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DPChallenge Forums >> Tips, Tricks, and Q&A >> What is going on with my flash? (indoor lighting)
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 10/18/2009 06:11:09 PM · #1
Okay, I have a paid headshot gig on Wednesday, and I'm practicing up because I'm still not used to using any artificial lighting (OddessyF22 lent me his old Nikon Speedlight SB-27) so I dragged my boyfriend upstairs for me to practice on--ignore the goofy expressions.

I had it mounted to an old crappy tripod with painter's tape for the time being because I don't have a lightstand. I had my camera mounted on a tripod, was using my 50mm lens, had my shutter release cable attached and a PC cord attached. All kind of irrelevant, but I'm including it anyway, just in case.


The first four takes were fine aside from crappy lighting while I fixed exposure and stuff.


I moved the light and got this shadow across a quarter of the frame, couldn't figure out how to get rid of it for the next 13, even moving to another room didn't help. I changed settings on the flash, I moved him around, no cords in the way of my lens, nothing. They all looked fine in the viewfinder and shitty in playback. I know it's nothing on my sensor or anything, I shut off the flash and it stopped doing it, so I know it's something I'm doing wrong with the lighting.


I don't know when this happened, it started taking up almost the entire frame even when I took the flash off the tripod and hand held it and moved it around. What could be happening? I had to stop because I was so frustrated at the whole thing.

What could I be doing wrong?
 10/18/2009 06:13:19 PM · #2
It looks like your shutter speed is faster than your sync speed, so you are seeing a shadow of your shutter. Check the sync speed on the flash and make sure not to make your shutter speed faster than that. On my canon the top speed is about 1/200 to 1/250. Hope this helps,

Claire

edit to add: You might want to put something in front of the flash to soften the light, perhaps a sheet? Good luck with your shoot!

Message edited by author 2009-10-18 18:14:26.
 10/18/2009 06:20:12 PM · #3
Originally posted by lovethelight:
It looks like your shutter speed is faster than your sync speed, so you are seeing a shadow of your shutter. Check the sync speed on the flash and make sure not to make your shutter speed faster than that. On my canon the top speed is about 1/200 to 1/250. Hope this helps,

Claire

edit to add: You might want to put something in front of the flash to soften the light, perhaps a sheet? Good luck with your shoot!


I am such a noob. Thank you! I feel retarded. I don't know what the sync speed is on it, I have to shoot in manual because it's a Canon camera and a Nikon flash--how can I tell the sync speed? That has to be it. The quarter ones are shot at 1/500, and the almost entirely covered ones are shot at 1/1250. The 1/320 and below don't have it. Is there a way to raise the sync speed? Making the flash more or less powerful, or changing camera settings? Or is it just a fixed thing?
 10/18/2009 06:27:30 PM · #4
Unfortunately I think sync speed actually has to do with your camera. I know nikon cameras can sync much faster than canons. You just need to make sure you stay at a shutter speed that doesn't miss some of the flash. I don't know a huge amount about it, I just know for the most part I can't go above about 1/250 and when I used a nikon I was going up into the thousands.
 10/18/2009 09:14:06 PM · #5
Yup it is sync speed--but this is no problem to fix. Keep your aperture set the same and just keep slowing down your shutter. I bet at 1/200 or 1/160 you'll be fine :)
 10/18/2009 09:45:34 PM · #6
Originally posted by chromeydome:
Yup it is sync speed--but this is no problem to fix. Keep your aperture set the same and just keep slowing down your shutter. I bet at 1/200 or 1/160 you'll be fine :)

What he said, sort of. You want to keep your shutter speed below 1/200, which is a fairly typical "sync speed" for many camera/flash combos. Set your shutter at 1/160 and keep narrowing your aperture (the aperture value increases as you narrow it down). Keep going until you see what you like. 1/160 at f/8 is a pretty common flash/exposure setting.
 10/18/2009 09:50:36 PM · #7
Originally posted by lovethelight:
I just know for the most part I can't go above about 1/250 and when I used a nikon I was going up into the thousands.

Was it a D40x, by chance? That camera uses a different shutter curtain than the rest of the DSLR world. Electronic vs. Leaf, or something like that.

If you're using a Canon flash like the 580 EX II on a Canon body, you should be able to hit the "high speed sync" button on the back of the flash....you can get up to around 1/800 or higher.
 10/18/2009 09:51:19 PM · #8
I think 1/200 is your max sync speed. That blackness in the shots caused by the shutter moving faster than the flash; the first part of the image beats the flash and doesn't get exposed, while the later parts do.

Here's something to remember when working with flash: aperture controls the flash exposure, shutter speed controls the ambient exposure.

What that means is, stopping the lens up or down without changing the flash settings will increase/decrease the amount of flashed light that exposes. The shutter speed will do the same with any natural light in the scene, but since there's a max sync speed, this only really works in weaker light (on sunny days, the ambient will be too bright).

Practice in an average room in the evening; get your subject lit well with the flash, then play with the shutter speeds. At 1/200, you should see that the subject remains well lit, but the background is very dark (if the ambient is low). Try again with the shutter at 1/30 and you should see the background brighten up a lot, while the subject remains about the same.
 10/18/2009 10:52:50 PM · #9
Once you get the sync speed figured out, you may be able to adjust the flash some as well. Most flashes have a manual mode where you can set the flash power to 1/2- 1/4-1/8 ect. If you lower the flash level, you can open the aperture some and get more ambient light if you want.
10/18/2009 11:47:55 PM · #10
Thank you for all your help, everyone! What do I do if I want a fairly small aperture? I usually shoot at around 3 or 4, I love the narrow depth of field. I guess there's no way around that, is there? When I was shoot at 1/320, that worked for me actually, the first picture up there was 1/320.
 10/19/2009 12:05:15 AM · #11
Try turning the flash level down some if you want to shoot wide aperture for shallow DOF. If you can't figure out how to turn it down, put a layer or two of white cloth over the flash lens to reduce the amount of light it can put out. That will also soften the light some.
10/19/2009 12:06:12 AM · #12
Originally posted by sammigurl:
Thank you for all your help, everyone! What do I do if I want a fairly small aperture? I usually shoot at around 3 or 4, I love the narrow depth of field. I guess there's no way around that, is there? When I was shoot at 1/320, that worked for me actually, the first picture up there was 1/320.


My advice would be to set your camera to manual, choose your desired aperture, set a high shutter speed (in the region of 1/150 - 1/200). After that just set your flash to manual and keep adjusting the power until you get the result you want. This is quite an imprecise way of doing things and you might waste battery power on your flash but at least it'll give you a feeling for how adjusting flash power affects the result, and you get your desired DOF.

Check out Strobist for a great intro on off camera flash. It takes a bit if reading but it's really worth it in the end.

p.s make sure you're ISO is at around 100 - 200 too or you'll find it hard to stop overexposures!

J
 10/19/2009 12:37:45 AM · #13
I'm wondering which cameras have an x-sync or flash sync button or knob to automatically put the camera in the correct sync speed?
 10/19/2009 12:54:02 AM · #14
If your flash happens to be so primitive you can't reduce the power output (unlikely) then you can flash through a scrim, or a sheet of paper, whatever, to reduce the light.

BTW, you said you "want a fairly small aperture", that you shoot around 3 or 4... That's a LARGE aperture (big hole, allows more light through); a small aperture would be like 16, 22, down in that range.

I you want to be shooting "wide open" (at a large aperture fore shallow DOF, you are going to have to have a system for reducing the flash output, whether it can be done on the unit (1/4 power, 1/2 power, whatever) or must be done by flashing through something translucent.

R.
 10/19/2009 12:54:09 AM · #15
Okay, I'll try this all again tomorrow afternoon with everything you've said in mind. Thank you!

And yeah, I know how to reduce the power on the flash and everything. I think it was just too close to him, even at 1/16th power.

Edit to provide more details.

Message edited by author 2009-10-19 00:55:49.
 10/19/2009 01:26:31 AM · #16
Originally posted by sammigurl:
Okay, I'll try this all again tomorrow afternoon with everything you've said in mind. Thank you!

And yeah, I know how to reduce the power on the flash and everything. I think it was just too close to him, even at 1/16th power.

Edit to provide more details.


I don't know how big your flash is, but you can use an exacto knife on a pingpong ball or some such to create a diffuser that slips on to reduce and soften the light considerably.

R.
 10/19/2009 11:13:11 AM · #17
Originally posted by david_c:
Originally posted by lovethelight:
I just know for the most part I can't go above about 1/250 and when I used a nikon I was going up into the thousands.

Was it a D40x, by chance? That camera uses a different shutter curtain than the rest of the DSLR world. Electronic vs. Leaf, or something like that.

If you're using a Canon flash like the 580 EX II on a Canon body, you should be able to hit the "high speed sync" button on the back of the flash....you can get up to around 1/800 or higher.


Yup it was a D40. I had no idea the 580 could do that, the flash is so expensive but it seems to have so many useful capabilities. I am not going to get it but for someone who isn't using any other form of strobe it seems like a great portable substitute.
 10/20/2009 06:27:25 AM · #18
Originally posted by faidoi:
I'm wondering which cameras have an x-sync or flash sync button or knob to automatically put the camera in the correct sync speed?


There is no controlling it, technically. It's a mechanical limitation because of how the shutter functions. In vertical curtain shutters (what many DSLR's have) you have two pieces that slide down in front. If you increase your shutter speed above your sync speed the full sensor is no longer exposed entirely during the flash because the second curtain starts to come down before the flash fires and the other curtain has reached the other side, hence the bars. Remember you don't have to shoot at the sync speed, you just can't exceed it.
You CAN manually set things and see what you can manage to push, different bodies will go to different amounts and you can also use the resulting light drop off to your advantage. See video
Dedicated flashes offer what is called (at least in Nikon-speak)Auto FP mode, which makes the flash function differently in that the flash pulses multiple times very close together in order to enable high shutter speeds with flash (as noted by david_c. The disadvantage? A giant, giant drop in flash power. You can do a similar (though admittedly different) thing to this yourself with non-dedicated flashes. It is explained well in this tutorial. It works because the scene is dark without the flash and the duration of the flash is extremely short, so the subject is only lit for the miniscule amount of time the flash tube lights for. The duration of the OP's SB-27 is noted here on page 91.
The D70 also syncs to 1/500, as noted in the tutorial, making it very versatile. There are other cameras with other types of shutters that enable them to have faster sync speeds as well. The D1x is another example of this which uses an electronic shutter in addition to the physical shutter so it essentially has an unlimited sync speed in practice.

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