fotografz Posted May 5, 2006 Share Posted May 5, 2006 Maybe an other side story to promote better understanding of how flash works? TITLE: "What's distance got to do with it?" First a little factoid: When you vary flash power like increase it or lower it, you are doing neither. You are increasing or decreasing the duration of how long it stays on. The amount of light is constant. BTW, this is why flash retains a constant color temperature whether weak or powerful ... it the same level of light every time. It's all so fast that you can't see it except the visual perception that there is more or less light coming from the flash. So, a flash can be 1/800th in duration when delivering it's maximum ... or 1/2500th of a second at it's minimum. Think of it like you would a shutter speed. BTW, this is why the shutter speed on the camera has no effect on light intensity from a flash. The sync speed of the camera is much lower than the flash duration. What DOES effect light intensity is distance. There is actually a formula to explain it but it just confuses some people. The fact we need to know is as light travels it's intensity lessens. That's why you have to pay attention to distance when using Manual flash. So, if you get the correct distance to subject set on the flash, the light falls off as it travels on further out to the background. That's why backgrounds in a dark room stay dark. But you can increase the amount of ambient light in the background by leaving the camera's shutter opened longer ... known as "dragging the shutter". It has little effect on the foreground flash subject because shutter speed doesn't effect flash (remember?) To illustrate the effect distance has on flash, I once saw some tourists on the observation deck of the Empire State building trying to shoot NYC with their P&S and flash at night. : -) Link to comment Share on other sites More sharing options...
picturesque Posted May 5, 2006 Author Share Posted May 5, 2006 Dolly--for the purposes of this assignment, don't put the diffuser on the flash--use the flash head straight ahead with no modifiers over it. Diffusers cut the power of a flash (how far it can go)--hence the distance change, and yes, these flashes are smart, but you have to be smarter to use them to their fullest potential. The distance goes away when you tilt the flash head up because tilting (and swiveling) assumes that you are bouncing the flash off a surface, and the flash has no way of knowing how far away the surface is--plus the fact that when you bounce, the beam of light has to go to a surface, bounce off the surface and go to your subject--no way for the flash to know this. Unfortunately, you can't do this assignment indoors (actually you theoretically can but it isn't the best situation for you to learn about fill flash outdoors) so wait for a better day--this assignment goes til the end of the month, so you have time. Link to comment Share on other sites More sharing options...
kari douma Posted May 5, 2006 Share Posted May 5, 2006 Thanks Nadine. I understood the reason for the ND filter, just didn't understand compensating for it with flash. Learning photography in this day and age, you don't always have to learn things before you do them. Your camera already knows how to do it! LOL! I'll work a little more with the exposures like you mentioned. (Yes, that beauty is my daughter!) Link to comment Share on other sites More sharing options...
kari douma Posted May 5, 2006 Share Posted May 5, 2006 Dolly, I use the SB800 too, and mine is metric. It displays distance in meters. Is yours in feet? Link to comment Share on other sites More sharing options...
picturesque Posted May 5, 2006 Author Share Posted May 5, 2006 I have to believe there is a way to show the distance scale in feet. There is a way to change from metric to feet on the 580EX, but it was a footnote buried in the manual. You might want to try and find it in the manual, Kari. Link to comment Share on other sites More sharing options...
mikestryinagain Posted May 5, 2006 Share Posted May 5, 2006 Nadine, we are getting rain here, so as soon as the sun returns I will actually do the outdoor fill assignment - samples are coming, I promise! Maybe I should try increasing dynamic range on a dull day (biting off more than I can chew I imagine!). Thanks for the volumns of info you all have posted here already! Link to comment Share on other sites More sharing options...
picturesque Posted May 5, 2006 Author Share Posted May 5, 2006 Kari, it's a custom function of the flash. Look on page 68 of the manual to learn how to change a custom function. Link to comment Share on other sites More sharing options...
picturesque Posted May 5, 2006 Author Share Posted May 5, 2006 Hi Michael--didn't see your post. Actually you can increase the dynamic range on a dull day with a flash. You set the camera to underexpose the ambient light, then use just enough flash to create the key light on your subject--the "just enough" part is the hard part with digital--you start at about 2 stops below "normal" and increase until you get just that little bit of key lighting on the skin, but that is a different thread. Link to comment Share on other sites More sharing options...
mikestryinagain Posted May 5, 2006 Share Posted May 5, 2006 Nadine, I figured that would be a future thread. Question on the 2 stop ND filter on the lens - whats the comp on the manual/auto flash, -2 stops as well? Link to comment Share on other sites More sharing options...
picturesque Posted May 5, 2006 Author Share Posted May 5, 2006 Michael--yes, but remember you cutting the light getting into your lens, "playing a trick" on your film/digital sensor, but your flash doesn't know this (is out of the loop) so you use the flash as if you hadn't put the ND filter on. So in the example used, with the 2 stop ND filter on, you use an aperture of f5.6 instead of f11, but you use the flash as if using f11 as your camera aperture, meaning, for a one stop less fill, you need f8 light for your subject. Gets really confusing with manual flash--even with auto thyristor. Any through the lens system won't get confused though. Link to comment Share on other sites More sharing options...
kari douma Posted May 6, 2006 Share Posted May 6, 2006 Thanks for the info on the flash Nadine and Dolly. I'll get that changed. I actually got to use some newly learned techniques today! I was an event photographer for the kickoff of an event called the Million Step Challenge. I had to take pictures of the days happenings. The registration was under a canopy. I metered outside the canopy, and used my flash on TTL-BL. I didn't have time to try manual. I was all over the place. I was just proud I tried this new technique. Before I would have metered for under the canopy, and blown out the background. This is straight from the camera, just resized JPEG.<div></div> Link to comment Share on other sites More sharing options...
picturesque Posted May 7, 2006 Author Share Posted May 7, 2006 Kari--there you go... Link to comment Share on other sites More sharing options...
wedding-photography-denver Posted May 7, 2006 Share Posted May 7, 2006 Well, Nadine/Marc/Ben and others, you rock. Seriously, I am so impressed with your willingness to take so much time in teaching this essential part of wedding work. Such a lot to read and so much detail. Great information, really. I don't remember 'getting it' as regards fill flash, but reading this thread has me thinking it will save some people months if not years of learning. Kudos. Link to comment Share on other sites More sharing options...
mikestryinagain Posted May 7, 2006 Share Posted May 7, 2006 Kari - nice balance of light there! Link to comment Share on other sites More sharing options...
kari douma Posted May 7, 2006 Share Posted May 7, 2006 Thank you Nadine. Thank you Michael. I owe it all to Nadine and Ben... and Marc, and CJo... ok, where do I stop? Link to comment Share on other sites More sharing options...
picturesque Posted May 7, 2006 Author Share Posted May 7, 2006 David--join in with some of your "pearls of wisdom", too... I'll be adding some info about flash power outdoors next week so stay tuned. Do we have any other assignments coming in? Link to comment Share on other sites More sharing options...
kari douma Posted May 7, 2006 Share Posted May 7, 2006 Nadine, Maybe you should start that as a new thread, kinda like part 2b or something? Then it wont be too burried. I was thinking of some qestions about flash power myself. (I'll wait until next week!) Link to comment Share on other sites More sharing options...
mikestryinagain Posted May 7, 2006 Share Posted May 7, 2006 Mine are coming soon Nadine. Another day of rain and clouds. I agree a new thread might be good for the next part. I am occassionaly having access problems with this thread and am not sure why. Link to comment Share on other sites More sharing options...
laurenm Posted May 8, 2006 Share Posted May 8, 2006 Nadine, just wanted to say thanks so much for doing this! I do plan to participate before the month deadline is up. I've been heavily distracted with my first wedding post processing. Link to comment Share on other sites More sharing options...
wedding-photography-denver Posted May 8, 2006 Share Posted May 8, 2006 Well I have a shot to offer today, using some of the discussion and advice here you can play and generally get pleasing results using the CWA method in cam. At least that is my finding. I think the camera (from my various tests) takes the center 20% of the image and applies 80% of its calculations from it. In this case it worked because I framed the white/black evenly to get the cameras meter to balance. This is a quick and reasonably decent way to get your light balanced for this kind of shot. I used less -comp on the flash, due to using it with a diffuser which takes about 2/3's of a stop from the flash output. I set my camera to Manual (before i began shooting in this area I took a quick reading and knew I wanted 1/200th and F10 for the backlight situation) and used center weighted average for the metering type. Shot with the 580ex dialed down -1/3 with the LSPJ pointed straight ahead (sometimes I will do -1 using the dome if the backlight is not so drastic/strong). Here is the result:<div></div> Link to comment Share on other sites More sharing options...
kari douma Posted May 8, 2006 Share Posted May 8, 2006 Thanks for the image and specs David! Nicely done! Link to comment Share on other sites More sharing options...
fotografz Posted May 9, 2006 Share Posted May 9, 2006 Funny, when shooting this past Saturday's wedding, I was faced with a no-shade sun drenched garden pics the Bride wanted. I thought of this assignment as I shot 2 dozen various shots all requiring everything posted in this thread ... and then some. It actually made it easier to accomplish because all of this information was fresh in my mind. Anyone can benefit from going over the basics. I posted this pic on Lauren's recent post: No shade anywhere to be found. Turned the Bride 3/4 back to sun, and applied fill flash.<div></div> Link to comment Share on other sites More sharing options...
fotografz Posted May 9, 2006 Share Posted May 9, 2006 Oh, Nadine ... maybe you should start a "Assignment #2 Results" thread since this one is getting buried with the learning part.<div></div> Link to comment Share on other sites More sharing options...
laurenm Posted May 9, 2006 Share Posted May 9, 2006 beautiful Marc! Yes, another thread would help those like me who are still trying to read this one. Although for many people's results, more discussion is required and thus is still "learning" info posted so maybe it would be confusing? Link to comment Share on other sites More sharing options...
kari douma Posted May 9, 2006 Share Posted May 9, 2006 "in camera pop-up flash used for fill : -)" Marc, you crack me up. You can make a beautiful portrait out of anything! All kidding aside, these are beautiful. The second one looks a little more shaded than the first. Was it? Or possibly a cloud? Link to comment Share on other sites More sharing options...
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