Long exposure warning

Apparently, light leaking in via and optical viewfinder is a myth, it just doesn't happen.

► http://improvephotography.com/2475/night-photography-light-leak-leakage/

I thought the main concern would be in sunlight with backlighting where direct rays would enter through the viewfinder. But I'm still wondering now about the possibility of it during live view ??

A long exposure and live view are kinda the same thing, in that the mirror is up for both.

Light leakage during long exposures is definitely real.
See OP example, and I've had a few of my own over time.

How would you explain the tests performed by those folks over at that article showing no such leaks?

Now Steve, you know, ya don't want to believe everything you see on the innernet Anyway, I thought the OP here said HE had done tests proving it was light leakage through the viewfinder ?

I'm not interested in their results to be honest Steve, as I know for sure I've had problems in the past from this very issue.

They didn't use my Pentax camera could be an answer.
Maybe other brands seal this area better...

Can it happen in Live View mode do you think guys?

I've covered the OVF as a matter of precaution rather than having leakage spoil an exposure.
However, that article (and many others) have tested this and found it to be untrue.

There are also articles about light leaks with the Sony A7 and other mirrorless cameras.
Here's one ► http://www.imaging-resource.com/news/2014/03/10/sony-a7-light-leak-round-II-of-I...
(Note that they find the Pentax K-3 and K-5 entirely lightfast )

What I did on Sunday, which was another fine day with bright sunshine, was again using the 10 stop ND filter set the aperture to give me 20 secs or more exposure.

With the camera in the shade no problems.

With the camera out of the shade and the sun behind but at an angle I got some mild problems.

With the sun more or less directly behind I got the same symptons as in my original post.

As above, that matches my experience also screwdriver222.

Live view mode is exactly the same as what's happening when the long exposure is taking the shot, so I fail to see the point of the comparison Nigel?
#whatamimissing?

The comments in your article Steve refer to it messing with exposure metering, but in my case all long exposures are done in full manual mode with me timing the exposure on a phone app countdown. I line up the shot as I want it, take note of the aperture and shutter speed (really time) value and input these into the app, so nothing is metered by the camera itself.

Well it's not my article - I'm not the author
But yes, some of the comments are saying that the covering up of the OVF during long exposures is due to metering inaccuracies and not light leaks when left uncovered. This perhaps demonstrates the confusion regarding this apparent phenomenon.

The few long exposures I have done have all been at night, so I've never come across the problem - but I did cover the OVF on the K-7 as a precaution. Since then I've only used the K-01 for LE's..

I'll try using the K-50 at some point with and without covering the OVF in daylight.

I'm sure there's a workaround .... Maybe set User mode, shade the viewfinder with your hand then quickly switch to M mode , take away your hand and press the shutter ... The shading from the hand will carry over from user mode ... Maybe, just maybe .... No, that's not logical at all !

All you need to do is shade the viewfinder with a hand, placed close but not touching the camera. We wouldn't want to induce camera shake.

We can all test this for ourselves if we feel we need to.

OK, well I just tried the torch test (LEDlenser P7) with the K-50.
Nothing got through to the sensor.

I wonder if it does something weird, like internally bounce through the filter itself etc.
Doesn't make a lot of sense, but all I know is that I've had the same results as above when I forgot to plug up the optical viewfinder.