A7/A7R Light leaks reported + White Orbs issue?

Started 7 months ago | Discussions thread
blue_skies
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Re: Metal mount side-effect ... ?
In reply to socode, 7 months ago

socode wrote:

Astrophotographer 10 wrote:

I tested my A7r this morning. Took off the lens, installed the body cap and took a 30 second ISO25600 shot. No light leaks. I also don't see any gap between the orange ring and the silver mount. I did this in a well lit room with the blinds open and it was sunny outside.

I see some are mounting their FE lens first and then trying to make it leak. How do you know light is simply not getting around the lens cap? They never look light tight to me.

Greg.

I think you're right. As a followup - I did the same test with A7R, lens, body cap only, and the same again on a couple of Canon DSLRs. One E-mount lens adapter shows up badly and is for the bin. Nothing shows without a lens attached.

All the cameras show the faintest ghosts at 30''/max ISO with lenses attached. I'm not going to worry about it, since for years I've obviously had a camera which is not perfectly light tight, at long exposures, high ISO, when I'm shining bright lights around the lens mount. Should be easy to avoid If ever stacking, I presume I'll shade/drape the body.

If anyone can report on the Novoflex FD adapters I'd be interested.

Guys, I tried this on the Nex-6 and Nex-7 and they also show light leaks. The pattern is different from the one on the A7, but it appears that light is simply reflecting through the metal mount, which forms a light tunnel of sorts.

Because both the lens and the mount are made of metal, and gap therein will allow light transmission by reflection. As minute as the gap is, and as little light as can penetrate, these sensors are extremely sensitive at ISO 25,600 and long exposures.

A mount lenses and body caps are made from black plastic. The light does not reflect, and a light tunnel does not form.

Adapters will likely leak more light as they are made against different tolerances than the lenses.

The tolerances, even on the OEM mount and lens, cannot be zero, or you would not be able to mount the lens at all. So I guess that even the slighest play, needed for insertion, enables light to form a light-tunnel of sorts which leaks light.

Again, I don't think that this is a real issue. I have seen leaks in bodies and adapters that show even in normal photography. This is not such a condition. I mean, any scene that requires ISO 25,600 and more than 10 seconds exposure is void of such (extreme) bright lights close to the mount.

Unless you shine your brightest flashlight on the camera mount during the exposure

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Cheers,
Henry

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