Does flash card speed affect read noise?

[focaldepth]

It's funny the things you think about while sleeping isn't it? Or is it just me?

Anyway for my DSLR I have a range of different speed CF cards.

I usually by at the knee in the price/performance graph.

I just bought a new one rated as 400x speed.

I was thinking great that could knock a few seconds off grabbing images when I wondered if reading at a higher speed affects chip temperature or read noise.

I know that cameras double buffer the data to keep speed up but has any one measured the effect?

[roundycat]

read noise is the statistical uncertainty in the measurement of the actual number of electrons in the charge well waiting to be measured. Once measured, that charge is converted to ADU by the ADC amplifier and then read out to memory. Assuming the read out (not the measurement) is accurate surely all you are doing is using faster RAM?

Dennis

[Catanonia]

Nothing to do with the speed of the card in my terms, the noise is the read from the chip to the internal memory of the camera, ier before it gets to the card and even pc.

Otherwise, noise would increase depending how long you took the card out of the camera to your pc as well.

Nice thinking though

[focaldepth]

Thanks for the comments.

Perhaps I should explain my thinking.

Read noise is partially temperature dependant.

Amp Glow is partially temperature dependant.

There are many other sources of noise.

All modern digital chips in effect use zero (near zero) power when idle and the power increases at the rate they switch.

Hence CCDs stay cool until you start taking pictures.

Chip temperature including amp glow come from heat sources in the camera (I don't know where in the camera).

I don't know where in the camera the ADC, buffer memory, image processor, flash card interface etc. are.

I was wondering if stressing the flash card interface harder would generate sufficient heat (and electrical noise) to cause a problem with imaging.

Has any one measured it?

If not, is there an idiots guide to measuring image noise? (guilty as I haven't googled it yet) It would be a fun thing to do when the stars are hiding.