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Focus speed of 1D(s) mkII/5D with flash IR assist.

Ben Rubinstein

pro member
I shoot weddings with a 5D. It's a great camera with only one failing, AF speed in low light (I always use center focusing point). I always shoot with flash and the check-focus-check using the IR assist light does not lend itself to fast shooting and when you are trying to shoot fleeting moments or fast moving dancing AF speed is crucial.

I know the 1D mkII focus speed is noticably faster than the 5D with the same lens (24-70L) and quieter too though I'm at a loss to explain how the sound is affected. However when the camera is using the IR assist light does it slow down to the same speed as the 5D? My 1Ds had no noticable speed advantage in low light when using the assist, compared to the 5D and even my 10D for that matter.

Would I be gaining speed by turning off the IR assist on my 5D in normal indoors light, not bright but not dark, say 1/60 f2.8 @ iso 400, would I lose accuracy? Would the 1D(s) mkII be significantly faster under the same conditions and darker with without the assist?

I remember Chuck mentioning on RG once that the 1 series does not have a low light AF advantage over the other bodies due to the added accuracy needed, however the 1D mkII has a pretty damn good reputation for focus speed.

Any thoughts?

p.s. one camera that knocked the pants off either my 5D or 1Ds was the D2X, wow is that super fast in low light, but let's not go there... ;-)
 

Daniel Harrison

pro member
apparently some of the new 30D 5D etc. have better "low light" abilities than some of the one series. As in they are rated to focus in less light. I still think the 1series has an advantage of accuracy when it does focus. Not to sure about the IR, give it a try and see what happens
 

Paul Caldwell

New member
I have found in my flash use, without the IR assist, the cameras will search forever, 1ds, or 1ds MKII.

This is with the older 550 flash mounted. My bodies, don't really have good AF in low light, as unless I hit on a subject with a good breakup, the lens will just search.

In my macro work, with the 50mm and 100mm, I often use flash and even then most times I will have the IR assist on.

PfC
 

Michael Tapes

OPF Administrator/Moderator
IR assist always makes things easier for the camera. You can use the assist built into the 550/580 etc, or the seperate STE-2, either way, with or without the flash firing..
 

Frank Werner

New member
1. Without IR Assist light the 1 series is noticable faster then the 5D/ 30D series in low light or in almost any situation.
2. The weird part is that with IR Assist the focussing speed slows down. As the camera communicates with the flash, there is a delay in focussing when using the Assist light. So if its not to dark focussing without IR Assist light is faster then with it. (that means sadly without flash, as I have found no possibilty to switch the IR Assist Light of my 580 EX off). If the light is really dim the IR Assist enables to focus in a nearly no light environment. At the RG forum was a long discussion about the delay in IR foucssing with the EX Flashes with contributions from Chuck, so you might do a search there if this is still possible for non paying members.

Frank
 

Michael Tapes

OPF Administrator/Moderator
You can turn off the "AF assist beam" on the 5D using custom function 5. On the 1D2N (and I assume other Series 1 cameras, you can turn it off using PF 15.
 

Alan T. Price

New member
Is it really IR (infra red) ? I thought it was just a red cross-hatch pattern for the camera to focus on.

Maybe the 1-series cameras are set to slow down in low light to ensure they get it right when trying to lock onto that cross-hatch pattern. This would be similar to the way they behave by slowing down AF when a teleconverter is attached, no matter how bright the scene. I'm sure there is no delay caused by camera-flash communication as the flash unit just projects a dumb red light and the camera just focuses on it. No information needs to be transferred.

The better of the non-pro bodies have bigger AF sensors that are more sensitive to low light and so perhaps they do not need to take things so slowly. Once things lighten up a bit the 1-series AF is at least as good if not superior.
 

Asher Kelman

OPF Owner/Editor-in-Chief
I know an event photographer who uses a red laser to put a dot on the person to focus on.

It would scare the heck out of me if I didn't see where he was!

Asher
 

Jan Luursema

New member
I don't know; with my 20D I always had the IR assist turned off because I felt it actually slowed the camera down. This might be wrong, but anyway, I never really had problems locking focus (accuracy is another thing, but let's not go there now ;)).
When I got my 1D2 the IR assist was on, so not by choice really, but I used it a little and I actually felt it helped focusing! I never had problems, even in really dark places. One time I was shooting in a place so hot my viewfinder fogged up, so I used the IR light to aim the camera! Worked pretty well..
So I had the feeling whatever disadvantage the 1D2 may have focusing in low light was made up by the IR assist.
 

Ben Rubinstein

pro member
I've started a new thread on the board below detailing my experiences with turning off the AF assist on the 5D, in short, with EV6+ the AF speed and lock is noticeably faster and to my mind almost a must for a moving subject. You can of course turn it back on for lower light but then if my experience shooting with the 1Ds means anything, the AF assist is the great equaliser vis a vis focus speed. Zone focusing is the key in such a situation with moving subjects.

Now if only Canon would make a bleeding focus switch like on Nikon, really makes a difference when needing to switch between one shot and AI servo and back many times per minute! When I apprenticed my boss shot with Nikon and to this day I remember with envy the speed and ease that he would switch mid focus to Servo focusing using the index finger of the hand supporting the lens with a flick taking a fration of a second. Not so with the Canon 'button (or two on the 1 series), twiddle dial while looking at the LCD screen, shutter release' and visa versa.
 

Ben Rubinstein

pro member
Shot a job last night in a hall with EV 9 brightness and the AF assist switched off, WOW I didn't realise the 5D could focus that fast! So far so good and the AF assist is staying firmly OFF!
 

Will_Perlis

New member
"I thought it was just a red cross-hatch pattern for the camera to focus on."

I'd bet almost anything you are correct. I'd think making the AF sensitive to "real" IR would have the system locking onto columns of hot air rising from cars, pavement, politicians, and such instead of the visible objects in back of them.

I've always turned the AF assists off. If it's too dark for me to focus manually then I find it's too dark to see if there's a picture there to be taken. It would be different if I were shooting indistint blobs I knew had to be included in the wedding album, then I think I'd make a separate focus-assist light. That wouldn't be very difficult.
 

Asher Kelman

OPF Owner/Editor-in-Chief
Ben Rubinstein said:
I've started a new thread on the board below detailing my experiences with turning off the AF assist on the 5D, in short, with EV6+ the AF speed and lock is noticeably faster and to my mind almost a must for a moving subject. You can of course turn it back on for lower light but then if my experience shooting with the 1Ds means anything, the AF assist is the great equaliser vis a vis focus speed. Zone focusing is the key in such a situation with moving subjects.
Could you give the url of the thread you started?

I looked on your website, which BTW is great, I've been there before, but there's no forum!

Where's the "below" you refer to?

Asher
 

Nill Toulme

New member
There was an extensive thread on this issue on the old RG forums a year or so ago. I don't remember the specifics, but the upshot was that there is some additional checking back and forth in the AF algorithms in the 1-series cameras (or at least in the Mark II's) that results in AF frequently being *much* slower, albeit perhaps ultimately more accurate, with the assist turned on.

Found the thread, here.

Nill
~~
www.toulme.net
 
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Kees Commandeur

New member
Slowing of AF-speed when using AF-assist light

This message I read about the slowing down of auto-focus speed, when using the auto-focus assist light on the dedicated flash, really made me think and check my own experience.... to which the answer was: that the above is true: without the help of the auto-focus helplight on the flash, the camera is perceivably quicker in finding its focus! So now I started looking for a quick way of setting things up, for me to enable a quick switch between the two modes that I need to work with in all light-conditions: in semi-darkness, the camera needs the extra focus-assist light on the flash, or it will not find a lock. And in the shaded light conditions of indoor parties, I am much better off without the assist light.
The only way to switch between these two modes on the 1ds-II, is to link it up to the computer, start the canon software and change the settings, which is not something you like to do during a photoshoot. The 'grand' solution that I found, is maybe something that many others are using already on a regular basis, or maybe you have found even quicker ways of changing this focus-assist setting 'on the go', but anyway, this is how I do it:
I have two memorycards in the camera and every card can store óne set of camera settings. So, with the help of the computer I make one setting with the assistlight off (P.Fn15) and store this setting on card 1. And likewise, I make one setting with the assistlight on and store this setting on card 2. Once I've done this, it is fairly easy to change the camera from one to the other setting, by loading it from either of the two cards. Another trick I heard, was not to use the focus-assist light on the flash at all, but to make use of small, low-power laserbeam, the one is sometimes used as a screenpointer during lectures. Simply point the laser-spot on the thing you want to shoot, push the shutter halfway down and .... voila, almost an immediate shooting resolution! Of course the last option can be somewhat disturbing in a hall full of people, esp. where there is a danger of shining the laser beam straight in the eyes of someone, which is mostly not really very dangerous, but is certainly not pleasent nor perfectly healthy. So here't is. Maybe it's just a load of nonsense to most of you more professional photographers, or maybe it is nothing new, but to me, it ís a new, simple way of dealing whith the subject.
 

Asher Kelman

OPF Owner/Editor-in-Chief
A faster approach is having two cameras! most wedding photographers have 2 or three cameras on them anyway.

Asher
 

René Damkot

New member
The only way to switch between these two modes on the 1ds-II, is to link it up to the computer, start the canon software and change the settings, which is not something you like to do during a photoshoot.
Once you've set a PFn, you can simply turn it 'on' or 'off' in the menu.
I've set Pfn 15 (and a few others I only use occasionally), and can switch it on or off by simply going into the PFn menu...
 
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