Locking the shutter open, how?


Elva

Link Posted 22/02/2010 - 13:07
I have a question? How does one lock the shutter open in the ’Bulb’ setting on a K-M. I wanted to do a long night sky exposure and wanted to open the shutter for a extended time longer that the camera can do by itself.
I can shoot it ....

fatspider

Link Posted 22/02/2010 - 13:13
You cant lock the shutter open in bulb unless you attach a remote cable release with a lock on it.

Theres no way to do it with the camera alone.
My Names Alan, and I'm a lensaholic.
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thoughton

Link Posted 22/02/2010 - 13:14
You need a wired remote, which has a sliding cover you can slide over the button once it is in the depressed position (thus keeping the button pressed). I use one from ebay which works fine. I forget how much it cost exactly, but it was something minimal like £5.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

iceblinker

Link Posted 22/02/2010 - 13:22
I'm sorry to be the bearer of bad news, but the K-m doesn't have a socket for a wired remote control.

Without modifying the camera, the only way to get an exposure longer than 30 seconds is to keep your finger on the shutter button or on a wireless remote control button, which obviously is not satisfactory for more than a minute or so.
~Pete

fatspider

Link Posted 22/02/2010 - 13:42
Following that little titbit from iceblinker I checked on the Km's specs, it doesn't have a Bulb setting?

Either way Elva your stuck, sorry!
My Names Alan, and I'm a lensaholic.
My PPG link
My Flckr link

iceblinker

Link Posted 22/02/2010 - 14:07
It does have a bulb setting in the menu, just not on the mode dial.
~Pete

thoughton

Link Posted 22/02/2010 - 14:23
I didn't know about the KM not having a wired remote socket. However I have tried a Chinese wireless remote on my K100DS and K20D and couldn't make it hold the shutter open. Does the Pentax one do this? (I asked about this last year, but was told even the Pentax one wouldn't).
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

Bob and his Pentax

Link Posted 22/02/2010 - 14:51
I'm not fully familiar with the K-M's specs and abilities but would the following be possible?

Take the longest posible exposure without using the noise reduction dark frame exposure. Immediately take a second exposure then a third and so on.
Then import the froames into photoshop (or similiar) as a stack of layers then merge them using the 'brigten' method so that the lighter pixels on all layers show through giving you star trails as long a s you want them.
Good luck

Bob

Pentax user since 1978, Digital since 1997.
Kit includes: K-7, K20D, K10D, *istDS, full set DA* lens, etc

iceblinker

Link Posted 22/02/2010 - 14:51
thoughton wrote:
I didn't know about the KM not having a wired remote socket. However I have tried a Chinese wireless remote on my K100DS and K20D and couldn't make it hold the shutter open. Does the Pentax one do this? (I asked about this last year, but was told even the Pentax one wouldn't).

Good question. I have a cheap Chinese one that also doesn't hold the shutter open for the K-7 in that mode. Fortunately, the K-7 and K-x has an alternative mode where you press once to open and again to close rather than needing to press continuously. Unfortunately, the other models do not have this option.
~Pete
Last Edited by iceblinker on 22/02/2010 - 14:53

Daniel Bridge

Link Posted 22/02/2010 - 15:14
My (Pentax) wireless remote will hold the shutter open in Bulb mode, that's on my K10D. Used it for a 3 minute exposure of Jodrell Bank in the Autumn.

Dan
K-3, a macro lens and a DA*300mm...

Anvh

Link Posted 22/02/2010 - 15:18
For long exposure mirror lock wouldn't matter since the short time that the mirror introduce a vibration is so short compared to the whole exposure time.
For example, with very long exposures you can even walk through the frame without that you see the person.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

Gwyn

Link Posted 22/02/2010 - 15:22
On my K20D the Pentax remote only works with Bulb as long as I keep my finger on the button. Could lead to cramp after a while .
There are cheapo remotes which have a lock though.

thoughton

Link Posted 22/02/2010 - 17:33
Anvh wrote:
For long exposure mirror lock wouldn't matter since the short time that the mirror introduce a vibration is so short compared to the whole exposure time.
For example, with very long exposures you can even walk through the frame without that you see the person.

Stefan, I think you might be the only person discussing mirror lockup
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

thoughton

Link Posted 22/02/2010 - 17:36
Daniel Bridge wrote:
My (Pentax) wireless remote will hold the shutter open in Bulb mode, that's on my K10D. Used it for a 3 minute exposure of Jodrell Bank in the Autumn.

Dan

That's very interesting Dan! Do you have to keep it pointed at the camera while you're holding the button?
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

Anvh

Link Posted 22/02/2010 - 17:53
thoughton wrote:
Anvh wrote:
For long exposure mirror lock wouldn't matter since the short time that the mirror introduce a vibration is so short compared to the whole exposure time.
For example, with very long exposures you can even walk through the frame without that you see the person.

Stefan, I think you might be the only person discussing mirror lockup



I really can't do two things at a time, I was convinced it was about mirror lock up while repairing someone's PC.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
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