Low-light focussing on a 5D2

dakid

dakid

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Hiya guys,

Was hoping for some advice please on how best to cope with the 5D2's poor low-light AF? I was shooting a wedding recently and - during the evening's dancing - end up shooting at ISO6400, f/1.4 and around 1/60 sec to get the exposure, but a good 75% of the shots are out of focus. I could see this at the time, and even tried manual focussing, but I'm not sure I necessarily increased my hit-rate much!

Does anyone have any tips, please?

Thanks,

Martin
 
Also if you are looking for just the AF assist beam but not the flash (during parts of the day where flash isn't allowed) you could use a ST-E2 or whatever it's called
 
andrewc said:
One thing is to put the 580EX2 on, set to flash disabled and it uses its own IR illuminator to aid focussing.
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That's a very good idea; thanks!

How noticeable would that be to the subjects? One of the reasons I shoot without flash - apart from the aesthetic - is to be a little less intrusive: how would the focussing-grid affect that?
 
Even though they call it an IR illuminator, it's a pretty visible red light to me. And no, I don't have infrared vision :)

If it was real invisible IR, I'm not sure that the camera would focus correctly as IR light refracts differently inside the lens (that's why some lenses have IR focusing marks).
 
dakid said:
That's a very good idea; thanks!

How noticeable would that be to the subjects? One of the reasons I shoot without flash - apart from the aesthetic - is to be a little less intrusive: how would the focussing-grid affect that?
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Assuming that they have some for of disco lighting going on anyway, I wouldn't imagine it'd be at all intrusive..
 
Not intrusive at all, I use an on camera flash just for AF assist (and as a deactive master)
Then have 2 430EX's as slaves in opposite corners of the room

The 580EX has a RED light af assist beam.
Both 430EX's have a red flashing light to say the slave is active

None of them are noticable with all the lights going on in the room anyway.
 
dakid said:
during the evening's dancing ...... f/1.4 .....1/60 sec
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The DOF at 1.4 will be VERY thin so even the slightest amount of movement in you or your subject will result in the focus point not being where you want it.
Given your longish exposure time (LONG considering people are dancing ;) ) I'd say that could also be a cause!
 
User Name said:
The DOF at 1.4 will be VERY thin so even the slightest amount of movement in you or your subject will result in the focus point not being where you want it.
Given your longish exposure time (LONG considering people are dancing ;) ) I'd say that could also be a cause!
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You might be surprised. With a focal length of 35mm, on a full-frame sensor, the DoF increases pretty rapidly with distance of subject.

1m = 0.07 metres DoF
2m = 0.27 metres DoF
3m = 0.62 metres DoF
4m = 1.12 metres DoF
5m = 1.77 metres DoF

Source: http://www.dofmaster.com/dofjs.html
 
grum said:
Still, isn't 1/60 pretty slow to capture people dancing anyway (unless you wanted a bit of motion blur)?
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Which other exposure-affecting setting do you suggest altering to change that? ;)
 
grum said:
Well I'd probably just use a flash :shrug:
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The main thing I'm trying to avoid! I don't like flash photography if I can help it, and although I do use it sometimes (first dance, etc.) and the results are ok, in general it's difficult with a single unit to get consistent lighting throughout the frame, and its intrusiveness is pretty extreme!
 
dakid said:
The main thing I'm trying to avoid! I don't like flash photography if I can help it, and although I do use it sometimes (first dance, etc.) and the results are ok, in general it's difficult with a single unit to get consistent lighting throughout the frame, and its intrusiveness is pretty extreme!
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How are you using the flash though? I admit for the exchanging of vows and special moments as such, flash would be a no go. But for other occasions flash is very helpful. Its not like the wedding guests don't know there is a photographer around and if you aren't machine gunning the shutter so that flashes are going off every few seconds then I think you'll be alright.
 
I think I've got this right ;) You can use the AF assist light just for focusing, and it is only active during focusing and turns off for the exposure. However, you can only disable the flash with a 580EX in master mode (so does not apply to the 430) and even then it still puts out a very low power pulse which is not enough to affect the exposure normally, but it does at very close range and low f-number/high ISO situations.

I suspect the OP's problem is mainly shallow depth of field, rather than the 5D2's AF capability. My 5D2 will focus fine in very low light if you give it something it can get its teeth into. If you try to AF on a flat toned area with no contrast in the dark then no AF system has a chance, but if you can find a white collar or cuff for it to latch on to it is transformed.

You have got very low light in that situation. Perhaps you could use the flash and it's AF beam, but point the flash head above and behind you, with a bit of power dialled in just to lift the overall light level a bit with some general bounce illumation.

The flash would be very unintrusive, bordering on the invisible, but would just lift the exposure level a bit to save you needing such a high ISO and low f/number. Plus you'd get the AF assist beam benefit.
 
hsuffyan said:
How are you using the flash though? I admit for the exchanging of vows and special moments as such, flash would be a no go. But for other occasions flash is very helpful. Its not like the wedding guests don't know there is a photographer around and if you aren't machine gunning the shutter so that flashes are going off every few seconds then I think you'll be alright.
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I do tend to rather over-do the whole quantity-of-photos thing, so flash is pretty intrusive when I'm shooting, hence why I restrict it. It certainly has its use, but in my style of shooting it's limited through choice :)
 
Are you using One Shot AF or AI Focus/AI Servo....and seeing mainly front focus errors?

Bob
 
HoppyUK said:
I think I've got this right ;) You can use the AF assist light just for focusing, and it is only active during focusing and turns off for the exposure. However, you can only disable the flash with a 580EX in master mode (so does not apply to the 430)
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Andrew is right. i have a 430II that i regularly use as AF assist only.
once u have enabled AF assist go into Exernal Flash control and disable the flash.

andrewc said:
On my 7D, 50D and probably 40D, I'd use the in-camera menu FLASH CONTROL to disable flash, and it only works I think on ONE SHOT or possibly AI FOCUS modes.
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dakid said:
I do tend to rather over-do the whole quantity-of-photos thing, so flash is pretty intrusive when I'm shooting, hence why I restrict it. It certainly has its use, but in my style of shooting it's limited through choice :)
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This won't help your original issue of not finding focus in low light, but have a look at your style of shooting too, so that you can develop deploy flash more often and effectively. On that note, I am not advising to rely on flash alone, but keep it in your armory.

I used to machine gun the shutter a fair bit (some situations warrant it), but I find that always trying to stay one step ahead of the action helps a lot. Recently I shot a B&G feeding each other cake, so I had my focus locked on the bride and was poised ready for the grin that came after the groom pushed in more cake than the bride expected. The flash fired once and I got the shot. A guest even complimented me on my timing, as the one flash/shutter made me look more professional.

Hopefully you'll find my comment helpful (y)
 
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hsuffyan said:
This won't help your original issue of not finding focus in low light, but have a look at your style of shooting too, so that you can develop deploy flash more often and effectively. On that note, I am not advising to rely on flash alone, but keep it in your armory.

I used to machine gun the shutter a fair bit (some situations warrant it), but I find that always trying to stay one step ahead of the action helps a lot. Recently I shot a B&G feeding each other cake, so I had my focus locked on the bride and was poised ready for the grin that came after the groom pushed in more cake than the bride expected. The flash fired once and I got the shot. A guest even complimented me on my timing, as the one flash/shutter made me look more professional.

Hopefully you'll find my comment helpful (y)
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Thank you. That is helpful :D
 
HoppyUK said:
I suspect the OP's problem is mainly shallow depth of field, rather than the 5D2's AF capability. My 5D2 will focus fine in very low light if you give it something it can get its teeth into. If you try to AF on a flat toned area with no contrast in the dark then no AF system has a chance, but if you can find a white collar or cuff for it to latch on to it is transformed.
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(y)

I've always been interested in available-light photography.. back when I was using film a few years ago, I used to push-process B&W film and shoot with a 50mm f/1.2 lens to get shots indoors with no flash.

Since going over to digital, it's opened up a whole new world for me. The 50mm f/1.4 and 5D2 combo allows you to shoot handheld by candlelight, and I've not had a problem focusing in these conditions.

That said, shooting dancing at ISO 6400, f/1.4 and 1/60 sec is a daunting task. I agree that it would be a real test of your technique, rather than the camera's capability. 1/60 sec isn't fast enough to freeze people moving around. Any 50mm lens isn't going to be as sharp wide open as it is stopped down. And the limited depth of field you get with f/1.4 will risk the subject having moved out of the zone of focus by the time you press the button.

Personally in these conditions I'd be using flash, maybe with a slowish shutter speed and second-curtain sync. I find that extreme available-light photography works best for candid shots.

A.
 
so low light, AI servo and ISO6400, f/1.4, 1/60 sec to get the exposure only 25% in focus

sounds about right for the 5D2 in my experience lol

also remember with iso6400 they are not going to be as sharp as iso 100 and f1.4 is very very thin DOF so easy to miss


dakid said:
Hiya guys,

Was hoping for some advice please on how best to cope with the 5D2's poor low-light AF? I was shooting a wedding recently and - during the evening's dancing - end up shooting at ISO6400, f/1.4 and around 1/60 sec to get the exposure, but a good 75% of the shots are out of focus. I could see this at the time, and even tried manual focussing, but I'm not sure I necessarily increased my hit-rate much!

Does anyone have any tips, please?

Thanks,

Martin
Click to expand...
 
Well, it was first time I'd had such low light, so will try again on Saturday at my next wedding-shoot (which I think will be my fifth) and see how it goes! :)
 
Had some guests at my summer cabin last week and one of the brought a 5Dmk2.. I was amazed how much better the 7d was in low light focusing as it was mostly candle light.

As much as I love canon gear, the old 9 point af is due for retirement!
 
vaizki said:
Had some guests at my summer cabin last week and one of the brought a 5Dmk2.. I was amazed how much better the 7d was in low light focusing as it was mostly candle light.

As much as I love canon gear, the old 9 point af is due for retirement!
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Would that I could afford a 1D MkIV!!
 
david1701 said:
I just flogged a mk3 - IQ>AF :D
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Yeah, but the Mk4 IQ at high-ISO is even better than the 5D2, plus it can actually focus in low-light! :)
 
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