Currently designing a mount for placing a point-and-shoot camera (that also records video) on my motorcycle. Seeking input from shutterbugs.
A significant feature will be the placement of a 1/8" sheet of scratch-resistant Lexan in front of the camera to protect it from bugs/debris. I would like to avoid problems with reflections that might compromise image quality, and also don’t want to confuse any autofocus action.
Questions:
How close to the camera’s lens can/should I put the Lexan?
Should the Lexan be at a non-right angle relative to the camera’s line of view?
Should I incorporate an overhead visor to block then sun when it’s in front of the camera (but not directly in sight)? I often see these things on high-dollar SLR camera lenses, but I have no idea how much they help.
Yes, as close to the lens as possible. Not only do you avoid the focus problems mentioned by Bongmaster, but you also avoid light reflecting on the plastic.
And don’t have it at an angle, for the same reason.
And how is auto-focus determined by the camera you intend to use? If it’s an active system it may not work at all because the camera may see the Lexan and not the image on the other side of the Lexan.
The OP is talking about a digital camera; I’ve never seen or heard of a digital camera with an “active” (ultrasonic) focus sensor. Most cameras use the imaging sensor and judge focus from the contrast.
Depending on the camera, it might be possible to set the focus manually. My old P&S had a very tedious menu interface to set manual focus, but it was possible. This would probably be very desireable for you shooting video from a motorcycle.
Otherwise, you might see if there is a way to mount regular SLR lens filters on the camera. That would be a lot easier than making up something from scratch.
If that’s the case, then it should happily ignore the presence of the Lexan, correct? That leaves reflections as my only concern, and it sounds like the way around that is keeping the Lexan as close as possible to the lens.
If you’re talking about something that protects only the lens, I think this won’t be adequate; it would leave the rest of the camera’s face unprotected, including the nested telescoping sections of the lens assembly. One good high-speed impact from a big greasy insect could drive all kinds of nasty crap into that mechanism.
Any thoughts on a sun visor? Helpful for eliminating stray reflections from an out-of-view sun, or waste of time?
Could you buy a lens hood for a larger lens, and glue it to your Lexan somehow? Lens hoods can be pretty cheap: for instance, I bought this one for about $4 (plus shipping) recently. They are designed to screw into the front of the right kind of lens, but if your Lexan is fixed relative to the camera, and you could glue it on, it would work. You’d just need to be careful that it was large enough not to crop the picture that you are taking.
I think the above advice (using a lens hood) is a good one; if there isn’t one available as an accessory, it shouldn’t be hard to make something similar. Just a black cylindrical shade that surrounds the lens and bridges the short gap between the lens and the windshield. The primary goal is to make sure the camera can’t see its own reflection, or a reflection of something behind the camera (e.g. the rider). A secondary goal is to shield the lens from sunlight, but I don’t think that’s as important.
You can eliminate pretty much any possible reflection by using a couple black cardboard tubes, one inside the other in a telescopic fashion, place them around the lens filling the space between the camera body and the lexan. The underwater case for my G11 camera uses something similar, a black rubber sleeve that surrounds the lens
