I have noticed that I frame my shots pretty tightly. I like the look but it sometimes becomes a problem when it’s time to print and I have to change the imaged dimensions.

Someone suggested that to ensure my compositions work for both 4x5 (or 8x10) AND 5x7 dimensions I should try masking my focusing screen. She suggested drawing with permanent marker but I just cant bring myself to do that. I shoot with a Canon 30D. Are the focusing screens removable? Do they make one with these dimensions on it? Is this even necessary? Any tips?

Thanks for your time,
Jenn

Check out CropLines. They've already cracked this nut.

take 2 pieces of scotch tape, put them on the sides of the screen and draw lines on the tape.

if it makes you feel better, dry erase marker can take sharpie off of slick surfaces. Google it. : )

I have the same problem sometimes. Im trying to work on it but I think masking my screen would be the last thing I try. Just seems unprofessional to me for some reason.

I used to do the exact same thing, my teacher told me to take three steps back once I have my composition and now I do it automatically, there isn't any need for drawing on your screen