Michelle Ross |
Flash/Camera Problems?
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Jon Close |
The first picture of the football players looks simply underexposed. I think you were simply beyond the useful range of the flash. The scoreboard picture looks better only because the lights in the scoreboard are bright enough to give good exposure. The scoreboard itself is underexposed. The maximum flash range is specified by it's guidenumber divided by the maximum aperture available on your lens. Vivitar's most powerful models (850AF, 283, 285HV) have a guidenumber of 120 ft. at ISO 100. The maximum aperture of your lens at 300mm is probably f/5.6. 120 ÷ 5.6 = 21 ft. as the limit when using ISO 100 film. Using faster film increases the flash's useful range. Each doubling of ISO extends the range by a factor of x1.414. So using ISO 200 gets you far limit of 120 x 1.414 ÷ 5.6 = 30 ft.; for ISO 400 it's 120 x (1.414)^2 ÷ 5.6 = 42 ft.; and for ISO 800 it's 120 x (1.414)^3 ÷ 5.6 = 60 ft.
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Michelle Ross |
Thanks Jon. I figured you would have an answer for me. . .the problem is I'm not 100% sure which film I had in for the football games. I know it was at least 400 speed but I was thinking I put in 800 speed because I knew I was wanting to take pictures in the dark. I was on the sidelines and mostly took the pictures when they were coming towards me and closer but I might have still been beyond the 60 feet. Another problem I was wondering about was my lens being extended to 300? Will this form a ring around the photos from the flash? I'm wanting to take basketball pictures soon and will be in a dark gym but it's small and I should be able to get fairly close. However, I'm worried about still getting images that are dull like the volleyball ones(however, I know that I used 200 speed film for that so that was probably a big problem). I tried to read all that I can about various things but find that my "sitution" just isn't always the same as what I read about. I appreciate your comments and taking time to answer me! Thanks
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