01-15-2015 04:07 AM
I have been using the PNY Elete Performance (90MB/s) in my K-50 without any problems. This is a good high speed card that does not cost you and arm and a leg if you want to try another card. $18.00 at Best Buy!
01-22-2015 04:30 PM
I have several Sandisk 16GB card with 80 m/s write speed and I have no issues with it. If it does not format in camera, then the card is defective. Return the card as defective and get it replaced.
I have a K3 as well as a K5IIS.
01-31-2016 03:38 PM
Still having same problem with K20D. Several years ago read online that there was a firmware fix comming out but never saw it.
I formatted card in camera & a couple seconds later got "memory card full" & "no card" errors when trying to shoot a scene.
The Sandisk Extreme Pro cards are the ones with the best performance and fewest issues. You can use slower, cheaper cards but you will not like the performance.
NOW, back to your issue. Because Sandisk are expensive and the best, they are also the most frequently COUNTERFEITED. You will find that most any Sandisk card that is unusually cheap is either a fake (TONS of them to be found in the usual places) or has been relabeled to a faster spec card. The most insidious version of the scam is to relabel a 4GB card as a 64GB, and hope you don't notice until the vendor has your money and is long gone. There is a program available to detect these cards:
Use at you own risk.