How you decide correct exposure with Flash ?

mjoshi123

I understand that FF bodies have some advantage when shooting low lights. But for people who dont have FF bodies to work with what is option ? I've got Sigma 30mm F1.4 & Canon 85mm F1.8 on Canon 60D and I personally start hating noise even in indoor personal shots above ISO 800. So how are you guys getting away with 3200 & 6400 ISO ? Please share some of your images and processing tips to help us newbies
Also I use 580EX II and try to follow 1/F rule for shutter which gives me in my case 1/30 (generally I tend not to go anything below 1/60 as I shoot only handheld) or 1/85.
Now with regards to getting correct exposure - how do you calculate that if you are using external Flash ? Here is my confusion. When I use flash (and I shoot only in RAW & Manual) I set my shutter (try above 1/60) and aperture (most of time stop it down 1 or 2 stops) with Evaluative metering mode. Many times my meter inside viewfinder shows that image is underexposed but in this circumstances I rely on my 580EX II to compensate for exposure light.
So technically speaking I'm letting my Flash guide my exposure under low light conditions.
Is there anything I can improve here ? What do you guys think ?

Chris Geiger

I do most of my indoor/reception shots at 1/125 F4 with iso from 3200 to 6400. I find many of my 1/60 and 1/90 shots have subject blur and shots with larger aperture sometimes miss focus. I also have 3 remote flashes that I use but for most shots flash is from on camera, bounced off the ceiling. With my Nikon D3s it's easy to remove the noise from an iso 6400 shot in lightroom. I would much rather have high iso than larger image sizes. I would shoot with more remote flash if my limit was iso 800.

mjoshi123

Thanks for sharing your tip. Some beautiful shots there. Do you use flash on bracket or directly mounted to hotshoe ?

Chris Geiger

I never use a flash bracket. The flash is either on the camera or fired via radio triggers.

r3t1awr3yd

mjoshi123 wrote: »

Here is my confusion. When I use flash (and I shoot only in RAW & Manual) I set my shutter (try above 1/60) and aperture (most of time stop it down 1 or 2 stops) with Evaluative metering mode. Many times my meter inside viewfinder shows that image is underexposed but in this circumstances I rely on my 580EX II to compensate for exposure light.
So technically speaking I'm letting my Flash guide my exposure under low light conditions.
Is there anything I can improve here ? What do you guys think ?

I seriously chimp in these circumstances. Before any wedding, I've no doubt already shot some pictures in that location with the correct lighting (at the rehearsal dinner. I always go to rehearsal dinners to create a rapport with the people at the venue in control of the lights, the DJ if they're there, the person in control of the order of events, and of course to meet the essential folks). Write down settings the day before to have an idea of what's close enough. Then, day of, chimp a few times to double check and you should be good to go.

skyoftexas

mjoshi123 wrote: »

I personally start hating noise even in indoor personal shots above ISO 800.

Well, there you have it. If you hate noise, then raising the ISO is not for you. You can reduce noise via software, but today's digital cameras are doing a much better job of "rendering" noise. Note, I say rendering. It is still there, but more palatable to some of us. However, you probably won't find it so. If you want to light up the background while using a speed light flash, you will have to up the ISO. The only alternative is to have enough flashes/lights to do it for you. I don't mind noise too much, if it is not blotchy. An example or two:

ISO 2500

marikris

Hey OP, do you have any example pics by any chance?
Also, do you only shoot with one on-camera light (bare front faced or bounced) or are you talking OCF?

NeilL

Oh you really need a lightmeter to do it proper!:D By the time you sweat all the twists and turns you describe you could have it down!

What exactly you do for correct exposure depends on what your exposure depends on. Simplistically, the crux is balance of ambient to flash, where the incident on the subject is perfect.

Ain't no other way to do that in a few seconds and have it in the bag than with a lightmeter!

At full size you can read the writing on the pages!












Canon 40D, 24-105mm f4L IS USM, 580EXII, Phottix triggers, Sekonic L358

Neil

mjoshi123

marikris wrote: »

Hey OP, do you have any example pics by any chance?
Also, do you only shoot with one on-camera light (bare front faced or bounced) or are you talking OCF?

I'll post some pics soon to show what I meant my noise. In current gen camera where everyone is in race to bottom wiht sutffing pixels in smaller sensors - noise becomes more noticable. I shoot wedding with 60D and with flash at ISO 1600 it was more noticable than at ISO 400-ISO 800 on 40D. I used 580EX II on 60D with bracket on ETTL. I used 430EX on 40D without bracket and I could tell you just by seeing which one were taken using 40D and which one was on 60D.

marikris

mjoshi123 wrote: »

I'll post some pics soon to show what I meant my noise. In current gen camera where everyone is in race to bottom wiht sutffing pixels in smaller sensors - noise becomes more noticable. I shoot wedding with 60D and with flash at ISO 1600 it was more noticable than at ISO 400-ISO 800 on 40D. I used 580EX II on 60D with bracket on ETTL. I used 430EX on 40D without bracket and I could tell you just by seeing which one were taken using 40D and which one was on 60D.

Oh yeah, definitely as you go downwards the canon family, noise gets more noticeable. The key is knowing how far you can push your camera, which you already know. I know you want info on crops, but on my 5d2, I had to shoot an outside wedding on iso 3200 and 2200 (without flash) and the album prints came out fine, and the images great on the computer, specially after running noise reduction. At those levels, exposure must be spot on, maybe even a little to the right.

I used to own an xti, and on iso 800, it was bordering horrible.

I shoot TTL on-camera bounce + OCF (1 or 2, maybe 3, depending on the venue and the look I want to achieve). OCF on TTL unless I'm getting something weird, then I go to manual. If I only have one on camera and I bounce, and find out I need more light, I use zoom my flash to concentrate the power.

Metering wise, I normally keep it on evaluative, though sometimes I use spot.

Here is an example where I zoomed the OCF, which was on camera left. I set my on camera flash not to fire. There were tons of mosquitoes that night (I mean swarms) and too many people nearby, so I wanted to isolate the action. Sorry for the large watermark. Both on 5d2, all bare flash.


ISO 800, F4, 1/60 @ 35mm. Flash zoomed.

3 flashes in this one, ETTL. 1 oncamera bounced + 2 cross lighting

ISO 800, f4, 1/60 @ 34mm

Have you experimented with the flash compensation? I go +1 - +3 when necessary. Anyway, hope I've been helping so far. I'm not the best at explanations

tenoverthenose

90% of my work these days is done with an off camera light with manual metering (both camera and light). It may go against conventional wisdom, but I don't use a light meter - I swear I can work faster without one.

marikris

tenoverthenose wrote: »

It may go against conventional wisdom, but I don't use a light meter - I swear I can work faster without one.

I do agree with this, but when you are yet unsure, that light meter comes in handy. When you have done this a few times, you pretty much know how much power you need and how far your light should be etc.

NeilL

mjoshi123 wrote: »

I could tell you just by seeing which one were taken using 40D and which one was on 60D.

What could you tell exactly?


Neil

NeilL

@ 10 & marikris

you are *still* using a meter! it's the reflective meter of your camera, and all kinds of stuff reflects differently, so when you get all kinds of stuff in a photo it doesn't do so well. you can take the shot straightaway, sure, but how bout all the chimping and reshooting and the fixing in post!

Neil

tenoverthenose

NeilL wrote: »

@ 10 & marikris

you are *still* using a meter! it's the reflective meter of your camera, and all kinds of stuff reflects differently, so when you get all kinds of stuff in a photo it doesn't do so well. you can take the shot straightaway, sure, but how bout all the chimping and reshooting and the fixing in post!

Neil

VERY much agreed - I am using the in camera meter. So I know how to use my in camera meter for ambient exposure, that's easy. I just do not use a dedicated light meter for my strobes.

After spending enough time with my lights, I can give a pretty good estimate of how much power I am going to need for a shot just by looking at the relationship between ambient exposure, subject / light distance, modifier, and the desired look. Within three frames I have it perfect.

I primarily shoot weddings and those first three frames (as needed) are often taken without letting the couple know I am testing settings. I should note that I also have remote power level control of my strobes. The couple is focused on each other or doing their own thing so as to keep the flow & mood up. For them it's a smooth experience.

I feel that if I had to stop and walk over to them to measure my strobe output, it would be slowing things down too much and breaking that flow.

Light_prod

yeah I just stick everything on manual and chimp until I get what I'm after. If the shutter starts dragging too much for what I'm after I'll lift the iso and push the shutter up bit by bit.

I've heard many people shooting manual but with the strobes on auto, personally I get extremely inconsistant results this way. Maybe I'm doing something wrong but in most case it hugely over exposes.

NeilL

Light_prod wrote: »

with the strobes on auto

on auto what? eg are you talking about flashes on ETTL?

Neil

Qarik

set your aperture and ss to whatever the shot calls for. Push your iso to the max you feel comfortable at. Look through your lens to see what the in camera light meter reads..if you are within a couple of stop center then your flash will do the rest.

If your flash can not do the rest because cielings are too high (assuming you bounce) or whatever reason..up your ISO. (asssuming you are already riding the ss and apereture to the limit) I think 1600 should be okay on 60D with a decent noise SW like LR3 or any of the stand alone packages.

Light_prod

yeah sorry I meant iTTL or TTL settings. they are always wacked.

basflt

Light_prod wrote: »

yeah sorry I meant iTTL or TTL settings. they are always wacked.

thats why they invented Flash-compensation , adjust it downwards , especially with white subjects

marikris

basflt wrote: »

thats why they invented Flash-compensation , adjust it downwards , especially with white subjects

I do agree that there are times on ETTL where there are inconsistencies between shots where there shouldn't have been.

basflt

yes , but leaving TTL at default is asking for it

if in doubt , it is better IMO to set FEC ( flash exposure compensation ) just a little bit on the dark side of correct

high ISO-noise = not funny
over-exposes whites = an unusable photo

marikris

I meant even with FEC there are still inconsistencies between shots where there shouldn't have been when nothing's changed.
But I wholeheartedly agree that you have to use FEC to be successful in ETTL, specially for weddings. You get used to it, like everything else with lots of practice, and it becomes second nature to dial it up and down.

zoomer

Use your blinkies. If they are going off in critical areas (dress) increase your shutter speed just until those areas are not blinking. I always shoot wide open when using flash. Use your blinkies as your light meter...very fast and accurate.
Do Not judge your exposures by looking at your on camera screen they will look good but be very underexposed, use your blinkies and histogram for your guide.
Assuming shooting in manual exposure, ttl flash. I start at aperture wide open (leave it there) with ss at 250 and adjust from there. Depending on ambient light start at iso 800 and go to 1600 if necessary.
I use a bracket with flash pointed up and a diffuser on the just the front of the flash.
Better to use more iso and expose properly than to use lower iso and blast the flash.
If you take your exposures dark and then need to bring them up in post that will increase your noise MUCH more than if you had shot them at a higher ISO but used a proper bright exposure.

Qarik

I do get variation in flash expsoure but most of the time it is becasue I am shooting too fast and it hasn't been able to charge up. Honestly though my TTL hits correct exposure 90% of the time as long as it is possible to do so. I almost never change my FEC. The only time I have to mess with FEC is when I am trying to acheive some effect or if I am doing fill flash.

NeilL

Well, I must confess to a certain wry amusement over all this hand wringing and heart aching that're supposed to be easier and quicker than incident metering!! With your camera metering, 3 bad things happen always:

* every time you move your focus point you get different values
* every time something about your subject changes you get different values
* the algorithms are trying to reduce DR

Aren't you hitting your head against a rock??!!

With an incident meter you measure the light illuminating the subject. A few quick measurements, including of background light and flash light ratio, and you've got the light situation down to a narrow range from where you can deal with variations intuitively to get perfect exposure, no matter that you move the camera around a bit, or your subject changes in some way, or other subjects come on the scene.

Measuring as your camera does the reflectiveness of things in your camera's view creates great variation in values, which the camera then tries to suppress, and which are constantly changing, often by large amounts!

No wonder there are all these workarounds you describe!

Neil

marikris

....Did we lose the OP?

zoomer

Real world, when you are shooting a wedding you need to not be messing with your equipment...it needs to just get out of your way. Light meters...don't think so.
Riding the blinkies and adjusting shutter speed from time to time can be done almost without even thinking about it with experience.

Matthew Saville

zoomer wrote: »

Real world, when you are shooting a wedding you need to not be messing with your equipment...it needs to just get out of your way. Light meters...don't think so.
Riding the blinkies and adjusting shutter speed from time to time can be done almost without even thinking about it with experience.

Took the words right out of my mouth. On a wedding day, I don't have time for much. Besides, no light meter or any other technique can match the accuracy of a properly shot RGB histogram with blinking highlights.

Especially since I shoot on Nikon, and can access separate highlight warnings for individual channels.

Sure, the histogram and highlight warning are NOT 100% accurate of the actual RAW file, but I can fake that easily enough if I just use the right white balance and keep my "Picture Controls" settings turned down.

But, to each their own. I'm jut trying to help anybody out there who is "aspiring"- this is just how I work, it may or may not work for you but it's worked for me for ~7 years. :-)


=Matt=

Matthew Saville

NeilL wrote: »

....
* every time you move your focus point you get different values

I don't know how this is true of all cameras. Maybe a select few, in certain metering modes. But it's NEVER been the source of exposure errors, for me.

NeilL wrote: »

* every time something about your subject changes you get different values

Sure, but it is only a change in light that I concern myself with. And when the light does change, I adjust my exposure in-camera and check my highlights much faster than I could ever walk over to the subject and take a reading.

NeilL wrote: »

* the algorithms are trying to reduce DR

...Huh? Not sure I understand this one. And again, I'm not sure it pertains to all metering modes on all cameras. Bottom line- if the light is tough, if it's more than the camera can fit into one exposure, it is still faster for me to click a shot and check my highlights.


BTW, here's one thing I'm not understanding about the "purist" perspective, and using the most accurate technique for a certain task- what ever happened to just getting damn good at knowing light? Back in the days of film, people used to brag about how they could just walk into a room and know what the exposure would be for a subject in this or that window light. Just because they'd shot that light a thousand times.

I'm all in favor of using the most accurate technique possible to gauge exposure and nail it every time. But I think we're totally forgetting about the oldschool method of simply committing things to memory, and constantly sharpening our own perceptive ability. Personally, I'm definitely no master at just guessing an exposure, but I can usually at least get myself close enough such that a single test shot gives me a histogram / highlight warning that lets me know exactly where I want to be.


Just some food for thought. ;-)

=Matt=

Ed911

Matthew Saville wrote: »

What ever happened to just getting damn good at knowing light? Back in the days of film, people used to brag about how they could just walk into a room and know what the exposure would be for a subject in this or that window light. Just because they'd shot that light a thousand times.=Matt=

I'm not sure what your point is, but my response is, because we don't have to do it that way anymore...now we have a much easier way to do it. Same thing happened to manual focus, and ISO on a roll...lol. I used to shoot those old relics...missed a lot of shots just setting up....no nice point and shoot functions like we have on today's nice SLR's. Just look at the millions and milllions of wonderful images posted all over the internet today...all with these new fangled light machines and post processing softwares...lol.

These are the good old days...take advantage of your technology.