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ludi
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Low-light photography -- tips and tricks?

Mon May 17, 2010 2:46 am

Some friends invited me to a seat at their table for a local charity fundraising banquet. Since they had an inside connection to the host, and since I was the only person who showed up with any camera equipment better than point-and-shoot, I did an impromptu photo shoot of the event for the use of the organization's director. I had my Rebel XS body and used three fast primes -- EF 50mm f/1.4 USM, EF 85mm f/1.8 USM, and EF 28mm f/2.8. I seemed to get the best results with 800 ISO and f/2 (+/- a stop or two), so I shot most of my images at those settings an selected the exposure time as required to capture enough light -- usually between 1/40 and 1/125.

The lighting and the subjects were both very challenging. The ceiling was about 15' overhead, open-architecture, and painted black. Illumination was entirely from overhead incandescent floods and a smattering of decorative candles. The walls were a dull tan and the carpet was a grey-red color. Prior to dinner people were milling about, eating hors d'ourves, investigating the silent auction items, talking, etc. so there was always some movement.

I got a decent 35 or 40 images out of the 100-odd frames that I shot, but very few were especially sharp. The focus distance for the 50mm and the 85mm tended to be pretty narrow, even when shooting across the room, which produced a lot of bokeh, both foreground and background, that wasn't always intended. Many images were also very grainy and required heavy noise reduction with post-processing.

All things considered, I'm pretty happy with the results considering the lighting and my lack of experience, but what things should I do to improve my technique in a future setting of this sort?
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JustAnEngineer
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Re: Low-light photography -- tips and tricks?

Mon May 17, 2010 5:17 am

http://www.usa.canon.com/consumer/contr ... goryid=141 :wink:

With the equipment that you had, the EF 50mm f/1.4 USM wide open (at f/1.4) would gather the most light. Set your ISO as high as you need for blur-free shots. A noisy sharp shot can be improved with noise reduction software, but a blurred shot is lost. A tripod or monopod would steady the camera against your movement, but if your subjects aren't still, you need a relatively fast exposure. Use the center auto-focus point to get your subjects in focus with the shallow depth of field that you have at f/1.4.
 
Voldenuit
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Re: Low-light photography -- tips and tricks?

Mon May 17, 2010 8:31 am

ludi wrote:
All things considered, I'm pretty happy with the results considering the lighting and my lack of experience, but what things should I do to improve my technique in a future setting of this sort?



Your shutter speeds were too slow for the focal lengths you used. When shooting hand held, your shutter speeds should be at least as fast as the reciporcal of the 35mm equivalent length of the lens. So, 1/80s for the 50/1.4 and 1/140s for the 85/1.8.

The 50/1.4 is a bit soft wide open, you may have to stop down to sharpen it up, but it will be a balancing act with the shutter speeds. not familiar with the 85/1.8, but the same may apply.

Consider using a flash (on-board or external) for low light human photography. An external flash would allow you to bounce flash, which is less harsh and can be less annoying to subjects.
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ludi
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Re: Low-light photography -- tips and tricks?

Mon May 17, 2010 10:54 am

I have a SpeedLite 380ex and a diffuser, but given the low light, a flash would have been excessively distracting. I tried a couple shots with the flash at one point, and found that the shadow-casting was too harsh.

So, if I'm reading you guys correctly:

1. Use the external flash if it is an option.

2. Open the lenses all the way up to start, then stop down only where necessary.

3. Use highest ISO setting available (1600 for my XS), and rely on noise reduction later to clean up the artifacts.

Anything else?

When shooting hand held, your shutter speeds should be at least as fast as the reciporcal of the 35mm equivalent length of the lens. So, 1/80s for the 50/1.4 and 1/140s for the 85/1.8.


"reciprocal of 35mm equivalent" -- so is that 1 / ( (EF lens actual size) * (1.6 crop factor) )?
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Voldenuit
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Re: Low-light photography -- tips and tricks?

Mon May 17, 2010 12:34 pm

ludi wrote:
"reciprocal of 35mm equivalent" -- so is that 1 / ( (EF lens actual size) * (1.6 crop factor) )?


Yes. Everyone has different hand steadiness, but for most people, this should give 90-95% sharp pictures.
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SPOOFE
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Re: Low-light photography -- tips and tricks?

Mon May 17, 2010 2:38 pm

3. Use highest ISO setting available (1600 for my XS), and rely on noise reduction later to clean up the artifacts.

A noise-free blurry shot is probably going to be less preferable to a noisy sharp shot. Probably.

For example, last week I was shooting a show with some lousy lighting conditions (the lights were very rapidly changing, literally shot-to-shot at the camera's fastest frame rate); I usually try to avoid high ISO's, but in this case I needed the speed to keep up with the performers and deal with the lighting (for instance, Tor was standing where he intermittently got some good white light amongst the flashings, but poor Mast was constantly awash in greens and blues and cyans). Both of those are at ISO 6400, I believe; it's strange that the ISO isn't recorded in the picture data.

In terms of using flash, if you simply got the unit a little further away from the camera - either wirelessly or tethered - you can get better results without the harsh shadows. And remember, if you're using a wide aperture anyway, the amount of light you need to add to a scene is much lower than what a good flash can provide. Even with high ceilings you can throw enough photons at your sensor by bouncing (unless the ceilings were black).
 
continuum
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Re: Low-light photography -- tips and tricks?

Mon May 17, 2010 2:43 pm

Everything said here so far has been pretty good.

If you have a sufficiently powerful flash (430EX II, 580EX II, or similar) you might want to pick up a diffuser. A small one like a Stofen Omnibounce or a homemade one out of an index card might still be too small for a room this big, but something like a Lightsphere might help.

If you are in this kind of lighting that forces you shoot wide-open, well, you're pretty much doing what you can. Crank up the ISO to the limit of what you find acceptable for noise, keep lenses around that are sharp wide open (the Sigma 50/1.4 is better than the Canon 50/1.4 in this regard, I think... check www.slrgear.com reviews or whatnot), and remember than when you shoot wide-open you will be dealing with very thin depth of field as a result.
 
FireGryphon
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Re: Low-light photography -- tips and tricks?

Tue May 18, 2010 5:41 pm

You can also try setting exposure compensation a bit high or a bit low. It depends on your camera, but generally, if you overexpose your picture a bit, you can dial it down later and touch it up in post processing. If you underexpose, or get a photo that is too dark, when you lighten it later you'll end up highlighting the noise, too. This is the case with my camera, but try it with yours to see what works best. Don't forget to shoot in RAW, since there's much more leeway in terms of noise reduction and exposure compensation when you post-process a RAW file than a JPEG.

The 50/1.4 is a bit soft wide open, but the shots are still usable and I'd definitely open wide if I needed to; I have the same lens, and I have done f/1.4 on occasion. I would have shot with this lens for most of the event, had I done the shoot, since it opens up widest, and in low light where the flash isn't happening, you need all the light you can get. 50mm (80mm equiv.) is also about the longest I'd try to shoot in close quarters, too. As you learned, 85mm is too narrow, and f/2.8 is too far stopped down for that environment, even though the 28mm (45mm equiv.) focal length is also good for the shoot. All things equal, though, the 80mm equiv. focal length lets you get shots of people without shoving your camera in their faces, and that's always good.

If I did the shoot, I'd keep the 50/1.4 on the whole time, put the ISO as high as feasible (1600 should be okay even on a Rebel XS, especially if you have good noise reduction software like Noiseware). I'd overexpose a stop or two with the intention of dialing it back down in software.

As a side note, I've seen people gloss over noise and other badly exposed images by running photographs through Topaz. Topaz-processed pictures can look ridiculously fake, but I've seen some creative things done with it that save pictures from being throwaways. I don't have personal experience with it, but am considering purchasing.

EDIT: If you intend to do more indoor photography, I'd invest in a good external flash. I have a Canon 430EXII. Not too expensive, but it's powerful and allows me to use it as a remote flash off-camera (the XS won't allow you to do this without a dedicated transmitter for a couple hundred $$$). The 430EXII also has a swivel head, so I can bounce the flash off of the ceiling or point it left or right to bounce off of a wall. I'd definitely invest in one if you have the money and feel like you may upgrade your photo kit, but the 270EX is less expensive, has less frills, but is still a very capable flash unit.

Also, if you post some pics, maybe we could discuss in more specific detail what's going on.
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SpotTheCat
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Re: Low-light photography -- tips and tricks?

Tue May 18, 2010 6:10 pm

Don't overexpose on digital. When you overexpose on digital, things get completely lost instead of just more noisy. Of course try to nail your exposure, but slightly underexposed usually comes off looking better after correction than slightly over exposed does. Colors change if one of the primary colors blows out, and you cannot get those back.
 
FireGryphon
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Re: Low-light photography -- tips and tricks?

Tue May 18, 2010 6:30 pm

SpotTheCat wrote:
Don't overexpose on digital. When you overexpose on digital, things get completely lost instead of just more noisy. Of course try to nail your exposure, but slightly underexposed usually comes off looking better after correction than slightly over exposed does. Colors change if one of the primary colors blows out, and you cannot get those back.


Overexposing with a point-and-shoot camera is a bad idea (with a P&S, I generally underexpose) but with SLR's that isn't necessarily true. In fact, if you read most message boards, you'll see that overexposing pictures on cameras like the 7D helps a great deal with high-ISO pictures. It's a technique that many people recommend. If you shoot in RAW, the image data is still there, so it's easy to recover it in PP. Darkening a photo subdues noise somewhat; it's when you have to brighten a darker photo that noise really starts to jump out (you can even see this on some cameras in high-contrast, low-ISO situations).

Note that this is a technique for sidestepping some of the trouble you get from noise in high ISO. Under normal conditions, you want to nail the exposure. Either way, it's best to try it out on your camera and see if it works. Like most PP, this is a technique that requires mastery of its fine art for it to work just right.
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ludi
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Re: Low-light photography -- tips and tricks?

Tue May 18, 2010 6:55 pm

FireGryphon wrote:
The 50/1.4 is a bit soft wide open, but the shots are still usable and I'd definitely open wide if I needed to; I have the same lens, and I have done f/1.4 on occasion. I would have shot with this lens for most of the event, had I done the shoot, since it opens up widest, and in low light where the flash isn't happening, you need all the light you can get. 50mm (80mm equiv.) is also about the longest I'd try to shoot in close quarters, too. As you learned, 85mm is too narrow, and f/2.8 is too far stopped down for that environment, even though the 28mm (45mm equiv.) focal length is also good for the shoot. All things equal, though, the 80mm equiv. focal length lets you get shots of people without shoving your camera in their faces, and that's always good.

The way the room was set up, I couldn't capture more than a single table in-focus unless I went down to the 28mm. It actually did all right at the minimum f/2.8 stop, although I only shot a handful of full-room shots before switching back to the 50mm. I have an opportunity to purchase a friend's 28mm f/1.8 USM and will probably do so, then eBay the f/2.8.

The 85mm with the APS-C crop was, indeed, too narrow for the most part. But I did manage to get a few candid shots of a couple charity staff members and volunteers from halfway across the room, so it was useful for that much.
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BiffStroganoffsky
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Re: Low-light photography -- tips and tricks?

Tue May 18, 2010 7:00 pm

If you want to retain the ambiance and not be too distracting with the flash, try using a camcorder type LED light that rides in the hot-shoe and runs of AA or AAA batteries. It might give enough light for the AF to work properly on cameras with problematic focusing algorithms and sensors *cough* Canon *cough*. You are giving up some details but you already were with low light anyways.
 
FireGryphon
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Re: Low-light photography -- tips and tricks?

Tue May 18, 2010 8:19 pm

ludi wrote:
The way the room was set up, I couldn't capture more than a single table in-focus unless I went down to the 28mm. It actually did all right at the minimum f/2.8 stop, although I only shot a handful of full-room shots before switching back to the 50mm. I have an opportunity to purchase a friend's 28mm f/1.8 USM and will probably do so, then eBay the f/2.8.

The 85mm with the APS-C crop was, indeed, too narrow for the most part. But I did manage to get a few candid shots of a couple charity staff members and volunteers from halfway across the room, so it was useful for that much.


Come on, we need pics! :D
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