[dgpaterson2000]

I recently succumbed to the temptation to buy a couple of the newer "faster" sdhc cards to use with my 645D. Up till now I have been using 15mB/sec 16gig Sandisk cards, and I bought two 45mB/sec 16gig Sandisks.

Shooting raw with a 15mB/s card, the time until the image/histogram appears on the rear screen is 12secs and write time (until the "card access lamp" goes out) is a further 5secs.

Shooting with a 45mB/s card, the time until the image appears is exactly the same; write time is reduced to 3secs. The total time from the shutter firing to the access lamp going out is therefore reduced from 17 to 15 seconds.

I conclude from this that - as far as the 645D is concerned - fast, expensive cards are a total waste of time and money and offer no benefits to 645D owners unless (possibly) the higher-spec'ed cards are to be use in extremes of temperature and humidity, where they might just be a little more resistant.

[derAngler]

Shooting raw with a 15mB/s card, the time until the image/histogram appears on the rear screen is 12secs and write time (until the "card access lamp" goes out) is a further 5secs.

Shooting with a 45mB/s card, the time until the image appears is exactly the same;

Maybe you should turn off the internal lens correction of your camera. Then it takes only around 4-5 sec to show the picture with the histogram. The lens correction you can still do in Lightroom or Photoshop afterwards if necessary.

[RonHendriks1966]

Well you only shortend the writetime due to hi writespeed and that is the only advantage the card can give. The 645D can not handle the UHS-I writespeed so the max writespeed would be 30 MB/s but is in practice lower then that.

[dgpaterson2000]

derAngler - I didn't know that, and you are absolutely right - processing time drops to under 5 seconds; much more bearable, but I really didn't need those faster memory cards!