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is this a joke? long exposure on p45+

drevil

Well-known member
Staff member
hi all,

i just wanted to try my first long time exposure with my p45+

switched to bulb, iso 50 etc. and fire away.....the but the led didnt flash....after i stopped the exposure the LCD showed me a message telling me that the bulb mode is not supported on the contax 645..................

WHAT THE....?....

the king of long time exposure isnt able to talk to the contax 645?

anybody knows a workaround?

best regards

mirko
 

dougpeterson

Workshop Member
hi all,

i just wanted to try my first long time exposure with my p45+

switched to bulb, iso 50 etc. and fire away.....the but the led didnt flash....after i stopped the exposure the LCD showed me a message telling me that the bulb mode is not supported on the contax 645..................

WHAT THE....?....

the king of long time exposure isnt able to talk to the contax 645?

anybody knows a workaround?

best regards

mirko
Hi Mirko,

Don't worry, there is a work around.

But first, a bit of background. You say "the king of long time exposure isnt able to talk to the contax 645?" - in fact it is the other way around. The Contax puts out a digital signal for timed exposures (e.g. 1/125th, 4" etc). But if you go to bulb mode beyond 32 seconds then the body does not produce these signals. Therefore the P45+ cannot know that it's still exposing. More modern bodies like the Phase One DF body provide a digital signal for any arbitrary length exposure including metered times up to an hour and bulb/time modes.

Working with a knowledgable dealer should ensure you don't unexpectedly run into such issues. I advise all our Contax clients on this issue and the workaround options (which I have outlined below).

The workaround is simple. Tape over the electrical contacts on the body (or on the back) so that the back and body are not communicating at all. Then start/stop the exposure on the back independently of the body. You can do this with a wakeup cable (to the multiport on the digital back) or with a dedicated device made by Kapture Group and carried by Kapture Group dealers (e.g. us - DT, CI, etc). The device from the KG makes the process slick/straight-forward. The process with a wakeup cable is just as effective, but is a bit more hokey.

With that device attached to the multiport of the back you would tap the device's wakeup button once, then toggle the "capture" switch to "start", then trigger the body bulb mode for the desired length, allowing the body shutter to close before then turning the device switch to "stop".
 

Zerimar

Member
^ My Hasselblad H2 works perfectly fine with it and the body can do an exposure for up to 18 hours and 12 minutes without being in bulb. Looks like I should be set..
 

Zerimar

Member
I have a CH-910 canon charger with a DC coupler and 7200 MaH batteries, where you can have two batteries simultaneously powering the Phase back, and when you remove one (when it's almost dead to replace it) It will not interrupt the power flow to the back. In theory I would have unlimited power in the field so long as I have batteries. I have not tested how long of an exposure I can do with the setup sporting 14,400 MaH of power, but it hasn't even hone down in battery level on the screen when I've been using it.
 

Landscapelover

Senior Subscriber Member
Hi Rick,

Thanks FYI. I have few questions.
How long does one battery last?
I want to repeat your answer again. Can you set up an exposure on Hasselblad H2 of more than 1 hour? How is about H1?

Thank you.
 

Zerimar

Member
Hi Rick,

Thanks FYI. I have few questions.
How long does one battery last?
I want to repeat your answer again. Can you set up an exposure on Hasselblad H2 of more than 1 hour? How is about H1?

Thank you.
I have not tested the length of time one set of batteries last. With the described combination it is around 6 times as much as a standard phase one battery.

You can just keep clicking the shutter to be longer and longer, on a H1 and H2 you are able to make it go up to a maximum of 18 hours and 12 minutes in 1/3 stop increments.

For these reasons the H2 and Phase One back are the ultimate combination for long exposure photography. 645DF bodies are limited to 1 hour exposure.

In theory the setup with the two large batteries attached to the P45+ should last for a 4 or 5 hour exposure.
 

dougpeterson

Workshop Member
So which bodies are compatible with P45+ for long exposures without problems?
Pretty much just a Contax issue.

No work-around required:
Phase One and Mamiya bodies (including DF, AF, AFD1/2/3, RZ Pro II, RZ Pro IID)
Hasselblad H1, H2, and H4X bodies
Hasselblad V bodies (500 series)
View Cameras (assuming a lens with a bulb mode)
Tech Cameras (assuming a lens with a bulb mode)

Work-around required:
Contax 645 for exposures longer than 32 seconds
 
Last edited:

Professional

Active member
Pretty much just a Contax issue.

No work-around required:
Phase One and Mamiya bodies (including DF, AF, AFD1/2/3, RZ Pro II, RZ Pro IID)
Hasselblad H1, H2, and H4X bodies
Hasselblad V bodies (500 series)
View Cameras (assuming a lens with a bulb mode)
Tech Cameras (assuming a lens with a bulb mode)

Work-around required:
Contax 645 for exposures longer than 32 seconds
Well, this is a great news, i have 2 bodies from above, maybe more in the future if i can afford it with that digiback, and Rick posted the power source to use for the back.

What about RB67 and large format bodies with necessary digital back adapter?
 
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