Flash/light meter readings

oblivion

oblivion

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Hi all, I am purchasing a lighting kit shortly having just used one in a studio. I used a flash meter to get the correct exposure and I understand the concept of its use and how handy it can be.

My question is do I really need to fork out the extra money on getting one when I can take a few test shots and adjust the f-stops accordingly to what (I believe looks a correct exposure). I understand this may be a little more time consuming to do but not by much surely.

I have a light meter reading app on my iPhone ad again I know this is only a guide but it cost me nothing.

Awaiting your thoughts
 
My opinion is , if you want to do it right and get professional results, then you'll need a meter, but you also need to know how to use it and also need to know how to correctly use studio lights, you can chimp but looking at a 3" screen is just a guidance.
 
I probably will get one anyway but may have to wait for the funds to be available. Having just purchased a very expensive laptop I will probably tether the images direct into Lightroom which will benefit me no end.

On a different topic altogether a few years ago I paid for a professional photographic company to take some family shots. In talking mega bucks now. I chose 4 pics altogether from the 200 taken and that set me back £800, however, they offered me the rest of the pictures on a dongle USB stick for £600 but stated I would not be able to print them due to the dongle software. I argued over this at the time stating that if I could see the picture on my pc then I could copy it and print it but they said it was not possible. Have you heard of this and we're they telling the truth? We were not discussing the copyright issue by the way but merely the ability to print them.

If this is true then what software is out there to do this especially for dongles?
 
oblivion said:
I probably will get one anyway but may have to wait for the funds to be available. Having just purchased a very expensive laptop I will probably tether the images direct into Lightroom which will benefit me no end.

On a different topic altogether a few years ago I paid for a professional photographic company to take some family shots. In talking mega bucks now. I chose 4 pics altogether from the 200 taken and that set me back £800, however, they offered me the rest of the pictures on a dongle USB stick for £600 but stated I would not be able to print them due to the dongle software. I argued over this at the time stating that if I could see the picture on my pc then I could copy it and print it but they said it was not possible. Have you heard of this and we're they telling the truth? We were not discussing the copyright issue by the way but merely the ability to print them.

If this is true then what software is out there to do this especially for dongles?
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The main advanatge of a meter is in setting up multiple lights and adjusting ratios. It's much easier, but for the most accurate overall exposure settings, read the LCD/histogram with blinkies enabled. That tells you what you've actually got, rather than what the meter thinks you should have. They are often not the same.

The images on the USB stick were probably very low res, so printable, but not very big. They will also not have been post processed much, if at all. Might have a watermark too.
 
I histogram is only any good, if you know what your expecting it to look like,
 
As said above, get the light meter when you can. Chimping is not very accurate, and having more than 1 or 2 lights will get difficult. :)
 
oblivion said:
You said the most accurate is the histogram and I read an article that says this is not true, see here http://www.scantips.com/lights/metering2.html

Just when I thought I was getting somewhere someone puts a downer on things!
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Looks like an interesting link. I'll read it later.

The point I was making is that the meter has no knowledge of what happens after the light enters the lens.

It assumes that the lens' transmission is the same as the f/number, which is often isn't. It assumes that the aperture closes down accurately to the set f/number (they're often a bit out, especially at high f/numbers), and it assumes that the sensor calibration is the same as the meter which is probably 18% grey whereas the camera may be 15% or even 12%. Not to mention user error with the meter of course, or things like Expose To The Right technique.

If all these things compound one way, you can find yourself a stop out. There was a thread on here a while ago where two cameras working in the same studio were giving different results that were at least that far apart. And the option of ETTR technique is not available to you at all without a histogram/blinkies.

Of course you have to know how to read the histogram, know your camera's calibration, and know how the in-camera pre-sets affect it (particularly the contrast setting in picture styles). But all that knowledge is available to you, if critical accuracy is the objective.
 
As Richard says, there can be variables - but once those variables are known they can be compensated for, so personally I don't think it's a real problem.

Relying on a monitor display though isn't an option - even if the monitor is calibrated correctly the apparent affect is influenced by the level of ambient light falling on it, which can vary enormously, so you basically have a choice of the two more objective methods, meter or histogram.

I'm very much 'a meter man' because I just find it so much easier/quicker than reading a histogram, but using a histogram is also a valid method, so I feel that, for most people and most situations, it really just comes down to personal choice.
 
Garry, most of the time you're right of course. You can use a meter reading and get reliably accurate results.

But the the variables of lens transmission and aperture accuracy can make a significant difference, and they are often not known and can also be variably variable!

With quality gear, no problem, but with a cheaper consumer grade zoom for example, transmission can vary from marked according to focal length (not to mention vignetting) and at higher f/numbers like f/11 or f/16, not only can the aperture be out, but it can change a bit shot to shot due to mechanical tolerances. Change lenses and you will often notice a slight difference.

I don't want to make a fuss about it, and it would be unlucky to have a serious problem, but the potential for error is there and the histogram/blinkies automatically takes everything into account whereas a hand meter cannot. If you want to be really accurate, or use ETTR technique, then the histogram is better. It's very easy to check of course and it can be interesting to compare the two methods ;)
 
Some very interesting feedback I must say and thank you for your input. Assuming a family member is generous enough come my birthday then what light meter should I be aiming for as there seems to be varied ones available, are they dependent on what lights you have or camera or both? For ref I have the canon 550d and am purchasing the d-lite it 4 kit shortly. How effective is the iPhone apps or metering in the meantime (if u have tried this) ?
 
oblivion said:
Some very interesting feedback I must say and thank you for your input. Assuming a family member is generous enough come my birthday then what light meter should I be aiming for as there seems to be varied ones available, are they dependent on what lights you have or camera or both? For ref I have the canon 550d and am purchasing the d-lite it 4 kit shortly. How effective is the iPhone apps or metering in the meantime (if u have tried this) ?
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It's very much a case of a meter is a meter is a meter, they vary in terms of features and build quality but they all do the job.

Personally I use a Minolta, mainly because if I drop it I can pick it up and carry on using it - with some meters, you just kick the bits into the corner if you drop them:)
 
oblivion said:
Some very interesting feedback I must say and thank you for your input. Assuming a family member is generous enough come my birthday then what light meter should I be aiming for as there seems to be varied ones available, are they dependent on what lights you have or camera or both? For ref I have the canon 550d and am purchasing the d-lite it 4 kit shortly. How effective is the iPhone apps or metering in the meantime (if u have tried this) ?
Click to expand...

Sekonic L-308s is the one most people use. Does everything you want for a reasonable price, £125-ish. 358 is nice too, couple of handy extra features, but the prices jump higher in the range.
 
HoppyUK said:
Looks like an interesting link. I'll read it later.

The point I was making is that the meter has no knowledge of what happens after the light enters the lens.

It assumes that the lens' transmission is the same as the f/number, which is often isn't. It assumes that the aperture closes down accurately to the set f/number (they're often a bit out, especially at high f/numbers), and it assumes that the sensor calibration is the same as the meter which is probably 18% grey whereas the camera may be 15% or even 12%. Not to mention user error with the meter of course, or things like Expose To The Right technique.

If all these things compound one way, you can find yourself a stop out. There was a thread on here a while ago where two cameras working in the same studio were giving different results that were at least that far apart. And the option of ETTR technique is not available to you at all without a histogram/blinkies.

Of course you have to know how to read the histogram, know your camera's calibration, and know how the in-camera pre-sets affect it (particularly the contrast setting in picture styles). But all that knowledge is available to you, if critical accuracy is the objective.
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I was mistaken. It's not an interesting link - poorly written, confusing, and not very helpful :thumbsdown:
 
HoppyUK said:
Sekonic L-308s is the one most people use. Does everything you want for a reasonable price, £125-ish. 358 is nice too, couple of handy extra features, but the prices jump higher in the range.
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^^^ This :)

I have one btw.
 
Amazon recommends the sekonic so I would probably get that one. It all seems a little far fetched when I can just make adjustments on the camera should the picture not look ok. I understand that the true colour of the picture when printed may differ slightly to what my pc shows. At the end of the day it's what I like that counts rather than "correct exposure" surely. Either way it will end up in Lightroom for adjustments slightly
 
oblivion said:
Amazon recommends the sekonic so I would probably get that one. It all seems a little far fetched when I can just make adjustments on the camera should the picture not look ok. I understand that the true colour of the picture when printed may differ slightly to what my pc shows. At the end of the day it's what I like that counts rather than "correct exposure" surely. Either way it will end up in Lightroom for adjustments slightly
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Yeah, its all in the edit LMFAO
 
Ok here comes the stupid question cus I feel real thick now, bear in mind in still learning. Today I received a D-lite it 4 kit lights which are great. Instructions are poor but thanks to YouTube I am getting by.

Ok, the stupid bit of me wants to know the following:

1) It came with a wireless trigger which I attached to my hotshoe. I set the camera to Manual and the shutter to 1/250 with ISO 200. When I take a picture the wireless trigger sets the lights off perfectly and all is great. I have no idea what would happen if I went with a higher shutter or lower so could someone explain that to me in baby language please.

2) I have no speedlight flash for my camera, other than the built in one. The kit came with a sync cable which blatently plugs into the back of the light but then to where I don't know? The instruction manual tells me to plug it into the light but that's it, nothing else......I can only assume that the other end would plug into a flash attached to the hotshoe (which I don't have).... If that's correct then where then would I attach the wireless trigger? God I sound pathetic don't I !

3) considering that I don't have a speedlight, and therefore just using the two softboxes, do I need to sync anything at all?

It's all a little confusing at the mo for me so please be gentle
 
oblivion said:
Ok here comes the stupid question cus I feel real thick now, bear in mind in still learning. Today I received a D-lite it 4 kit lights which are great. Instructions are poor but thanks to YouTube I am getting by.

Ok, the stupid bit of me wants to know the following:

1) It came with a wireless trigger which I attached to my hotshoe. I set the camera to Manual and the shutter to 1/250 with ISO 200. When I take a picture the wireless trigger sets the lights off perfectly and all is great. I have no idea what would happen if I went with a higher shutter or lower so could someone explain that to me in baby language please.

2) I have no speedlight flash for my camera, other than the built in one. The kit came with a sync cable which blatently plugs into the back of the light but then to where I don't know? The instruction manual tells me to plug it into the light but that's it, nothing else......I can only assume that the other end would plug into a flash attached to the hotshoe (which I don't have).... If that's correct then where then would I attach the wireless trigger? God I sound pathetic don't I !

3) considering that I don't have a speedlight, and therefore just using the two softboxes, do I need to sync anything at all?

It's all a little confusing at the mo for me so please be gentle
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What camera do you have, and just to be clear, is that a Skyport trigger you have, or Skyport Speed?

Edit: Oh, right, I see above it's a Canon 550D. That will only sync up to 1/200sec, and unless that's a Skyport Speed you've got, realistically 1/160sec with that trigger. If you go too high, you'll get a black band at the bottom of the pic but you can go as low as you like, except that this can allow ambient light to influence the exposure.

The sync cable plugs into a PC port on the camera, that you don't have. You'd need to buy a hot-shoe/PC adapter, but there's no point. Use the radio trigger to fire both heads as they both have receivers built in.
 
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Yes the 550d. Thanks for replying. The kit as you say has built in receivers so I just attach the skyport to my hotshoe, but do I still need to sync anything as all I have done is attach it and started taking pictures ad it all seems to be working great. The manual says to hold down the test button for 5 secs which I have not yet done but need to probably read the manual again
 
Oh right, according to the manual the normal and speed sync mode is available with my kit. It states the speed mode will sync DSLR up to 1/250s and normal will sync DSLR up to 1/160s. I take it from that then I can shoot at 1/250s giving me some extra stops?
 
oblivion said:
Oh right, according to the manual the normal and speed sync mode is available with my kit. It states the speed mode will sync DSLR up to 1/250s and normal will sync DSLR up to 1/160s. I take it from that then I can shoot at 1/250s giving me some extra stops?
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Although some clever stuff can be done with radio triggers that allows people to push the limits a bit, the weak link (or bottleneck) in the system is always the camera shutter.

The camera shutter needs to be fully open when the flash is fired, if it isn't then only part of the sensor is uncovered at the time that the flash fires and you typically see an out of focus black line at the bottom of the frame, caused by the second shutter curtain starting to close.

Logic tells us that the smaller the sensor, the smaller the area that needs to be uncovered by the shutter and that because of that it should be possible to use a higher shutter speed with flash on a cropped frame camera than on a full frame one, but full frame cameras tend to be designed for the pro market and the shutter, although larger, moves faster and can allow faster shutter speeds to be used.

On your camera, the limit is 1/200th second, full stop. You may or may not get away with using 1.250th but it isn't worth the risk trying it because there is nothing to be gained from doing so. Other camera models may vary. If you want to use really fast shutter speeds with flash then you need to use a camera fitted with a between lens (not a focal plane) shutter but there are very few of those cameras on the market and they aint cheap:)

But this is all theoretical as far as you are concerned, because you are using your flash kit indoors and the amount of ambient (constant) light in the room is going to be too low to visibly affect your flash shots. If you were shooting outdoors in bright sunlight it would be different.

That's the long(ish) answer.
The short answer is to set your camera shutter speed to no faster than 1/200th, my normal setting is 1/125th second.
 
oblivion said:
Oh right, according to the manual the normal and speed sync mode is available with my kit. It states the speed mode will sync DSLR up to 1/250s and normal will sync DSLR up to 1/160s. I take it from that then I can shoot at 1/250s giving me some extra stops?
Click to expand...

The Skyport speed mode will only sync up to 1/250sec, if your camera allows it. Nominally, the 550D will only run clean up to 1/200sec regardless, but there is often a little leeway and you might get a way with it, though you may get a slighly different result with different flash heads/guns, and certainly with different triggers.

Easy enough to test. Point the flash at a plain wall and take a series of pictures from say 1/125sec to 1/400sec (all other exposure settings the same). At the higher end, you will get a dark band appearing at the bottom, which is a shadow of the focal plane shutter closing.

You may also find that at around 1/250sec you are not getting the dark band, but there is very slight shading at the bottom and the overal exposure is fractionally darker. That's the flash pulse as it ramps up to full brightness, just as the shutter is closing. So to make sure every exposure is always 100% clean, knock the shutter speed down one click.

There is no downside to this in a studio situation, as any ambient light will be massively outweighed by the flash. It only becomes an issue when trying to balance ambient daylight exposure with flash outdoors.
 
Many thanks again for your responses, I'm getting there and have lots to practice. I have two lights in the kit and have been using one as a background and the other to light my subject (my kids). The results are impressive with a lovely clean white background. All I need to try now is to create a black background and I'm happy. Someone suggested to underexpose whilst using a light source close to the face, another idea was to use a very fast shutter to guarantee the black shot and manually fire the flash, seems tricky to me.

My other half got me a 4 hour studio beginners session for Xmas which I used up last week. Whilst there I mentioned I was getting some lights and the "professional photographer" asked me if I had any questions. I said yes actually, I had read up about the "inverse square law" and that some people said this affects the indoor use of lights in a smallish room, and could he give me his opinion. He looked at me gone out asking what the "inverse square law is"?

Either I have been told porkies or the YouTube clip about this is wrong or this is not common knowledge amongst photographers? I lost a little confidence at that point thinking surely he should know this?
 
oblivion said:
Many thanks again for your responses, I'm getting there and have lots to practice. I have two lights in the kit and have been using one as a background and the other to light my subject (my kids). The results are impressive with a lovely clean white background. All I need to try now is to create a black background and I'm happy. Someone suggested to underexpose whilst using a light source close to the face, another idea was to use a very fast shutter to guarantee the black shot and manually fire the flash, seems tricky to me.

My other half got me a 4 hour studio beginners session for Xmas which I used up last week. Whilst there I mentioned I was getting some lights and the "professional photographer" asked me if I had any questions. I said yes actually, I had read up about the "inverse square law" and that some people said this affects the indoor use of lights in a smallish room, and could he give me his opinion. He looked at me gone out asking what the "inverse square law is"?

Either I have been told porkies or the YouTube clip about this is wrong or this is not common knowledge amongst photographers? I lost a little confidence at that point thinking surely he should know this?
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We can only hope that he misunderstood the question. The inverse square law is crucuial to studio photography. It is simply this - double the distance of the light to subject, and the brightness is reduced to one quarter - two stops. Strictly speaking the ISL only applies to a point light source, but it holds pretty true for any light used in photography. Basically, the light falls off very quickly and you can use this to your advantage.

For example, if you want to make your white background darker, as you mentioned above, move it back and at the same time move the light closer to the subject to increase the relative ISL fall-off. Though you'll struggle to make is completely black, with a bit of distance it will go dark grey.

Another thing you need to know is angle of incidence equals angle of reflection, ie light bounces of a surface (eg a reflector) at the same angle it strikes, like a snooker ball off the cushion.

The other one is that the larger the light source, the softer the shadows, eg softbox/brolly vs small light modifier. And also, size is relative to distance so with a big softbox, as you move it back the light will become harder.

These three factors are fundamental and will be relevant to every picture you take.
 
oblivion said:
I too thought he misunderstood so I told him it was all to do with light fall off. I explained there is a really good clip online and he still looked at me
gone out!!!

Clip here if you wanted to see it http://www.youtube.com/watch?v=nk9cTa3UthM&nomobile=1
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Very good video :thumbs:

I like the way that he not only explains the ISL, but also demonstates how to use it to your advantage, and avoid problem situations.

Send it to your tutor ;)
 
I think I cracked it. I have managed to produce a white background and a black background using only two lights (with no actual background per say).

Equipment:
2 x D-Lite it 4 lights
Canon 550d
Skyport wireless trigger

White background - I just placed one of the lights behind to act as a background and the other light in front. I also used one of the lights without the soft box and used the cone instead to light up a wall and the other light to shine on a face.

Black background - I shone one light to the side of the face very close on low power, shut all the curtains in my living room and had my subject stand in the middle far away as possible from the living room window.

Both came out extremely well and I am impressed.

I need to figure out if I can achieve the same look in the daytime as I did this last night which helped.

I also need to figure out how I can achieve a black background look using only two lights if say I had 4 people to shoot. My initial thoughts are to place a light to either side of the subjects with them stood directly in the middle, I'm sure that would work
 
If I can remember how to put a picture on here I would show you what I've managed to do so far
 
So you used one of your flash heads fitted with a softbox as a white background? That's fine, just use the minimum possible power and get your subject as far in front of it as you can.

Getting a black background involves making sure that no light hits the background, that's easily achieved with any light source, especially if it's honeycombed, simply by doing as you did and by having the light at the side and pointing slightly towards the camera - but does that produce the lighting effect you actually want?

It's far more difficult when the light is in front of the subject and some of it is reaching the subject. In this situation you need to do two things:
1. Have the subject as far away from the background as you can, so that the light that passes your subject then has a long way to travel before reaching the background.
2. Have your light as close to the subject as possible, so that the inverse square law helps to ensure that very little light reaches the background. Basically, a white background will turn black with something like 5 stops of underexposure, so...

Light 2' from subject and subject 2 ' from background, light loses 2 stops between subject and background

Light 2' from subject and subject 4 ' from background, light loses 4 stops between subject and background

Light 4' from subject and subject 2 ' from background, light loses 1 stop between subject and background

Pulling the curtains is pretty irrelevant, so is turning off the room lights. To test whether I'm right or not, set the shot up for flash, let's assume that your shutter speed is 1/125th and your aperture is f/11.
Now switch off the flash and take the shot with just the ambient light (the light that happens to be in the room) Is there enough detail on your camera monitor to affect the shot when you take it with the flash? If the sensor is black or nearly black then there is nothing to worry about.
 
I see what your saying, like above I think I started this thread mentioning I don't yet have a light meter (birthday is Oct so waiting till then).

For the black background shots I had my lad stand in the middle of the room. To his right side i had the flash and attached to it was the softbox. My canon settings were in manual with an Iso of 100, shutter of 1/125 and messing with the aperture I found the best shots came out at f11 but I am unsure why as I would have though f5.6 may produce a better picture.

The fastest shutter I could get to was 1/400 but then I got black bars appearing. The flash was being triggered by the skyport each time. If I chose f22 It kept going too much underexposed
 
I found the best shots came out at f11 but I am unsure why as I would have though f5.6 may produce a better picture.
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I don't know why you would think that. If f/11 produced the best shots then that's because the flash power was set to the amount of light that gave a good exposure at f/11. To get the same exposure at f/5.6 you would need to reduce the ISO to 25 (which you can't do on your camera) or use a 0.6 neutral density filter.
If I chose f22 It kept going too much underexposed
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To get a correct exposure at f/22 you would need to quadruple either the flash power or the ISO.

the fastest shutter I could get to was 1/400 but then I got black bars appearing
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As already explained 3 times in this thread, your maximum possible shutter speed is 1/200th second, although it would make sense to use 1/160th or 1/125th instead, to make sure. DO NOT USE 1/400TH SEC
 
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