AF hit ratio with 100L and portraits?

[Marsu42]

I was recently practicing portrait photography with my old 60d and the 100L, usually set to f2.8. Unfortunately, I find the af misses a lot, much more than in macro photography - am I doing something wrong?

I was using focus & recompose on the eye due to the lack of af points on the 60d, and in good light the lens missed about 1/3rd (some near misses, some real out of focus), and in bad light the af hit ratio was a sheer catastrophe but that's simply because the 60d doesn't af in dim light. I wonder:

* Is my technique wrong? The 100L has a very slow af as a macro lens, but is 1/3rd misses in focus & recompose with aperture wide open what I should expect... I waited for the af confirm after all? For macro, I nearly never shoot wide open.

* Is my camera af broken or maybe dirty? I recently also find my 70-300L @f4 missing somewhat more often than I remember. Btw I never tested the lenses for afma since my 60d hasn't got it anyway.

Edit: I could add some sample pictures if that helps, I didn't throw the bad ones away yet.

 

[ajfotofilmagem]

A matter of focus and then recompose can be the cause of picture backfocused. You must test without recompose, and see if the focus is really accurate. I also use cameras to focus points unreliable, and prefer the safety of the central focal point. :-\ Often, I end up doing the focus on the nose, and then recompose, and the eye will be in focus. ??? It sounds strange, but try.

 

[mackguyver]

I'd try the focus limiter first - that should be a big help. You might try adjusting the AFMA if you can, too. Other than that, I'd try putting it on a tripod to test the AF under a more controlled circumstance. Also, I don't know your experience level with fast lenses, but the DOF at f/2.8 at 100mm is more shallow than most people consider - it's possible that you're just moving the camera forwards or backwards 1/2" or so, after locking focus, which would be enough to move focus from the eye to the ears or eyebrows, respectively.

 

[cayenne]

I was recently practicing portrait photography with my old 60d and the 100L, usually set to f2.8. Unfortunately, I find the af misses a lot, much more than in macro photography - am I doing something wrong?

I was using focus & recompose on the eye due to the lack of af points on the 60d, and in good light the lens missed about 1/3rd (some near misses, some real out of focus), and in bad light the af hit ratio was a sheer catastrophe but that's simply because the 60d doesn't af in dim light. I wonder:

* Is my technique wrong? The 100L has a very slow af as a macro lens, but is 1/3rd misses in focus & recompose with aperture wide open what I should expect... I waited for the af confirm after all? For macro, I nearly never shoot wide open.

* Is my camera af broken or maybe dirty? I recently also find my 70-300L @f4 missing somewhat more often than I remember. Btw I never tested the lenses for afma since my 60d hasn't got it anyway.

Edit: I could add some sample pictures if that helps, I didn't throw the bad ones away yet.

Take this as coming completely from a noob who hasn't tried it yet (but is on the list of things to try when time presents itself)...

But maybe try setting backbutton focus...focus as you need, then recompose and not have to worry about losing the focus point set...?

Would that help maybe?

C

 

[awinphoto]

In studio, my lens of choice is the 100mm L BUT due to lack of space, I often swap out for shorter lenses and use this lens for newborns, or head/shoulders or 2/3 view. I use the 5d3 and so I do not focus/recompose, but my hit rate is usually very high... I may get the occasional 10% every now and then that are just a hair off. I also check AFMA every 1-2 weeks to ensure it's dead on. Since the 60D doesn't have AFMA, could that be a factor? I do notice however that if I get a nice tight headshot or head and shoulders or whatever, focus is extremely reliable, but if i back up to the point where I'm doing a 2/3 or full body shot, focus maybe drops to that 10% miss rate give or take...

 

[Lichtgestalt]

* Is my technique wrong? The 100L has a very slow af as a macro lens, but is 1/3rd misses in focus & recompose with aperture wide open what I should expect... I waited for the af confirm after all? For macro, I nearly never shoot wide open.

ah.. which macro exactly has a faster AF?
we are speaking about the 100 L 2.8 IS here right?
the lens also has a limiter.. did you use it?

maybe you expectations are wrong.
but for a real macro the AF is pretty good.... try a tamron and you know what slow AF means.

i use the 100L all the time for portraits and it´s a beautiful lens to work with.

 

[privatebydesign]

It should easily be able to nail that type of use every time. You do need to be careful with focus and recompose, a technique I hate, but is some images are way off then there is another issue.

I recently used the 100L for some portraits of a lady on a swing, Servo kept up with her 100% wide open. I'd recommend you do some static testing of your lens with some good contrast subjects to work out where your issue is.

 

[Mt Spokane Photography]

Focus and recompose, at f/2.8 and a close distance is going to be a big issue.

Definitely use the focus limiter to get speedy autofocus.

One of the nice functions of Reikan Focal (Pro version) is the ability to test a lens / camera combination for AF consistency. If a lens is inconsistent, it can be due to worn or bent/cracked internal parts. I've had it happen to me with a used lens I bought. Canon fixed it up right away.

 

[Marsu42]

Hmmmm, thanks for all these great suggestions! I recon I won't be able to get around thorough static testing to see where the focus & recompose issue originates from, I'll report back if I have new information. To sum it up these are the possibilites mentioned:

1. broken lens with inconsistent focus, possibile b/c I do outdoor macro a lot - though it's fine at macro distances.

2. backfocus because of f&r, possible fix: focus nose (or focus somewhere else to allow for the focus shift)

the lens also has a limiter.. did you use it?

Sure, I'm using that - but still the round trip from infinity is still a lot slower than other Canon lenses (24-70L2 anyone?)... maybe I'm getting impatient sometimes and lack the calmness that is required for focus & recompose - or maybe it's just that f&r is more difficult @f2.8 and 160mm (100L on crop) than I imagined.

maybe you expectations are wrong. but for a real macro the AF is pretty good.... try a tamron and you know what slow AF means. i use the 100L all the time for portraits and it´s a beautiful lens to work with.

I'm getting great results from the lens, it's my favorite, but with the current hit ratio I wouldn't dare to use it for mission-critical shootings like a wedding. A 5d3 would solve the problem, but I lack the €3000 and cannot use servo af because my camera has too few af points ... so I've got to work on my technique if other potential tech problems aren't the reason :-o

 

[Mt Spokane Photography]

the lens also has a limiter.. did you use it?

Sure, I'm using that - but still the round trip from infinity is still a lot slower than other Canon lenses (24-70L2 anyone?)... maybe I'm getting impatient sometimes and lack the calmness that is required for focus & recompose - or maybe it's just that f&r is more difficult @f2.8 and 160mm (100L on crop) than I imagined.

While its certainly not the equal of the 24-70MK II, its lightning fast when compared to the 100mm USM Macro, so its all relative. I used to miss 80% of the focus with my old Macro, not because it was inaccurate, but because I used AI Servo to account for my slight motion toward or away from a close subject, and with AI Servo, the shutter will fire before focus is achieved, I couldn't hold my breath long enough for the focus to complete, I believe.

 

[cayenne]

Focus and recompose, at f/2.8 and a close distance is going to be a big issue.

Definitely use the focus limiter to get speedy autofocus.

One of the nice functions of Reikan Focal (Pro version) is the ability to test a lens / camera combination for AF consistency. If a lens is inconsistent, it can be due to worn or bent/cracked internal parts. I've had it happen to me with a used lens I bought. Canon fixed it up right away.

I'd looked into maybe trying to get the Focal Pro...but it doesn't seem quite ready to work fully with the Canon 5D3??

http://www.reikan.co.uk/focalweb/index.php/why/requirements/#msc

I'm hoping to maybe try the Magic Lantern AFMA in the near future..which I thought I read is supposed to work in auto for the 5D3?

Or, am I misguided here...still trying to figure all this stuff out.

C

 

[Loswr]

I'd looked into maybe trying to get the Focal Pro...but it doesn't seem quite ready to work fully with the Canon 5D3??

http://www.reikan.co.uk/focalweb/index.php/why/requirements/#msc

Yes, you have to change the AFMA values yourself with FoCal - that's actually due to a limitation in the Canon SDK that prevents software from changing the AFMA.

No idea about the ML options.

 

[mackguyver]

I'd looked into maybe trying to get the Focal Pro...but it doesn't seem quite ready to work fully with the Canon 5D3??

http://www.reikan.co.uk/focalweb/index.php/why/requirements/#msc

Yes, you have to change the AFMA values yourself with FoCal - that's actually due to a limitation in the Canon SDK that prevents software from changing the AFMA.

No idea about the ML options.

Manual Mode (http://www.reikan.co.uk/focalweb/index.php/tests/manual-mode/) works particularly well as a workaround for the 5DIII. It's actually far faster than the automated test, expecially after you've done it once or twice. You you bang out two shots (moving the manual focus to near infinity before each shot) at -20, -15, -10, etc., load the RAW files to your PC, and have Focal run it's analysis. It takes me about 5-10 minutes max. I usually follow it up with some fine tuning - i.e. if Focal says +8 is the setting, I'll go back and shoot 2 frames at +6, +7, +8, +9, +10, and then re-run the analysis, but generally the initial setting is accurate.

Just make sure you don't use back button AF or it won't record the AFMA setting in the metadata (I have Neuro to thank for that tip!). Also, turn off IS and make sure you use a really solid tripod/head.

 

[CarlTN]

In studio, my lens of choice is the 100mm L BUT due to lack of space, I often swap out for shorter lenses and use this lens for newborns, or head/shoulders or 2/3 view. I use the 5d3 and so I do not focus/recompose, but my hit rate is usually very high... I may get the occasional 10% every now and then that are just a hair off. I also check AFMA every 1-2 weeks to ensure it's dead on. Since the 60D doesn't have AFMA, could that be a factor? I do notice however that if I get a nice tight headshot or head and shoulders or whatever, focus is extremely reliable, but if i back up to the point where I'm doing a 2/3 or full body shot, focus maybe drops to that 10% miss rate give or take...

Agree. Without AFMA, you're asking for trouble. One of the many reasons I never liked the 60D. My 50D had AFMA and it worked great, so the 60D was not an upgrade in my opinion (other than its video ability...which most 60D owners seem to use often, to good effect). I upgraded from the 50D after 4 years, to the 6D. I absolutely loved the 50D, but it does not really compare favorably in any way to the 6D. On occasion it could probably focus my 135 f/2 lens a bit faster than the 6D does, but for all other lenses I've used on both, the 50D's AF was not quite as good. Both bodies needed AFMA for my 135L...the 50D's was "+2" and the 6D's is "+3". This 135L can wayyy out-resolve the resolution of the 6D (and could go past the 50D's too). But with the 6D it's still more than enough resolution considering the wider FOV and a few extra MP in the tradeoff. The 100L is known to AF slower than the average lens, but for portrait photography I suppose that's less of a factor.