topic Re: my EF 100mm f2 has problem focusing on low contrast objects and eyes in EF & RF Lenses

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

theorium — Wed, 29 May 2024 09:16:56 GMT

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.

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

jrhoffman75 — Wed, 29 May 2024 10:25:44 GMT

@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?

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

theorium — Wed, 29 May 2024 12:52:18 GMT

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

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

shadowsports — Wed, 29 May 2024 14:09:39 GMT

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

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

ebiggs1 — Wed, 29 May 2024 15:01:32 GMT

Sounds like you just need more light.

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

theorium — Wed, 29 May 2024 16:59:05 GMT

thanks, but no that's not the problem

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

theorium — Wed, 29 May 2024 17:00:16 GMT

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

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

Tronhard — Wed, 29 May 2024 18:45:22 GMT

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.

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

jrhoffman75 — Wed, 29 May 2024 18:57:01 GMT

@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.

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

deebatman316 — Thu, 30 May 2024 00:16:16 GMT

I would like to confirm which lens you have. Canon has released 3 revisions of this lens over the years. The L lens is the most up to date version of the lens.

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

theorium — Thu, 30 May 2024 10:39:46 GMT

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

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

p4pictures — Fri, 31 May 2024 17:34:20 GMT

There is an EF 100mm f/2 USM that was launched in 1991 - it's similar to the EF 85mm f/1.8 USM launched in 1992. They are both different to the macro 100mm lenses which were all f/2.8 maximum aperture including the most recent EF 100mm f/2.8L Macro IS USM.

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

deebatman316 — Fri, 31 May 2024 17:48:41 GMT

Yes I am aware of that that. The manual for this lens is no longer available anymore. It's design is based off the EF 85mm F/1.8 USM lens. It is also not a Macro lens either like its F/2.8 counterparts. My uncle used owned the original EF 100mm F/2.8 Macro lens from 1990 it used an Arc Form Drive (AFD) AF motor. Not the newer Micro Motor seen in newer designed lenses released in 1993 onward.

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

jrhoffman75 — Fri, 31 May 2024 18:10:08 GMT

Maybe this:

01_CT1-8536_ENG.pdf