J T wrote:Tier4GEVO wrote:I've been usually using 1/725 in daylight videos of trains...
I've never heard of such a setting. Can a vid expert explain this for me?
Shutter speeds are a setting in almost every non-ancient camcorder (or camera that takes video just fine). It is simply the length of the time the sensor is exposed to light. It is one of the three typical setting components of photography - ISO and Aperture being the other two.
Generally speaking, normal shutter speeds for video are recommended 2x the frame rate. 1/60 is suitable for general applications. And in low light, the sensor is exposed to a good amount of light due to the low shutter speed. It works great for almost anything besides motion and HAS to work for everything at night regardless of what you are filming. Nobody can use a 1/500 shutter When motion comes in to play, such as filming a kid on the soccer field, filming a plane landing, trains (duh!), we experience motion blur. This is combated by raising shutter speeds so the speed of the exposure to light is comparable to the speed of the moving object you are filming. This way, if you were to pause a video of a train, it won't be all blurred out. There is an extent to having natural motion blur being OK, but when the whole train is just looking like an out of focus blob, it's not very likable.
The average Sony camcorder and small-sensor camera is great at this. You raise the shutter speed, get the results you want. Doesn't matter if the aperture is small (giving you a shallow depth of field) because the sensor is so small it can't even give you that result.
The issue with many large sensor cameras (APS-C, APS, Micro 4/3, Full Frame) is that for filming trains, the aperture needs to be higher. On large sensors, you can achieve a blurred background (shallow depth of field). Many senior high school photos are shot with very low-number aperture lenses such as F/1.7 and less. The smaller the number, the more light that can be let in. The issue is that you want a DEEP depth of field on a train (everything in focus). On large sensors, we need to actually raise the aperture number (allow less light in for better whole-shot focus) so we get what we want. This overall lets considerably less light in, and combined with a high shutter speed, the video may get "dark". If you use too much ISO gain, you experience video graininess (commonly referred to as video "noise"). While a bright sunny day is OK to use the best of both worlds settings, on cloudy days or darker settings, SOMETHING has to be sacrificed.
Filming a train with a F/1.7 on a larger sensor than 1 inch will result in a portrait-type blurry background, again, which we want to avoid for this type of video.
Using the same F/1.7 on a smaller sensor, it doesn't matter if the aperture is the same, the sensor is too small to give a shallow background anyways.
While daylight can be harder to achieve with these large sensors, night performance trumps everything else. If you slap a F/1.7 on the 4/3 sensor compared to a similar number aperture on a $300 Handycam by Sony, the differences are astonishing. Sensor sizes increase exponentially, which is why a 1/3 although looking like double a 1/5.8(6-ish), it is actually much more than that.
I may have rambled, I apologize, but my point is that one setting affects something else in many cameras, and many compensations and sacrifices are made in the real-world of motion videography, especially when less-than-sunny conditions are in effect.