Flash photography and 'noise' question..
Flash photography and 'noise' question..
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Discussion

XKjimmy

Original Poster:

4,142 posts

212 months

Thursday 6th December 2012
quotequote all
Hi all,

I was recently asked to take photographs for a smart event, capturing people there. The camera I was using was a 5D MK 2. It was my first time using a speedlite, which was a 430EXII, the flash was bounced off the celling.
I was pleased with how they came out and they were, I did notice the noise was quite high in some of them though, here is an example normal then cropped in. The ISO was set at 800 to capture the surroundings.




Cropped


Is this caused by too high ISO?

The EXIf data is 1/125s
F8
ISO 800

Thanks

James.

Simpo Two

92,708 posts

294 months

Thursday 6th December 2012
quotequote all
You'll always find problems if you zoom in enough to find them.

I do a lot of this kind of photography (people indoors with bounce flash) and my main observation is how dark the b/g looks, coupled with slight burnout of foreheads. It looks very harsh for bounce flash.

Going to f8 to 'capture the surroundings' was a mistake IMHO, making the flash work harder and needing the higher ISO; you want the people nice, not the coving in the b/g. All f8 does is reduce light and add DOF you don't need. And when using flash, what counts is the balance between flash light and ambient light, not aperture.

Another reason for the noise is over-sharpening, so that might be something to look at. But if it's not visible on an A4 print, I wouldn't worry unduly about it.

XKjimmy

Original Poster:

4,142 posts

212 months

Thursday 6th December 2012
quotequote all
HI Simpo,

Many thanks for the reply.

With the dark background in this image, it seemed to be worse in that example, here's another one in the room where most of the guests were congregating.


Your right though, the harsh lights on the foreheads did come through in the photos.

Very helpful information that, and taken on board for next time. I did try to get used to the flash and the camera before the event, doing test shots (much to the OH's annoyance..)

I did get a bit carried away with the over sharpening too...

Thanks

James.

RobDickinson

31,343 posts

283 months

Thursday 6th December 2012
quotequote all
Noise will always show more in dark areas, just a fact of life, should clean up ok tho.

james_tigerwoods

16,347 posts

226 months

Friday 7th December 2012
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So what F stop and ISO should you aim for in this scenario?

raredevil

144 posts

204 months

Friday 7th December 2012
quotequote all
In indoor situations like that you should not use a low ISO, especially with flash. Having a higher ISO allows the ambient light to come through which is essential for a balanced shot like those above. 800 ISO I would say was about right.

If a low ISO was used the flash would over power the ambient light causing harsh frontal lighting on the subjects.

As a rule always 'boost' the ISO for indoor shots with flash. I think F8 is a good choice considering the proximity to the subjects and especially if using autofocus.




Edited by raredevil on Friday 7th December 14:23

Simpo Two

92,708 posts

294 months

Friday 7th December 2012
quotequote all
james_tigerwoods said:
So what F stop and ISO should you aim for in this scenario?
I aim for f3.5 and IS0400.

In exceptional circumstances (very dark, need more flash range) I'll go to f2.8 and ISO800 but only under duress.

raredevil said:
In indoor situations like that you should not use a low ISO, especially with flash. Having a higher ISO allows the ambient light to come through which is essential for a balanced shot like those above.
Increasing ISO merely boosts the sensitivity of the sensor. How does the sensor know which part of the light is ambient and which is flash?

Elderly

3,735 posts

267 months

Friday 7th December 2012
quotequote all
Simpo Two said:
I aim for f3.5 and IS0400.

In exceptional circumstances (very dark, need more flash range) I'll go to f2.8 and ISO800 but only under duress.
The difference is that the OP is using a (more modern?) full frame camera than
your crop sensor camera (D200?).
Like for like he would need a smaller aperture than you to get the same depth of field
and he can also use a higher ISO setting without any more noise than you.

The OP also said "The ISO was set at 800 to capture the surroundings",
was the fact that his image was f8 a coincidence, or are we all at cross-purposes?

NB. I know NOTHING about flash smile

james_tigerwoods

16,347 posts

226 months

Friday 7th December 2012
quotequote all
Elderly said:
I know NOTHING about flash smile
Mr Jobs?

getmecoat

Simpo Two

92,708 posts

294 months

Friday 7th December 2012
quotequote all
Elderly said:
The difference is that the OP is using a (more modern?) full frame camera than
your crop sensor camera (D200?). Like for like he would need a smaller aperture than you to get the same depth of field and he can also use a higher ISO setting without any more noise than you.
Re DOF, you're correct but it's not a significant issue. But he can certainly use more ISO, yes.

Elderly said:
The OP also said "The ISO was set at 800 to capture the surroundings",
was the fact that his image was f8 a coincidence, or are we all at cross-purposes?
We don't know as he didn't say what exposure mode he was using.

XKjimmy

Original Poster:

4,142 posts

212 months

Friday 7th December 2012
quotequote all
Hi Simpo,

I was using Manual exposure mode, I did a quick bit of reading up before the event and f 8 was suggested. It didn't seem to work as I had hoped though frown
I did some practice shots before at 400 ISO as you recommended earlier in the thread. they looked much cleaner.
I'll certainly use a larger aperture for next time though.

Simpo Two

92,708 posts

294 months

Friday 7th December 2012
quotequote all
f8 is a good general purpose aperture, especially outdoors. It's also where lenses usually give their best results so this is probably why it was suggested. But in a darkish room with limited lighting, not the best.

My thought process is roughly this:

'It's a bit dark in here, light is important. I'll use a big hole to shovel as much in as possible, and that will also make my flash go further. It also means I can keep ISO down and get the best shutter speed so I don't get camera shake*. Check DOF isn't important'

Indoors I normally use aperture priority. Big hole for max light, spin-off shallow DOF often a benefit to isolate subject. If DOF is more important, eg a group of people with rows, use smaller hole. You can achieve just the same on manual exposure of course, it just needs more thinking.


(*though in this case the fill-flash usually negates any camera-shake)

james_tigerwoods

16,347 posts

226 months

Friday 7th December 2012
quotequote all
On a semi related note - what are fill flash rules?

XKjimmy

Original Poster:

4,142 posts

212 months

Friday 7th December 2012
quotequote all
Many thanks for that Simpo, very useful. Shall certainly use a larger aperture for my next event. Another problem with the building where the event was held is that the ceilings were higher than I thought they would be so bouncing the flash wasn't that effective, was having to work very hard! I did have an omnibounce diffuser but didn't use it.

Simpo Two

92,708 posts

294 months

Friday 7th December 2012
quotequote all
james_tigerwoods said:
On a semi related note - what are fill flash rules?
Fill flash balances the flash light with ambient light, so the exposure is made by both of them rather than 100% flash. Obviously near things get more flash whilst far things are ambient; if this looks too obvious I fix it in processing. I use the camera's fill flash setting ('TTL-BL') but you can do it manually if you prefer. Of course if you're shooting in significant gloom then there's little ambient light anyway so the flash does most of the work.


XKjimmy said:
Another problem with the building where the event was held is that the ceilings were higher than I thought they would be so bouncing the flash wasn't that effective, was having to work very hard! I did have an omnibounce diffuser but didn't use it.
Yep, the higher the ceiling (and the less reflective) the harder it gets. Personally I can't see the point of those yogurt pot things; the direct light source is still not very big and half the light goes the wrong way.

XKjimmy

Original Poster:

4,142 posts

212 months

Friday 7th December 2012
quotequote all
It did seen to be quite a tricky venu, the the lights were quite low power and there was lots of wood paneling, didn't seem much to bounce off which was a shame. Very true about the omniboune. Very expensive for a bit of plastic! Seemed to reduce the power of the flash too, much prefer with without.

james_tigerwoods

16,347 posts

226 months

Friday 7th December 2012
quotequote all
I did the photography for my father in law's 60th at Shorpe United's ground in their large function room - that worked a treat with a low white ceiling and my SB600. it's those outdoor shots of family where the shadows are all off, especially at this time of year, that I really struggle with....

james_tigerwoods

16,347 posts

226 months

Friday 7th December 2012
quotequote all
On a semi related note - what are fill flash rules?

RobDickinson

31,343 posts

283 months

Friday 7th December 2012
quotequote all
The op was doing a decent job imo.

Could have shot at iso 400 and f5.6 if dof was suitable.

Manual mode is a requirement for this kind of shot.

For fill flash on canon use Tv or Av mode and adjust the flash power with FEC

Simpo Two

92,708 posts

294 months

Friday 7th December 2012
quotequote all
james_tigerwoods said:
On a semi related note - what are fill flash rules?
Rules? Me no familiar with this!


RobDickinson said:
Manual mode is a requirement for this kind of shot.

For fill flash on canon use Tv or Av mode and adjust the flash power with FEC
So to recapitulate, you have to use manual exposure but can also use aperture and shutter priority automatic exposure? Righty-dokey skip nuts