question regarding gw690III and "T"

[viablex1]

just looking for experience with shooting exposures from 10 to 20 seconds.

do you usually use the lens cap to terminate the exposure when it is set to "T".?

my question is how long does an exposure have to be so when you use the lens cap it doesn't mess it up?

don't know if I worded that right.

 

[sanmich]

If you mean that the movement is not very precise and on short exposure times it could mess your exposure, you are right in theory, but as long as we are talking several seconds exposure, my guess is that it shouldn't change anything.

 

[viablex1]

Hey thanks,

I have used the message for several minutes but was wondering if a shorter exposure would show the cap coming toward the camera, but I guess vibration is important as well

 

[DamenS]

Damn fine question, that - if it were say a 2 second exposure would the placement of the lens cap over the lens appear in the image ? Anybody ?

 

[FrankS]

No it won't (as long as there is no spotlight on the camera to illuminate the hand and lens cap as it approaches the camera.) Your hand with lens cap shouldn't approach the camera from the front where it will be in the frame and possibly register on film during a short time exposure. Have the cap ready to put on the lens directly at the side (or top or bottom) of the lens, then just slide it across the front of the lens and click it on.

I've done this with a 45sec exposure at night. I used a hat to cover the lens, then turned the shutter speed dial to terminate the time exposure.

 

[viablex1]

Damn fine question, that - if it were say a 2 second exposure would the placement of the lens cap over the lens appear in the image ? Anybody ?

you worded it perfect that is the actual question!!!!

thanks😀

 

[Frank Petronio]

Maybe, just maybe, that 2-second example could be a problem if you move slowly... but you're probably covering the lens itself in only 1/30, 1/15th of a second tops, which would be only 2-3% of the exposure, not really enough to matter.

But timing a 2-second exposure is tough too. Most people would extend things to 4-5 seconds by stopping down so there is a little more margin of error. At 4 seconds, if your timing is half-a-second off, you still get pretty close... wheras half-a-second of a two-second exposure is a much larger portion!

On longer exposures I would just move the shutter speed or crank the camera, the vibration would be at the end and a minimal portion of the exposure, with no effect.

 

[DamenS]

Maybe, just maybe, that 2-second example could be a problem if you move slowly... but you're probably covering the lens itself in only 1/30, 1/15th of a second tops, which would be only 2-3% of the exposure, not really enough to matter.

But timing a 2-second exposure is tough too. Most people would extend things to 4-5 seconds by stopping down so there is a little more margin of error. At 4 seconds, if your timing is half-a-second off, you still get pretty close... wheras half-a-second of a two-second exposure is a much larger portion!

On longer exposures I would just move the shutter speed or crank the camera, the vibration would be at the end and a minimal portion of the exposure, with no effect.

Thanks for the response Frank - I'm actually still laughing at the thought of the contortions (and swearing) you would have to undergo to try to reach that pesky,stiff shutter speed ring at the front of the lens whilst simultaneously keeping it covered with a hat !!!