As a new owner of one of these, I don't know that I will be using it to adjust shutter speeds, but rather to verify what they are.
I own a number of older cameras. Rather than spend money on film to check them out, I believe this to be more cost effective. (I already own the iPad.)
If speeds are off, then I can either factor in the actual speed, or send it for a CLA. Not to mention I've always wondered what "I" is, on a T-B-I shutter.
Not affiliated.... You know the drill...
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