Originally posted by bavd I would not be surprised if pentax lowered the jpg quality
I think you have a point. Somewhere Pentax changed from 4 star jpeg as the best possible quality to 3 star jpeg as the best possible quality. K5 series still has 4 star, K-01, K30, K50, K-3, K-S1 only have 3 star.
Reason: I don't know.
Pentax specifies the approximate storage capacity in the user manuals; both the K5 series and the K30/50 can store the same amount in 3 star (makes sense as they use the same sensor); that means that the compression algorithm is the same for both at 3 star. And I don't see reasons why the 3 star algorithm in any of the cameras would differ.
K5: 4 star jpeg: 134 images
K5: 3 star jpeg: 214 images
K30: 3 star: 214 images
For the K20D, it's 4x34 = 136 (at 4 star), nearly the same as the K5; also makes sense as the K5 sensor is only a little larger.