I tested for a light leak using a 5 minute exposure a few days ago, but with the Sony A7 that I used I could find no evidence of one. Perhaps it varies by camera. But having no native lens to test, this test was done using the Novoflex adapter with ASTAT tripod mount using the Zeiss ZF.2 18mm f/3.5 Distagon. Possibly that would affect a light leak behavior (e.g., torque or tension on the lens mount).
As shown below, this 257 second exposure is pushed 2 stops and on top of that the Shadows/Highlights feature was used to brighten the very dark foreground. There is no evidence of a light leak that I can detect, and if there is/was one on this particular A7, it ought to show up on the very dark edge and corner areas at left/right/bottom.
The multiple image of the moon is presumably the clouds hiding and revealing it.
All camera systems have growing pains, but some issues fall into the “what were/are they thinking!” area.
So let’s take stock of where the Sony A7 / A7R platform stands in terms of being a professional solution:
- Shutter vibration issues with the A7R.
- 11 + 7 bit lossy file recording (in direct conflict with misleading claims of 14-bit recording) making it an issue for certain high dynamic range fine details, like star trails.
- A disorganized and confusing menu system, one of the worst on the market (see how-to pages for configuration suggestions). Along with no “My Menu” and no ability to remove crapware like Sony Play Memories and similar.
- As per above, an apparent light leak problem that might require repair for some camera bodies.
- A total of two (2) prime lenses and one zoom designed for the new system. Many other lenses can be used with adapters, but the native lens line is severely limited to say the least.
The new Sony full-frame mirrorless system is in its infancy and certainly the sensor quality is outstanding in most all respects. So I’m giving Sony some time to produce a “rev B” of the A7R which might change the equation substantially—I am not a buyer at this point, since the shutter vibration invalidates lens testing in general. Fixing the first two items would go a long way to making the A7R a winner. In the meantime, the A7 avoids the shutter vibration issue by dint of its electronic first curtain shutter option.