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my EF 100mm f2 has problem focusing on low contrast objects and eyes

theorium
Contributor

I have an EF100mm f2 that I use on my EOS 6D (also taste on EOS500D). there are a lot of instances when it goes on an endless hunt for focus and never stops till I move it. it starts going in and out. it mostly happens on low contrast objects but it happens on high-contrast things too, which the most annoying one is focusing on eyes.
I want to know if it's a common issue with this oldy lens or if I should send it for repair.

13 REPLIES 13

jrhoffman75
Legend
Legend

@theorium wrote:

I have an EF100mm f2 that I use on my EOS 6D (also taste on EOS500D). there are a lot of instances when it goes on an endless hunt for focus and never stops till I move it. it starts going in and out. it mostly happens on low contrast objects but it happens on high-contrast things too, which the most annoying one is focusing on eyes.
I want to know if it's a common issue with this oldy lens or if I should send it for repair.


The AF system needs contrast to focus. What focusing mode are you using? Do other lenses show a similar behavior when trying to photograph the same subjects?

John Hoffman
Conway, NH

1D X Mark III, M200, Many lenses, Pixma PRO-100, Pixma TR8620a, Lr Classic

I tried with my Tamron 24-70 and the infamous 50mm f/1.8 II and they had difficulty pinpointing the focus but were more successful and didn't on loop

shadowsports
Legend
Legend

Greetings,

In addition to John's suggestions, please ensure you are not attempting to focus on a subject closer than the lenses MFD (12 inches).  

EF 100 f2.8 Manual

~Rick
Bay Area - CA


~R5 C (1.0.7.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, ~RF 200-800 +RF 1.4x TC, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve ~ImageClass MF644Cdw/MF656Cdw ~Pixel 8 ~CarePaks Are Worth It

thanks, but no that's not the problem

ebiggs1
Legend
Legend

Sounds like you just need more light.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

kinda yes, so is the behaviour of the lens normal you say?


@ebiggs1 wrote:

Sounds like you just need more light.


Specs for 6D show AF down to EV -3. That's basically full moon at night.

John Hoffman
Conway, NH

1D X Mark III, M200, Many lenses, Pixma PRO-100, Pixma TR8620a, Lr Classic

Tronhard
VIP
VIP

Hi and welcome:
It would be helpful to know precisely what settings you using for focus:
Focus type - One shot, AI, or Servo
selectable focus points = 61, Only cross-type, 15 Points, 9 points
Has anything else changed?  A different setting of any kind, a front filter etc.?

Thank you.


cheers, TREVOR

The mark of good photographer is less what they hold in their hand, it's more what they hold in their head;
"All the variety, all the charm, all the beauty of life is made up of light and shadow", Leo Tolstoy;
"Skill in photography is acquired by practice and not by purchase" Percy W. Harris

one shot , 9 points (using the center) no filters,
based on the questions everyone is asking, I am assuming the lens has a problem.

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