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#14. "RE: Auto fail at wide angles"
In response to Reply # 13


Sawbridgeworth Hertfordshire, GB
          

Well I am glad that you have been able to put the issue to bed. My earlier suggestions were all aimed at making sure that the old lens was properly tested. Will you explore repair options on the old lens or just bin it as not worth further action?

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                
Omaha Registered since 07th Jan 2012Mon 13-Feb-12 06:37 PM
461 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#15. "RE: Auto fail at wide angles"
In response to Reply # 14


Omaha, US
          

The old one is going in the drawer. Sort of hate to throw it away, but since the new one covers 100% of the focal range of the old (and then some), and seems to be doing it better, I see no use for the old one.

And its not worth even a diagnostic bill from a repair shop, so in the drawer it sits.

Visit my Nikonians gallery
Most of my Nikon photos end up here.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Forums Lobby GET TO KNOW YOUR CAMERA & MASTER IT Nikon D90/D80/D70 (Public) topic #250623 Previous topic | Next topic


Take the Nikonians Tour and learn more about being a Nikonian Wiki /FAQ /Help Listen to our MP3 photography radio channels Find anything on Nikon and imaging technology - fast!

Copyright © Nikonians 2000, 2014
All Rights Reserved

Nikonians®, NikoScope® and NikoniansAcademy™ are trademarks owned by Nikonians.org.
Nikon®, Nikonos® and Nikkor® are registered trademarks of Nikon Corporation.