Lighting experts PLEASE HELP! - DPChallenge Forums

03/04/2005 09:27:47 PM · #1

Hi everyone! My lights arrived last night and I set up to experiment today. I am determined to do it right and learn the ins and outs rather than just clicking away and fixing stuff from the RAW file. So, with that in mind, I started shooted, analyzed the photo and histogram, made an adjustment, shot again and so on fine tuning things a bit at a time. So far so good. I started out today with one AB 800 and a softbox. My studio-in-progress is a room that has a LOT of natural light, so I really didn't need much from the bee. I started with it at full power, which was WAY too much, then turned it all the way down to 1/32 power, which worked but required a pretty high aperature. I wanted to blur the background somewhat, so I set it to 1/24th power after a while and opened the aperature a bit more.

I have some questions though, and hope that the lighting experts here will be kind enough to help me master this skill. I'll try to be specific.

FIRST ISSUE:
There seem to be times when the lighting in shots is different even though NOTHING has changed! Here's an example:

Notice how the first one is darker than the second, and not just in reflected light as a result of her looking up - even the backdrop is darker in the first. Any idea on what could be the cause of this?

SECOND ISSUE:
I shot the first of this series at f8, 1/125. That was WAY too bright, so I brought the shutter speed down to 1/500 which darkened the shot as expected, but why did only the top portion of the shot expose?? Since I'd only changed shutter speed, I bumped it back up a notch to 1/350, which resulted in the 3rd shot below. Again why is the bottom portion of the shot not visible (although it is a smaller portion)? Bumping the shutter speed another notch to 1/250 gave me the 4th shot below. That really confused me because shouldn't it be brighter as I opened the shutter for a longer time period with no other variables changing?

To recap, as I understand it, judging just by the numbers the image should be brightest at 1/125 and darkest at 1/500. What gives?

THIRD ISSUE:
I'm trying to figure out what is causing this strange shadow in her face. She's sitting directly in front of the softbox. My only guess is that I noticed by the catchlights that I am covering a teensy corner of the softbox in the shot that has the shadow in the face. (See close up.) But it's only a little bit. I guess I need to know if I really need to be THAT careful not to get in front of it at all?? I posted a second shot and closeup from that same series where I couldn't see myself in the catchlight. Notice that one also has no shadow. I may have answered my own question here. I'm just looking for feedback/confirmation on my hypothesis.

Thanks for any and all feedback you have to offer on these issue. I'm anxious to learn!

:)
Dawn

Mick

03/04/2005 09:37:49 PM · #2

Originally posted by just-married:

There seem to be times when the lighting in shots is different even though NOTHING has changed!

Do you think that this might be because you were using a mix of window light and strobe light? The ambient light gets brighter, so the shot gets brighter. Just a thought.

Originally posted by just-married:

I shot the first of this series at f8, 1/125. That was WAY too bright, so I brought the shutter speed down to 1/500 which darkened the shot as expected, but why did only the top portion of the shot expose??

The maximum synch speed of the camera is 1/250. If you want less light, then you need to either go to a smaller aperture, or turn down the lights. I usually shoot in a dark room so I can control all of the light.

Originally posted by just-married:

I'm trying to figure out what is causing this strange shadow in her face. She's sitting directly in front of the softbox. My only guess is that I noticed by the catchlights that I am covering a teensy corner of the softbox in the shot that has the shadow in the face.

I think you figured this one out. Standing in front of the softbox will cause shadows.

gwphoto

Canon EOS-1D Mark II

03/04/2005 09:51:17 PM · #3

If you don't have a flash meter you need to get one and then you need to shoot in manual mode.

KevinRiggs

Canon EOS-1Ds

03/04/2005 10:03:16 PM · #4

Dawn,

You make 1 correction and you'll find yourself in much more manageable waters: the 10D has a x-sync of 1/200th" (close Mick). Never ever set your shutter speed faster than 1/200th of a second if you want to achieve consistent results with the 10D. You can always go slower and just turn down the lights if you want (like 1/125th" or 1/60th") but nothing faster than 1/200th".

Once you make that change I think you'll notice that you can start to see consistent results and even predict what results you'll get.

With B-800's I'd suggest picking up a Cokin filter system ("P" size filter holder - P stands for professional which simply means that the filters are bigger across to accomodate the larger aperture lenses). The filter holder will cost about $10 USD. You also need a filter adapter that screws into the lens (example 52mm threads for $10 USD) so that you can then mount the filter holder onto the adapter ring. Last of all you finish this solution out by purchasing a neutral density filter like the P-153 for $12 USD or so. This $30 solution will allow you to turn up your lights and keep the f/8 aperture you've used or conversely leave you lights set to their very low output and ~TADA~ use a wider aperture on the lens to create some lovely bokeh around your beautiful model.

You don't have to go in for a filter system like this but for such an inexpensive investment you get more versatility out of your lighting.

Hope this helps,

Kev

dwterry

Canon EOS-1D Mark III

03/04/2005 10:07:28 PM · #5

About your shutter speed... you need to wrap your head around this idea:

If a strobe is your "main light" then shutter speed does NOT matter insofar as exposure is concerned.

In other words, if you had NO ambient light, and used only a strobe to light your subject, then 1/4, 1/30, 1/125, 1/200 will all produce the exact same exposure.

Why? Because your strobe is faster than any of those speeds. It turns on and off so fast that any one of those speeds is long enough to capture the full blast of the strobe.

Now... if your shutter speed is *too* fast, you'll simply be out of synch. Part of the shutter will still be closed as the strobe goes on and off. That's why the bottom of your picture lacked light.

So... ignoring for the moment the need for a specific shutter speed to either stop or to blur a moving subject, all that really matters then is your aperture and how much "ambient" light you want to let in.

If you're in a studio and you're controlling all the light, then it doesn't much matter. Use whatever shutter speed is appropriate for your subject.

However, if you're shooting a portrait of a businessman in his office, you would probably want to use a strobe as your main light, but with a *slow* enough shutter to let ambient light into the picture to give the businessman a "setting".

You could go as low as 1/4 second to get the effect you want. And don't worry, the man shouldn't get blurred by a slower shutter. The strobe will "freeze him" (as long as he doesn't move much). And if your camera is on a tripod, then the rest of the scene will also be frozen.

But before you do anything else ... run out and buy yourself a light meter. If you're going to use strobes you simply *must* understand your light. And your camera's light meter simply won't answer the question.

animes2k

03/04/2005 10:09:43 PM · #6

Originally posted by KevinRiggs:

You don't have to go in for a filter system like this but for such an inexpensive investment you get more versatility out of your lighting.

Why would you recommend shooting through a cheap filter in front of your quality glass instead of simply getting ND gels for the lights? They may end up cheaper ($5/ea), come in various densities and don't get between your quality glass and your subject... As it is, except for extreme envrionments, I don't even use filters on my lenses for protection - there's a reason I bought top of the line glass :)

Just a thought... ND gels on the lights seem like a better option (in studio) than ND in front of the lens. Indirect ambient light in the room shouldn't pose very much of a problem unless you're shooting with very low output from your strobes.

Message edited by author 2005-03-04 22:10:41.

KevinRiggs

Canon EOS-1Ds

03/04/2005 10:12:16 PM · #7

Originally posted by dwterry:

If a strobe is your "main light" then shutter speed does NOT matter insofar as exposure is concerned.

David's right. Brain fart on my part.

Good catch.

Kev

dwterry

Canon EOS-1D Mark III

03/04/2005 10:14:43 PM · #8

By the way, I took a look at your recent uploads in your portfolio. Your "Beside Myself" image is absolutely adorable! I've been trying some child photography lately and have come up with nothing that is even half as beautiful or creative as this image of yours!

KevinRiggs

Canon EOS-1Ds

03/04/2005 10:18:43 PM · #9

Originally posted by animes2k:

Originally posted by KevinRiggs:
You don't have to go in for a filter system like this but for such an inexpensive investment you get more versatility out of your lighting.

Why would you recommend shooting through a cheap filter in front of your quality glass instead of simply getting ND gels for the lights?

'Cause so far I've not seen any degradation in the quality of the shots. Frankly I think either solution would benefit Dawn's situation. I'm sure if you'd like to start a new thread regarding the negative effects of ND filters on pro glass you'll get some readers. I would like to see that topic discussed. Until you posted I was unaware that anyone found any reasonably measurable difference. From my standpoint, since either would work and the filters are useful for situations in which the photographer can't control the level of light I figured filters are just fine.

Kev

Sony DT 18-70mm f/3.5-5.6 Aspherical ED Zoom Lens for Sony Alpha

03/04/2005 10:46:56 PM · #10

Wow - you guys are not only helpful, but lightening fast!
OK, so let me process and respond.

First, I agree I do need to order a light meter. That's on the agenda; I've just been on a buying spree and haven't had time to research meters yet. Suggestions are welcome, of course.

Moving on, the whole "camera max synch speed" made perfect sense. Duly noted, and I love that it was such a simple answer. With one additional question. Mick notes it at 1/250. Kevin at 1/200. When I'm in manual mode and I click through shutter speeds, I don't seem to have a setting for 1/200. Is there a special way to set this, or have I missed something? Or does that mean that I shouldn't set it faster than 1/125 as that is the fastest speed possible which is lower than 1/200? This is, of course, not yet considering the shutter speed lesson David gave.

Which brings me to the mind-blowing ideas that David presented. Um, WOW. Ok, portrait work is new to me, and until tonight I've only used natural light, so this idea is completely foreign to me. It makes sense. It does. (Still convincing myself a little bit, though I know you're right. Hard to unlearn things.)

So, it seems I need to marry two concepts: shutter speed fast enough to stop motion (as I intend to shoot children, and they move quickly and unexpectedly) but slow enough to let the ambient light lend atmosphere. I guess it actually works the opposite of my thinking. I was thinking "I have so much light already, I only need a little more", but it seems I should be thinking "I have so much light that I need enough to drown that out." Do I understand that correctly? And if so, can you suggest a starting point. I'm in a room that has very bright natural light. All of the children's portraits in my portfolio were done with ambient light only. So, will the strobe light bright enough to act as my main light without blowing the highlights? (I have another 800 with an umbrella if necessary.)

OK, Cokin Filter vs ND gels:
First, cool concept! Seems very neat. I need to read some more one that, but my brain is overheating. I will come back to this idea. I don't suppose the gels vs filter makes much difference in my case as quality glass is not something I can afford at the moment. LOL. Still, I'd like to know if I can use gels in combination with a softbox or other light modifier?

David - your compliment brought a huge smile to my face. Thank you.

OK, off to bed tonight. Thanks so much for all of your help. I hope you'll be willing to further clarify on the questions I've raised here. I really do appreciate your efforts.

g'night.
Dawn

kiwinick

Sony DSLR-A550

03/04/2005 11:17:11 PM · #11

the easist way to sync your lights is to use a progammed flash at -3stops flash compensation and shoot in apature priority. Iuse this with my minolta 800si and studio flash all the time.

dwterry

Canon EOS-1D Mark III

03/04/2005 11:21:07 PM · #12

Originally posted by just-married:

Ok, portrait work is new to me, and until tonight I've only used natural light

And don't get me wrong... natural light is BEAUTIFUL light. :-) If you can use natural light, so much the better.

Originally posted by just-married:

So, it seems I need to marry two concepts: shutter speed fast enough to stop motion (as I intend to shoot children, and they move quickly and unexpectedly)

I have a friend who is using hot lights instead of strobes (1000W bulbs). The main reason is that he doesn't have to wait for the lights to recycle. But also because, as you said, kids move fast!

He has the new Canon 20D and just fires of round after round. That camera will shoot something like 5 frames a second for 20 frames straight (maybe more, I dunno). Anyway, he uses it to capture the cutest expressions.

I've gone the strobe route (can't stand hot lights in small places). So we have very different methods of shooting. I have to take time to set mine up and then hope they hold still. He has a lot more fun. :-)

Originally posted by just-married:

but slow enough to let the ambient light lend atmosphere.

Yes. *If* the setting is an essential part of the portrait. For example, your photo "Beside Myself" doesn't necessarily "need" ambient light (it could have been lit by strobes). But a portrait where a room or other setting plays an important role will be very different.

Another example... a bride standing at the window. In this case, the ambient light might be your main light and your strobe is just playing filler.

Originally posted by just-married:

I was thinking "I have so much light already, I only need a little more", but it seems I should be thinking "I have so much light that I need enough to drown that out." Do I understand that correctly?

Whether or not you drown out the ambient light really depends on the effect you're going for. For me, in my "tiny studio" ambient light doesn't contribute much at all. But out on location it does.

Originally posted by just-married:

I'm in a room that has very bright natural light. All of the children's portraits in my portfolio were done with ambient light only.

Wow, that's impressive. What shutter speed, aperture and ISO are you using?

Originally posted by just-married:

So, will the strobe light bright enough to act as my main light without blowing the highlights? (I have another 800 with an umbrella if necessary.)

Sure. If you want less ambient light, you simply increase shutter speed. If you want more, then you decrease it.

I'd start with what you already know (from your current ambient light photos) and adjust from there.

Let us know if you have any questions about using a light meter when you get it.

animes2k

03/05/2005 05:29:27 AM · #13

Originally posted by KevinRiggs:

Originally posted by animes2k:

Originally posted by KevinRiggs:
You don't have to go in for a filter system like this but for such an inexpensive investment you get more versatility out of your lighting.

Why would you recommend shooting through a cheap filter in front of your quality glass instead of simply getting ND gels for the lights?

'Cause so far I've not seen any degradation in the quality of the shots. Frankly I think either solution would benefit Dawn's situation. I'm sure if you'd like to start a new thread regarding the negative effects of ND filters on pro glass you'll get some readers. I would like to see that topic discussed. Until you posted I was unaware that anyone found any reasonably measurable difference. From my standpoint, since either would work and the filters are useful for situations in which the photographer can't control the level of light I figured filters are just fine.

The relative merits of filters (in general) has been discussed plenty of times, I'm sure. I decided I'd try it without filters and for most situations, prefer it. The proper filter is key, of course (skylight/uv/etc) as a protection measure. If you get the wrong one, you've got a color shift (however minor) introduced (can't remember which one it is, now)... My biggest filter issue came with my 16-35, as flare and reflections would pose a problem (even with a very expensive BW filter) and I've been happy without them for a while now.

I don't have any ND filters, but would consider them for some of the autosports work I do under full sunlight - I don't necessarily want a fast shutter (pans and motion blurs). I have used a circular polarizer to limit light in the past, though. It helps.

I just figured in this case (in a studio) ND gels would be ideal - I've used them before, they work great and they're really rather cheap. If you have the desire for natural-light filtering then yes, an on-lens filter would be ideal. It's all a matter of what you need to achieve.

03/05/2005 07:45:44 PM · #14

Originally posted by dwterry:

I have a friend who is using hot lights instead of strobes (1000W bulbs). ...just fires of round after round. That camera will shoot something like 5 frames a second for 20 frames straight (maybe more, I dunno). Anyway, he uses it to capture the cutest expressions.

I use continuous mode quite a bit as well. The strobes seem pretty good at keeping up so far. The 10D only goes 9 shots at a time. I've had to wait for the camera more often than the lights when I practiced with a friend's strobes. This definitely seems to be a key in capturing those fleeting expressions.

Originally posted by dwterry:

Originally posted by just-married:
I'm in a room that has very bright natural light. All of the children's portraits in my portfolio were done with ambient light only.

Wow, that's impressive. What shutter speed, aperture and ISO are you using?

Usually 1/60 or 1/90, f3.5, 400. The slow shutter limits me though and I often lose a shot because the baby moved or because I didn't have the camera still enough. (A tripod has been totally impractical for the kind of sessions I've been doing.) This is actually the reason I've decided to buy lights - controllable, reliable, predictable.

Thanks for all the answers and encouragment. I need to upload todays shots and see how I did. I also need to start looking for a meter. :)

03/05/2005 07:48:27 PM · #15

Originally posted by kiwinick:

the easist way to sync your lights is to use a progammed flash at -3stops flash compensation and shoot in apature priority.

I don't understand what this means. I need the for dummy's version please. ;)

Mick

03/05/2005 08:29:53 PM · #16

Originally posted by KevinRiggs:

You make 1 correction and you'll find yourself in much more manageable waters: the 10D has a x-sync of 1/200th" (close Mick). Never ever set your shutter speed faster than 1/200th of a second if you want to achieve consistent results with the 10D.

This is interesting. I just checked the 10D manual and you're right. It says, "The EOS 10D can synchronize with compact, non-Canon flash units at shutter speeds of 1/200 sec. or slower. With larger studio flash units, the flash sync speed is 1/60 sec. or slower." But, I have used my 10D to fire my B400s at 1/250 many times and never noticed any problems with the exposures. I normally shoot around 1/125 or so though.

Mick

03/05/2005 08:42:32 PM · #17

Originally posted by just-married:

Moving on, the whole "camera max synch speed" made perfect sense. Duly noted, and I love that it was such a simple answer. With one additional question. Mick notes it at 1/250. Kevin at 1/200. When I'm in manual mode and I click through shutter speeds, I don't seem to have a setting for 1/200. Is there a special way to set this, or have I missed something? Or does that mean that I shouldn't set it faster than 1/125 as that is the fastest speed possible which is lower than 1/200?

Kevin was right, the flash sync speed on the 10D is 1/200 sec. or slower. However, to set the camera to 1/200 you need to tell the camera to use 1/3 stop increments. This is done by changing the setting of custom function #6 from 1/2-stop to 1/3-stop.

Sorry for the confusion.

Prof_Fate

03/06/2005 08:46:26 AM · #18

Originally posted by just-married:

Those shots yo have that are darker than others, but all underexposed - if you ar using continous shooting you have found the problem - perhaps your camera can do 9 FPS, but the stobes CANNOT resyslte that fast, so they willl fire with a partial charge and less light. Read the AB manuals - full power recharge can take a second or more!

As to adjusting light levels - you can move the strobes farther back from the subject, set them at lower settings, add more diffusing material.

A friend of mine that does glamour studio type work never sets his AB800 above 50% - WAY too bright (F11 ISO 100 1/200sec) Make sure your ISO is at 100 not 400. You can custom WB (and should) or use the FLASH setting.

There are as many ways to set up the lights as there are people here at DPC. Get a book or two and have a read. Unless you have a need for the daylight, make the room dark. One of the benefits of strobes in total light control, so lose the ambient light!

After my first experience with strobes, I don't want to go back to hot lights!

gwphoto

Canon EOS-1D Mark II

03/06/2005 09:55:16 AM · #19

Photographing small children is like trying to put tooth paste back in the tube. The best thing you can do is find several different noise making devices, ie; whistles, clickers or someting. Get your shot ready and framed, use some kind of a cable release to trip the shutter and just watch for the moment, activate the noise maker and when the child looks up to see what made the noise, click the shutter.. It works most of the time until they get use to the noise... A cable release will save your back.

les0910