I think this lens would be amazing, but i think it needs to be Â£400 cheaper.
This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
If the 5d mkiii had noise improvement would it make using f2.8 better for low light as you can use higher ISO?
Yes, but at some point there's a limit. There are two parts of noise, the camera's own ("read noise") and noise in light itself (photon shot noise). Most people forget about shot noise and assume that noise at high ISO is just contributed from the camera electronics. Actually, the shot noise is often dominating (I have not found out where the line goes, but perhaps some other reader of this forum knows).
The signal-to-noise ratio of the shot noise reduces the more light you gather, that is lower shutter speeds, larger apertures, larger sensor size. That is you always want to gather as much light as possible, to be able to use as low ISO as possible.
One other factor to know about is that not all f2.8 are the same concerning light transmission, and it is not only about vignetting. There can be quite large differences between lenses, some lenses can transmit a half stop less light than others at the same aperture. For example the 24-70 f/2.8 has a transmission corresponding to ~f/3.4 while a large aperture prime lens set at f/2.8 typically has much better transmission (did not find an example measurement unfortunately, but it can easily be observed in testing).
Can you give some details of the power supply and construction? What did it cost to put it together?
11 coulums of 9 LEDs each, in a half inch grid. A metal core PCB for good heat dissipation, for usage as a flash its thermal capacity would be enough, as a video light two heat sinks intended for high end graphics cards helped...500W for 1Âµs is simpler then 100W for indefinite time.
Groups of 3 LEDs each get their own driver, for a forward voltage of about 10V, a powerFET as a constant current source, powered by a 12V lead acid battery, buffer caps and charging current limiter don't do a thing for constant illumination.
As a video light its a wasteful design, driving the LEDs at just about 1/4 their rated power because they are to tightly packed and using linear regulation - but thats just a secondary use...
Overall costs in the 1500â‚¬/$ range, but if you want just a video light you could get away with the new XM-L LEDs and about 25â‚¬/$ per 100W of tungsten filament. Thats if you buy enough parts to get past the markup of low volume dealers.
For inspiration: take a look at a Fenix TK35/41 for what a single Cree XM-L can do, or a TK45 to give you an impression of 3 XP-Gs. Both give you ~3 stops more then the average video light.