![nikon f90x nikon f90x](https://live.staticflickr.com/4909/46249860974_398c586c46_b.jpg)
For cameras with built-in diopter control, use additional Nikon eyepiece diopters only if your vision dictates that optimum viewfinder sharpness cannot be achieved with the built-in diopter adjustment control.
#NIKON F90X MANUAL#
Please check your instruction manual to see if additional threaded Nikon eyepiece diopters can be combined with your camera's built-in diopter control.
![nikon f90x nikon f90x](http://www.kodaklist.com/media/images/site_library/194_DSC_8412b.jpg)
Ask them to determine your diopter from (your corrective prescription) when viewing an object at distance of approximately one meter.
![nikon f90x nikon f90x](https://ae01.alicdn.com/kf/HTB12jeQKFXXXXb3XVXXq6xXFXXXh/2pcs-1set-Camera-Shutter-Remote-Control-Flash-PC-Sync-Terminal-Cap-Cover-for-Nikon-F5-F100.jpg)
The use of a neutral correction eyepiece will change the diopter value of the camera from minus one to zero.
#NIKON F90X PLUS#
In other words, if you require a diopter of plus 3, simply add a plus 3 diopter to your camera. No combination of the camera's base value of minus one and a given accessory diopter's value is required to arrive at the final desired value. The eyepiece's diopter value is, when combined with the viewfinder's minus one value, the end-result value. Use a little electonic memo recorder to record it. If you need to record the data for each frame Rachel, then you have two alternatives. How ever the Photo secretary from some peoples point of view was a bit of a disapointment.