Video camera vs photo camera

<p>What is the difference between the two cameras? How can a vid camera take so many shots a second at decently high resolutions while a camera whith a burst rate of 8fps is consider top class? How film video cams do it? This seems like such a logical question and yet no one seems to be asking it.</p>

<p>digital motion picture cameras take so many images per sec for a couple reasons:<br>

1. There is no mechanical shutter, just electronic re-exposing of the image. This means one can use high fps, but without an optical viewfinder, only an electronic one. A DSLR is limited in still camera mode by the speed the mirror/shutter can recycle. For the few DSLR cameras that can shoot video, the mirror and shutter are locked open in movie mode and the image is viewed only on the LCD monitor. Recording times are limited by the space on the memory card. I think 8fps is about as fast as a DSLR mirror can go up and down before failure.<br>

2. High resolution images require a lot of data processing and storage. To do this, digital movie cameras take lower resolution images than most DSLR still cameras and have much more memory to store it on, or a tape or disk drive to store it all.<br>

There are a couple of exceptions in the professional arena such as the Arriflex D-20 camera that has a rotating mirror shutter, like a 35mm movie camera, and a reflex optical viewfinder. The camera alternates exposing the chip and the viewfinder as the mirror shutter spins. Data is downloaded via cable to the storage device of one's choosing. I believe the image recorded is about 2000 pixels wide. The camera costs well over $100,000. Dalsa made a 4000 pixel spinning mirror camera called the "Origin" that required massive amounts of data storage. The data load was so great that the camera was not widely used and they've discontinued development of the system.</p>

<p>There is also a much larger margin for quality and resolution with motion picture vs. static picture. Motion tends to distract the eye, where on a photo you can easily pick out every flaw.<br>

This means video camears don't need the same mega resolution that photo cameras do. IE... my old rebel XT spits out 3400px wide images, while super high end 1080p resolution video is still only 1900px wide.</p>

<p>Because video cameras don't have "decent resolutions". For example the Canon HV10, which is a decent HD camcorder has a 2.96 Megapixel CMOS image sensor and can shoot 1920x1080 video. Typical P&S digicams these days have 8-10MP sensors and DSLRs have 10-24MP sensors.</p>

<p>The new Canon EOS 5D Mk II DSLR can shoot 1920x1080 HD video at 30fps of course.</p>

<p>BG, I worked on one show where they used a Dalsa. The producers wanted to be able to do one take, and get crop to tighter shots in post.<br>

You had a have an very specialized video engineer (god knows what he cost the production) in addition to the regular camera department guys, you still had to check the gate after good takes because the rotating mirror attracted dust, and it was as big as a house, and made noise.<br>

Dalsa must have had a very good sales pitch, because it would have been less trouble and money to simply shoot film.</p>

<p>I think Dalsa was forced to basically rent out the cameras for nothing to drum up business that never came:)</p>

<p>As for film, zooming in on a 35mm film frame would be a very low quality choice. I can see why they chose Dalsa if they had to do this for some funny reason...</p>

<p>They did come out with a newer, smaller version that was only as big as a ... cottage.</p>

<p>BG, so why don't DSLRs just lock the mirror and open the shutter during the burst shoot to achieve much higher speeds? So technically a video camera is like a normal camera only working in constant burst mode?</p>

<p>No. Normal video cameras don't have a mechanical shutter. They electronically gate the sensor, which is exactly what the 5D MkII does in video mode.</p>

<p>With a 100,000 cycle shutter life, at 30fps you'd have to replace the shutter every hour if you did it that way!</p>

<p>There are image quality reasons why a mechanical shutter is better for still photography. Keeping the sensor in the dark when not in use is a good thing.</p>

 

<p>I see, thanks, you have satisfied my curiosity :)</p>

<p>Look at the Red system <a href="http://www.red.com/epic_scarlet/">http://www.red.com/epic_scarlet/</a></p>

<p>You can make stills or video at high resolution.</p>

 

<blockquote>

<p>Look at the Red system <a rel="nofollow" href="http://www.red.com/epic_scarlet/" target="_blank">http://www.red.com/epic_scarlet/</a><br>

You can make stills or video at high resolution.</p>

</blockquote>

<p>All you need is about 60,000+ dollars and you're good to go.</p>

 

<p>Tim, you'd also have issues of a blacked out view finder on an SLR camera if the mirror stayed locked up for a burst. You would be reduced to guessing the framing of the image as soon as you held down the shutter button.</p>

<p>True, but hey could make it optional, when framing is top prority flip the mirror, when a photogropher wants 30fps, then the mirror stays up...</p>

<p>Bob's first comment adequately tells the story. Either you want to make films (or videos) or you want to make still photos. Only rarely do people do both well. </p>

<p>Regarding unmaintained life in the days when I has access to these data, late model Canon F1, Leica M2, M3, M4, and Nikon RF cameras in the 1960's, Perhaps the Nikon F early SLR's should be good for 1,000,000 exposures provided that you didn't deliberately mistreat them. I just had my 1961 Nikon RF's rangefinder repaired for the first time in 2008 (47 years ain't too bad, y'all).</p>

<p>Lynn</p>