Reconyx; the deer look straight into the lens due to the noise from the color correcting filter clicking in or out of the light path. Reconyx trigger so fast that the little filter slaps into place. Quite noisey day or night. Silent Image series was monchromatic so no moving filter. Rapidfire series has the filters as does the hyperfire series. Noise aside, they are the fastest. I have checked Silent Image cameras to 4--5 images per second. A way to eliminate the filter noise is to remove the switching solenoid and lock the filter to IR mode. Weird day images, but quiet. This is advanced camera tweaking, not suitable for many 'researchers'.
I always thought hunters liked a horned animal looking into the camera so they could fantasize about the rack. They have a lot of images of dead animals on their phones that they proudly display.
The noise that humans can hear is a small part of noisy trail cameras. The ultrasonic noise is obnoxious, especially when the capacitors charge up and discharge for the flash. Special meters are needed to detect the ultrasonic noise. Generally speaking, Reconyx send more noise out of the left side of the case. Years ago, I bought a trail camera mount that had a ball fixture with quick release and steel mounting plate. I never found out if the fake camo scheme was painted or powder coated ( outgassing factor ). The mounting plate was a reflector/projector for ultrasonic noise. Scrapped it and made a wood mounting plate. I do not waste money on bear boxes. Trail cameras are not very directional in noise transmission and can be termed to have 'spherical projection' even though it is asymmetrical. They are screamers.
An additional factor is ultraviolet reflectence. Deer have impressive vision in low light situations in the UV spectrum below 400nm. Humans see nothing in this region due to a yellow pigment in our lens that blocks UV. Trail cameras, mounting straps, boxes and cables may have a UV blue appearance to forest animals with low light vision. Green is the absolute worst color for a human to use to disguise themselves and equipment. Never attempt to imitate a 'biological green'..Dawn and dusk, the change of rod(black and white) night vision and cone (color) day vision is when your artificial greens stand out. Manufacturers will put UV reflective components in outdoor equipment to protect the item from harmful UV light. A low cost black light for testing can be found for less than $20. You and your equipment might look like glow bugs. Forest animals don't like that.