What ISO setting with flash bounced

I am an ameture photographing family/friends indoor & outdoor. I am avid follower of this forum and have acquired good working knowledge through it. Thanks folks. One more problem in this post which I am facing.

Camera setting: 50% of my photographs are indoor of family and friends. I typically bounce flash from roof with camera settings - Manual, 1/100 to 1/200, F4 or F5.6, ISO - Auto (camera always selects 400 which is max in manual mode), flash set to +1.2/3.

Problem statement: with above settings with approx 10 ft focussing distance to people group, the photographs are 1+ stop underexposed (histogram shows that full pic is on left of first line from right edge of histogram). I take pics in RAW and correct this in pp and get grainy result. High flash setting creates another problem in few pics where faces are over exposed and overall pic still under exposed.

When I take same picture in Av or Tv modes with ISO set to auto, the camera always selects 1600 ISO. With lower focus distance or higher apperture the ISO selection comes down to 800.

If I set ISO to 800 pic is only 1/2 stop under exposed and results OK after pp. If I set ISO to 1600, the exposure is good, but the picture is grainy at 100% and less sharpness (eyebrows not visible at 100%)

Question: Does it mean that I have to always take pics with flash at 800/1600 ISO with resultant avg / poor pic quality. Or am I missing some thing

Again thanks.

1/100 to 1/200, f4 to f5.6, at ISO less than 1600, will need a lot of light!
Flash the only light source in the pictures?
Try lowering shutter speed as well. If these people are posing, 1/60-ish should help

I typically use ISO 400 for bounced flash with a low ceiling such as a residential, office or classroom setting. For higher ceilings you'll need a higher ISO.

Today's cameras do a great job even at ISO 3200. Don't be afraid to crank it up when you need to. Since it requires less flash power, a higher ISO also gives you faster flash recycling and longer battery life.

If your flash photos are underexposed, the first thing to do is turn up your Flash Exposure Compensation. If that doesn't help and you get a long recycle time (indicating the flash is firing at high power), then increase the ISO as needed.

Here's my introductory course on bounced flash:
https://photography-on-the.net …php?p=1585420#p​ost1585420

ssmanak wrote in post #14803656
I am an ameture photographing family/friends indoor & outdoor. I am avid follower of this forum and have acquired good working knowledge through it. Thanks folks. One more problem in this post which I am facing.

Camera setting: 50% of my photographs are indoor of family and friends. I typically bounce flash from roof with camera settings - Manual, 1/100 to 1/200, F4 or F5.6, ISO - Auto (camera always selects 400 which is max in manual mode), flash set to +1.2/3.

Problem statement: with above settings with approx 10 ft focussing distance to people group, the photographs are 1+ stop underexposed (histogram shows that full pic is on left of first line from right edge of histogram). I take pics in RAW and correct this in pp and get grainy result. High flash setting creates another problem in few pics where faces are over exposed and overall pic still under exposed.

When I take same picture in Av or Tv modes with ISO set to auto, the camera always selects 1600 ISO. With lower focus distance or higher apperture the ISO selection comes down to 800.

If I set ISO to 800 pic is only 1/2 stop under exposed and results OK after pp. If I set ISO to 1600, the exposure is good, but the picture is grainy at 100% and less sharpness (eyebrows not visible at 100%)

Question: Does it mean that I have to always take pics with flash at 800/1600 ISO with resultant avg / poor pic quality. Or am I missing some thing

Again thanks.

No you don't have to always be at 800/1600. Remember, shutter speed and aperture also plays a role in exposure. It is why it's best to learn manual mode. Slower shutter speed will let in more ambient light, which will contribute to the final exposure. At 1/100th, the ambient light might not register. It's best to practice from 1/10th - 1/100th with aperture of f/4, and iso 400..

if you are saying at 1/100th, f4, and iso 400, the photo seems to be 2stops underexpose, try slowing down your shutter speed to 1/25th. More ambient light will be hitting the sensor, hence it will not be too underexpose. Play around with the exposure. Or, at 1/100th, f2 and iso 400 can be used.

some possible solutions:

say at 1/100th ss, f/4, iso 400 = 2 stops underexposed

1. 1/25th ss, f/4, iso 400 (gain 2 stops from SS)
2. 1/100th ss, f/2, iso 400 (gain 2 stops from aperture)
3. 1/100th ss, f4, iso 1600 (gain 2 stops from iso)
4. 1/50th ss, f/2.8, iso 400 (gain 1 stop from ss, 1 stop from aperture = 2 stops)
5. 1/50th ss, f/4, iso 800 (gain 1 stop from ss, 1 stop from iso = 2 stops)
6....
7....
8....

and so on to give you another 2stops of light.

Another method would be increasing the power of your flash. Say you are at 1/8th power, adjusting it to 1/2 power will gain you 2 stops.

I hope it helps..i may be wrong, feel free to correct me.. =)

ssmanak wrote in post #14803656
I am an ameture photographing family/friends indoor & outdoor. I am avid follower of this forum and have acquired good working knowledge through it. Thanks folks. One more problem in this post which I am facing.

Camera setting: 50% of my photographs are indoor of family and friends. I typically bounce flash from roof with camera settings - Manual, 1/100 to 1/200, F4 or F5.6, ISO - Auto (camera always selects 400 which is max in manual mode), flash set to +1.2/3.

Problem statement: with above settings with approx 10 ft focussing distance to people group, the photographs are 1+ stop underexposed (histogram shows that full pic is on left of first line from right edge of histogram). I take pics in RAW and correct this in pp and get grainy result. High flash setting creates another problem in few pics where faces are over exposed and overall pic still under exposed.

When I take same picture in Av or Tv modes with ISO set to auto, the camera always selects 1600 ISO. With lower focus distance or higher apperture the ISO selection comes down to 800.

If I set ISO to 800 pic is only 1/2 stop under exposed and results OK after pp. If I set ISO to 1600, the exposure is good, but the picture is grainy at 100% and less sharpness (eyebrows not visible at 100%)

Question: Does it mean that I have to always take pics with flash at 800/1600 ISO with resultant avg / poor pic quality. Or am I missing some thing

Again thanks.

When I shoot indoors and there is some ambient light (lamps, maybe window light) I use manual mode, 1/160, f6.3 and ISO 400 or 800 with a Yongnuo ETTL flash. The pics come out with acceptable exposure, sometimes I have to adjust in post

Thanks all.
I have couple of constraints --
first constraint (self made) that I take pics hand held (lazy to take out / carry around tripod). As a result I try and keep the shutter speed above 100.
Second constraint seems to be technical, to keep acceptable DOF for goup of persons (2 or more) & keep the apperture to F4 or F5.6.
Third constraint is camera - picture quality is not seriously affected upto ISO 800. 1600 ISO is actually OK for home use, however my family is spoiled with some day light pictures I take with my L glass. This camera suffices for all my work. I do not wish to spend money to upgrade (may be I will look at 70D if sensor is upgraded - not what they have done for 650D).

I always felt that Sigma flash is quite strong and it throws good light. Does any member feels that I should change my flash.

I am going to try out shutter speeds below 100 & 800 ISO combination to check if I am steady and pic is sharp.

As stated, if flash is the predominate light source then you are going to have to do whatever it takes to get the light for the picture, either higher ISO, flash power, or larger aperture.

Remember that higher ISO does not immediately mean lesser quality. Getting sufficient exposure minimizes the noise problem.

If you are bouncing flash to complement ambient light then you are dependent on getting an exposure that puts ambient within one to 1 and a half stops of proper exposure. Again, the light will dictate what you have to do with camera settings.

There are no magic bullets. Just practice, testing and experience.

ssmanak wrote in post #14804427
Third constraint is camera - picture quality is not seriously affected upto ISO 800. 1600 ISO is actually OK for home use, however my family is spoiled with some day light pictures I take with my L glass. This camera suffices for all my work. I do not wish to spend money to upgrade

Get over it. Quit pixel peeping and quit worrying about noise. Have you ever seen prints from ISO 1600 film? Today's entry level DSLRs are in a whole different league. People bounced flash with film, and you can bounce flash with your camera.

Curtis N wrote in post #14812018
Get over it. Quit pixel peeping and quit worrying about noise. Have you ever seen prints from ISO 1600 film? Today's entry level DSLRs are in a whole different league. People bounced flash with film, and you can bounce flash with your camera.

Agreed. In fact pp technique is also important for high iso pics. At present I am using dpp. I am wondering will shifting to lr4 help. Also should I upgrade flash.

watt100 wrote in post #14804161
When I shoot indoors and there is some ambient light (lamps, maybe window light) I use manual mode, 1/160, f6.3 and ISO 400 or 800 with a Yongnuo ETTL flash. The pics come out with acceptable exposure, sometimes I have to adjust in post

Thats some pretty bright indoor ambient. Id be surprised that ambient is contributing at all in most indoor settings with those settings.

JakAHearts wrote in post #14813482
Thats some pretty bright indoor ambient. Id be surprised that ambient is contributing at all in most indoor settings with those settings.

I just picked those as a starting point. When I can bounce the flash off a white ceiling in an average size room I can use any number of settings and the pics turn out pretty good because the ETTL in the flash takes care of the exposure. I frequently use ISO 800 and 1600 and get good results so I'm not sure what problems the OP has with "grainy results"

This is an off-the-wall suggestion here, but it hit me. I notice you have a Sigma 530 DG flash. So do I. When I bought my 7D and started using the flash on it, everything, and I mean everything, was underexposed by 1-3 stops unless I cranked it up to 1600 to 3200 ISO, which was essentially bringing in more ambient light). The 530 is a powerful flash (in line with the Canon 530EX), so I was confused by the results I was getting. I found I could crank up +3 stops of flash exposure and get fairly consistent results that were pleasing.

When I bought an older 40D for a backup body, I put the flash on it to see if it had the same results. The flash worked like a champ on the 40D, no flash exposure compensation needed. Strange. I've subsequently found that the 530 was compatible with older Canons, but not with newer ones. You may be suffering the same problem on your 500D (T1i). I bought a used 430EX II flash on here, put it on my 7D and haven't had any problems since.

One thing I did find is that if I bounced the Sigma flash, it would consistently underexpose, but if I clicked the head down to normal, straight-ahead, it would expose properly. See if that is the same on your setup.

Size of the venue, color of walls, amount of environmental lighting all have an impact.

Bouncing the speedlite can make it an accent light to the ambient, or make it a key light with direction to enhance the shot.

The only realistic answer to the OP's question is that ISO is one of the three camera controls useful for arriving at a proper exposure, which may use the bounced flash as primary or accent light depending on the situation.

For this shot the light was bounced to the left of the camera, the ambient light gave an exposure somewhere around 1/60 F2.8 at ISO 800.

That's a beautiful shot David.