A700 LCD

[Thincat]

A question for David, or any other technical whizz. The A700's LCD is specified as 921k dots in some listings and 921k pixels in others. Are the terms dot and pixel interchangeable, and does this mean that the LCD has double the resolution of a "standard" LCD (235k pixels). Some sites claim that the it takes 3 dots to make a pixel, so it's basically 307k pixels. Is this true?

[David Kilpatrick]

Essentially it's a RGB pixel device not a R, G, B one - really it is equal to 640 x 480, or 307,200 pixels but each location is a true RGB dot (layered, not side by side). Like Foveon sensors in the Sigma DSLRs, they triple this figure to get the 'pixel count' compared to traditional technology.

David

[Thincat]

Thanks for the reply. Does that mean that the A700 LCD has 4 times the number of dots/pixels than the A100, for example? I notice on the Nikon website that the D200 has the LCD specified as 230k dots and the D300 as 921k dots. Yet Canon, for example, list their LCD as 230k pixels. Do they really mean dots or does it have 690k dots? Has the industry been using the term pixel incorrectly and now Sony/Nikon have corrected it.

[David Kilpatrick]

The new LCDs are genuinely higher resolution - true VGA. But they are counting the triphosphor dots - 300k red, 300k blue, 300k green. The Canon spec does not, it treats each cluster of RGB as one dot. The real difference in resolution is 230k to 310k, not 230k up to 920k. Sony and Nikon are squeezing the highest figure they can from the specification. The Canon spec is more accurate really. The Canon LCD looks much coarser, as each RGB pixel is like a small sandwich of colours. The A700 pixel is more like a single dot which can change colour. I will have to get my macro gear fired up.

Here is one of my stock library shots of a TFT LCD screen structure showing R G B components - each triple strip counts as a single pixel for screen dimension purposes. This image was taken using a Minolta 25mm f2.5 micro lens on bellows on the Alpha 700.



The new camera screens are supposed to use a structure which is different, and each pixel looks more like a single dot which changes brightness and colour, instead of a set of three. I have not tried to photograph the A700 screen using the macro rig, maybe I will.

David

[Thincat]

That's interesting - I noticed that the A700 screen looks a lot sharper than the standard ones. I'm still a little confused by the manufacturers' specs though. Sony list the A100/A200 LCD as 230k dots and the A700 LCD as 920k dots - and N*k*n list the D200 as 230k dots and the D300 as 920k dots. Does that mean that the A100 has 78k pixels and the A700 has 307k pixels - or have they got their specs wrong. Should the A100 be 690k dots? I notice on the dyxum site they list the A100 as 230k pixels and the A700 as 920k pixels and the same with DPR. To the dedicated spec-reader it does look like they've doubled the resolution on the A700, but you reckon this is not the case.

[David Kilpatrick]

The screens of the D200 and Alpha 100 are roughly 320 x 240 (I do not have the exact pixel dimensions) and the Alpha 700/D300 screens are 640 x 480.

Sony's comments about RGB being one location have confused me. They turn out to be nonsense.



See the latest article:

http://photoclubalpha.com/2008/01/20/a7 ... esolution/

The Alpha 700 screen really IS 921,000 pixels versus 230,000 but in both cases it would be more accurate to say 307,000 versus 77,000...

David

[tompower53]

I think what really matters is that the A700 LCD is much much better than the A100. It only matters what our eyes see and they don't see individual pixels, dots whatever they just see a way better LCD - yes?

[Thincat]

David, you're a star. I think that's the most complete answer to any question I've ever seen. Thanks!