Importing, processing, edit and export .tif files in R - r

Question

I'm working with a .tif image captured from a Sequoia Parrot sensor. I want to do radiometric calibration and export the resulting image in the same format (.tif).
I import the image as a raster, then process with some algorithms and finally try to export as a .tif file but it is impossible to open. The resulting file is 7 MB but the image cannot be viewed.
Here is my script:
setwd("/where the images are/")
rlist=list.files(getwd(), pattern="TIF$", full.names=F)
options(digits=20)
for(i in rlist){
data <- raster(i)
meta <- exifr(i, recursive = FALSE, quiet = TRUE, exiftoolargs = NULL)
SM <- meta$SensorModel
SM <- strsplit(SM, ",")[[1]]
A <- as.numeric(SM[1])
B <- as.numeric(SM[2])
C <- as.numeric(gsub("[^0-9\\.]", "", SM[3]) )
Ep <- meta$ExposureTime ## Epsilon
f <- meta$FNumber ## Focus Number
ys <- meta$ISO ##ISO
I <- f^2*(data-B)/(A*Ep*ys+C)
I <- flip(I,"x")
I <- flip(I,"y")

Answer 1

Is original script well indented? With your example image, everything works right.
I made small changes for better understanding:
library(raster)
library(exifr)
setwd("/where the images are/")
rlist=list.files(getwd(), pattern="TIF$", full.names=F)
options(digits=20)
for(i in seq_along(rlist)){ # small change
data <- raster(rlist[i]) # small change
meta <- exifr(rlist[i], recursive = FALSE, quiet = TRUE, exiftoolargs = NULL) # small change
SM <- meta$SensorModel
SM <- strsplit(SM, ",")[[1]]
A <- as.numeric(SM[1])
B <- as.numeric(SM[2])
C <- as.numeric(gsub("[^0-9\\.]", "", SM[3]) )
Ep <- meta$ExposureTime ## Epsilon
f <- meta$FNumber ## Focus Number
ys <- meta$ISO ##ISO
I <- calc(data,fun = function(x){f^2*(x-B)/(A*Ep*ys+C)}) # small change
I <- flip(I,"x")
I <- flip(I,"y")
print(plot(I))
}