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View Full Version : Sigma f/2.8 is not enough for indoor picturess!



jcanon701
12-25-2007, 09:11 PM
got a sigma 18-50mm f/2.8 lens for my general lens and some have said this lens was decent in low light indoor conditions but it's not enough!!! unless i want underexposed pictures..

does anyone else agree who has a similar lens? i'm planning to get teh canon 50mm 1.4 or 1.8 really soon

Rooz
12-25-2007, 09:58 PM
1.8 will make a bit of difference but the dof you will be working with is so small that its difficult to take good pictures. you want high quality indoor pics...get a flash.

DonSchap
12-25-2007, 10:42 PM
Indoor = 28mm shot @ ISO-800 ... f/4 ... 1/60 sec ... WB (White Balance) set for flash, AWB or 5600K ... and, of course, a flash!

Indoor = 28mm shot @ ISO-3200 ... f/2.8 ... 1/15 sec ... WB for tunsten ... no flash ... and nobody moves! That means neither the photographer or the subject. That's simply what it takes. If you cannot provide these settings from your camera ... you either need to add more light or, yeah, get a flash.

A f/2.8 aperture just gets you into the ballpark that a f/4 lens simply cannot. Don't misunderstand the limitations.

Here's a rather terse example of these two settings.
Ambient light example
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28mm shot @ ISO-3200 ... f/2.8 ... 1/15 sec ... WB for Tungsten ... no flash ... Manual-mode (don't mind the cast shadow of the AC-130 on the wall, I'm not taking it down.) Most Intro-DSLRs cannot deliver this ISO setting.

Flash Example
31830
28mm shot @ ISO-800 ... f/4 ... 1/60 sec ... WB (White Balance) set for flash. Nearly all cameras can do these settings with pop-up flash. Auto-mode.

Same image ... external flash attached:
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28mm shot @ ISO-800 ... f/4.5 ... 1/60 sec ... WB=AWB ... Auto-mode


No touch up :cool: You can see that the pop-up flash seriously hardens the image ... and that the ext E-TTL flash makes a subtle and controlled change in the overall white balance. You will often struggle with white balance with ambient lighting. It's a tough mix, but this shot would look a lot worse at f/4 and ISO-1600 under ambient conditions. Here, check it out:

Ambient light example
31831
28mm shot @ ISO-1600 ... f/4 ... 1/15 sec ... WB for Tungsten ... no flash ... Manual-mode

Obviously, an unacceptable exposure level. You're screwed and tatooed with this one. It would be extremely hard to make use of an image this dark. If I hadn't used the SONY ... you'd be struggling with Stability issues at 1/15-second shutter speed, also. This is about the best you would ever be able to acheive with most intro-level cameras and basic f/3.5-5.6 lenses ... with no flash or image-stability. In fact: Call it a "lucky shot!" Your alternative would be to use a much longer exposure time (1/2 to 1/8 sec) and to get a wired-release and use a tripod, indoors, regularly. Handheld is simply out of the question.

Ambient light example (bonus lens: 50mm f/1.4)
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50mm shot @ ISO-1600 ... f/1.4 ... 1/45 sec ... WB for Tungsten ... no flash ... Manual-mode (this would be doable with an intro body, but your shadows will be hurtin') It's kind of sad to think that you would be limited to lenses of f/1.8 or wider to get a shot. Kind of eliminates nearly every zoom on the market :eek:

Once again ... f/2.8 simply allows you to take it indoors, but it won't guaranty any image. f/1.4 gets you more light ... but, you're going to have a fight on your hands with sharp-focusing and depth of field. It's been a struggle for photographers forever ... you'll need more light!

Also ... one other consideration is that a 50mm f/1.4 really tightens up on an APS-C sensor camera. Look at the difference in the images ... that 50mm acts like a short telephoto. Anything closer than ten feet away is going to fill the lens. A 28mm f/1.8 lens is a chunk of change, also, but it will provide a wider and more usable indoor shot.

The Mangler
12-25-2007, 10:45 PM
you want high quality indoor pics...get a flash.

Yup.

Even with the 50mm 1.4 I don't have enough light indoors a lot of the time.

jcanon701
12-26-2007, 05:41 PM
yeah... i was trying my best not to use a flash (i only have the pop up one that comes with the camera body at the moment) because they ruined my pictures with it's hard frontal light. But whenever i didn't use the pop up flash, the pictures would always be blurred because people just can't stay that still.

I guess i'll have to get a flash... i have no idea what to get though. I generally use it when i shoot pictures indoors in lowlight - mostly for gatherings.

i'll look for threads but if anyone knows a thread already please post.

suggesting the actual flashes to get would also be helpful, thanks

Rooz
12-26-2007, 05:52 PM
i think its the 430ex.

jcanon701
12-26-2007, 06:22 PM
Thanks rooz

I was reading about using an external flash and they said something about FLASH EXPOSURE COMPENSATION

Do you need to change the FEC everytime you use the external flash?

When you do need to change it, how do you know how much to change it by? Or is it just done by experimenting... it seems a little troublesome especially for lowlight indoor events where the distance of the subject will constantly alter the effect of the lighting, causing you to constantly have to stop and change teh FEC.... or is that just the nature of indoor photography with external flash?

thanks

jcanon701
12-26-2007, 06:30 PM
One more thing - about ISO

people have said that it can ruin pictures. but i've never seen any examples of a high ISO ruining pictures.

i have a canon rebel xti and ISO goes up to 1600. Yes the images do get grainier, but not to the point where they get 'RUINED'.

are there certain ISO's should i just stay away from or something... sorry.. all these questions.

LAST THING. (for now). when using an external flash, ISO can be kept at 100 right? thanks

The Mangler
12-26-2007, 07:22 PM
One more thing - about ISO

people have said that it can ruin pictures. but i've never seen any examples of a high ISO ruining pictures.

i have a canon rebel xti and ISO goes up to 1600. Yes the images do get grainier, but not to the point where they get 'RUINED'.

are there certain ISO's should i just stay away from or something... sorry.. all these questions.
Usually you'll want to stay as low as possible to avoid the grain or noise (same thing, noise is digital grain...basically). Sometimes high ISO is your only option (too far away to use a flash...), so even though it doesn't look as good, it might be the only way to get the shot.


LAST THING. (for now). when using an external flash, ISO can be kept at 100 right? thanks
Yes, when using the flash all other settings can be pretty much whatever you want. Use low ISO (100, or lower if your camera can go lower) & whatever aperture you need to get the DOF you want. I usually keep the shutter time on 1/200 (that's the flash sync speed for my camera), but you could change this too if you wanted to.

toriaj
12-26-2007, 07:50 PM
Hey guys, correct me if I'm wrong here, but I have had the best results with on-board flash (:rolleyes:) when I use a high ISO, the longest shutter speed I can, a medium-large aperture such as 5.6, and the lowest flash level I can manage and still get a decent exposure.

That way I use as much ambient light as possible, to minimize the harsh effect of the on-board flash.

Often I get better results by underexposing by a stop or so and pulling up the exposure in PP, than if I tried to get the image fully exposed in-camera.

(btw, after trying to get pics of kids inside, after dark, this holiday really makes me consider getting the SB600 :D)

edit: here's a pic I took using the above technique, along with a small amount of noise reduction. Not a Great picture, but it did the job. (See why I want the SB600??)

18mm, 1/45 sec., f/4, ISO 800, flash compensation -3.
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DonSchap
12-26-2007, 07:53 PM
Look,

High ISO tends to screw with large, solid areas and can reduce fine detail to mud.

Normally, it looks like tiny flecks of purple and green, usually seen in shadowed or solid areas ... but can be various other colors. Basically, its the sensor working overtime ... grabbing light as much as it can. In areas where there is no light ... the sensor kind of makes flaky decisions.

If you limit yourself to mostly ISO-800 as your highest usable ISO, you'll do okay. If you find yourself using ISO-1600 ... better consider a better lens (wider aperture) or a new, high-level camera capable of a decent ISO-1600. They are few and far between, at this stage of the game.

Here are some High ISO comparisons on a portion of standard Color Rendition Chart (100% crop), using a "ceiling bounced" external flash as a light source and WB=5600K (standard flash approximation):

ISO-800 31847 ISO-800
ISO-1600 31848 ISO-1600
ISO-3200 31849 ISO-3200
ISO-6400 31850 ISO-6400

Now, these are out of a SONY α700, but it gives you an idea on how the image begins to corrupt as you increase your ISO-setting. You get entirely new colors forming. Where it was rather smooth at ISO-800 ... it has gotten rather rough looking at ISO-6400.

So, you decide ... does high ISO deliver the kind of image you want? Often, the intro-DSLR ISO-1600 looks more like the depicted α700's ISO-6400. YMMV ;)

Rooz
12-26-2007, 08:49 PM
One more thing - about ISO

people have said that it can ruin pictures. but i've never seen any examples of a high ISO ruining pictures.

i have a canon rebel xti and ISO goes up to 1600. Yes the images do get grainier, but not to the point where they get 'RUINED'.

are there certain ISO's should i just stay away from or something... sorry.. all these questions.

LAST THING. (for now). when using an external flash, ISO can be kept at 100 right? thanks

with external flash you can be more flexible with iso cos your flooding the photo with light which minimises any graininess and shadows which is Don pointed out gives the muddiness.

a little experimenting will work out what gets the best result. the 430 is a TTL flash so it will adjust and meter automatically with your camera.