Question about shooting with a flash

[prometeo34]

L&G maybe this question in silly but I need some light in this matter.

Situation: " Shooting manual with my D40x attached I have an SB-600 flash. I Play with my aperture and shutter speed in order to get the right exposure (in the middle of the indicator, which is the 0). My question is oes the camera take in account the flash or in the contrary if I get a good exposure and I have the flash I can get overexposition?.

I know is a really obvious answer but I am kind of confused here.

Thanks in advance and regards.

Carlos

[highbarger]

The meter reading that you get in manual does not include an estimation of the effect of your flash. It is strictly reading the ambient light. I don't use Nikon, and I'm not familiar with the SB600, but I'll assume that you can set the flash to auto mode which will attempt to balance the flash with the ambient light. You should also be able to dial in +/- compensation as well. Hope that helps...

[prometeo34]

Thank you very much for your answer.

Regards

Carlos

[dougsmit]

A neat feature of the f/stop system is that the amount of light needed to take a shadow up to twice as light only raises middle tones a little and highlights hardly at all since each stop along the way is half/double its neighbors.

[blumesan]

Originally Posted by dougsmit

A neat feature of the f/stop system is that the amount of light needed to take a shadow up to twice as light only raises middle tones a little and highlights hardly at all since each stop along the way is half/double its neighbors.

Doug--
Could you elaborate a bit on this. I always thought that when I increase the exposure by one stop it is increased by one stop for all the tones.

Cheers/Mike

[dougsmit]

Originally Posted by blumesan

Doug--
Could you elaborate a bit on this. I always thought that when I increase the exposure by one stop it is increased by one stop for all the tones.

Cheers/Mike

If we have light values separated by stops and the darkest is a value of one then the next is two followed by four, eight, sixteen and thirty-two. If we add a flash fill with value of one, our new levels are 2, 5, 9, 17 and 33. This makes the contrast between darkest and lightest (2:33) less than it was before (1:32). Certainly there will be a need to adjust the exposure if you add enough 'fill' that it becomes the main light source but a weak fill have more effect on shadow values proportionally than on highlights.

[waple]

Originally Posted by dougsmit

If we have light values separated by stops and the darkest is a value of one then the next is two followed by four, eight, sixteen and thirty-two. If we add a flash fill with value of one, our new levels are 2, 5, 9, 17 and 33. This makes the contrast between darkest and lightest (2:33) less than it was before (1:32). Certainly there will be a need to adjust the exposure if you add enough 'fill' that it becomes the main light source but a weak fill have more effect on shadow values proportionally than on highlights.

I may be just dumb, but I don't understand a bit of that.

[blumesan]

Originally Posted by dougsmit

If we have light values separated by stops and the darkest is a value of one then the next is two followed by four, eight, sixteen and thirty-two. If we add a flash fill with value of one, our new levels are 2, 5, 9, 17 and 33. This makes the contrast between darkest and lightest (2:33) less than it was before (1:32). Certainly there will be a need to adjust the exposure if you add enough 'fill' that it becomes the main light source but a weak fill have more effect on shadow values proportionally than on highlights.

Doug--
Thanks for your reply. This theory is completely new to me . Can you provide some reference so that I can learn more? I always believed that increases in light value worked geometrically not arithmatically. How does using a fill flash differ from using a reflector or just increasing the ambient light falling on your subject?

[cyclohexane]

The in-camera meter display disregards flash; it is only for ambient light.

The SB-600 works in either TTL (through the lens) or M (Manual) modes. In M, you set the flash output, and it remains constant. With TTL, the camera will fire a quick, barely visible preflash to determine the correct flash output using the in-camera metering cell before raising the mirror when you squeeze the shutter release. Your metering mode will impact how well the flash metering works, even though it only displays a reading for ambient light.

For Nikon's i-TTL, I have found that I get the best results using spot metering. Center-weighted is okay if your subject takes up most of the frame and is evenly-toned, and Matrix just seems to do its own little thing with flash.

Choose spot metering on the camera, and then dial in some negative flash exposure compensation on the flash based on what you're shooting. A good guideline is "-1 for people, -2 for other things" as a start. Chimp your shot, and then adjust accordingly. Usually, with this set-up, the flash exposure should only be 1/3 stop off after the first shot. I find myself using -2/3 or -1 2/3 for people.

Obviously, when spot metering a person, don't spot meter off of their clothing.

[jfrancho]

Originally Posted by dougsmit

A neat feature of the f/stop system is that the amount of light needed to take a shadow up to twice as light only raises middle tones a little and highlights hardly at all since each stop along the way is half/double its neighbors.

I am at a total loss at comprehending how this applies to flash photography.

[blumesan]

Originally Posted by jfrancho

I am at a total loss at comprehending how this applies to flash photography.

Schuks John, I was counting on you to help explain it to me.

[dougsmit]

Originally Posted by blumesan

Doug--
Thanks for your reply. This theory is completely new to me . Can you provide some reference so that I can learn more? I always believed that increases in light value worked geometrically not arithmatically. How does using a fill flash differ from using a reflector or just increasing the ambient light falling on your subject?

Fill flash is a lot like a reflector but easier to control. You are adding light to the parts of the subject in shadows either way. Just increasing the light (opening up the aperture or using a slower shutter will cause more exposure in shadows but will have equal effect on the highlights. The idea behind flash fill or reflectors is to add a secondary light source that will boost the shadows. Someone asked for links?
Canon Digital Learning Center - Fill-in flash use with EOS cameras and speedlites
Using Fill Flash
Nigel Dennis Wildlife Photography

One last word: Avoid overdoing the flash fill. The idea is to make the scene look like it was taken by the natural light and not to be overpowered by the flash. I'm sorry I am completely incapable of explaining it clearly.

[blumesan]

Doug--

Thank you for the links. I have carefully read each of them. None of them suggested that the use of a fill flash has a its greatest effect on the shadows, less on the midtones and least on the highlights. If I understood correctly, that is what you are saying in your earlier post, and I still cannot fathom how that can be so.