Originally posted by theofon For the k70 im worried from some reviews i've read talking about aperture failures or something like that.
To the best of my knowledge, no reviews from owners on this site have mentioned aperture control issues.
Originally posted by Kozlok Aperture failure is real, but not exceptionally common.
What they said ^ ^ ^
While issues with aperture control are not unknown, they are not particularly common either. Several months ago, there was speculation of a problem with the K-70 in that regard such that a dedicated thread for reportage seemed a good idea. I curate that thread. A retrospective search was done on here on Pentax Forums and new reports have been monitored such that I believe we have a pretty good handle on whether aperture control in general or specific concern over failure of the "aperture control block" component* might be warranted. Curating the thread has turned out to be a boring job with only five reports with confirmed problems with aperture control and of those five, one confirmed with failed aperture control block.
Steve
* The concerns about aperture control on the K-70 stem from a very common failure present on the K-30, K-50, and K-500 model cameras and to a far less extent on the K-S1 and K-S2 models. On those cameras, the failure was traced to an assembly often referred to as the aperture control block. The K-70 uses a component of similar design, hence the concern of similar risk.