135L & 5D AI servo mode

[Eden Yip]

hello,

i acquired this lens in mar and just have some more time to test it out yesterday...

i tried it with 5D at F2 AI servo to capture lion dance, walking by ppl and doggies. from more than 100 shots, only 10% is tact sharp (blowing up to 100%, some even way OOF). i know at F2 DOF is narrow but i was shooting from 5ft to 20ft, hence the DOF is not paper thin.

b4 this test i used it indoor for a few family gathering. The lens seems AF ok at one-shot mode and the subject was relatively close (about within 10ft). i test it to focus to far subjects (infinity) and the AF was noticably less accurate.

with this low keeper percentage i am wondering if the 5D AI servo is not fast enough to work with 135 at F2, or, any trick to use AI servo? i set the camera to AF when pressing . i also notice that in some OOF samples, the subjects were standstill...

 

[thx1138]

hello,

i acquired this lens in mar and just have some more time to test it
out yesterday...

i tried it with 5D at F2 AI servo to capture lion dance, walking by
ppl and doggies. from more than 100 shots, only 10% is tact sharp
(blowing up to 100%, some even way OOF). i know at F2 DOF is narrow
but i was shooting from 5ft to 20ft, hence the DOF is not paper
thin.

b4 this test i used it indoor for a few family gathering. The lens
seems AF ok at one-shot mode and the subject was relatively close
(about within 10ft). i test it to focus to far subjects (infinity)
and the AF was noticably less accurate.

with this low keeper percentage i am wondering if the 5D AI servo
is not fast enough to work with 135 at F2, or, any trick to use AI
servo? i set the camera to AF when pressing . i also notice that
in some OOF samples, the subjects were standstill...

Hmm your best case scenario is at 20' where DOF is only 9.5" and at 10' you are down to 2.3" and at 5' you get 0.5". I'd say DOF is thin even at 20' and razor thin by 10'.

I don't think it's the cameras fault. Try f/4 at least which even at 20' still only yields 19" DOF.

 

[dchao]

-no text-

 

[MacAllan30]

ISO and shutter speed? Where you in Tv mode?

My 135 is a great, but I've needed to improve my hand holding technique with this lense. Experience has also taught me that minimum shutter speed ~ 1/200...

Post some pics would be helpful.

Mac

 

[Eden Yip]

all at F2, crop at about focus pt. RAW. Standard Style, no PP. only resizing.





focus at about doggie's mouth but sharp at the string





again focus at doggies' head. but OOF.





focus at the gal's shirt... just walking speed... still OOF?





focus at baby's head. note the board at the bottom right sharper



below was taken at a relatively close distance, indoor. quite sharp.

 

[dchao]

AI servo mode in the 5D is not so fast. It's OK for tracking subjects that are moving at constant speed. But other than that, so too slow, specially if the DOF is very thin.

For 5D in AI servo mode, I recommend an aperture of at least f/4. If you need to shot anything above f/2.8, get an 1D instead.

 

[thx1138]

all at F2, crop at about focus pt. RAW. Standard Style, no PP. only
resizing.

Looks like some were backfocused. Those chains are sharp on the dog.

 

[Eden Yip]

rite... that's what i am thinking...in most of the slightly out focus shots, the objects behind or adjacent to the target were sharper.. another possibility is that the 5D is so slow (as dchao mentioned) .. the doggie (or other subjects i was trying to capture) was walking toward me and the 5D responded so slowly capturing the object behind the target...

and... i tried to focus to infinity and the pic was not tact sharp... i am thinking again if it is due to the mismatch of motor freq that made my 35L AF inaccurately...

btw, i checked your profile... you have a 1D2 and 135L.. are you able to capture moving object at F2? as dchao suggested a 1d2 is required for capturing at F2.8 or faster...

all at F2, crop at about focus pt. RAW. Standard Style, no PP. only
resizing.

Looks like some were backfocused. Those chains are sharp on the dog.

 

[brianric]

I had the same problem with my 30D and 28-135 last week and I was at 1/800 sec, F10 at ISO 250. My 100-400 at ISO 400 was fine.

hello,

i acquired this lens in mar and just have some more time to test it
out yesterday...

i tried it with 5D at F2 AI servo to capture lion dance, walking by
ppl and doggies. from more than 100 shots, only 10% is tact sharp
(blowing up to 100%, some even way OOF). i know at F2 DOF is narrow
but i was shooting from 5ft to 20ft, hence the DOF is not paper
thin.

b4 this test i used it indoor for a few family gathering. The lens
seems AF ok at one-shot mode and the subject was relatively close
(about within 10ft). i test it to focus to far subjects (infinity)
and the AF was noticably less accurate.

with this low keeper percentage i am wondering if the 5D AI servo
is not fast enough to work with 135 at F2, or, any trick to use AI
servo? i set the camera to AF when pressing . i also notice that
in some OOF samples, the subjects were standstill...

 

[thx1138]

rite... that's what i am thinking...in most of the slightly out
focus shots, the objects behind or adjacent to the target were
sharper.. another possibility is that the 5D is so slow (as dchao
mentioned) .. the doggie (or other subjects i was trying to
capture) was walking toward me and the 5D responded so slowly
capturing the object behind the target...

and... i tried to focus to infinity and the pic was not tact
sharp... i am thinking again if it is due to the mismatch of motor
freq that made my 35L AF inaccurately...

btw, i checked your profile... you have a 1D2 and 135L.. are you
able to capture moving object at F2? as dchao suggested a 1d2 is
required for capturing at F2.8 or faster...

Eden I haven't tried AI servo at f/2 yet. I'll see if I can give it a go this weekend.

 

[Eden Yip]

no txt

 

[thx1138]

Eden did you see my first post? Your DOF is razor thin at f/2 from 10' or less and even at 20" it's not large but large enough to get a face focus.

 

[Eric Chi]

Eden,

It seems to me you should do a lens focus chart test for you 135 f2. At least on my 20D, the 135 f2 is very usable and I have made shots with much closer focus distance (narrower DOF) in continuous frames and AI-servo mode. No problem.

Eric.

all at F2, crop at about focus pt. RAW. Standard Style, no PP. only
resizing.





focus at about doggie's mouth but sharp at the string





again focus at doggies' head. but OOF.





focus at the gal's shirt... just walking speed... still OOF?





focus at baby's head. note the board at the bottom right sharper



below was taken at a relatively close distance, indoor. quite sharp.

 

[Jason L]

try disabling it........

 

[Eden Yip]

but my problem appears more evident when shooting at a distance. i guess, though longer DOF, the focus converges much rapidly at longer distance, and any minor error in motor movement would induce significant focus error...

you can see from the pic of my dad... which was taken at F2 one-shot mode.. the lens was able to nail the focus....

have u ever tried 20D to capture moving objects from 15ft or longer... and AI servo at distant object, e.g. far buildings....

It seems to me you should do a lens focus chart test for you 135
f2. At least on my 20D, the 135 f2 is very usable and I have made
shots with much closer focus distance (narrower DOF) in continuous
frames and AI-servo mode. No problem.

Eric.

all at F2, crop at about focus pt. RAW. Standard Style, no PP. only
resizing.





focus at about doggie's mouth but sharp at the string





again focus at doggies' head. but OOF.





focus at the gal's shirt... just walking speed... still OOF?





focus at baby's head. note the board at the bottom right sharper



below was taken at a relatively close distance, indoor. quite sharp.

 

[Eden Yip]

hmm.. i was thinking if the hidden pts would enhance focusing at AI-servo mode....

 

[Russell]

I have had the 135L for about a week. I really like the lens, it is sooo sharp.

But, I have found that it can mis-focus more than I thought it would.

Here is an example where you can see where the focus points were but it actually focused behind it. I have put the lens on a tripod and focused on newsprint at f/2 and it is dead on so I don't know why it does this sometimes. At the bottom you'll see some Servo shots that came out great, which were taken only a few minutes after the first one. Honestly I seem to have more trouble in single shot mode than servo.

In general I must say I love the lens. Enough to make me want more primes.

Russell











--
Hello, My name is Russell and I'm a Lensaholic!!!

http://www.photobama.com
http://www.pbase.com/sardian

See profile for gear.

 

[dchao]

Just a quick note:

If you want to focus test, use the center AF sensor which has the highest precision.

When to use automatic AF selection then? When the subject is isolated and quite a distance away from the background.

 

[Russell]

The attached photo wasn't a focus test, it was just a photo I took while I was waiting for my daughter to get her boots on.

But, I have a lot of shots taken with the center point only that does exactly the same thing. I have found that if I don't use the focus and re-compose method, but instead, pick a point that is on top of my subject and don't re-compose, I don't have as much trouble.

I'm not complaining, I love the lens, but it does seem to be a little more picky than my other lenses when it comes to correctly locking focus.

Russell
--
Hello, My name is Russell and I'm a Lensaholic!!!

http://www.photobama.com
http://www.pbase.com/sardian

See profile for gear.

 

[Eden Yip]

from the flower shot... i can see the camera was locking on at the center a corner of a green leaf behind the flower... this little green in pink gives the better color contrast for the camera locking focus....

for the pics of your lovely kid... were these shots taken at F2?

what was your keeper percentage that your 1D2 was able to capture your moving kid at F2?

I have had the 135L for about a week. I really like the lens, it is
sooo sharp.

But, I have found that it can mis-focus more than I thought it would.

Here is an example where you can see where the focus points were
but it actually focused behind it. I have put the lens on a tripod
and focused on newsprint at f/2 and it is dead on so I don't know
why it does this sometimes. At the bottom you'll see some Servo
shots that came out great, which were taken only a few minutes
after the first one. Honestly I seem to have more trouble in single
shot mode than servo.

In general I must say I love the lens. Enough to make me want more
primes.

Russell











--
Hello, My name is Russell and I'm a Lensaholic!!!

http://www.photobama.com
http://www.pbase.com/sardian

See profile for gear.