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Author Topic: hblad lenses and long time exp. with mf backs  (Read 4980 times)
rainer_v
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« on: September 21, 2006, 08:43:23 PM »
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i have the problem that my newer h-blad lenses (black ones ) dont trigger my emotion backs longer than one second, if connected with the sync cable. doesnt matter how long i will hold the shutter in "b" mode, the back stops after 1 second.
this does not happen with old ( silver ) lenses, they work fine.
any idea how to modify or whats to do?
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rainer viertlböck
architecture photographer
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www.tangential.de
Eric Zepeda
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« Reply #1 on: September 22, 2006, 08:32:26 AM »
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Ranier, I noticed something similar when recently shooting with a Sinarback 54 on a Sinar X with the autoaperture shutter. When I tried to do long exposures with the shutter on B, it would not work. I had to change the exposure time in CaptureShop for it to work correctly.

With the e75, I assume you are shooting untethered. Perhaps there is a menu setting similar to Phase's "Long latency/Short Latency" that might affect long exposure sync's with the newer lenses? The other suggestion is to shoot tethered to see if the problem replicates itself if you set the exposure time in CaptureShop.

I have to stop by the NY Sinar dealer today. I'll check to see if they've experienced something similar.

Cheers,

Eric
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Morgan_Moore
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« Reply #2 on: September 22, 2006, 10:15:30 AM »
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You could try this..

-Put the back in X synch mode

-leave the lead into the back dangling

-Open the camera shutter

-Fire the back by shorting out the dangling lead with a key or pin (closing the circuit)

-keep the key in place for the required duration (closing the circuit)

-close the shutter

THEN rellease the key opening the circuit again

The shutter must be closed before the the circuit is opened else you will get a very bad black reference

Should your experiments work you could then get an engineer to make you an elegant solution using the same principal - see my thread - 'shutterless' and my unanswered questions on the eyelike usergroups

Or await a better answer !
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Sam Morgan Moore Cornwall
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rainer_v
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« Reply #3 on: September 22, 2006, 12:08:05 PM »
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i will try so, just wonder why the ld lenses are working fine. its not a emotion mistake,- the sync switch off after 1sec in the lenses....

thanks

Quote
You could try this..

-Put the back in X synch mode

-leave the lead into the back dangling

-Open the camera shutter

-Fire the back by shorting out the dangling lead with a key or pin (closing the circuit)

-keep the key in place for the required duration (closing the circuit)

-close the shutter

THEN rellease the key opening the circuit again

The shutter must be closed before the the circuit is opened else you will get a very bad black reference

Should your experiments work you could then get an engineer to make you an elegant solution using the same principal - see my thread - 'shutterless' and my unanswered questions on the eyelike usergroups

Or await a better answer !
[a href=\"index.php?act=findpost&pid=77273\"][{POST_SNAPBACK}][/a]
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rainer viertlböck
architecture photographer
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www.tangential.de
Morgan_Moore
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« Reply #4 on: September 22, 2006, 12:24:05 PM »
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the sync switch off after 1sec in the lenses....

Well if you think about the original purpose of synch it is to fire a flash so why would a designer feel the need to keep the contact 'closed'

Another try is if you have a second body is to plug the lead into that one and fire it that way (old lense attached) !!

Kapture group make some pretty wacky leads that might help

S
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Sam Morgan Moore Cornwall
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rainer_v
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« Reply #5 on: September 22, 2006, 09:51:27 PM »
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noone modified such lenses? ofcourse 2. body might work,-but all this is really complicate... for a simple detail. it makes my black lenses practical useless together with the e22, which i use on the h-blad. i use mostly longer focals forarchitecture  details.... need to stop down for dof.


Quote
the sync switch off after 1sec in the lenses....

Well if you think about the original purpose of synch it is to fire a flash so why would a designer feel the need to keep the contact 'closed'

Another try is if you have a second body is to plug the lead into that one and fire it that way (old lense attached) !!

Kapture group make some pretty wacky leads that might help

S
[a href=\"index.php?act=findpost&pid=77281\"][{POST_SNAPBACK}][/a]
« Last Edit: September 22, 2006, 09:51:58 PM by rehnniar » Logged

rainer viertlböck
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Morgan_Moore
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« Reply #6 on: September 23, 2006, 12:29:50 AM »
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I am sure you can get around it without modifying all your lenses or getting rid of them - speak to Kapture Group or an engineer

Here is an image of my nikon/sinar/linhof/eyelike camera fired with an old copal shutter - I havnt tried it in Bulb !

You could try this too if you have any old copals..

It really annoys me not to be able to put any piece of glass I want in front of my chip

I am going to make a universal (any lense) Copal Three camera !!!!!!!!
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Sam Morgan Moore Cornwall
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rainer_v
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« Reply #7 on: September 23, 2006, 08:45:06 AM »
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looks great, i even have a backup copal with me.... i can use it therefore.
thanks folks.


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I am sure you can get around it without modifying all your lenses or getting rid of them - speak to Kapture Group or an engineer

Here is an image of my nikon/sinar/linhof/eyelike camera fired with an old copal shutter - I havnt tried it in Bulb !

You could try this too if you have any old copals..

It really annoys me not to be able to put any piece of glass I want in front of my chip

I am going to make a universal (any lense) Copal Three camera !!!!!!!!
[a href=\"index.php?act=findpost&pid=77337\"][{POST_SNAPBACK}][/a]
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rainer viertlböck
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Morgan_Moore
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« Reply #8 on: September 23, 2006, 08:57:49 AM »
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I dont know that it works on bulb

You must close the lense (on the camera) before the contact (to keep the black ref black)

Go play ...
« Last Edit: September 23, 2006, 08:58:15 AM by Morgan_Moore » Logged

Sam Morgan Moore Cornwall
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Fritzer
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« Reply #9 on: September 23, 2006, 09:35:27 AM »
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Quote
the sync switch off after 1sec in the lenses....

Well if you think about the original purpose of synch it is to fire a flash so why would a designer feel the need to keep the contact 'closed'

Another try is if you have a second body is to plug the lead into that one and fire it that way (old lense attached) !!



S
[a href=\"index.php?act=findpost&pid=77281\"][{POST_SNAPBACK}][/a]


Morgan, are you sure of what you said there ?

I don't know about those particular lenses, but I used to do a lot of long time exposure with attached flash synch, and never run into that problem.

All the lenses I have used so far, LF w/ different shutters, Mamiya, Hasselblad, a few 35mm systems, etc. do nothing but produce a very brief initial short of the synch, after that the the contact is opened immidiately ( --> no further synchronizing).

If that wouldn't be the case, a connected flash would just keep firing till the shutter is closed, as is the case when you shorten the synch cabel manually, e.g. with a screw driver, and keep it on the contacts.

Hence I assume those lenses send a second signal through the synch after 1 second, closing down the digital back. Just an assumption; but I can't believe the initial signal lasts longer than a split second with any lens.
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Morgan_Moore
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« Reply #10 on: September 23, 2006, 11:11:01 AM »
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"Hence I assume those lenses send a second signal through the synch after 1 second, closing down the digital back. Just an assumption; but I can't believe the initial signal lasts longer than a split second with any lens"

Well I dont know! - you might be right -someone would need to filldle with an oscilloscope to find out - not my style

What I do know is my copal lense works in front of the camera and has the same triggering effect when not attached to the camera - if it were send ing a second pulse on the close moment surely it would fire the flash twice

The copal lense pictured is probably older than digital photography - it is not a digital that is for sure - I bought it for $50

However it works I hope it fires Rainers lenses - hopefully he will report back

I just love playing with 'classic glass' and 22mp technology - if I get it sorted I can try all my 'redundant' lenses on my back; Nikkor, MF mamiya and even use it as a pin hole camera - whatever

If the files did not rely on a black reference it would be easy
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Sam Morgan Moore Cornwall
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rainer_v
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« Reply #11 on: September 24, 2006, 03:04:34 AM »
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yes it works. and as said before i have at first to shut down the lense shutter, than the copal. and yes,- its one signal in the h-lenses. it shortens the circuit and it unlooks it after one second, and the older lenses ( silver ) do not do this, they shorten the circuit and stay in this  mode unless you release the shutter.


Quote
"Hence I assume those lenses send a second signal through the synch after 1 second, closing down the digital back. Just an assumption; but I can't believe the initial signal lasts longer than a split second with any lens"

Well I dont know! - you might be right -someone would need to filldle with an oscilloscope to find out - not my style

What I do know is my copal lense works in front of the camera and has the same triggering effect when not attached to the camera - if it were send ing a second pulse on the close moment surely it would fire the flash twice

The copal lense pictured is probably older than digital photography - it is not a digital that is for sure - I bought it for $50

However it works I hope it fires Rainers lenses - hopefully he will report back

I just love playing with 'classic glass' and 22mp technology - if I get it sorted I can try all my 'redundant' lenses on my back; Nikkor, MF mamiya and even use it as a pin hole camera - whatever

If the files did not rely on a black reference it would be easy
[a href=\"index.php?act=findpost&pid=77406\"][{POST_SNAPBACK}][/a]
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rainer viertlböck
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Morgan_Moore
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« Reply #12 on: September 24, 2006, 06:09:39 AM »
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yes it works.

Cool. is it a practical solution or just too fiddly for real world use?
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Sam Morgan Moore Cornwall
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Fritzer
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« Reply #13 on: September 24, 2006, 08:50:29 AM »
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yes it works. and as said before i have at first to shut down the lense shutter, than the copal. and yes,- its one signal in the h-lenses. it shortens the circuit and it unlooks it after one second, and the older lenses ( silver ) do not do this, they shorten the circuit and stay in this  mode unless you release the shutter.
[a href=\"index.php?act=findpost&pid=77459\"][{POST_SNAPBACK}][/a]

I still think this is bad information. In my experience, a lens shutter does not keep the circuit shortened over any period of time; I might be mistaken, but an attached flash will not keep firing in B or T mode, hence the circuit must be opened right after starting the exposure.

Maybe someone can enlighten us on how exactly a DB is switched on and off.
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rainer_v
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« Reply #14 on: September 24, 2006, 11:30:31 AM »
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well bad info or good info, but thats how it works. if i shorten the sync cable to the back the back exposes, if i lift off the connection it stops to expose.


Quote
I still think this is bad information. In my experience, a lens shutter does not keep the circuit shortened over any period of time; I might be mistaken, but an attached flash will not keep firing in B or T mode, hence the circuit must be opened right after starting the exposure.

Maybe someone can enlighten us on how exactly a DB is switched on and off.
[a href=\"index.php?act=findpost&pid=77480\"][{POST_SNAPBACK}][/a]
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rainer viertlböck
architecture photographer
munich / germany

www.tangential.de
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