How much flash exposure compensation?
With the recent posts on lighting the formal wedding photos with bounce flash, the question came up, “How much flash exposure compensation (FEC) was used?” (FEC) was used. (The image above is from the sequence.) I thought it would make a good separate short article on the topic.
My settings for that photograph: 1/100th @ f3.2 @ 800 ISO
and flash was bounced TTL flash.
How much FEC did I dial in? I could answer that my FEC was +0.7 EV, but that numerical value might not contain enough real information …
For a start, you’d have to keep in mind whether you want flash as fill-flash, or as a main source of light .. or something in-between.
Also, it necessary to realize that different camera+flash combinations respond differently than other camera+flash combinations.
As an example, have a look at these articles:
– More subtle fill-flash from the Nikon SB-900;
– Comparison between the Nikon and Canon flash systems.
You’ll see that in the same situation, you’d have to dial in -3 EV on the Canon 5D (with 580EX II) and -5ev on the Nikon D3 (with SB-900) to get the same results for subtle fill-flash.
So any time you’re given the FEC value as part of the EXIF data with any image, you have to keep that fact into account – that different flash systems react differently. And they in turn react differently with different camera bodies.
With the D3 + SB-900, I use -0.7 EV as my default FEC when I use on-camera flash as my main source of light. With the Canon 1D mk2 and Canon 5D, I would use +0.3 EV as my default, but with the 1DmkIII, I would use 0EV as my default when flash is the dominant light source.
All of this is in addition to various other factors that influence the amount of FEC needed. These are mentioned on the page on flash exposure compensation, but let’s go over some of them:
Since TTL flash is an automatic metering mode, there are a number of things to keep in in mind when considering how much FEC might required for correct exposure:
– the tonality of your subject / scene,
– how you compose your image,
– whether your subject is central or off-center,
– how large your subject is in your frame,
– how strong the back-lighting is.
With the sequence of photographs of the bride, I had to keep in mind that the white dress will fool the camera’s flash metering system. Since the composition is quite straightforward, that wouldn’t have much of an effect on the TTL exposure, even with me pulling back the zoom for wider shots, or zoom in tighter. But the white dress and back-lighting would have a definite effect.
On-Camera Flash Photography – revised edition
This book is explains a cohesive and thorough approach to getting the best from your on-camera speedlight.
Particular care was taken to present it all with a logical flow that will help any photographer attain a better understanding of flash photography.
You can either purchase a copy via Amazon USA and Amazon UK, or can be ordered through Barnes & Nobles and other bookstores. The book is also available on the Apple iBook Store, as well as Amazon Kindle. Also check out the Amazon Kindle store.
Learn more about how the cover image was shot.
For a clear understanding of exposure metering, I would highly recommend that you read up on the Zone System.
As a quick approximation, consider that your camera’s meter will try and expose for the subject+scene as a mid-tone, or try and average out what it sees, as an average of a mid-tone. Something like block #5 in this diagram.
So if you point your camera to a scene containing predominantly lighter tones, (somewhere around blocks 7 – 8), then your camera’s meter will try to expose for the scene as if it is pointed at a scene which looks like block #5. Therefore, to get correct exposure, you have to push your exposure up so that the lighter tones actually appear as lighter tones, and not darker tones.
This is where you’d use your FEC to push up your flash exposure to give you correct exposure. Do keep in mind this is NOT the same as over-exposure. You are exposing correctly by pushing your exposure up.
Back to the image at the top .. the bride and the white dress and backlighting would most likely be similar to blocks #7 to 8. I now have to dial my FEC up, since my camera will try to expose for the subject+scene as a mid-tone such as block #5. With TTL flash, you’d anticipate this since you can see your scene is darker / lighter than average, and take a test shot … and then adjust your FEC to taste further if needed.
With TTL flash, this does become an “educated guess & adjust” process .. and there is variation in exposure as you change your composition. But I can work faster with TTL flash in certain situations than I would be able to with manual flash.
With that image, my FEC was at +0.7EV since I needed 1.3 stops more light than my usual default to keep all the tones brighter. If I didn’t dial my FEC up from my default, the image would’ve been under-exposed. So I needed more flash to expose correctly. How much flash exposure compensation do you need? It would depend on what camera and flash you are using, and what the scenario is that you find yourself in … as well as your intended results.
Specific values for FEC might not tell you the entire story, since you need to adjust your FEC as is needed.
Related articles
- Bridal portraits with on-camera bounce flash
- Tutorial: Flash exposure compensation
- Tutorials: Flash Photography Techniques
Hello Neil,
good news from Europe (UK). As of today your book “On Camera Flash” is available in England. I got yesterday a message from amazon.co.uk saying that your book will now be shipped to me. I pre ordered your book maybe 2 months ago and 1 hour ago the postman was ringing at the door.
Unfortunately I don’t have a flashlight for my Nikon D700 yet, so I will be shooting my first wedding as a second shooter in November just with “available light”.
Neil,
I have been a long time follower of your blog for several years. I really appreciate all your efforts in de-mystifying many of the technical aspects of flash and ambient exposure. Your book is an excellent resource that I recommend as well as your blog on a consistent basis.
I am gradually working toward doing weddings. I remember sometime back(couple of years ago I think) a post you did just after a workshop here in Raleigh, NC. You mentioned a photographer Brian Mullins(http://wwww.brianmullinsphotography.com) on one of your posts. I find it a small world that my first wedding second shooter gig this past July was with Brian. He is an amazing wedding photography and spoke very highly of you and your efforts. He is a founding member and very active in weddingphotographicsociety.com which puts together many of the local Raleigh wedding photographers sharing ideas to elevate the wedding photography industry. I still have much to learn but I really appreciate the efforts that you and Brian for the photography community.
Keep up the good work, wish you were still doing workshops down here in Raleigh. I was a little too early in game last time.
Steve
Neil…On plate 14-2(bottom), you used 1/320 second. Why was high speed sync used?
Couldn’t you have used your maximum flash speed? Your book is great and if you plan a second book I would like to see more overview of the scene and more of the positioning of the snoot i.e.up, down….Enjoyed the book a great deal and found it very informative….lokking foward to book #2..
Cappy … I went into HSS for no real reason than shooting fast that is where I ended up for that sequence of images. No motive, but concentrating on the shoot. Ideally I should’ve stayed at max sync speed so that my flash recycles faster, etc … but working close-up to the couple and only needing the barest hint of flash, it didn’t make much difference. At some level it becomes more important to keep the flow of the shoot.
Hi Neil, I’ve one Q regarding exposing correctly using FEC.
Would use FEC Lock at +1 FEC on the bride’s dress (white) before recomposing and firing the shutter and flast be more effective?
We decided to expose correctly on the brighter area in the photo. That way, we can be assure of consistent exposurre with the bride in the photos.
Hope to hear from you.
Origor .. I haven’t ever done it like that, but your method absolutely makes sense, and should give you some consistency from image to image.
I know EV doesn’t add to FEV in canons, but with Nikon at least, could you set EV+1, always spot on the bride’s dress, and not really need to mess with FEV much?
Val, if I understand your intended method correctly, I do think it will then hamper your composition, since you’d have to keep the spot-meter directed at the dress for each image in that sequence. You wouldn’t be able to change your composition?
Val,
You’ve got to keep in mind that EC is totally separate from FEC, no matter which brand of camera you use. When you’re dealing with on-camera flash photography like this, EC only corresponds to metering and compensate for the ambient light. FEC, however, corresponds to metering and compensate with the flash firing to light your subject.
Albert, with Nikon, the overall EC also influences the flash exposure while you shoot in manual exposure mode with your camera.
Check the link to how I achieve more subtle fill-flash with the Nikon D3 & SB-900 combination. I do it by dialling down the EC as as well as the FEC.
Hi Neil
Interested in this – if your camera meter see the dress won’t it make the same zone 5 change so even adding X amount fec would still see the camera pulling the image back to zone 5? What would happen if the camera was used to push the exposure for the dress back up say with +1ev as an example? The result on Nikon cameras, would see the flash fire also taking into account the + ev in this example even though the flash would actually be set at zero fec.
Have I missed something fundamental here?
By the way, also now waiting on delivery of your book.
Cheerio
Hoddo
Hoddo .. I’m not sure I follow your train of thought.
If your camera needs to have the EC / FEC adjusted to compensate for a scene with brighter tones than average, then that EC / FEC you dialled in will bring the exposure up to where you want it. So I’m not sure why you’d think you’d be back at the middle grey / average tone again?
Explain it some more?
“– how you compose your image,
– whether your subject is central or off-center,”
I saw no mention of FV Lock with the Nikon systems.
I use this feature all the time, so much so I’ve dedicated one of my function buttons to it.
Is this something you would recommend Neil when re-composing?
Pete .. using FV Lock certainly makes sense. I haven’t used it though, so can’t make a direct comment on it .. but pre-judging how much FEC to add, and then using FV Lock definitely makes sense, and will bring some consistency into using TTL flash.
Just finished reading On-Camera Flash and enjoyed it very much. I’m sure it will make more and more sense as I begin putting your suggestions to use. I’m a beginning photographer and only have a camera and an on-camera flash. I’m trying to learn how to make the most of what I have and your book gave me a great headstart. Just wanted to say thanks.
I think I know what Hoddo is angling at. He/she was maybe wondering whether the camera’s desire to expose for middle grey would override the FEC by taking it into account in its calculations and then still exposing for middle grey. So he/she was then asking whether to get around this problem you’d bump the exposure up on the camera rather than on the flash (which would stay at 0 FEC), I guess to really give the camera the message!
I think you’ve answered that when you say the FEC would take your exposure up to where you want it, rather than the camera cancelling it out.
But I’m still wondering myself when you’d use EC on the camera and when you’d use FEC. If I zoom in to fill my frame with a white dress, bump up the EC to nearly +2 to show the camera I want that to be white, then step back and take a shot with bounced flash, should I be pushing up the FEC as well as making that EC change?
Thanks Neil.
Catherine .. it sounds to me like the previous question would best be asked and illustrated with some specific examples in mind. A generic answer would just be confusing. But then, I’m still confused by that question. ; )
Back to your question … it sounds like you are shooting in an auto mode? And then locking your exposure? You’re making it tougher for yourself in working like that. You’d be better off shooting in manual, and metering the exposure like that, but dialing your settings so that your camera’s meter shows 1.7 – 2 stops over. ie … correct exposure.
In that case, you have taken care of the ambient exposure. Then your flash should be more of a fill-flash, rather than a dominant source of light. Hence you’d be working with a FEC of around -3EV.
Hopefully this makes sense.
If you were photographing your subject, and relying on flash to be the dominant source of light, then you’d have to work differently again in figuring out whether you have correct exposure. Then you’d most likely have ambient light (somewhat) under-exposed, and using TTL flash to take care of proper exposure. This then implies working with FEC around 0EV .. or perhaps more. And now we’re right back to the top of this article again.
Neil,
Not clear on this statement:
“With that image, my FEC was at +0.7EV since I needed 1.3 stops more light than my usual default to keep all the tones brighter. ”
How did you figure out that by +0.7EV FEC you’ll have 1.3 stops more light ?.
TIA,
JohnG
In a previous post I mentioned that I have my D3 and SB-900 combination set to -0.7EV as my default FEC.
Link this to the idea of pushing the tonal values up to the edge for the white areas of my subject via the histogram, I knew I had to be around there .. +1.3EV over normal, for correct exposure.
Since -0.7 is my default, adding 1.3 EV gets me to +0.7EV