REVscene - Vancouver Automotive Forum

bighead · 03-29-2009, 08:14 PM

i'm new to camera and i like to get some further advise from some expert.

i like to know when i should use RAW? currently my default setting is L on XSI.

also, my friend have lend me his Sigma 17-50 F2.8. i have try to take pics on F3.2 on low light condition, but the pics quality is way worse than i'm using the kit lens 17-55 Canon. i have try using my 580 flash while i'm using both lens. anyone can give me advise to solve this problem.

thank you

Senna4ever · 03-29-2009, 11:17 PM

If you're using a DSLR, it's a waste to not shoot RAW.

What do you mean by 'worse'? More noise? Not as sharp? Why are you shooting at f3.2 instead of f2.8?

niforpix · 03-30-2009, 07:55 AM

You should always shoot raw.

Can you post some examples of bad vs good images?

bighead · 03-30-2009, 09:44 AM

Quote:

Originally Posted by Senna4ever

If you're using a DSLR, it's a waste to not shoot RAW.

What do you mean by 'worse'? More noise? Not as sharp? Why are you shooting at f3.2 instead of f2.8?

yes, it's digital Canon XSI.

by worse is much more blurry and the pics quality is so yellow like you take pics without flash(i do have my external flash on). The reason i use 3.2 is i try to capture more light but prevent the background soft out.

not sure if that make sense to you guys

i'm at work now so not able to post any pics. i will try to post up some sample tonight

Tim Budong · 03-30-2009, 11:25 AM

set the white balance to "flash"
what ISO are you shooting at?
and exactly how close are you to the actual subject....

ddr · 03-30-2009, 12:02 PM

correct me if i'm wrong, but using f3.2 will cause the background to be less blurry than f2.8 (not by much i think), but it'll capture less light than f2.8

if they're blurry maybe try a faster shutter speed? tripod?

i was confused because i thought using flash would almost certainly give you enough light to not give you blurry images, maybe unless the flash was out of sync?

roastpuff · 03-30-2009, 04:35 PM

If he's not using M mode and has the shutter speed set automatically in Av mode, the camera will try to expose as if not using flash.

"The issue at hand is the way that Canon cameras handle exposure & flash in different modes and light levels. If the camera is in auto or P mode (in low light) with the flash up, it will default to 1/60 and the max aperture. Which is probably what your camera was doing. However, with a Canon, when you put it into Av or Tv mode, the camera does not default to 1/60 but instead gives you settings for the ambient light and assumes that you are using flash for fill or are trying to balance flash with ambient. So in low light, it will likely give you slow shutter speeds. The camera is basically giving you settings as if the flash was not on...but because it is, you might get a shot that is somewhat balanced in terms of flash and ambient exposure."

From another forum.

Learn how to use M mode - judge your own flash exposure by trial and error. Av mode is terrible in low-light, especially with a non-IS lens like the Sigma 18-50.

bighead · 03-30-2009, 07:48 PM

Quote:

Originally Posted by roastpuff

If he's not using M mode and has the shutter speed set automatically in Av mode, the camera will try to expose as if not using flash.

"The issue at hand is the way that Canon cameras handle exposure & flash in different modes and light levels. If the camera is in auto or P mode (in low light) with the flash up, it will default to 1/60 and the max aperture. Which is probably what your camera was doing. However, with a Canon, when you put it into Av or Tv mode, the camera does not default to 1/60 but instead gives you settings for the ambient light and assumes that you are using flash for fill or are trying to balance flash with ambient. So in low light, it will likely give you slow shutter speeds. The camera is basically giving you settings as if the flash was not on...but because it is, you might get a shot that is somewhat balanced in terms of flash and ambient exposure."

From another forum.

Learn how to use M mode - judge your own flash exposure by trial and error. Av mode is terrible in low-light, especially with a non-IS lens like the Sigma 18-50.

After i have search all day at work(didn't do any work today

), you are rite. i need to the how to set the M mode. if i use TV or AV mode. the shutter automatic goes to much slower speed to compensate which causing the motion blurry.
there is one thing i still not understand why it only happen to the Sigma lens and not happen to the Canon kit lens?
did i miss anything?

roastpuff · 03-30-2009, 07:54 PM

Quote:

Originally Posted by bighead

After i have search all day at work(didn't do any work today

), you are rite. i need to the how to set the M mode. if i use TV or AV mode. the shutter automatic goes to much slower speed to compensate which causing the motion blurry.
there is one thing i still not understand why it only happen to the Sigma lens and not happen to the Canon kit lens?
did i miss anything?

Canon kit lens has IS (Image Stabilisation). It helps with slow shutter speeds, while the Sigma lens does not have IS - the aperture is larger, however, allowing more light to come in and allowing higher shutter speeds than the largest aperture that the Canon kit lens can achieve (f2.8 constant vs f3.5-5.6 depending on zoom). This is especially useful when shooting objects that are moving fast (sports, cars etc) because IS cannot stop subject motion - useful for still objects only, basically. Though, the kit lens' IS can help with panning motion...

[HuCk DuCk] · 03-31-2009, 09:26 AM

Quote:

Originally Posted by dragonone

correct me if i'm wrong, but using f3.2 will cause the background to be less blurry than f2.8 (not by much i think), but it'll capture less light than f2.8

if they're blurry maybe try a faster shutter speed? tripod?

i was confused because i thought using flash would almost certainly give you enough light to not give you blurry images, maybe unless the flash was out of sync?

blurry is not the term you're looking for.

there's multiple explanations here, a) bokeh, b) with a smaller f-stop, the exposure is longer, hence a more "clear" image

ddr · 03-31-2009, 02:47 PM

gotcha, i thought blurry would b more obvious, but yes bokeh, and they can come in all sorts depeding on the lens

roastpuff · 03-31-2009, 03:46 PM

I think the OP is just having trouble with getting sharp, properly exposed pictures at night-time, and having WB issues because of ambient + flash mixing in.

bighead · 03-31-2009, 05:07 PM

Quote:

Originally Posted by roastpuff

I think the OP is just having trouble with getting sharp, properly exposed pictures at night-time, and having WB issues because of ambient + flash mixing in.

yes, i have a hard time to get proper image at low-night indoor pics with the Sigma but i think i kinda get the idea.
thx for all of your help.

BTW, WB is referring to????

roastpuff · 03-31-2009, 06:18 PM

The White Balance setting on the camera - might be why the picture is coming out all yellowy and stuff, because WB is set incorrectly. Play around with it to get the best white balance setting for each situation - daylight, tungsten, fluorescent, flash etc.

bighead · 03-31-2009, 08:15 PM

i have better idea take a stand still pics but once my son is in motion. i still get in blurry pics, not everytime works.
i think i need much much more practice.

[HuCk DuCk] · 04-01-2009, 12:03 AM

rule of thumb, if you're shooting slower than 1/focal length of lens, use a tripod....

if you're shooting slower than 1/15 a second.... either have crazy steady hands, or use a tripod and mirror lockup

ykwong · 04-04-2009, 07:10 PM

Quote:

Originally Posted by bighead

i have better idea take a stand still pics but once my son is in motion. i still get in blurry pics, not everytime works.
i think i need much much more practice.

you've only concentrated on the aperture, don't forget the shutter speed, a good rule of thumb is about 1/250 as a minimum to stop action without ghosting

as well, I find that with sigma, the white balance can get thrown off, at times, my photos will have a yellowish tint, but I can always fix that by shooting in raw and adjusting the w/b manually in photoshop CS3

roastpuff · 04-04-2009, 07:23 PM

About 1/60-1/100 works in most cases, unless it happens to be sports or rather fast movement.

The 1/focal length rule is very important for non-blurry pictures!

Senna4ever · 04-05-2009, 03:30 AM

Quote:

Originally Posted by roastpuff

The 1/focal length rule is very important for non-blurry pictures!

....for static objects.

Sigma is known for the warmer tone of their glass, so that might explain the warmness of the images.

roastpuff · 04-07-2009, 09:30 AM

Well, yes for static objects. Or fairly non-moving ones. The OP's not shooting sports...

We can get into the discussion of stopping moving objects in another thread.

ddr · 04-07-2009, 10:13 AM

He's shooting his baby that's always moving about

roastpuff · 04-07-2009, 02:00 PM

Quote:

Originally Posted by dragonone

He's shooting his baby that's always moving about

Babies don't move that fast. If OP shoots 1/40-1/60 without flash that's definitely enough to freeze most motion...

bighead · 04-14-2009, 08:31 AM

Quote:

Originally Posted by roastpuff

About 1/60-1/100 works in most cases, unless it happens to be sports or rather fast movement.

The 1/focal length rule is very important for non-blurry pictures!

are you referring not to take a close up pics? sorry to being NOOB

roastpuff · 04-14-2009, 11:08 AM

No, I'm talking about keeping the shutter speed high enough (1/focal length) to avoid camera shake, especially with a non-IS lens.

i.e. if you have the Tamron 17-50 fully zoomed in to 50mm, your shutter speed should be 1/50 or above in order to avoid the picture getting blurry.

77civic1200 · 04-14-2009, 11:18 AM

^you forgot to add the crop factor in =)