Light Meter - What am I doing wrong?

[ReJai]

Hello everyone!

I am sort of new to photography. Most of my time I work with video editing. I have a question about a Sekonic L308S light meter I recently purchased. I currently have a photography task to accomplish very soon..... I have an SB900 Speedlight in a stand with a white umbrella, and a Canon 70D camera. My task is to take some portrait pictures of couple of people. I also have a white background set up hanging on a stand. I have been trying to practice pictures at my house in my home office and someone told me about getting the light meter to make my life easier.

I have set up a wireless device on the camera and the Speedlight. I set up the meter correctly to read flash and fire the shot so the meter can read the flash light (on Manual Mode) coming in, the ISO is also correctly set in both camera and meter.

I have the meter aperture set up for 125 so I can get a clear image, the F stop gives me 4.05 My camera is set to Manual mode and when I try to match the 125 aperture and the 4.0 shutter speed my camera will not allow. When I insert the first value of 125 I cannot set the other value to 4.0. Can anyone help here and let me know what am I doing wrong?

Thanks very much in advance!

Renata

 

[Dave442]

Are you using a lens that goes to f/4? Some kit lenses only go to f/4.5.

 

[480sparky]

........... Manual mode and when I try to match the 125 aperture and the 4.0 shutter speed my camera will not allow. When I insert the first value of 125 I cannot set the other value to 4.0. Can anyone help here and let me know what am I doing wrong?

Thanks very much in advance!

Renata

125 will be your shutter speed. 4.0 will be the aperture.... 1/125sec and f/4.

Are you measuring the actual speedlight flash itself, or is the meter set up to read ambient light?

 

[480sparky]

At anything longer than 24mm or 28mm, you probably won't have f/4 available.

 

[ReJai]

........... Manual mode and when I try to match the 125 aperture and the 4.0 shutter speed my camera will not allow. When I insert the first value of 125 I cannot set the other value to 4.0. Can anyone help here and let me know what am I doing wrong?

Thanks very much in advance!

Renata

125 will be your shutter speed. 4.0 will be the aperture.... 1/125sec and f/4.

Are you measuring the actual speedlight flash itself, or is the meter set up to read ambient light?

That is correct! I switched the Aperture and Shutter Speed. The meter is set to read flash, ISO is equal in meter and camera.
Thanks!

 

[ReJai]

Are you using a lens that goes to f/4? Some kit lenses only go to f/4.5.

Thanks for your reply! I am using a Canon EFS 18-135mm 1:3.5 - 5.6

 

[ReJai]

At anything longer than 24mm or 28mm, you probably won't have f/4 available.

Which type of lenses would you recommend?

 

[480sparky]

The lens you have will work just fine. You're not setting your ISO high enough to allow smaller apertures.

 

[ReJai]

The lens you have will work just fine. You're not setting your ISO high enough to allow smaller apertures.

Thanks! I will try doing this with a high ISO and see how it goes.

 

[AKUK]

Another option is to stop your lens down further, so that it won't go to the maximum aperture when you adjust the zoom. f/8 is probably the optimum sharpness on that lens (normally 2 stops down from maximum). Set the aperture to this and when you zoom in and out, the aperture will remain the same. Then just pump more juice out the flash or boost the ISO so you use less flash power but get the same exposure.

If possible though, always use a constant aperture lens when working with flash, especially if using monolights and manual speedlites. It's easy to get caught out with a variable aperture lens, if you adjust the zoom. Having said that, you can still get caught out with a fixed prime. It's one quirky feature and a downside to my Micro-Nikkor 105mm f/2.8 VR. It's not actually a constant aperture despite being a prime lens. At closest focus the maximum aperture is in fact f/4.8 - not f/2.8. As you focus further away the aperture widens and eventually hits f/2.8 at 3m/10ft. Naughty Nikon, naughty!

 

[The_Traveler]

Are you using a lens that goes to f/4? Some kit lenses only go to f/4.5.

Thanks for your reply! I am using a Canon EFS 18-135mm 1:3.5 - 5.6

It may be that, at the focal length you are using, the minimum aperture is F5.6.

 

[ReJai]

Another option is to stop your lens down further, so that it won't go to the maximum aperture when you adjust the zoom. f/8 is probably the optimum sharpness on that lens (normally 2 stops down from maximum). Set the aperture to this and when you zoom in and out, the aperture will remain the same. Then just pump more juice out the flash or boost the ISO so you use less flash power but get the same exposure.

If possible though, always use a constant aperture lens when working with flash, especially if using monolights and manual speedlites. It's easy to get caught out with a variable aperture lens, if you adjust the zoom. Having said that, you can still get caught out with a fixed prime. It's one quirky feature and a downside to my Micro-Nikkor 105mm f/2.8 VR. It's not actually a constant aperture despite being a prime lens. At closest focus the maximum aperture is in fact f/4.8 - not f/2.8. As you focus further away the aperture widens and eventually hits f/2.8 at 3m/10ft. Naughty Nikon, naughty!

Thank you for the additional info! I also have a 50mm lens, do you think that would be a better choice for the portraits with a white background? My main concern is to have a very clear picture with a "pretty white" background without shadows. I just feel like the meter is not helping me that much. I have my Speedlight set in Manual... I adjust the amount of light in a way I believe it will give me a good "clarity" to the picture. What do you think about the 50mm lenses?

 

[AKUK]

Your problem isn't so much in the lens but in your light. If you're trying to light a white backdrop and your model with one strobe, you're going to struggle. The main reason is that for your backdrop to go white, ideally you need to pump more power onto that than onto your subject. Since your subject is closer to the flash than the backdrop is, this isn't going to happen, as they'll be receiving significantly more light than the backdrop due to the inverse square law. For example, if the flash is 1m in front of the model and they in turn are 1m in front of the backdrop, only 25% as much light will be illuminating the backdrop compared to hitting your model. You also have the problem of getting as big a spread of light as possible so the backdrop is all evenly white and without gradation into grey.

What you ideally want to do is light the backdrop independently. This way you can correctly expose your model and get the backdrop the degree of white that you want. If you can, get another two speedlites (Yongnuo would be favourite for the price point) then you could fire the two new strobes from opposite sides onto the backdrop to illuminate it. You can then do a reflective meter reading on the backdrop and aim to get it about 2 stops above the light hitting your model.

For arguments sake, lets say you have f/5.6 worth of light hitting your model in incident reading. If you want the backdrop to be white, you need to hit that with f/11-f/13 worth of light in a reflective reading. If you throw more light onto it, you'll find that it wraps around your model and you start losing them to the backdrop.

All the meter will do is tell you what the various values are, like the unknown variables in an equation. It's not going to magically solve your lighting problems. Only you can do that by looking at the situation and thinking of ways to get around it. Additional lighting is going to be the answer here.