# 5D mark ii low light focusing



## sactown024 (Aug 25, 2013)

Hey everyone I wanted to know if anyone else hast his issue with the mark ii. I have been shooting more weddings recently and my camera basically becomes useless during a dark reception, it will not lock focus on anything, even white shirts.

I shot a wedding last night and I literally had to focus on glow sticks and then snap the picture. I was using fast glass (1.4 and 2.8), is this a common issue or do I have a bad body?

I am getting ready to sell this thing and upgrade to a mark iii, I can't risk missing shots.


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## tirediron (Aug 25, 2013)

I'm not a Canonite, so I don't have any first-hand experience, but it doesn't like the camera is doing anything wrong to me.  Trying to lock on to a sea of black in a dark room is virtually impossible, and white shirts are no better.  Your camera's AF system relies on contrast, so you need to get some black tux and white shirt in the frame for it to find the contrast.  Have you tried manually focusing?


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## paigew (Aug 25, 2013)

Yes you need contrast. Or manual focus.


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## Dao (Aug 25, 2013)

I wonder if the wedding allows the flash AF assist beam (not the flash, just the Red beam).


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## curtyoungblood (Aug 25, 2013)

I use the 5dii every day, and while the AF will hunt a little in REALLY low light, I don't usually find it to be bad enough to keep me from getting a shot, particularly if I am in conditions where I can reasonably expect to get a decent shot. 

The only caveat is that I really only use the center focus point in this camera. It is a cross-type focus point, while the rest are not. If you're using the other focus points, I wouldn't really expect it to focus well in anything other than great light.


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## Gavjenks (Aug 25, 2013)

The 5D Mk III will also not be able to focus on solid colors in a really dark room reliably. Nor any camera, really.

Before you go and sell your camera body, can you give us some *sample shots*, along with EXIF data, to get an idea of just how dark and low contrast you mean by "a dark reception?"



Also, another option to consider is putting a modern flash on your hotshoe, one with the red box on the bottom like a Canon or a Yongnuo.  Don't actually USE the flash, but by just having it on there, your camera will use the *infrared focus assist *beam that is part of the flash unit, and you will be able to focus almost perfectly on just about anything within 50 feet or so, even in pitch black. It is very subtle, mostly in infrared (invisible) as the name suggests, and will not bother guests.


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## kathyt (Aug 25, 2013)

The Mark ii is troublesome in low light and can be very difficult to grab focus.


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## Big Mike (Aug 26, 2013)

I agree with what has been said so far.  Yes, the 5DII will have problems focusing in low light...but so will most other cameras.  The catch is that we tend to expect more from such an expensive camera.  

The best solution is to use a flash with goo AF assist beam.  (I don't think it's infrared...it's just red).  
And you can set it so that the AF assist beam works but the flash won't fire.

If you don't want the bulk of a flash (when not actually needing a flash), you could get the ST-E2 (but not the ST-E3), which also has an AF assist light.


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## Gavjenks (Aug 26, 2013)

> The best solution is to use a flash with goo AF assist beam. (I don't think it's infrared...it's just red).


Hm is it?  Everybody talks about it as IR everywhere, but only random people now that I actually check, not the manufacturers, which means it's probably not.

If not, I wonder why not. The IR filter doesn't cover the AF sensors.  And I know IR focuses at a different distance than visible light, but it could just like choose to turn IR on only when it's REALLY dark, and then arithmetically adjust for the difference.

Will investigate later.


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## Big Mike (Aug 26, 2013)

I think the whole IR thing has to do with the ST-E2 and similar gadgets.  

Most people seem to think that a master flash (the Canon 580EX for example), communicates with it's slave flashes via Infrared.  But actually (AFAIK) it uses pulses of light from it's main flash bulb...right before the exposure (pre-flash).  

Some people even think that because the plastic panel on the front of these flashes is red...it means infrared.  I'm pretty sure that's incorrect.  

So it makes sense that if they think the flash is using infrared for communication, it's also using it for a focusing aid.  It might be, but I don't think so.  
I think it just uses regular visible light (colored red by the plastic panel) for it's focusing aid.  

As far as I know, the only IR used is by the ST-E2.  This is a flash 'master' unit...but without the flash.  And because it doesn't have a flash bulb, it must use something else to communicate with it's slaved units....so it uses IR.


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## Big Mike (Aug 26, 2013)

> All of Canon&#8217;s Speedlite flash units for EOS cameras have patterned red AF assist lights - sometimes called AF auxiliary lights in older Canon manuals - built in. These are clear red panels on the front which use one or two high-brightness LEDs to project red circles of light striped with dark lines, in order to give the camera a high-contrast pattern to focus on. Red is chosen in part because high-output red LEDs are readily available, but also because red light does not cause the pupils of the eye to dilate as much as does white light. _The red light is sometimes described as being &#8220;near infrared,&#8221; though it is in fact visible_.



Maybe not as reliable a source as the manufacturer's website...but probably the 'best' source for information on EOS flash is the so-called 'EOS Flash Bible'.


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## TCampbell (Aug 26, 2013)

Use a Speedlite with an AF assist-beam such as a 580EX II, a 600EX-RT, etc.  The beam projects a pattern that the camera can use to lock focus in dark situations.

Big Mike is correct... Canon speedlites that use optical wireless are actually using VISIBLE light -- there is no "IR".  I am guilty of once believing it was IR based and, yes, that red panel on the front sure does lead one to suspect (incorrectly) that it's using IR light.


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## sactown024 (Aug 27, 2013)

Thanks everyone, I use a 580ex ii on camera and  2 ocf setup on stands at receptions.

I was trying to figure out how to turn on the red focus assist on my 580ex ii at the reception but couldn't get to work so ill have to look into that more today.

Since I use OCF I use a yongnuo 622c trigger and the on camera flash mounted on top of the 622c (I like to use on camera flash as a bounce in conjunction with the OCF), not sure if that effects that 580ex ii focus assist.

Posting pics won't help much since the images I did get throughout the night were lit completely with with OCF so you wouldn't get an idea of how dark it was.


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## Big Mike (Aug 27, 2013)

Keep in mind that for the AF assist light to work, the camera has to be in 'One Shot' AF mode.  
It may also be a problem that you're mounting the flash onto the trigger, not directly on the camera.

Your set up sounds similar to what I often do.  One or two remote lights, with one on-camera speedlite.  What I do, is put the flash on the hotshoe, and attach the radio transmitter to the camera's PC port.  This leaves the transmitter hanging loose, so I use a rubber band to hold it against the side of the flash.  I might use some velcro next time.


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## sactown024 (Aug 29, 2013)

Yeah I would love to do that but I use the yongnuo 622c and I think they are hotshoe mount only, not 100% on that but ill have to look!


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## sactown024 (Aug 29, 2013)

Okay it looks like it does have sync cord port... I don't use ettl often but does pc sync cable transfer ettl?


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## curtyoungblood (Aug 29, 2013)

The 622c has a hot shoe mount on it. Have you tried mounting the transmitter on the camera with a flash on top? It is certainly designed for the flash to work that way, although who knows if AF Assist will work.


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