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Canon Live View


dcheung

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Does anyone know how fast the live view can refresh? If you were to move the

camera around quickly, does the live view keep up?

 

The other question I'm curious about is that does the feed from the CMOS into

the live view only pass the pixels needed (230,000 points) or does it need to

pass everything (10MP) then the unnecessary pixels are taken out? What I'm

getting at is that is it hardware encoded to output only a 230K points so that

the bandwidth needed isn't too big for a decent refresh rate? If so, then this

would in turn make it slightly more difficult to make a higher resolution LCD

like the Nikons. If so, then a larger bandwidth would be required to pass 1MP

of data at the same refresh rate if canon LCD's went to 1MP.

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Not really answering your query, but I think the difference quoted between Nikon and Canon LCD resolutions is down to semantics.

 

As it turns out the Nikon IS slightly higher resolution, but not by that much.

 

From memory, the Canon quotes approx 230,000 pixels, whereas the Nikon quoted around 900,000 "dots".

 

With the colour LCD having a red, a green and a blue "dot" for each pixel, you can divide Nikons quoted number of "dots" by three to get a comparable resolution with the Canon.

 

I thought that one was particularly sneaky.

 

Cheers,

Guy

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Well, Canon is equally sneaky then, since none of the manufacturers, Canon included, mean individually addressable RGB triples when they say "pixels". If you want to count the physical dots on the screen, it's 230K vs 900K. If you want to count "pixels" = dots/3, it's 77K vs 300K. Either way, the new Nikons (and the new Sony) have four times as many whatevers. If you actually look at the displays (or at high-res pictures of the displays), the difference is obvious.

 

Not that it makes the actual pictures any better of course.

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So is there any definitive report which is NOT misleading and states that dots are the same as pixels?

 

The report is correct that the VGA spec (which Nikon says it is using) is 640x480 which is 307000. SVGA was always called 800x600, but Nikon says it's only using VGA.

 

Obviously it has multiplied this nummber by three for some reason or another. If the native resolution was greater than 800x600 then surely they would have quoted SVGA or better (I'm sure they're not in the habit of underselling themselves).

 

Canon doesn't quote VGA, as its 230k doesn't quite meet the required 307000 mark.

 

The report does indeed suggest that if you counted the dots (using Nikons definition of "dots") on a Canon display, you'd find 690000 of them. I have no idea if this is the case or not, but from what I understand, I guess it would be true. Is there any information out there more credible than this (Popular Photography magazine) which states that it is not? Do you know if PP have published a clarification?

 

 

Weiyang,

What do you mean by "the live view sends out"? if you're talking about the sensor being scanned by the processor then I would imagine that the full 10MP is scanned into fast memory (obviously this isn't slowed down by the write speed of the card and the exposure compensation etc, so 30fps is only three times what is already acheivable on the 1DMk3 and they're using the same processor, so there's no reason why a 30fps couldn't be acheived).

 

That said, it's also likely that only the information relevant to the live-view is pulled from memory to populate the screen. The "Live View system" - as a whole - always just sends out 230k, as the output stage of the live view system (the LCD) cannot "send out" any more than that. I'm not sure if there is software for the PC which will let you view higher Live View resolutions, but I doubt it.

 

cheers,

Guy

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