low light metering

[kfridge]

Hi,

just a quick question, with probably a long answer...!

what kind of metering (spot, evaluative etc.) should I use for taking pics in low light...I'm going to be taking some shots inside a church at the weekend for a christening and was just wondering what the best to use would be.

my kit will be a canon 40d, 50mm 1.8 (also have an 17-85 and 70-300 kit lenses), monopod (if necessary) and maybe a 380ex flash (not the best, but its all I have!)

TIA

 

[tdodd]

I don't have a lot of experience of these things but I did shoot a wedding, once, and learned a lot from some schoolboy errors. So I'll offer some advice but feel free to take it with a pinch of salt. Here goes....

Personally I'd be more concerned about which exposure mode to use rather than which metering mode. I got caught out quite badly when shooting a wedding in Av mode and evaluative metering with a 580EX flash. I don't know how well you know the Canon flash system but it is quite prone to underexpose shots, unless you take steps to compensate, and it will thoughtfully underexpose your background for you to give the flash headroom to illuminate your subject without blowing it out. The unfortunate result is typically underexposure of everything - unless you take charge.

Given that the conditions for shooting a christening in a church will be much the same as for a wedding, here's my advice.....

Use manual exposure. Set ISO to at least 800 and possibly even 1600. Set shutter speed no slower than 1/60. I've seen subject movement ruin shots at that sort of speed and slower - laughter, clapping, anything really, will blur at 1/60 or less. Having IS and/or a monopod will not save you from subject movement. See what sort of aperture you need with that setup. If your lens can open up wide enough, or get within 1 stop of the "correct" exposure then all well and good. You can make up the difference with some flash. With that sort of manual setup the ambient exposure will be taken care of and will not be thrown off by backlighting from windows, lights etc, or thrown off by lights and candles in the foreground.

Now obviously metering is important for the initial setup but really I think you can choose whichever mode you are most comfortable with, take a test shot, chimp the histogram, tweak your manual settings as necessary and then you are pretty much set. Unless the lighting changes you should be able to largely stop worrying about exposure. The flash gun should take care of any little tweaks to foreground/subject lighting but the rest of the church should be sorted. You may need to ride the FEC control a bit if your subject suddenly has a predominance of white/bright tones or a predominance of blacks. The Canon flash system is set up very conservatively to avoid blowing anything, so reflections and specular highlights can trick it into quenching early. Keep a watchful eye on such occurences.

People do say that the flash system is more predictable if you use average flash metering rather than ETTL2. I have found this to be true. If you have the opportunity I suggest you practice with the flash and experiment with different settings to see what works best for you.

That's about all I can offer. I'm afraid in my case it's more theoretical rather than from practical experience but even if I don't know exactly what to do I certainly know what not to do!

Here are some tips from a highly regarded guru of flash photography, with some fantastic wedding photographs. May I recommend you browse through his advice on exposure and flash techniques....

http://planetneil.com/tangents/exposure-metering/

 

[kfridge]

brilliant, thanks for that...I had already thought of going manual rather than Av so those guidelines will be useful. I'll be getting to the church early enough to be able set things up beforehand so hopefully won't have to do much tweaking of the settings when the time comes!

I suppose when you first do something like this the preparation seems endless!

 

[tdodd]

Another thought - I presume you'll be shooting raw. I know it saved my bacon when I got my poor exposures at the wedding. The other important thing to think about is white balance. Again, raw will make fixing WB a lot easier in post if you don't get it spot on on the day. But think about the issues raised by using flash at all. If the ambient lighting is yellowish tungsten lamps and candles and you try to mix in blueish flash you'll have quite a challenge to resolve the two colour temperatures to something that works overall. The advice I was given, after I cocked up, was to get a coloured gel for my flash gun, in order to match the colour of the flash light to tungsten and avoid all the problems of mixed lighting.

Here is a typical example of one of the photos I took, first out of camera, and then following a couple of tweaks in DPP. As you can see, the original was underexposed and the (auto) WB was well off. Raw helped me salvage the photos and make something half reasonable from it. Even so, you may be able to detect that the flash has left a slightly blue cast on the registrar's book and the bride's (off white/cream!) dress. By the way, the backlight from those windoes was playing havoc with my Av exposures. Shooting in manual would have locked down the exposure for the room, regardless of where I was aiming the camera.

 

[kfridge]

yes, I'll be shooting in RAW...I'm hoping to get things right so I don't have to do too much!

thanks for all the advice - I shall attempt to put it to good use!