Custom calibration for IR converted cameras
When you have us convert your camera we also calibrate the focus for infrared light. With point and shoot cameras this is done to the built in lens. Once calibrated, the P&S camera will accurately focus in infrared light, without any further need for focus adjustment from the user.
Digital SLR cameras are bit trickier and we require further input from you in order to calibrate to IR. Since IR light focuses at a different point than visible light and since each lens can have a different focus shift and since zoom lenses can have a different shift depending on where they are in the zoom range – we can only calibrate a DSLR camera to one specific lens of your choice. And if the lens you choose is a zoom lens, then we will calibrate to the wide end of that lens.
You may still be able to use other lenses with the camera but there may be a shift in focus for which you will need to compensate yourself. This can be done with a greater depth of field, but this only masks the focus error. The other way is to take a series of test shots and manually shifting the focus color until you find the right amount of shift needed to get the image back in focus. Then you can use a bit of nail polish to mark the point on the lens, basically creating your own IR focus mark.
Now, even though you set your own focus mark you may still be unable to focus at infinity. This is because each lens focus color has only a set amount of movement and the amount of focus shift that may be needed to correct the focus may be out of range for your lens.
By this point I know what you may be thinking – my camera has a feature where I can fine tune the focus within the camera’s settings. This is true and can be used instead of the nail polish IR focus marks BUT the lens focus color travel limit still applies. You can tell the camera the right amount of shift but then at infinity the camera cannot instruct the lens to travel beyond what it is physically capable of. So therefore that infinity issue can still arise.