flippin' f stop

[cunim]

I rarely use the 645DF with my IQ back, but when I do one thing drives me nuts. The iris is constantly resetting itself. After puzzling about this for a while, I discovered why.

The lens release button on the side is very sensitive. During normal use of the camera my hand brushes by the button and that causes a momentary disconnect of the lens electronics (not the lens). The result is that the body resets the f stop to the closed position. The button doesn't need to move much - just a twitch is enough.

As I said, happens to me all the time and I usually first notice it when looking at the image on the back and wondering why it is suddenly dark.

Maybe I am holding the camera strangely. Anyone else experienced this?

Peter

 

[Bob]

That is one DF issue I have not experienced.
Can you tell if the pin is seating properly in the lens?
-bob

 

[cunim]

That is one DF issue I have not experienced.
Can you tell if the pin is seating properly in the lens?
-bob

Not sure how I could tell. The lens is seated firmly, can't be wiggled, and seems to work fine. Happens on multiple lenses.

Moving the release button 1mm does nothing. Moving it about 2mm causes the reset. That is about 1/3 of its travel. My hand moving over the camera often moves the button 2mm. Perhaps the spring in the button is too weak? Odd that others do not appear to have this issue.

 

[GrahamWelland]

Interesting that you are causing that much movement in the lens release. It sounds related to the way you must be holding the body and the strength of the release itself. I assume this only happens when you're cradling the camera/lens in portrait mode?

The release on my DF body is certainly easy to move for the first couple of mm but obviously not beyond that without positive action to release the lens. That said, it's not loose and does have some tension to it. Maybe you need to just have it checked/serviced if it is moving too easily.

You could avoid the problem altogether of course by sticking an L bracket on the body or perhaps considering the body grip? More bulk certainly but you'll never have the problem again!